tag:theconversation.com,2011:/us/topics/nitrogen-2499/articles
Nitrogen – The Conversation
2024-02-13T13:20:14Z
tag:theconversation.com,2011:article/215127
2024-02-13T13:20:14Z
2024-02-13T13:20:14Z
Flowers grown floating on polluted waterways can help clean up nutrient runoff and turn a profit
<figure><img src="https://images.theconversation.com/files/573604/original/file-20240205-30-14awa7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6173%2C4087&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The cut flowers could pay for themselves and even turn a profit.</span> <span class="attribution"><span class="source">Margi Rentis</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Flowers grown on inexpensive floating platforms can help clean polluted waterways, over 12 weeks extracting 52% more phosphorus and 36% more nitrogen than the natural nitrogen cycle removes from untreated water, according to our <a href="https://doi.org/10.1016/j.envadv.2023.100405">new research</a>. In addition to filtering water, the cut flowers can generate income via the <a href="https://www.ers.usda.gov/data-products/chart-gallery/gallery/chart-detail/?chartId=106472">multibillion-dollar floral market</a>. </p>
<p>In our trials of various flowers, giant marigolds stood out as the most successful, producing long, marketable stems and large blooms. Their yield matched typical <a href="https://www.lsuagcenter.com/articles/page1662131594449">flower farm production</a>.</p>
<h2>Why it matters</h2>
<p><a href="https://www.epa.gov/nps/basic-information-about-nonpoint-source-nps-pollution">Water pollution</a> is caused in large part by runoff from farms, urban lawns and even septic tanks. When it rains, excess phosphorus, nitrogen and other chemicals wash into lakes and rivers.</p>
<p>These nutrients feed algae, leading to widespread and harmful algae blooms, which can severely lower oxygen in water, creating “<a href="https://unstats.un.org/sdgs/report/2021/goal-14/">dead zones</a>” where aquatic life cannot survive. Nutrient runoff is a critical issue as urban areas expand, affecting the health of water ecosystems. </p>
<p>Water pollution is an escalating crisis in our area of Miami-Dade and Broward counties in Florida. The <a href="https://storymaps.arcgis.com/stories/b5d43852c8984a4c8db4d077ec04bd35">2020 Biscayne Bay fish kill</a>, the largest mass death of aquatic life on record for the region, serves as a stark reminder of this growing environmental issue.</p>
<h2>How we do our work</h2>
<p>We study <a href="https://case.fiu.edu/earth-environment/agroecology/">sustainable agriculture</a> and <a href="https://crestcache.fiu.edu/">water pollution</a> in South Florida.</p>
<p>Inspired by traditional floating farm practices, including the Aztecs’ <a href="https://www.bbc.com/travel/article/20221009-the-return-of-aztec-floating-farms">chinampas in Mexico</a> and the <a href="https://www.pbs.org/video/the-secret-islands-of-the-everglades-lncj6r/">Miccosukees’ tree island settlements in Florida</a>, we tested the idea of growing cut flowers on floating rafts as a way to remove excess nutrients from waterways. Our hope was not only that the flowers would pay for themselves, but that they could provide jobs here in Miami, the center of the U.S. cut-flower trade.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An outdoor tank contains a large floating perforated mat. Each hole contains a young plant." src="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chemical conditions in the test tanks were the same as in nearby polluted waterways.</span>
<span class="attribution"><span class="source">Jazmin Locke-Rodriguez</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We floated 4-by-6-foot (1.2-by-1.8-meter) mats of inexpensive polyethylene foam called <a href="http://www.beemats.com/">Beemats</a> in 620-gallon (2,300-liter) outdoor test tanks that mirrored water conditions of nearby polluted waterways. Into the mats we transplanted flower seedlings, including zinnias, sunflowers and giant marigolds. The polluted tank water was rich in nutrients, eliminating the need for any fertilizer. As the seedlings matured into plants over 12 weeks, we tracked the tanks’ improving water quality. </p>
<p>Encouraged by the success of the marigolds in our tanks, we moved our trials to the nearby canals of Coral Gables and Little River. We anchored the floating platforms with 50-pound (22.7-kilograms) weights and also tied them to shore for extra stability. No alterations to the landscape were needed, making the process simple and doable.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Closeup photo of base of a marigold plant showing a tangle of visible roots." src="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some plants grow roots in places – such as the stem – other than where their original roots began.</span>
<span class="attribution"><span class="source">Jazmin Locke-Rodriguez</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>What still isn’t known</h2>
<p>The success of the giant marigolds might be linked to the extra roots that grow from their stems known as <a href="https://propg.ifas.ufl.edu/05-cuttings/01-terminology/01-cuttingterms-adventitiousroot.html">adventitious roots</a>. These roots likely help keep the plants stable on the floating platforms. Identifying additional plants with roots like these could help broaden plant choices. </p>
<p>Future raft designs may also need modifications to ensure better stability and growth for other cut-flower and crop species. </p>
<h2>What’s next</h2>
<p>Our promising findings show floating cut-flower farms could be a sustainable option for mitigating water pollution. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Nim52wi_4z4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How floating cut-flower farms can clean polluted waterways.</span></figcaption>
</figure>
<p>One of us (Locke-Rodriguez) is expanding this research and working to scale up floating farms in South Florida as a demonstration of what could take place in the many locations facing similar issues worldwide.</p>
<p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take on interesting academic work.</em></p><img src="https://counter.theconversation.com/content/215127/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jazmin Locke received funding from the USDA-NIFA-NNF and NSF-CREST as a PhD student to help fund this dissertation research at Florida International University.</span></em></p><p class="fine-print"><em><span><a href="mailto:jayachan@fiu.edu">jayachan@fiu.edu</a> receives funding from USDA-NIFA. </span></em></p>
Phosphorus and nitrogen contribute to water pollution and cause harmful algal blooms. New research shows how mats of floating flower beds can take advantage of these nutrients while cleaning the water.
Jazmin Locke-Rodriguez, Post Doctoral Associate in the Institute of Environment, Florida International University
Krishnaswamy Jayachandran, Professor of Agroecology, Florida International University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/214364
2023-10-08T19:26:21Z
2023-10-08T19:26:21Z
There’s a hidden source of excess nutrients suffocating the Great Barrier Reef. We found it
<figure><img src="https://images.theconversation.com/files/551919/original/file-20231003-17-uvt38a.jpg?ixlib=rb-1.1.0&rect=46%2C108%2C5083%2C3337&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Coral impacted by excess nutrients in the Great Barrier Reef.</span> <span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>The Great Barrier Reef is one of Australia’s most important environmental and economic assets. It is estimated to contribute A$56 billion per year and supports about 64,000 full-time jobs, <a href="https://www.barrierreef.org/the-reef/the-value">according to the Great Barrier Reef Foundation</a>. However, the reef is under increasing pressure. </p>
<p>While much public attention is focused on the <a href="https://theconversation.com/severely-threatened-and-deteriorating-global-authority-on-nature-lists-the-great-barrier-reef-as-critical-151275">impacts of climate change</a> on the Great Barrier Reef and the <a href="https://theconversation.com/australian-government-was-blindsided-by-un-recommendation-to-list-great-barrier-reef-as-in-danger-but-its-no-great-surprise-163159">debate around its endangered status</a>, water quality is also crucial to the reef’s health and survival.</p>
<p>Our new study, published today in the journal <a href="https://doi.org/10.1021/acs.est.3c03725.">Environmental Science and Technology</a>, found that previously unquantified groundwater inputs are the largest source of new nutrients to the reef. This finding could potentially change how the Great Barrier Reef is managed.</p>
<h2>Too much of a good thing</h2>
<p>Although nitrogen and phosphorous are essential to support the incredible biodiversity of the reef, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0272771416301469">too much nutrient</a> can lead to losses of coral biodiversity and coverage. It also increases the abundance of algae and the ability of coral larvae to grow into adult coral, and impacts seagrass coverage and health, which is crucial for fisheries and biodiversity. </p>
<p>Nutrient enrichment can also promote the breeding success of <a href="https://link.springer.com/article/10.1007/s00338-010-0628-z">crown-of-thorns starfish</a>, whose increasing populations and voracious appetite for corals have decimated parts of the reef in recent decades. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A side by side underwater photo collage of vivid healthy coral and pale murky coral" src="https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=252&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=252&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=252&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pristine coral and coral affected by excess nutrient in the Great Barrier Reef.</span>
<span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>What are the sources of nutrients driving the degradation of the reef? Previous studies have <a href="https://www.reefplan.qld.gov.au/__data/assets/pdf_file/0031/45994/2017-scientific-consensus-statement-summary-chap02.pdf">focused on river discharge</a>. According to one estimate, there has been a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0025326X11005583">fourfold increase in riverine nutrient</a> input to the Great Barrier Reef since pre-industrial times.</p>
<p>This past focus on rivers has emphasised reducing surface water nutrient inputs through changing regulations for land-clearing and agriculture, while neglecting other potential sources. </p>
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<strong>
Read more:
<a href="https://theconversation.com/floods-of-nutrients-from-fertilisers-and-wastewater-trash-our-rivers-could-offsetting-help-203235">Floods of nutrients from fertilisers and wastewater trash our rivers. Could offsetting help?</a>
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<p>However, the most recent nutrient budget for the Great Barrier Reef found river-derived nutrient inputs can account for only a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0278434311003025">small proportion of the nutrients</a> necessary to support the abundant life in the reef. This imbalance suggests large, unidentified sources of nutrients to the reef. Not knowing what these are may lead to ineffective management approaches.</p>
<p>With recent government funding of <a href="https://www.barrierreef.org/what-we-do/reef-trust-partnership">more than $200 million to tackle water quality on the reef</a> which is largely focused on managing river water inputs, it is crucial to make sure other nutrient sources are not overlooked.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram listing nutrient sources to the reef" src="https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=270&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=270&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=270&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=339&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=339&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=339&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The source of potential groundwater inputs to the Great Barrier Reef.</span>
<span class="attribution"><span class="source">Douglas Tait</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>We found a new nutrient source</h2>
<p>Our research team decided to try and track down this missing source of nutrients.</p>
<p>We used natural tracers to track groundwater inputs off Queensland’s coast. This allows us to quantify how much invisible groundwater flows into the Great Barrier Reef, along with the nutrients hitching a ride with this water. Our findings indicate that current efforts to preserve and restore the health of the reef may require a new perspective.</p>
<p>Our team collected data from offshore surveys, rivers and coastal bores along the coastline from south of Rockhampton to north of Cairns. We used the natural groundwater tracer radium to track how much nutrient is transported from the land and shelf sediments via invisible groundwater flows.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-a-disgruntled-scientist-looking-to-prove-his-food-wasnt-fresh-discovered-radioactive-tracers-and-won-a-nobel-prize-80-years-ago-214784">How a disgruntled scientist looking to prove his food wasn't fresh discovered radioactive tracers and won a Nobel Prize 80 years ago</a>
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</em>
</p>
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<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A blue and white ship sailing on a calm ocean" src="https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The AIMS research vessel, Cape Ferguson.</span>
<span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We found that groundwater discharge was 10–15 times greater than river inputs. This meant roughly one-third of new nitrogen and two-thirds of phosphorous inputs came via groundwater discharge. This was nearly twice the amount of nutrient delivered by river waters.</p>
<p>Past investigations have revealed that groundwater discharge delivers nutrients and affects water quality in a <a href="https://www.nature.com/articles/s43017-021-00152-0">diverse range of coastal environments</a>, including estuaries, coral reefs, coastal embayments and lagoons, intertidal wetlands such as mangroves and saltmarshes, the continental shelf and even the global ocean.</p>
<p>In some cases, this can account for <a href="https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.4319/lo.2011.56.2.0673">90% of the nutrient inputs</a> to coastal areas, which has major implications for global biologic production. </p>
<p>Nevertheless, this pathway remains overlooked in most coastal nutrient budgets and water quality models.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A beach early in the morning with people digging into the sand" src="https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=339&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=339&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=339&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=426&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=426&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=426&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The research team sampling groundwater near the Great Barrier Reef.</span>
<span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>A paradigm shift needed?</h2>
<p>Our results suggest the need for a strategic <a href="https://niwa.co.nz/our-science/freshwater/tools/kaitiaki_tools/land-use/agriculture/mitigation">shift in management approaches</a> aimed at safeguarding the Great Barrier Reef from the effects of excess nutrients.</p>
<p>This includes better land management practices to ensure fewer nutrients are entering groundwater aquifers. We can also use ecological (such as seaweed and bivalve aquaculture, enhancing seagrass, oyster reefs, mangroves and salt marsh) and hydrological (increasing flushing where possible) practices at groundwater discharge hotspots to <a href="https://www.frontiersin.org/articles/10.3389/fmars.2018.00470/full">reduce excess nutrients in the water column</a>. </p>
<p><a href="https://medium.com/water-food-nexus/water-recycling-and-reuse-in-agriculture-for-circularity-of-food-and-water-f08fe4b131b3">The reuse of nutrient-rich groundwater</a> for agriculture also needs to be explored as it represents an untapped and inexpensive nutrient source.</p>
<p>Importantly, unlike river outflow, nutrients in groundwater can be <a href="https://www.sciencedirect.com/science/article/abs/pii/S004896972035539X">stored underground for decades</a> before being discharged into coastal waters. This means research and strategies to protect the reef need to be long-term. The potential large lag time may lead to significant problems in the coming decades as the nutrients now stored in underground aquifers make their way to coastal waters regardless of changes to current land use practices.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A vivid landscape of colourful corals in an underwater photo" src="https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pristine corals on the Great Barrier Reef.</span>
<span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The understanding and ability to manage the sources of nutrients is pivotal in preserving global coral reef systems.</p>
<p>While we need to reduce the impact of climate change on this fragile ecosystem, we also need to adjust our policies to manage nutrient inputs and safeguard the Great Barrier Reef for generations to come.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/out-of-danger-because-the-un-said-so-hardly-the-barrier-reef-is-still-in-hot-water-210787">Out of danger because the UN said so? Hardly – the Barrier Reef is still in hot water</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/214364/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors receive funding from the Australian Research Council, the Herman Slade Foundation and the Great Barrier Reef Foundation. </span></em></p><p class="fine-print"><em><span>Damien Maher receives funding from the Australian Research Council, Hermon Slade Foundation, Great Barrier Reef Foundation. </span></em></p>
While the Great Barrier Reed needs nutrients to support the ecosystem, it is possible to have too much of a good thing.
Douglas Tait, Senior Researcher, Southern Cross University
Damien Maher, Professor, Southern Cross University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/198903
2023-02-08T08:48:18Z
2023-02-08T08:48:18Z
Pulses are packed with goodness: Five cool things you should know about them
<figure><img src="https://images.theconversation.com/files/508577/original/file-20230207-19-vtdp97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">pbd Studio/shutterstock</span></span></figcaption></figure><p>Each year on February 10, the United Nations commemorates what probably sounds to many like a strange occasion: <a href="https://www.un.org/en/observances/world-pulses-day">World Pulses Day</a>. </p>
<p>But, as a researcher focused on <a href="https://www.slcu.cam.ac.uk/people/nadia-radzman">forgotten and underutilised legumes</a>, I think the initiative is an important step towards food security. Getting people to eat more pulses can ultimately help achieve <a href="https://www.un.org/sustainabledevelopment/hunger/">UN Sustainable Development Goal 2: Zero Hunger</a>.</p>
<p>First, for clarification, “legumes” and “pulses” have different meanings. “Legumes” are all plants belong to the family <em>Leguminosae</em> or <em>Fabaceae</em>, while “pulses” are the dried seeds of legume plants. Pulses include beans, lentils and chickpeas.</p>
<p>One reason that legume plants offer such promise in ending hunger is that they don’t need good soil or nitrogen fertilisers. Plants need nitrogen to build important molecules such as protein and DNA. Most legumes can thrive in poor soil by fixing nitrogen gas from the air for their own use. This happens through symbiotic interaction with friendly bacteria known as rhizobia. The rhizobia are housed inside structures called nodules on the plant’s roots.</p>
<p>Thanks to their nitrogen-fixing ability, pulses are nutritional powerhouses: high in protein and fibre, and low in fat. </p>
<p>But that’s not the only interesting thing about legumes and pulses. In honour of World Pulses Day 2023, I would like to highlight five pulses that have unique properties and stories.</p>
<h2>1. The African yam bean: high protein beans and underground tubers</h2>
<p>The African yam bean (<em>Sphenostylis stenocarpa</em>) offers two servings of food: beans and underground tubers. The tubers have higher protein content than any non-legume tuber crops like potato and cassava, and the beans are also high in protein. Their nutritional value was proved <a href="https://link.springer.com/chapter/10.1007/978-1-4613-0433-3_18">during the Nigerian Civil War (1967-1970)</a> when the beans were cooked with amaranthus, telfaria or cassava leaves to feed the malnourished in war-affected areas.</p>
<p>This crop is native to Africa and was <a href="https://link.springer.com/article/10.1007/BF02866625">once grown across the African continent</a>. Researchers have proposed that it may have been <a href="https://link.springer.com/article/10.1007/BF02866626">domesticated multiple times in west and central Africa</a>. Today, it is <a href="https://www.sciencedirect.com/science/article/pii/S240584402032301X">mostly grown as security or subsistence crop</a>, rather than commercially. But its high protein content and drought tolerance are attracting increasing interest.</p>
<h2>2. Common bean: diversity and environmental versatility</h2>
<p>The common bean (<em>Phaseolus vulgaris</em>) comes in many varieties around the world. Examples are black beans, red kidney beans and pinto beans – they look different but they are the same species. What’s special about them is that they can <a href="https://link.springer.com/article/10.1023/A:1024199013926">pair with a larger number of rhizobial species</a> than <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2015.00945/full">other legumes</a> can. This may have helped the common bean to thrive outside its native land and diversify in various habitats around the world. It’s able to fix nitrogen in different environments, making it a resilient legume species.</p>
<h2>3. Pea: a role in early understanding of genetics</h2>
<p>The pea (<em>Pisum sativum</em>) is among the oldest domesticated crops in the world. It contributed to the understanding of genetics, thanks to <a href="https://www.britannica.com/biography/Gregor-Mendel">Gregor Mendel’s</a> famous <a href="https://www.nature.com/scitable/topicpage/gregor-mendel-and-the-principles-of-inheritance-593/">experiment</a> with pea plants. Mendel observed the way that different physical properties of the pea plants were inherited: pod shape, seed shape, seed colour, unripe pod colour, flower colour, stem length, and flower placement. He crossed two pea plants that had different properties and observed the seven traits in the subsequent generations for two years. From this experiment, he established <a href="http://www.dnaftb.org/1/bio.html">Mendel’s Rules of Inheritance</a> – still applicable in modern day genetic study. </p>
<p>The rich genetic diversity of the pea is also <a href="https://www.mdpi.com/2073-4395/2/2/74">a valuable resource for important crop traits</a> that can withstand various weather conditions due to climate change.</p>
<h2>4. Chickpea: built for drought</h2>
<p>Many pulses are drought tolerant and use less water for production than animal-sourced proteins, especially beef. Chickpea (<em>Cicer arietinum</em>) is known to be <a href="https://www.frontiersin.org/articles/10.3389/fpls.2019.01759/full">highly drought tolerant</a>. Most of this crop is grown under rainfed conditions in arid and semi-arid areas. This special ability to grow where water is scarce is <a href="https://link.springer.com/article/10.1007/s10722-006-9197-y">more prominent in wild species of chickpea</a>. Wild chickpeas can also tolerate temperatures up to 40°C – another valuable genetic resource for better drought tolerance in modern chickpeas. </p>
<p>Still, chickpea yield is highly compromised when there is lack of water. Therefore, <a href="https://www.nature.com/articles/s41588-019-0401-3">scientists are looking for beneficial traits</a> that can reduce the yield loss in chickpeas during drought. This may contribute to a more secure food source in the midst of climate change.</p>
<h2>5. Lupins: special cluster roots to seek nutrients</h2>
<p>White lupins (<em>Lupinus albus</em>), yellow lupins (<em>Lupinus luteus</em>) and pearl lupins (<em>Lupinus mutabilis</em>) can <a href="https://link.springer.com/article/10.1023/B:PLSO.0000016544.18563.86">form special roots</a> to get more nutrients without the need for additional fertilisers. Plants need not only nitrogen but phosphorus. Usually it’s given to plants in fertiliser to increase crop yield. <a href="https://extension.umn.edu/phosphorus-and-potassium/understanding-phosphorus-fertilizers#process-619211">Phosphate fertiliser is made from phosphate rock</a> –- a non-renewable resource which is rapidly depleting through agricultural use. The white, yellow, and pearl lupins have unique root modifications called cluster roots that can liberate phosphorus from soil particles when the nutrient is low. These roots <a href="https://link.springer.com/article/10.1007/s11104-004-2725-7">look like bottlebrush</a> and are formed only when the level of phosphorus in the soil is low. These cluster roots <a href="https://academic.oup.com/aob/article/110/2/329/2769292">exude negatively charged compound called carboxylate</a> that can liberate phosphorus from the soil and make it available for the plant to use. So lupins do not have to rely on phosphate fertilisers and can even help neighbouring plants by increasing the phosphorus level in the soil.</p>
<h2>Food security</h2>
<p>Pulses deserve our attention not just on February 10 but every day. The five pulses I’ve presented here can serve as sustainable protein sources and make food systems more diverse. They can greatly contribute to better food security in the future.</p><img src="https://counter.theconversation.com/content/198903/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nadia Radzman is a research associate at the Sainsbury Laboratory Cambridge University that receives funding from the Gatsby Foundation. She is the co-chair of Cambridge University Food Security Society and a steering committee member of the Cambridge Global Food Security interdisciplinary research centre.</span></em></p>
Pulses are important for many reasons. They are packed with nutrition, resilient and crucial for achieving food security in Africa.
Nadia Radzman, Research Associate in Plant Biology, University of Cambridge
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/186286
2022-07-18T12:26:45Z
2022-07-18T12:26:45Z
To reduce harmful algal blooms and dead zones, the US needs a national strategy for regulating farm pollution
<figure><img src="https://images.theconversation.com/files/474164/original/file-20220714-32338-xz3rmp.jpeg?ixlib=rb-1.1.0&rect=52%2C0%2C8713%2C5835&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Satellite photo of an algal bloom in western Lake Erie, July 28, 2015.</span> <span class="attribution"><a class="source" href="https://eoimages.gsfc.nasa.gov/images/imagerecords/86000/86327/erie_oli_2015209_lrg.jpg">NASA Earth Observatory</a></span></figcaption></figure><p>Midsummer is the time for forecasts of the size of this year’s “dead zones” and algal blooms in major lakes and bays. Will the <a href="https://www.nola.com/news/environment/article_bfc1ba32-e2ac-11ec-9909-5fd0e4edb56b.html">Gulf of Mexico dead zone</a> be the size of New Jersey, or only as big as Connecticut? Will Lake Erie’s bloom blossom to a <a href="https://www.toledoblade.com/local/2014/08/03/Water-crisis-grips-area/stories/20140803090">human health crisis</a>, or just devastate the <a href="https://www.ectinc.com/projects/economic-benefits-costs-of-reducing-harmful-algal-blooms-in-lake-erie/">coastal economy</a>? </p>
<p>We are scientists who each have spent almost 50 years figuring out <a href="https://scholar.google.com/citations?user=ARkaE6cAAAAJ&hl=en">what causes dead zones</a> and what it will take to resuscitate them and reduce <a href="https://scholar.google.com/citations?user=-K4wV5QAAAAJ&hl=en">risks of toxic blooms of algae</a>. Researchers can <a href="https://theconversation.com/forecasting-dead-zones-and-toxic-algae-in-us-waterways-a-bad-year-for-lake-erie-43747">forecast</a> these phenomena quite well and have calculated the nitrogen and phosphorus pollution cuts needed to reduce them. </p>
<p>These targets are now written into formal government commitments to clean up <a href="https://doi.org/10.1016/j.jglr.2016.09.007">Lake Erie</a>, the <a href="https://doi.org/10.1073/pnas.1705293114">Gulf</a> and the <a href="https://doi.org/10.1002/eap.2384">Chesapeake Bay</a>. Farmers and land owners nationwide received US$30 billion to support conservation, including practices designed to reduce water pollution, from <a href="https://www.ewg.org/news-insights/news-release/new-ewg-database-details-30-billion-spent-us-farm-conservation-programs">2005 to 2015</a>, and are scheduled to receive $60 billion more between <a href="https://crsreports.congress.gov/product/pdf/IF/IF12024#:%7E:text=Spending%20for%20agricultural%20conservation%20programs,are%20reauthorized%20with%20no%20changes.">2019 and 2028</a>. </p>
<p>But these efforts have fallen short, mainly because controls on nutrient pollution from agriculture are <a href="https://doi.org/10.3389/fmars.2019.00123">weak and ineffective</a>. In our view, there is no shortage of solutions to this problem. What’s needed is technological innovation and stronger political will. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/474157/original/file-20220714-32176-2cyi2q.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing a zone with low oxygen values along the Louisiana coast." src="https://images.theconversation.com/files/474157/original/file-20220714-32176-2cyi2q.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/474157/original/file-20220714-32176-2cyi2q.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=299&fit=crop&dpr=1 600w, https://images.theconversation.com/files/474157/original/file-20220714-32176-2cyi2q.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=299&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/474157/original/file-20220714-32176-2cyi2q.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=299&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/474157/original/file-20220714-32176-2cyi2q.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=376&fit=crop&dpr=1 754w, https://images.theconversation.com/files/474157/original/file-20220714-32176-2cyi2q.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=376&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/474157/original/file-20220714-32176-2cyi2q.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=376&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Gulf of Mexico hypoxic (dead) zone in 2021, which measured 6,334 square miles (16,400 square kilometers). Lower values represent less dissolved oxygen in the water.</span>
<span class="attribution"><a class="source" href="https://nrtwq.usgs.gov/nwqn/Sites/GULF_PRELIM/cruise2021-Final_2021_map_KM.jpg">Louisiana Universities Marine Consortium</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Problems return to Lake Erie</h2>
<p>State and federal agencies have known since the 1970s that overloading lakes and bays with nutrients generates huge blooms of algae. When the algae die and decompose, they deplete oxygen in the water, creating dead zones that can’t support aquatic life. But in each of these “big three” water bodies, efforts to curb nutrient pollution have been slow and halting. </p>
<p>The U.S., Canada and cities around Lake Erie started working to reduce phosphorus pollution in the lake from domestic and industrial wastes <a href="https://clevelandhistorical.org/items/show/58?tour=12&index=11">in 1972</a>. Water quality quickly improved, dead zones shrank and harmful algal blooms became less frequent. </p>
<p>But the scourges of <a href="https://doi.org/10.1016/j.jglr.2014.02.004">low-oxygen waters and sometimes-toxic algae</a> reappeared in the mid-1990s. This time, the source was mostly runoff from farm soils saturated with phosphorus from repeated applications of fertilizer and manure. Climate change made matters worse: Warmer waters hold less oxygen and <a href="https://blog.nature.org/science/2014/08/27/understanding-the-lake-erie-algal-bloom-toledo-water-shutdown/">cause faster growth of algae</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/474182/original/file-20220714-33068-wgdrw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bar chart showing phosphorus entering Lake Erie 1967-2001." src="https://images.theconversation.com/files/474182/original/file-20220714-33068-wgdrw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/474182/original/file-20220714-33068-wgdrw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=324&fit=crop&dpr=1 600w, https://images.theconversation.com/files/474182/original/file-20220714-33068-wgdrw3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=324&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/474182/original/file-20220714-33068-wgdrw3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=324&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/474182/original/file-20220714-33068-wgdrw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=407&fit=crop&dpr=1 754w, https://images.theconversation.com/files/474182/original/file-20220714-33068-wgdrw3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=407&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/474182/original/file-20220714-33068-wgdrw3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=407&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Phosphorus loads to Lake Erie, 1967-2001. Nonpoint sources are wide areas without a distinct discharge point, such as farm fields.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1016/j.jglr.2014.02.004">Scavia et al., 2014</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Slow progress in the Chesapeake Bay</h2>
<p>Nitrogen and phosphorus reach the Chesapeake Bay from sources including wastewater treatment plants; air pollution emitters, such as factories and cars; and runoff from urban, suburban and agricultural lands. In 1987 the federal government and states around the bay agreed to reduce these flows by <a href="https://www.epa.gov/chesapeake-bay-tmdl/chesapeake-bay-agreements">40% by the year 2000</a> to restore water quality. But this effort relied on voluntary action and failed to make much progress. </p>
<p>In 2010 the states and the U.S. Environmental Protection Agency entered <a href="https://www.epa.gov/chesapeake-bay-tmdl/chesapeake-bay-tmdl-document">a legally binding commitment</a>, to reduce pollutant loads below prescribed maximum levels needed to restore water quality. If the states make inadequate progress, the EPA can limit or rescind their permitting authority, and the states may lose federal funding. </p>
<p>Nitrogen and phosphorus pollution has been <a href="https://www.chesapeakeprogress.com/clean-water/2017-watershed-implementation-plans">reduced</a> primarily by tightening permit requirements and upgrading wastewater treatment plants. Air pollution controls for power plants and vehicles have also reduced nitrogen reaching the bay. Water quality has improved, and the yearly dead zone has <a href="https://doi.org/10.1016/j.scitotenv.2021.152722">shrunk modestly</a>. </p>
<p>But with the commitment’s 2025 deadline nearing, nitrogen loads have been reduced by less then 50% of the targeted amounts, phosphorus by <a href="https://www.chesapeakebay.net/news/pressrelease/bay_program_model_shows_decline_in_nutrient_sediment_pollution_entering_the">less then 64%</a>. Most of the remaining pollution comes from <a href="https://doi.org/10.1002/jeq2.20101">farm runoff and urban stormwater</a>.
Intensifying agriculture in rural areas and sprawl in urban areas are counteracting other cleanup efforts. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Og4gYUR_m94?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Cleaning up water bodies with large watersheds, like the Chesapeake Bay (64,000 square miles/165,000 square kilometers, involves many states and thousands of pollution sources.</span></figcaption>
</figure>
<h2>Failure in the Gulf of Mexico</h2>
<p>The Gulf of Mexico dead zone forms every year during the summer, fueled by nutrients washing down the Mississippi River from Midwest farms. It <a href="https://www.noaa.gov/news-release/larger-than-average-gulf-of-mexico-dead-zone-measured">typically covers at least 6,000 square miles</a>, sometimes expanding up to 9,000 square miles (23,000 square kilometers), and affects an area very rich in fisheries. </p>
<p>In 2001, the EPA and 12 Mississippi River basin states agreed to take action to reduce the Gulf dead zone by two-thirds by 2015. Researchers estimated that this would require <a href="https://www.epa.gov/sites/default/files/2015-03/documents/2008_1_31_msbasin_sab_report_2007.pdf">reducing nitrogen loads reaching the Gulf by about 45%</a>, mostly from the Corn Belt. </p>
<p>Now that deadline has been <a href="https://www.epa.gov/sites/default/files/2015-10/documents/htf_report_to_congress_final_-_10.1.15.pdf">extended to 2035</a>. Nitrogen and phosphorus loadings at the mouth of the Mississippi River <a href="https://nrtwq.usgs.gov/nwqn/#/GULF">haven’t budged in 30 years</a>, so actions taken to date have <a href="https://www.epa.gov/ms-htf/history-hypoxia-task-force">failed to shrink the Gulf dead zone</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/474158/original/file-20220714-32145-o1yeg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bar chart showing measurements of the Gulf of Mexico dead zone since 1985." src="https://images.theconversation.com/files/474158/original/file-20220714-32145-o1yeg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/474158/original/file-20220714-32145-o1yeg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/474158/original/file-20220714-32145-o1yeg7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/474158/original/file-20220714-32145-o1yeg7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/474158/original/file-20220714-32145-o1yeg7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/474158/original/file-20220714-32145-o1yeg7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/474158/original/file-20220714-32145-o1yeg7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Since 2017 the Gulf of Mexico dead zone has covered an average of 5,380 square miles (14,000 square kilometers), which is 2.8 times larger than the 2035 target set by a federal task force.</span>
<span class="attribution"><a class="source" href="https://www.noaa.gov/news-release/larger-than-average-gulf-of-mexico-dead-zone-measured">LUMCON/NOAA</a></span>
</figcaption>
</figure>
<h2>Overwhelmed by agriculture</h2>
<p>In 2020, the EPA and Ohio <a href="https://epa.ohio.gov/static/Portals/35/tmdl/MaumeeNutrient/Maumee-Nutrient-TMDL-062022.pdf">adopted an agreement</a> similar to that for the Chesapeake to reduce phosphorus pollution below a prescribed maximum load from the Maumee River watershed at the western end of Lake Erie, where algal blooms occur most often. To date, Mississippi River basin states and even the EPA have <a href="https://doi.org/10.15779/Z38T727G2Q">opposed similarly mandating maximum pollution loads</a> to reduce the Gulf of Mexico dead zone. </p>
<p>Despite substantial government subsidies to implement various agricultural management practices, nitrogen and phosphorus pollution in streams in <a href="https://doi.org/10.1371/journal.pone.0195930">Iowa</a> and <a href="https://www2.illinois.gov/epa/topics/water-quality/watershed-management/excess-nutrients/Documents/NLRS-2021-Biennial-Report-FINAL.pdf">Illinois</a> has actually increased over the 1980-1996 baseline of the Gulf agreement. </p>
<p>Even with increasing crop yields and more efficient use of fertilizer, the expansion and intensification of agriculture in the Midwest has overwhelmed any water quality gains. One driver is ethanol production, which has increased <a href="https://www.eia.gov/todayinenergy/detail.php?id=36892">fortyfold</a> since the Gulf action plan was adopted in 2001. Today, over 40% of corn grown in the U.S. is <a href="https://www.ers.usda.gov/topics/crops/corn-and-other-feedgrains/feedgrains-sector-at-a-glance/">used for ethanol</a>, mostly in the Midwest, while most of the rest is used to feed animals. </p>
<p>In all three regions, the growth of large-scale livestock farms – <a href="https://www.vox.com/the-highlight/22344953/iowa-select-jeff-hansen-pork-farming">hogs in the Midwest</a>, <a href="https://www.delmarvanow.com/story/news/2021/10/29/84-poultry-operations-raised-water-pollution-concerns-yet-few-fined-report-environmental-watchdog/6180639001/">poultry around the Chesapeake Bay</a> – is also contributing to nutrient pollution. <a href="https://doi.org/10.1016/j.resconrec.2020.105065">Improper management of animal waste</a> adds to nitrogen and phosphorus loads in soils and local waters. </p>
<p>Studies show that agriculture contributes <a href="http://scavia.seas.umich.edu/wp-content/uploads/2018/02/Final-Report-Update-20160415.pdf">85% of Lake Erie’s Maumee River phosphorus load</a>, <a href="https://pubs.usgs.gov/circ/1486/cir1486.pdf">65% of the Chesapeake Bay’s nitrogen load</a> and 73.2% of the nitrogen load and 56% of the phosphorus load to the <a href="https://doi.org/10.1111/1752-1688.12905">Gulf of Mexico</a>. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1223304943265648642"}"></div></p>
<h2>Incentives aren’t working</h2>
<p>We believe the evidence is clear that the largely voluntary approaches taken to date, with technical assistance and substantial public financing, are not working. </p>
<p>Economists have called for a <a href="https://doi.org/10.1111/1752-1688.13010">fundamental shift in policies controlling agricultural pollution</a>. Instead of offering polluters subsidies to clean up their operations, these experts argue, the strategy should be to pay farmers for performance, based on environmental outcomes that can be measured <a href="https://doi.org/10.13031/trans.12379">or predicted</a> at appropriate scales and specific places. </p>
<p>Under this approach, government would set limits on the amount of nutrients that can be lost to the environment, and farmers would choose how to meet them, based on what kinds of action work best for their specific soils and climate. For example, <a href="https://doi.org/10.1038/s41586-020-03042-5">restoring wetlands</a> within the watershed could help to capture nutrients that unavoidably wash off of farmlands. </p>
<p>The ongoing shift to electric vehicles offers an opportunity to grow far less grain for ethanol, which <a href="https://theconversation.com/the-us-biofuel-mandate-helps-farmers-but-does-little-for-energy-security-and-harms-the-environment-168459">doesn’t even help the climate</a>. And in the long run, developing <a href="https://www.scientificamerican.com/article/heres-how-much-food-contributes-to-climate-change/">efficient, plant-based food systems</a> would both reduce nutrient pollution and limit climate change. </p>
<p>In June 2022, the Government Accountability Office concluded that federal agencies charged with preventing and controlling harmful algal blooms and dead zones under a <a href="https://www.govinfo.gov/content/pkg/PLAW-105publ383/pdf/PLAW-105publ383.pdf">1998 law</a> have <a href="https://www.gao.gov/assets/gao-22-104449.pdf">failed to establish a national program</a> to address these issues. Fifty years after the federal Clean Water Act was enacted, we believe such a program is long overdue.</p><img src="https://counter.theconversation.com/content/186286/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Donald Boesch does not work for, consult, own shares in, or receive funding from any company or organization that would benefit from this article. He currently receives no external funding, but previously received funding from the National Science Foundation, Environmental Protection Agency, National Oceanic and Atmospheric Administration, and the Walton Family Foundation.</span></em></p><p class="fine-print"><em><span>Donald Scavia does not work for, consult, own shares in, or receive funding from any company or organization that would benefit from this article. He has received research funding from the National Science Foundation, Environmental Protection Agency, National Oceanic and Atmospheric Administration, and the Erb Family Foundation.</span></em></p>
Nutrient pollution fouls lakes and bays with algae, killing fish and threatening public health. Progress curbing it has been slow, mainly because of farm pollution.
Donald Boesch, Professor of Marine Science, University of Maryland Center for Environmental Science
Donald Scavia, Professor Emeritus of Environment and Sustainability, University of Michigan
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/183418
2022-06-14T12:30:35Z
2022-06-14T12:30:35Z
Fertilizer prices are soaring – and that’s an opportunity to promote more sustainable ways of growing crops
<figure><img src="https://images.theconversation.com/files/468526/original/file-20220613-11-9yinfb.jpg?ixlib=rb-1.1.0&rect=14%2C0%2C4905%2C3275&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A farmer spreads fertilizer on a field in Berks County, Pa.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/farmer-spreads-fertilizer-on-his-field-on-a-saturday-night-news-photo/1315197588">Harold Hoch/MediaNews Group/Reading Eagle via Getty Images</a></span></figcaption></figure><p>Farmers are coping with a <a href="https://www.fb.org/market-intel/too-many-to-count-factors-driving-fertilizer-prices-higher-and-higher">fertilizer crisis</a> brought on by soaring fossil fuel prices and industry consolidation. The price of synthetic fertilizer has more than <a href="https://www.agweb.com/news/crops/crop-production/fertilizer-prices-just-fell-30-one-day-farmers-saw-prices-skyrocket-133">doubled</a> since 2021, causing great stress in farm country. </p>
<p>This crunch is particularly tough on those who grow corn, which accounts for half of U.S. nitrogen fertilizer use. The National Corn Growers Association predicts that its members will <a href="https://www.regulations.gov/comment/AMS-AMS-22-0027-1349">spend 80% more in 2022 on synthetic fertilizers</a> than they did in 2021. A recent study estimates that on average, this will represent <a href="https://dt176nijwh14e.cloudfront.net/file/481/Study%20.pdf">US$128,000 in added costs per farm</a>.</p>
<p>In response, the Biden administration <a href="https://www.usda.gov/media/press-releases/2022/03/11/usda-announces-plans-250-million-investment-support-innovative">announced a new grant program</a> on March 11, 2022, “to support innovative American-made fertilizer to give U.S. farmers more choices in the marketplace.” The U.S. Department of Agriculture will invest <a href="https://www.dtnpf.com/agriculture/web/ag/news/business-inputs/article/2022/05/11/usda-aid-precision-ag-fertilizer">$500 million</a> to try to lower fertilizer costs by increasing production. But since this probably isn’t enough money to construct new fertilizer plants, it’s not clear how the money will be spent.</p>
<p>I direct the <a href="https://sustainability-innovation.asu.edu/food/">Swette Center for Sustainable Food Systems</a> at Arizona State University and have held senior positions at the USDA, including serving as deputy secretary of agriculture from 2009 to 2013. In my view, producing more synthetic fertilizer should not be the only answer to this serious challenge. The U.S. should also provide support for nature-based solutions, including farming practices that help farmers reduce or forgo synthetic fertilizers, and biological products that substitute for harsher chemical inputs.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/A8qTRBc8Bws?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Peas, beans and clover add nitrogen to soil naturally and can supplement or substitute for synthetic nitrogen fertilizer.</span></figcaption>
</figure>
<h2>Too much fertilizer in the wrong places</h2>
<p>All plants need nutrients to grow, especially the “big three” macronutrients: <a href="https://www.bhg.com/gardening/yard/garden-care/what-do-nitrogen-phosphorus-and-potassium-do/">nitrogen, phosphorus and potassium</a>. Farmers can fertilize their fields by planting <a href="https://tilthalliance.org/resources/how-legumes-fix-nitrogen-in-your-soil/">crops that add nitrogen to soil naturally</a> or by applying animal manure and compost to soil. </p>
<p>Since World War II, however, farmers have relied mainly on manufactured synthetic fertilizers that contain various ratios of nitrogen, phosphorus and potassium, along with secondary nutrients and micronutrients. That shift happened because manufacturers produced huge quantities of ammonium nitrate, the main ingredient in explosives, during the war; when the conflict ended, they <a href="https://cropwatch.unl.edu/fertilizer-history-p3">switched to making nitrogen fertilizer</a>.</p>
<p>Synthetic fertilizers have greatly enhanced crop yields and are rightly credited with <a href="https://www.unep.org/news-and-stories/story/fertilizers-challenges-and-solutions">helping to feed the world</a>. But they <a href="https://ourworldindata.org/reducing-fertilizer-use">aren’t used evenly around the world</a>. In poor regions like sub-Saharan Africa, too little fertilizer is available. In wealthier areas, abundant synthetic fertilizers have contributed to overapplication and serious <a href="https://theconversation.com/a-few-heavy-storms-cause-a-big-chunk-of-nitrogen-pollution-from-midwest-farms-146980">environmental harm</a>. </p>
<p>Excess fertilizer washes off of fields during storms and runs into rivers and lakes. There, it fertilizes huge blooms of algae that die and decompose, depleting oxygen in the water and creating “dead zones” that can’t support fish or other aquatic life. This process, <a href="https://oceanservice.noaa.gov/facts/eutrophication.html">eutrophication</a>, is a major problem in the <a href="https://www.canr.msu.edu/news/on_the_re_eutrophication_of_lake_erie">Great Lakes</a>, the <a href="https://mde.maryland.gov/programs/water/TMDL/TMDLImplementation/Pages/overview.aspx">Chesapeake Bay</a>, the <a href="https://www.noaa.gov/news-release/larger-than-average-gulf-of-mexico-dead-zone-measured">Gulf of Mexico</a> and <a href="https://www.usgs.gov/mission-areas/water-resources/science/nutrients-and-eutrophication">many other U.S. water bodies</a>. </p>
<p>Excess nitrogen can also contaminate drinking water and <a href="https://www.dhs.wisconsin.gov/publications/p02559.pdf">threaten human health</a>. And fertilizers, whether animal-sourced or synthetic, are a significant source of <a href="https://doi.org/10.1038/s41586-020-2780-0">nitrous oxide</a>, a potent greenhouse gas. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/468499/original/file-20220613-12-kty283.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Green scum covers water around a dock." src="https://images.theconversation.com/files/468499/original/file-20220613-12-kty283.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468499/original/file-20220613-12-kty283.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468499/original/file-20220613-12-kty283.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468499/original/file-20220613-12-kty283.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468499/original/file-20220613-12-kty283.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468499/original/file-20220613-12-kty283.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468499/original/file-20220613-12-kty283.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Heavy nutrient runoff from farmlands produces chronic blooms of algae in Lake Erie, the smallest Great Lake by volume.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/ejuTfh">NOAA</a></span>
</figcaption>
</figure>
<h2>What’s causing the crisis</h2>
<p>One reason U.S. fertilizer prices have spiked is that farmers are beholden to imports. COVID-19 disrupted supply chains, especially from China, a major fertilizer producer. And the war in Ukraine has cut off access to <a href="https://www.cropnutrition.com/resource-library/what-is-potash">potash</a>, an important potassium source, from Russia and Belarus. </p>
<p>Another factor is that the fertilizer industry is <a href="https://www.g20-insights.org/policy_briefs/promoting-competition-in-the-fertilizer-industry-and-efficiency-in-the-fertilizer-use-to-improve-land-productivity-and-sustainability/#_ftn4">highly concentrated</a>. There is little competition, so farmers have no choice but to buy fertilizer at the market price. Several U.S. state attorneys general have called on economists to study <a href="https://www.agweb.com/news/crops/crop-production/usda-attorney-generals-call-economists-study-soaring-fertilizer-costs">anti-competitive practices in the fertilizer industry</a>.</p>
<p>The USDA is seeking information on <a href="https://www.regulations.gov/document/AMS-AMS-22-0027-0001">competition and supply chain concerns in fertilizer markets</a> with a public comment deadline of June 15, 2022. But out of 66 specific questions the department posed with this request, only one addresses what I believe is the key issue: “How might USDA better support modes of production that rely less on fertilizer, or support access to markets that may pay a premium for products relying on less fertilizer?”</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1535263187288961026"}"></div></p>
<h2>Rethinking how to grow crops</h2>
<p>I see an opportunity for the Biden administration to take a fresh look at biological products as substitutes for synthetic fertilizers. This category includes <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/biofertilizer">biofertilizers and bionutrients</a> – natural materials that provide crop nutrition. Examples include microorganisms that extract nitrogen from the air and convert it into forms that plants can use, and fertilizers converted from manure, food and other plant and wood wastes. </p>
<p>Another category, <a href="https://www.bpia.org/solutions-provided-by-biological-products-biostimulants/">biostimulants</a>, comprises natural materials that enhance uptake of plant nutrients, reduce crop stress and increase crop growth and quality. Examples include algae and other plant extracts, microorganisms and <a href="https://soilbiotics.com/files/Humic_Acid_Explained.pdf">humic acids</a> – complex molecules produced naturally in soil when organic material breaks down.</p>
<p>In the past, critics dismissed natural products like these as “<a href="https://www.farmprogress.com/management/beware-snake-oil-fertilizers">snake oil</a>,” with little scientific evidence to show that they worked. Now, however, most experts believe that while <a href="https://doi.org/10.3389/fsufs.2021.606815">much remains to be learned</a>, current biofertilizers “offer huge potential in terms of <a href="https://doi.org/10.3389/fpls.2018.01473">new and more sustainable crop management practices</a>.” </p>
<p>Studies have demonstrated many benefits from these products. They include <a href="https://doi.org/10.3389/fmicb.2018.01606">less need for fertilizer</a>, <a href="https://doi.org/10.1007/s11104-014-2131-8">larger crop yields</a>, <a href="https://ucanr.edu/sites/CEStanislausCo/files/319748.pdf">enhanced soil health</a> and <a href="https://doi.org/10.1016/j.scitotenv.2021.148913">fewer carbon emissions</a>. </p>
<p>Large synthetic fertilizer companies like <a href="https://www.agweb.com/news/crops/crop-production/mosaic-eyes-expansion-biological-products">Mosaic</a>, <a href="https://www.ocpgroup.ma/press-release/ocp-sa-and-fertinagro-biotech-sl-announce-establishment-joint-venture-jorf-lasfar">OCP</a> and Nutrien are distributing, acquiring or investing in these biological technologies. Agribusiness giant Bayer has <a href="https://www.wired.com/story/farmers-can-now-buy-designer-microbes-to-replace-fertilizer/">partnered with Ginkgo Bioworks</a> in a joint venture called <a href="https://joynbio.com/about">Joyn</a> whose mission is creating “sustainable ag biologicals for crop protection and fertility that meet or exceed the performance of their chemical counterparts.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/468496/original/file-20220613-16-b1t9iz.jpg?ixlib=rb-1.1.0&rect=50%2C0%2C5568%2C3709&q=45&auto=format&w=1000&fit=clip"><img alt="A hand spreads pellets and crushed rock over dirt." src="https://images.theconversation.com/files/468496/original/file-20220613-16-b1t9iz.jpg?ixlib=rb-1.1.0&rect=50%2C0%2C5568%2C3709&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468496/original/file-20220613-16-b1t9iz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468496/original/file-20220613-16-b1t9iz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468496/original/file-20220613-16-b1t9iz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468496/original/file-20220613-16-b1t9iz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468496/original/file-20220613-16-b1t9iz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468496/original/file-20220613-16-b1t9iz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A farmer spreads two types of organic fertilizers – bone meal pellets and rock phosphate – before planting spinach in Golden, Colo.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/david-wann-spreads-organic-fertilizers-bone-meal-pellets-news-photo/649873342">Joe Amon/The Denver Post via Getty Images</a></span>
</figcaption>
</figure>
<h2>Offering more choices</h2>
<p>Panicked U.S. farmers facing daunting fertilizer prices are looking for options. In public comments on USDA’s fertilizer initiative, the <a href="https://www.regulations.gov/comment/AMS-AMS-22-0027-1064">Illinois Corn Growers Association</a> urged the department to investigate why farmers apply fertilizers at levels higher than necessary, while others noted a shortage of agronomists sufficiently trained to guide farmers on how best to sustainably fertilize their crops. </p>
<p>I believe now is an opportune time for USDA to offer incentives for adopting biologicals, as well as practices that organic farmers use to replace synthetic fertilizers, such as <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/programs/?cid=nrcs142p2_044349">crop rotation</a>, <a href="http://cwmi.css.cornell.edu/composting.htm">composting</a> and <a href="https://www.csuchico.edu/regenerativeagriculture/ra101-section/integrating-livestock.shtml">raising crops and livestock together</a>. A first step would be to deploy technicians who can advise farmers about sustainable practices and biological products. The department recently announced a new $300 million initiative to <a href="https://www.usda.gov/media/press-releases/2022/06/01/usda-announces-framework-shoring-food-supply-chain-and-transforming">help farmers transition to organic production</a>; this is the right idea, but more help is needed. </p>
<p>The agency could also provide one-time payments to farmers in exchange for reducing their use of synthetic fertilizers, which would help to compensate them as they shift their production methods. In the longer term, I believe the USDA should develop new crop insurance tools to protect farmers from the risks of transitioning to more sustainable options. In my view, this kind of broad response would yield more value than a taxpayer-funded, status quo approach to synthetic fertilizers.</p><img src="https://counter.theconversation.com/content/183418/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kathleen Merrigan worked for six years at the US Department of Agriculture, most recently serving as Deputy Secretary of Agriculture from 2009-2013. She is a venture partner at Astanor Ventures, a European-based agtech firm that invests in a wide range of innovations, including in the biocontrol/biostiumulant sector. She previously served on the board of directors of Marrone Bio Innovations and holds stock in the company. </span></em></p>
Farmers are contending with huge spikes in fertilizer prices. The Biden administration is paying US companies to boost synthetic fertilizer production, but there are other, more sustainable options.
Kathleen Merrigan, Executive Director, Swette Center for Sustainable Food Systems, Arizona State University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/181037
2022-05-19T12:23:07Z
2022-05-19T12:23:07Z
Restoring the Great Lakes: After 50 years of US-Canada joint efforts, some success and lots of unfinished business
<figure><img src="https://images.theconversation.com/files/464009/original/file-20220518-11-qy3i71.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4000%2C2311&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Children participate in a water fight in Lake Ontario in Mississauga, Ontario, during a heat wave on June 5, 2021. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/children-have-a-water-fight-at-lake-ontario-in-mississauga-news-photo/1233295324">Zou Zheng/Xinhua via Getty Images</a></span></figcaption></figure><p>The Great Lakes cover <a href="https://theconversation.com/the-impulse-to-garden-in-hard-times-has-deep-roots-137223">nearly 95,000 square miles</a> (250,000 square kilometers) and hold over 20% of Earth’s surface fresh water. <a href="https://coast.noaa.gov/states/fast-facts/great-lakes.html">More than 30 million people</a> in the U.S. and Canada rely on them for drinking water. The lakes support a multibillion-dollar maritime economy, and the lands around them provided many of the raw materials – timber, coal, iron – that fueled the Midwest’s emergence as an industrial heartland.</p>
<p>Despite their enormous importance, the lakes were <a href="https://www.ijc.org/en/great-lakes-1972-water-quality-agreement">degraded for well over a century</a> as industry and development expanded around them. By the 1960s, rivers like the Cuyahoga, Buffalo and Chicago were so polluted that they were <a href="https://www.environmentalcouncil.org/when_our_rivers_caught_fire">catching fire</a>. In 1965, Maclean’s magazine called Lake Erie, the smallest and shallowest Great Lake, “<a href="https://archive.macleans.ca/article/1965/11/1/death-of-a-great-lake">an odorous, slime-covered graveyard</a>” that “may have already passed the point of no return.” Lake Ontario <a href="https://scholar.uwindsor.ca/cgi/viewcontent.cgi?article=1012&context=ijcarchive">wasn’t far behind</a>.</p>
<p>In 1972, the U.S. and Canada signed the <a href="https://www.ijc.org/sites/default/files/C23.pdf">Great Lakes Water Quality Agreement</a>, a landmark pact to clean up the Great Lakes. Now, 50 years later, they have made progress, but there are new challenges and much unfinished business. </p>
<p>I <a href="https://scholar.google.com/citations?user=G4RniBIAAAAJ&hl=en">study the environment</a> and have written four books on U.S.-Canadian management of their shared border waters. In my view, the Great Lakes Water Quality Agreement was a watershed moment for environmental protection and an international model for regulating transboundary pollution. But I believe the people of the U.S. and Canada failed the Great Lakes by becoming complacent too soon after the pact’s early success. </p>
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<a href="https://images.theconversation.com/files/463989/original/file-20220518-15-6nn6jw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of the Great Lakes-St. Lawrence Basin" src="https://images.theconversation.com/files/463989/original/file-20220518-15-6nn6jw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463989/original/file-20220518-15-6nn6jw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=443&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463989/original/file-20220518-15-6nn6jw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=443&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463989/original/file-20220518-15-6nn6jw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=443&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463989/original/file-20220518-15-6nn6jw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=557&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463989/original/file-20220518-15-6nn6jw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=557&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463989/original/file-20220518-15-6nn6jw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=557&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The Great Lakes-St Lawrence River Basin spans nearly half of North America, from northern Minnesota to New England.</span>
<span class="attribution"><a class="source" href="https://www.ijc.org/en/watersheds/great-lakes">International Joint Commission</a></span>
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<h2>Starting with phosphates</h2>
<p>A major step in Canada-U.S. joint management of the Great Lakes came in 1909 when they signed the <a href="https://www.ijc.org/en/boundary-waters-treaty-1909">Boundary Waters Treaty</a>. The Great Lakes Water Quality Agreement built on this foundation by creating a framework to allow the two countries to cooperatively restore and protect these border waters. </p>
<p>However, as an executive agreement, rather than a formal government-to-government treaty, the pact has no legal mechanisms for enforcement. Instead, it relies on the U.S. and Canada to fulfill their commitments. The <a href="https://www.ijc.org/en/who/role">International Joint Commission</a>, an agency created under the Boundary Waters Treaty, carries out the agreement and tracks progress toward its goals. </p>
<p>The agreement set common targets for controlling a variety of pollutants in Lake Erie, Lake Ontario and the upper St. Lawrence River, which were the most polluted section of the Great Lakes system. One key aim was to reduce nutrient pollution, especially phosphates from detergents and sewage. These chemicals fueled huge blooms of algae that then died and decomposed, depleting oxygen in the water. </p>
<p>Like national water pollution laws enacted at the time, these efforts focused on point sources – pollutants released from discreet, readily identifiable points, such as discharge pipes or wells.</p>
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<a href="https://images.theconversation.com/files/463987/original/file-20220518-20-uyapnj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of the Great Lakes and connecting water bodies in profile." src="https://images.theconversation.com/files/463987/original/file-20220518-20-uyapnj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463987/original/file-20220518-20-uyapnj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=250&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463987/original/file-20220518-20-uyapnj.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=250&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463987/original/file-20220518-20-uyapnj.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=250&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463987/original/file-20220518-20-uyapnj.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=314&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463987/original/file-20220518-20-uyapnj.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=314&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463987/original/file-20220518-20-uyapnj.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=314&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">This profile view of the Great Lakes shows that Lake Erie is much shallower than the other lakes. As a result, its waters warm faster and are more vulnerable to algal blooms.</span>
<span class="attribution"><a class="source" href="https://twitter.com/NOAA_GLERL/status/1270022370640658437/photo/1">NOAA</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Early results were encouraging. Both governments invested in new sewage treatment facilities and convinced manufacturers to <a href="https://www.nytimes.com/1970/05/03/archives/detergents-listed-in-phosphate-order.html">reduce phosphate loads in detergents and soaps</a>. But as phosphorus levels in the lakes declined, scientists soon detected other problems.</p>
<h2>Toxic contaminants</h2>
<p>In 1973, scientists reported a perplexing find in fish from Lake Ontario: <a href="http://dx.doi.org/%2010.1126/science.185.4150.523">mirex, a highly toxic organochloride pesticide</a> used mainly to kill ants in the southeast U.S. An investigation revealed that the <a href="https://www.nytimes.com/1976/09/03/archives/new-jersey-pages-chemical-flowing-illegally-into-niagara-toxic.html">Hooker Chemical company</a> was discharging mirex from its plant in Niagara Falls, New York. The contamination was so severe that New York State <a href="https://aliciapatterson.org/stories/northern-fish-mystery">banned eating popular types of fish</a> such as coho salmon and lake trout from Lake Ontario from 1976 to 1978, shutting down commercial and sport fishing in the lake. </p>
<p>In response to this and other findings, the U.S. and Canada updated the Great Lakes Water Quality Agreement in 1978 to cover all five lakes and focus on chemicals and toxic substances. This version formally adopted an <a href="https://ijc.org/sites/default/files/2019-05/WQB_PracticalStepstoImplementanEcosystemApproachinGreatLakesManagement_December1995.pdf">ecosystem approach</a> to pollution control that considered interactions between water, air and land – perhaps the first international agreement to do so. </p>
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<figcaption><span class="caption">A tour of the Great Lakes and the nature in and around them.</span></figcaption>
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<p>In 1987, the two countries identified <a href="https://www.ijc.org/en/what/glwq-aoc">the most toxic hot spots</a> around the lakes and adopted action plans to clean them up. However, as <a href="https://press.ucalgary.ca/books/9781552388952/">scholars</a> of North American environmental regulations <a href="https://press.uchicago.edu/ucp/books/book/chicago/M/bo3629140.html">acknowledge</a>, both nations too often allowed industries to police themselves. </p>
<p>Since the 1990s, <a href="https://www.dec.ny.gov/data/DecDocs/932121/Report.HW.932121.2009-03-26.ToxicsChemicalsInTributariesToLakeOntario.pdf">studies</a> have identified toxic pollutants including <a href="https://doi.org/10.1021/acs.estlett.8b00019">PCBs</a>, <a href="https://doi.org/10.1016/j.envint.2020.106065">DDT</a> and chlordane in and around the Great Lakes, as well as lead, copper, arsenic and others. Some of these chemicals <a href="https://doi.org/10.1021/es501509r">continued to show up</a> because they were persistent and took a long time to break down. Others were banned but leached from contaminated sites and sediments. Still others came from a range of point and nonpoint sources, including <a href="https://www.ijc.org/sites/default/files/D9.pdf">many industrial sites</a> concentrated on shorelines.</p>
<p>Many hazardous sites have been slowly cleaned up. However, toxic pollution in the Great Lakes <a href="https://www.regions.noaa.gov/great-lakes/index.php/great_lakes-restoration-initiative/toxics/">remains a colossal problem</a> that is largely unappreciated by the public, since these substances don’t always make the water look or smell foul. Numerous <a href="https://ehp.niehs.nih.gov/doi/10.1289/ehp104">fish advisories</a> are still in effect across the region because of chemical contamination. Industries constantly bring new chemicals to market, and <a href="https://www.pbs.org/newshour/science/it-could-take-centuries-for-epa-to-test-all-the-unregulated-chemicals-under-a-new-landmark-bill">regulations lag far behind</a>.</p>
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<h2>Nonpoint sources</h2>
<p>Another major challenge is <a href="https://www.epa.gov/nps/basic-information-about-nonpoint-source-nps-pollution">nonpoint source pollution</a> – discharges that come from many diffuse sources, such as runoff from farm fields. </p>
<p><a href="https://doi.org/10.1086/684646">Nitrogen levels</a> in the lakes have risen significantly because of agriculture. Like phosphorus, nitrogen is a nutrient that causes large blooms of algae in fresh water; it is one of the main ingredients in fertilizer, and is also found in human and animal waste. <a href="https://greatlakes.org/campaigns/sewage-overflows/">Sewage overflows</a> from cities and <a href="https://elpc.org/blog/the-great-lakes-cafos-and-water-quality/">waste and manure runoff</a> from industrial agriculture carry heavy loads of nitrogen into the lakes.</p>
<p>As a result, algal blooms have <a href="https://www.glerl.noaa.gov/res/HABs_and_Hypoxia/bulletin.html">returned to Lake Erie</a>. In 2014, toxins in one of those blooms forced officials in Toledo, Ohio, to <a href="https://greatlakes.org/2019/08/five-years-later-lessons-from-the-toledo-water-crisis/">shut off the public water supply</a> for half a million people. </p>
<p>One way to address nonpoint source pollution is to set an overall limit for releases of the problem pollutant into local water bodies and then work to bring discharges down to that level. These measures, known as <a href="https://www.epa.gov/tmdl/overview-total-maximum-daily-loads-tmdls">Total Maximum Daily Loads</a>, have been applied or are in development for parts of the Great Lakes basin, including <a href="https://greatlakes.org/2020/02/statement-development-of-a-pollution-diet-for-western-lake-erie/">western Lake Erie</a>.</p>
<p>But this strategy relies on states, along with <a href="https://www.freshlawblog.com/2016/06/02/us-epas-great-lakes-restoration-initiative-grants-for-voluntary-action-a-striking-contrast-to-the-chesapeake-bay-tmdl/">voluntary steps by farmers</a>, to curb pollution releases. Some Midwesterners would prefer a regional approach like the strategy for Chesapeake Bay, where states asked the U.S. government to write a sweeping <a href="https://www.chesapeakebay.net/what/programs/total_maximum_daily_load">federal TMDL for key pollutants</a> for the bay’s entire watershed.</p>
<p>In 2019, Toledo voters adopted a <a href="https://theconversation.com/how-giving-legal-rights-to-nature-could-help-reduce-toxic-algae-blooms-in-lake-erie-115351">Lake Erie Bill of Rights</a> that would have permitted citizens to sue when Lake Erie was being polluted. Farmers <a href="https://www.michiganradio.org/environment-science/2020-02-28/lake-erie-bill-of-rights-declared-unconstitutional">challenged the measure in court</a>, and it was declared unconstitutional.</p>
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<h2>Warming and flooding</h2>
<p><a href="https://nca2018.globalchange.gov/chapter/21/">Climate change</a> is now complicating Great Lakes cleanup efforts. Warmer water can affect oxygen concentrations, nutrient cycling and food webs in the lakes, potentially <a href="https://theconversation.com/warmer-wetter-wilder-38-million-people-in-the-great-lakes-region-are-threatened-by-climate-change-170195">intensifying problems</a> and converting nuisances into major challenges. </p>
<p>Flooding driven by climate change threatens to <a href="https://theconversation.com/climate-change-threatens-drinking-water-quality-across-the-great-lakes-131883">contaminate public water supplies</a> around the lakes. Record-high water levels are <a href="https://theconversation.com/great-lakes-flooding-the-warning-signs-that-homes-must-be-moved-122697">eroding shorelines and wrecking infrastructure</a>. And new problems are emerging, including <a href="https://www.greatlakesnow.org/2021/05/chemical-impact-microplastic-pollution/">microplastic pollution</a> and “forever chemicals” such as <a href="https://news.wisc.edu/study-finds-tributaries-play-significant-role-in-great-lakes-pfas-loading/">PFAS and PFOA</a>. </p>
<p>It will be challenging for the U.S. and Canada to make progress on this complex set of problems. Key steps include prioritizing and funding cleanup of toxic zones, finding ways to halt agricultural runoff and building new sewer and stormwater infrastructure. If the two countries can muster the will to aggressively tackle pollution problems, as they did with phosphates in the 1970s, the Great Lakes Water Quality Agreement gives them a framework for action.</p><img src="https://counter.theconversation.com/content/181037/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Macfarlane has received funding from the Social Sciences and Humanities Research Council and Western Michigan University. </span></em></p>
Cleaning up the Great Lakes was a big job when the US and Canada undertook it in 1972. Today it’s far more challenging.
Daniel Macfarlane, Associate Professor of Environment and Sustainability, Western Michigan University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/170158
2022-03-15T15:32:59Z
2022-03-15T15:32:59Z
Microalgae is nature’s ‘green gold’: our pioneering project to feed the world more sustainably
<figure><img src="https://images.theconversation.com/files/451044/original/file-20220309-21-1nh0beb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Chlorella, a species of microalgae grown for the ALG-AD project in Devon.
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/unicellular-green-algae-large-cells-1042159933">Shutterstock</a></span></figcaption></figure><p>As a young child in the mid-1960s, my days were spent living an idyllic rural life on a dairy farm in the village of Lewdown in the heart of Devon. I recall many happy days exploring the glorious countryside, living a life in balance with nature and the environment – or at least, that’s how it felt.</p>
<p>But I also remember the ever-present slurry pit full of manure down at the end of our cowshed. It wasn’t fenced off, and my mum would remind me on regular occasions that to stray too close could mean death by drowning in what was, in essence, an enormous vat of smelly cow pats. As a five-year-old, I stayed well clear.</p>
<p>What we didn’t know then was that this pit of farm manure posed not only a hazard to me, but to our environment. Manure, which is often returned to the land as a nutrient fertiliser <a href="https://www.ag.ndsu.edu/publications/environment-natural-resources/environmental-implications-of-excess-fertilizer-and-manure-on-water-quality">without consideration of its wider impacts</a>, releases greenhouse gases including methane, carbon dioxide and nitrous oxide, and other harmful nitrogenous gases such as ammonia. It can also lead to nitrogen-rich run-off into water courses, <a href="https://www.scientificamerican.com/article/fertilizer-runoff-overwhelms-streams/">polluting rivers, lakes and coastlines</a> – with knock-on effects on fish mortality and tourism.</p>
<p>In short, what I thought was an idyllic childhood, living on a farm in balance with nature, wasn’t quite that. Subsequently, as a bioscientist, I’ve spent much of my life researching microorganisms that can help maintain a healthy planet. Nearly 60 years later, I find myself leading a <a href="https://www.nweurope.eu/projects/project-search/alg-ad-creating-value-from-waste-nutrients-by-integrating-algal-and-anaerobic-digestion-technology/">pioneering Europe-wide project</a> dedicated to transforming potentially harmful waste into something positive. In the process, we can help to build a “<a href="https://theconversation.com/what-a-sustainable-circular-economy-would-look-like-133808">circular economy</a>” that regenerates nature and keeps materials in circulation. And at the centre of this work are some remarkable microscopic organisms – our “green gold”.</p>
<h2>Jewels of nature</h2>
<p>We all know how important trees are in terms of <a href="https://theconversation.com/there-arent-enough-trees-in-the-world-to-offset-societys-carbon-emissions-and-there-never-will-be-158181">sequestering carbon</a>, yet we tend to overlook the two-thirds of our planet that is covered by water. Our seas and oceans are filled with organisms that are equally vital to the Earth’s life cycles, yet because they are individually less visible to the naked eye than land plants, we largely ignore them.</p>
<p>Microalgae – not to be confused with macroalgae (seaweeds) – are massively abundant in our seas, freshwater lakes and rivers. These tiny organisms are important “<a href="http://sites.nd.edu/madelyn-martinez/2019/04/22/the-importance-of-primary-producers/">primary producers</a>” on our planet, acting as biomass factories. They use sunlight through the process of photosynthesis to convert inorganic molecules (carbon dioxide, nutrients and water) into proteins, fats and carbohydrates, plus a host of other organic compounds that help them grow and survive. These tiny microorganisms support all life in our oceans and, with their high turnover rates, contribute to <a href="https://www.science.org/doi/10.1126/science.281.5374.237">around 50% of</a> the planet’s primary production.</p>
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<p>There are literally hundreds of thousands of species of microalgae. A commonly occurring group are the diatoms, of which there are an estimated 20,000 species. With beautifully intricate, snowflake-like cell walls made of glass, diatoms are true jewels of nature. Another common group are the coccolithophores, covered in elaborate, frisbee-like calcium carbonate chalk plates. During the Cretaceous period, which ended 66 million years ago, enormous blooms of coccolithophores formed the white cliffs of Dover.</p>
<p>As microalgae do not have roots, leaves and stems, they can use carbon dioxide and nutrients more efficiently than land plants, enabling them to grow more rapidly. They can be relatively easily cultivated and harvested to produce biomass crops (“algaculture”) which can be used as food or for bioenergy. Algal biomass also contains a wide range of useful molecules that can be used in bioplastics, biofuel, health products, cosmetics and food ingredients.</p>
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<p><strong><em>This story is part of Conversation Insights</em></strong>
<br><em>The Insights team generates <a href="https://theconversation.com/uk/topics/insights-series-71218">long-form journalism</a> and is working with academics from different backgrounds who have been engaged in projects to tackle societal and scientific challenges.</em></p>
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<p>My growing appreciation of these fascinating microorganisms, with their amazing ability to grow on waste nutrients and produce something useful, inspired me to want to help address the twin global challenges of sustainability and environmental protection. Using nature’s “green gold” to clean up waste nutrients while also producing sustainable feeds and other products seemed to me a no-brainer.</p>
<p>Back in the 70s, I recall my A-level biology teacher, Mr Montague, introducing us to the carbon and nitrogen cycles and explaining how important the balance of each of these cycles is to life on our planet. I even remember him talking about the greenhouse effect and temperature rise. But we didn’t realise back then just how severe the threat of carbon dioxide-related climate change was – or how nitrogen would emerge as a major contributor to the complex environmental challenges we face today.</p>
<h2>Towards a circular economy</h2>
<p>To have any hope of meeting <a href="https://theconversation.com/glasgow-climate-pact-where-do-all-the-words-and-numbers-we-heard-at-cop26-leave-us-171704">our global climate change targets</a> and achieving a sustainable equilibrium, we need to work towards a circular economy that eliminates waste and pollution, keeps materials in circulation and regenerates nature. This must replace our existing linear “use and discard” model which has led to unbalanced nutrient cycles.</p>
<p>In response to this, farmers, the food industry and waste-water companies are <a href="https://iopscience.iop.org/article/10.1088/1755-1315/476/1/012074/pdf">increasingly turning to anaerobic digestion</a> (AD) to process their waste. AD is a natural process in which bacteria in large tanks called digestors feed on organic waste – sewage, food waste, farm manure and other agricultural waste – to produce a biogas, rich in carbon and hydrogen, that can be captured and used to generate renewable electricity and heat.</p>
<p>The nitrogen component of the organic waste is retained in a thick liquid called digestate, which can be returned to the land by farmers as a naturally produced fertiliser – preferable to synthetic fertilisers produced using energy-intensive and CO₂-emitting processes. However, as the AD industry has expanded, so the increased production and returning of digestate to the land poses a risk of nutrient pollution.</p>
<p>As a result, many areas in the United Kingdom and Europe are now restricted by the <a href="http://adlib.everysite.co.uk/adlib/defra/content.aspx?doc=18647&id=18649">Nitrate Directive</a> and <a href="http://adlib.everysite.co.uk/adlib/defra/content.aspx?id=000IL3890W.17USYFLDOH012T">nitrate vulnerable zone</a> (NVZ) legislation, introduced to prevent pollution through excessive use of nitrogen returned to the land. Currently, <a href="https://www.gov.uk/government/collections/nitrate-vulnerable-zones">55%</a> of land in England is designated an NVZ, while the <a href="https://en.wikipedia.org/wiki/Nitrate_vulnerable_zone#:%7E:text=parties%20and%20farmers.-,Northern%20Europe,as%20well%20as%20marine%20eutrophication.">entirety of Wales</a> is in the process of becoming another such zone.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/biofuel-how-new-microalgae-technologies-can-hasten-the-end-of-our-reliance-on-oil-176723">Biofuel: how new microalgae technologies can hasten the end of our reliance on oil</a>
</strong>
</em>
</p>
<hr>
<p>One way of overcoming this regulatory challenge is through the use of microalgae. And so, in 2017, our Europe-wide, circular economy project <a href="https://www.nweurope.eu/projects/project-search/alg-ad-creating-value-from-waste-nutrients-by-integrating-algal-and-anaerobic-digestion-technology/%22%22">called ALG-AD</a> was born. The ultimate goal is to convert nitrogen that poses a risk to the environment into microalgae that can be used in sustainable animal feed, replacing existing, highly resource-intensive sources of feed in the process. Using funding from the <a href="https://www.nweurope.eu/">INTERREG North-West Europe programme</a>, Swansea University partnered with ten other organisations throughout north-west Europe – a densely populated and intensely agricultural area that is particularly vulnerable to nitrate pollution of groundwater. The whole of <a href="https://en.wikipedia.org/wiki/Nitrate_vulnerable_zone#:%7E:text=parties%20and%20farmers.-,Northern%20Europe,as%20well%20as%20marine%20eutrophication.">Belgium, Germany, the Netherlands and Denmark</a> are also already designated NVZs.</p>
<p>By recycling unwanted nitrogen into something useful, we can prevent it escaping into the atmosphere and into waterways, thereby reducing pollution to both land and atmosphere. The microalgae naturally convert the nitrogen into protein and other nutritional molecules which can be used back in the food chain. Five years on from the project’s launch, we have already shown that such a circular economy solution is workable on an industrial scale.</p>
<h2>A new source of protein</h2>
<p>The projected growth of the planet’s population over the next half-century means global food production is <a href="https://www.britishcouncil.org/sites/default/files/global_food_security_how_do_we_feed_a_growing_population_web.pdf">expected to increase</a> by at least 50%. We are also all being encouraged to reduce consumption of meat protein to reduce greenhouse gas emissions and deforestation. New sources of protein are therefore a top priority, and microalgae are strong contenders. Companies such as Nestlé are already <a href="https://www.nestle.com/randd/news/allnews/partnership-corbion-microalgae-plant-based-products">researching microalgae</a> as an alternative source of protein, both as animal feed and food for humans.</p>
<p>While the microalgal production industry is still in its infancy, the ability to produce a new source of protein without the issues associated with <a href="https://theconversation.com/why-eating-grass-fed-beef-isnt-going-to-help-fight-climate-change-84237">meat</a> and <a href="https://theconversation.com/brazils-thriving-soy-industry-threatens-its-forests-and-global-climate-targets-56973">soya</a> is very attractive. Furthermore, being able to cultivate microalgae close to where they will be used by farmers in animal feed offers another distinct advantage.</p>
<p>A big challenge for our European project has been to test this technology for development at full working scale. We have therefore worked directly with the AD industry as it processes food and farm waste, providing us with industrially produced nitrogen (in digestate) to cultivate our microalgae.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/451051/original/file-20220309-32-19e624a.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451051/original/file-20220309-32-19e624a.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=339&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451051/original/file-20220309-32-19e624a.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=339&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451051/original/file-20220309-32-19e624a.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=339&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451051/original/file-20220309-32-19e624a.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=426&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451051/original/file-20220309-32-19e624a.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=426&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451051/original/file-20220309-32-19e624a.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=426&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The 7,000 L Algal photobioreactor, constructed in a heated greenhouse at Langage-AD in Devon.</span>
<span class="attribution"><span class="source">Photo: Claudio Fuentes- Grünwald</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In the UK, just 30 miles from the Devon farm on which I lived as a child, we have built <a href="https://www.youtube.com/watch?v=APsobJ62_K0&t=4s">a pilot “algae-AD”</a> facility at an AD company sited next to Langage Dairy Farm. <a href="https://www.langagead.com">Langage-AD</a> has the capacity to process 20,000 tonnes of food waste a year, producing biomethane that generates heat and electricity. We were provided with a large, heated greenhouse situated right next to where the waste is processed. This was the ideal location for our “algal photobioreactor”, a series of vertical see-through tubes in which microalgae are grown in an aqueous medium containing nutrients that are exposed to both daylight and artificial light.</p>
<p>Two sister photobioreactor facilities have been built in Brittany in France and Ghent in Belgium. All partners have undertaken in-depth studies to determine how to <a href="https://doi.org/10.1016/j.chemosphere.2021.133180">best process</a> the digestate and <a href="https://www.sciencedirect.com/science/article/pii/S0956053X20304797">optimise nutrient uptake</a>. Too much and we found that our microalgae didn’t like it; too little and not much happened.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/APsobJ62_K0?wmode=transparent&start=4" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The algal cultivation facility at Langage-AD.</span></figcaption>
</figure>
<p>Promisingly, we have found that microalgae grown on digestate are <a href="https://www.sciencedirect.com/science/article/abs/pii/S0960852420316230">richer in protein</a> compared with microalgae grown on more typically-used inorganic nutrients, with protein levels reaching up to around 80% of the total biomass produced. This is well over double the amount of protein contained in meat and soya products. In a world where there is an <a href="https://allianceforscience.cornell.edu/blog/2020/07/fao-predicts-global-shortage-of-protein-rich-foods/">increasing protein shortage</a> and alternatives to meat are sought, this is a real bonus.</p>
<p>Currently, around <a href="https://ourworldindata.org/soy">75% of the world’s soya crop</a> is used as a source of protein in animal feed. As with beef production, soya production has come under scrutiny for its role in deforestation, particularly in <a href="https://theconversation.com/brazil-signs-agreement-to-halt-deforestation-but-bolsonaro-cannot-be-trusted-171091">Brazil</a> and Argentina. In addition, the transportation of soya across the globe generates a huge carbon footprint. To top it all, transporting soya to high agricultural areas disturbs the global balance of nitrogen, leading to “nutrient hotspots” and an increase in NVZs.</p>
<p>Our studies have confirmed <a href="https://link.springer.com/article/10.1007/s12155-022-10397-2">the potential of microalgae</a> as a protein source to supplement and replace soya protein. However, the scale of microalgal cultivation is currently not big enough to make a significant impact on soya markets. Therefore, our real-life feed trial experiments have so far concentrated on testing microalgae as a food supplement, to improve the health of piglets and <a href="https://www.youtube.com/watch?v=bdz2A_qLIHw">of fish</a>. But we know that the market for algae-based animal feed and ingredients is set to <a href="https://www.prnewswire.com/news-releases/algae-based-animal-feed-and-ingredients-market-to-grow-by-usd-750-65-millionkey-drivers-and-market-forecasts17000-technavio-research-reports-301294508.html">grow rapidly</a>.</p>
<h2>Rolling out these novel biotechnologies</h2>
<p>To date in the UK, we have focused on two commonly occurring freshwater species of green microalgae, <em>Chlorella vulgaris</em> and <em>Scenedesmus obliquus</em> (both from the division Chlorophyta). Both species contain good levels of proteins and a host of molecules with beneficial properties for health, which we are still exploring.</p>
<p>But yet another amazing thing about microalgae is their diversity. There are tens of thousands of other species with a breathtaking variety of form and function, still waiting to be explored.</p>
<p>Now, supported by the groundwork of our research, it is up to pioneering businesses, regulators and investors to work together to enable the roll-out of these novel biotechnologies more widely. As we move to a society and economy more circular than linear, which uses its waste while preventing environmental contamination, it seems that microalgae will become more familiar to us all in one form or another.</p>
<p>Our project has already demonstrated that microalgae have strong potential in helping reduce food security-related issues such as land scarcity, climate change and inefficient and unsustainable fertiliser usage, as well as associated nutrient leakage and water pollution. In so doing, they can be used to raise environmental standards in Europe and throughout the world. Indeed, our work supports the recently announced <a href="https://ec.europa.eu/commission/presscorner/detail/en/ip_21_5916">European Green Deal</a>, promoting the circular economy and protection of nature, and the new <a href="https://ec.europa.eu/info/food-farming-fisheries/key-policies/common-agricultural-policy/new-cap-2023-27_en">Common Agricultural Policy</a> with its strong emphasis on environment-friendly farming practices and agro-ecology.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/451058/original/file-20220309-25-172ve9y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graphic showing Common Agricultural Policy key objectives" src="https://images.theconversation.com/files/451058/original/file-20220309-25-172ve9y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/451058/original/file-20220309-25-172ve9y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/451058/original/file-20220309-25-172ve9y.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/451058/original/file-20220309-25-172ve9y.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/451058/original/file-20220309-25-172ve9y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/451058/original/file-20220309-25-172ve9y.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/451058/original/file-20220309-25-172ve9y.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For the period 2023-27, the Common Agricultural Policy (CAP) will be built around these 10 key objectives.</span>
<span class="attribution"><a class="source" href="https://ec.europa.eu/info/sites/default/files/food-farming-fisheries/key_policies/images/the-10-cap-objectives_en.jpg">EC</a></span>
</figcaption>
</figure>
<p>However, it is still relatively early days. As with any waste-related technology, legislation and regulation needs to be <a href="https://www.nweurope.eu/projects/project-search/alg-ad-creating-value-from-waste-nutrients-by-integrating-algal-and-anaerobic-digestion-technology/publications/the-alg-ad-project-reports-and-deliverables/">carefully considered</a>. For now, the simplest way forward is to use anaerobically digested vegetable-based waste rather than animal-based waste, thereby eliminating the possibility of any animal waste or animal contamination passing back into the food chain.</p>
<p>We would also like to further increase the uptake of digestate into the algae and, like any new and developing technology, we need to balance up the cost and overall environmental benefits. To achieve this, we are gathering results from across the partnership and consolidating our data for use in <a href="https://link.springer.com/article/10.1007/s12155-022-10397-2">life cycle analysis</a>. This will also enable interested farmers, food producers and other industries to decide <a href="https://www.youtube.com/watch?v=5P_u28_y6RY">if the technology</a> is for them, and what they might best achieve according to their particular needs.</p>
<p>Another way microalgae can be used to help in agriculture is as <a href="https://www.sciencedirect.com/science/article/abs/pii/S0734975021000604">biostimulants</a> – natural products that, when applied in small quantities, enhance nutrition uptake and improve stress tolerance, thus reducing the need for chemical fertilisers. We are also delving further into the many other valuable components within microalgal cells, including molecules that have benefits as human and animal <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/immune-system-modulator">immune modulators</a>, anti-inflammatories and antivirals. The full benefits of microalgae to produce new products are just waiting to be reaped.</p>
<p>Ironically, throughout my working life, I didn’t exactly heed the advice of my mum all those years ago, to stay away from the dangerous mix of nutrients that was brewing in the manure pit at the end of our cowshed. But I would like to think, in not doing so, that I have been part of a revolution in the way we regard and treat waste, ensuring that the valuable nutrients in cow manure and other organic waste can increasingly be used for the benefit of us, and our planet.</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=112&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=112&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=112&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=140&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=140&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=140&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>For you: more from our <a href="https://theconversation.com/uk/topics/insights-series-71218?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Insights series</a>:</em></p>
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<li><p><em><a href="https://theconversation.com/how-china-combined-authoritarianism-with-capitalism-to-create-a-new-communism-167586?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">How China combined authoritarianism with capitalism to create a new communism</a></em></p></li>
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<p class="fine-print"><em><span>Carole Llewellyn receives funding from the Interreg North-West Europe programme and Welsh Government on the ALG-AD, project, NWE520.</span></em></p>
The inside of story of a pioneering programme to convert nitrogen into microalgae that can generate sustainable animal feed.
Carole Anne Llewellyn, Professor in Applied Aquatic Bioscience, Swansea University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/174782
2022-02-02T19:09:45Z
2022-02-02T19:09:45Z
Japan wants to burn ammonia for clean energy – but it may be a pyrrhic victory for the climate
<figure><img src="https://images.theconversation.com/files/443089/original/file-20220128-22-1qn4mc7.jpg?ixlib=rb-1.1.0&rect=0%2C5%2C3866%2C2579&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">名古屋太郎</span></span></figcaption></figure><p>Coal is at the centre of Australia and Japan’s long partnership in energy trade. But as Japan seeks to slash its emissions in coming decades, this relationship will change. </p>
<p>Japan is aiming to reach net-zero greenhouse gas emissions by 2050. One way Japan plans to achieve this is to <a href="https://www.ammoniaenergy.org/articles/japans-road-map-for-fuel-ammonia/">combust ammonia alongside coal in its coal-fired power plants</a>. </p>
<p>Ammonia is made by combining hydrogen and nitrogen. When ammonia is burned for energy, the process does not produce carbon dioxide (CO₂), and so offers potential for Japan to reduce greenhouse gas emissions. </p>
<p>Australia is well placed to become a key global supplier of ammonia. But the climate gains from Japan’s shift will depend on how the ammonia is produced in Australia.</p>
<figure class="align-center ">
<img alt="coal and machinery at terminal" src="https://images.theconversation.com/files/443090/original/file-20220128-6942-2qxitq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443090/original/file-20220128-6942-2qxitq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=367&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443090/original/file-20220128-6942-2qxitq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=367&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443090/original/file-20220128-6942-2qxitq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=367&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443090/original/file-20220128-6942-2qxitq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=461&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443090/original/file-20220128-6942-2qxitq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=461&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443090/original/file-20220128-6942-2qxitq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=461&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Japan’s demand for Australian thermal coal may change as it embraces ammonia as a fuel.</span>
<span class="attribution"><span class="source">Darren Pateman/AAP</span></span>
</figcaption>
</figure>
<h2>A new way for coal plants?</h2>
<p>The value of Australia’s thermal coal exports to Japan reached about <a href="https://publications.industry.gov.au/publications/resourcesandenergyquarterlydecember2021/documents/Resources-and-Energy-Quarterly-December-2021.pdf">A$7 billion</a> in 2020 – 40% of the total value of our thermal coal exports that year.</p>
<p>Japan is aiming to reach net-zero greenhouse gas emissions by 2050. To meet this goal, it has pledged to reduce emissions by 46% by 2030 compared to 2013. </p>
<p>The energy sector makes up by far the <a href="https://unfccc.int/documents/271503">largest share</a> of Japan’s emissions. In the 2020 financial year, thermal coal provided about <a href="https://www.renewable-ei.org/en/statistics/energy/?cat=electricity">31% of Japan’s electricity</a>.</p>
<p>To reduce energy emissions, Japan is seeking to <a href="https://theconversation.com/japan-is-closing-its-old-dirty-power-plants-and-thats-bad-news-for-australias-coal-exports-144452">phase out inefficient coal plants</a>. In addition, it’s moving to burn ammonia alongside coal in remaining plants. </p>
<p>Large pilot trials in Japan have demonstrated the feasibility of a coal combustion mix with 20% ammonia. Japan’s biggest power plant operator, JERA, <a href="https://www.jera.co.jp/english/information/20220107_822">is now investing</a> in a project to demonstrate the feasibility of a 50% ammonia mix. The Japanese government is <a href="https://www.reuters.com/markets/commodities/japans-jera-develop-ammonia-related-tech-with-green-fund-backing-2022-01-07/">helping fund</a> the project.</p>
<h2>It matters how ammonia is made</h2>
<p>Whether using ammonia helps tackle climate change depends on how it’s made.</p>
<p>Currently, ammonia is produced on an industrial scale by combining hydrogen and nitrogen using the so-called “<a href="https://www.britannica.com/technology/Haber-Bosch-process">Haber Bosch</a>” process. Today, the hydrogen used in this process is typically produced from gas using a method that releases <a href="https://www.iea.org/reports/ammonia-technology-roadmap">a lot</a> of CO₂. </p>
<p>Hydrogen can also be produced with electrolysis <a href="https://www.weforum.org/agenda/2021/12/what-is-green-hydrogen-expert-explains-benefits/">powered by renewable electricity</a> – creating what’s known as “green” hydrogen. This process is currently more expensive than the gas method. </p>
<p>If renewable energy is used to power the processes that extract nitrogen from the air and combine it with hydrogen, then ammonia made with green hydrogen can be produced with near-zero emissions intensity. </p>
<p>Australia’s abundant energy resources, and existing trade relationships, mean it could become a major supplier of ammonia to countries decarbonising their energy sources. </p>
<p>In Australia, ammonia is predominantly made from fossil fuels. This <a href="https://ageis.climatechange.gov.au/Chart.aspx?OD_ID=114088004404&TypeID=3">resulted in</a> 2 million tonnes of greenhouse gas emissions in 2019. </p>
<p>However, there are projects underway to inject green hydrogen into <a href="https://www.incitecpivot.com.au/about-us/about-incitec-pivot-limited/media/international-partnership-to-investigate-green-ammonia-supply-from-australias-hydrogen-hubs">existing facilities</a>, and <a href="https://asianrehub.com/">others</a> seeking to produce green ammonia at scale. </p>
<p>Projects to make ammonia <a href="https://asia.nikkei.com/Spotlight/Environment/Climate-Change/Mitsui-to-build-900m-blue-ammonia-plant-in-Australia">from gas</a>, where carbon emissions are captured and stored, are also being developed. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/asias-energy-pivot-is-a-warning-to-australia-clinging-to-coal-is-bad-for-the-economy-169541">Asia's energy pivot is a warning to Australia: clinging to coal is bad for the economy</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/443093/original/file-20220128-6942-yk1dok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443093/original/file-20220128-6942-yk1dok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443093/original/file-20220128-6942-yk1dok.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443093/original/file-20220128-6942-yk1dok.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443093/original/file-20220128-6942-yk1dok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=511&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443093/original/file-20220128-6942-yk1dok.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=511&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443093/original/file-20220128-6942-yk1dok.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=511&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fortescue Future Industries, headed by Andrew Forrest (centre), is investigating the feasibility of green ammonia production Queensland.</span>
<span class="attribution"><span class="source">Darren England/AAP</span></span>
</figcaption>
</figure>
<h2>Will Japan’s plan help the climate?</h2>
<p>By burning ammonia in its coal plants, Japan will reduce its national emissions. We <a href="https://authors.elsevier.com/c/1eOUp_LqUdMyR2">calculate</a> that replacing 20% of the coal burned in Japan’s expected 2030 coal fleet with ammonia would avoid emitting 40 million tonnes of CO₂ a year.</p>
<p>But what if Japan burns ammonia made in Australia from fossil-fuel based hydrogen? In that case, the emissions savings made in Japan will be wiped out by the emissions released in Australia when the ammonia was produced. Emissions would simply be transferred between nations, at no gain to the planet. </p>
<p>Some emissions produced in Australia could be avoided using carbon capture and storage (CCS). However, the feasibility of this technology is in real doubt. And <a href="https://theconversation.com/australia-is-at-a-crossroads-in-the-global-hydrogen-race-and-one-path-looks-risky-157864">significant CO₂</a> would still be released to the atmosphere in Australia due to fugitive emissions – those that escape during the production process – and because CCS doesn’t capture all CO₂.</p>
<p>So clearly, only ammonia production powered by renewable energy will reduce CO₂ emissions in both Japan and Australia. </p>
<p>It’s worth noting that under the scenario outlined above, the reduction in our thermal coal exports to Japan would lead to a fall in fugitive emissions from coal mining in Australia. </p>
<p>We estimate a reduction in fugitive emissions of between 1 and 10 million tonnes each year by 2030, assuming a one-to-one reduction in coal exports to Japan. This fall would offset emissions created by installing the renewable energy needed to power clean ammonia production in Australia.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/japan-is-closing-its-old-dirty-power-plants-and-thats-bad-news-for-australias-coal-exports-144452">Japan is closing its old, dirty power plants – and that's bad news for Australia's coal exports</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="wind farm on hill crest" src="https://images.theconversation.com/files/443095/original/file-20220128-6524-16dgqvg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443095/original/file-20220128-6524-16dgqvg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443095/original/file-20220128-6524-16dgqvg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443095/original/file-20220128-6524-16dgqvg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443095/original/file-20220128-6524-16dgqvg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443095/original/file-20220128-6524-16dgqvg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443095/original/file-20220128-6524-16dgqvg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Only ammonia production powered by renewable energy will reduce CO₂ emissions in both Japan and Australia.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What to do</h2>
<p>Under the current global system of national emissions reporting, there is no incentive for Japan to buy more expensive, zero-emissions ammonia from Australia or elsewhere.</p>
<p>So if the international trade in ammonia grows, national governments must introduce policies to reduce emissions along the ammonia supply chain.</p>
<p>In Australia, that could mean a tougher national emissions target – and a detailed roadmap laying out how to get there – to make it harder for businesses to invest in new polluting ammonia production. </p>
<p>But this won’t stop Japan’s power plant operators from buying emissions-intensive ammonia from other countries if it’s cheaper. So clearly, some form of international cooperation is required.</p>
<p>This could come in the form of certification, similar to that currently being <a href="https://consult.industry.gov.au/hydrogen-guarantee-of-origin-scheme">developed</a> for hydrogen. In the case of ammonia, certification would <a href="https://www.ammoniaenergy.org/wp-content/uploads/2021/10/AEA-Low-Carbon-Ammonia-Certification-Discussion-Paper.pdf">tell consumers</a> how much greenhouse gas was emitted during the production phase.</p>
<p>And incentives must also be in place to ensure buyers choose low-emissions ammonia. This may involve transferring emission reductions from one country’s greenhouse gas ledger to another – a <a href="https://unfccc.int/process-and-meetings/the-paris-agreement/the-glasgow-climate-pact/cop26-outcomes-market-mechanisms-and-non-market-approaches-article-6">mechanism discussed</a> at the recent COP26 climate conference in Glasgow.</p>
<p>Japan may succeed in using ammonia to cut the environmental burden of its coal power fleet. But unless that ammonia is produced with little or no emissions, the victory will be pyrrhic. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australia-is-at-a-crossroads-in-the-global-hydrogen-race-and-one-path-looks-risky-157864">Australia is at a crossroads in the global hydrogen race – and one path looks risky</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/174782/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>In addition to his academic work, Llewelyn Hughes provides advice to a number of companies operating in the renewable energy sector in Japan.</span></em></p><p class="fine-print"><em><span>Fiona J Beck has received funding from the Australian Research Council and the Australian Renewable Energy Agency to develop renewable energy technologies. </span></em></p>
Any climate gains from Japan’s shift will be wiped out entirely unless Australia moves to zero-emissions ammonia production.
Llewelyn Hughes, Associate Professor of Public Policy, Crawford School of Public Policy, Australian National University
Fiona J Beck, Senior research fellow, Australian National University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/175610
2022-01-27T19:01:09Z
2022-01-27T19:01:09Z
Gut microbes help hibernating ground squirrels emerge strong and healthy in spring
<figure><img src="https://images.theconversation.com/files/442826/original/file-20220126-27-13smcdk.jpg?ixlib=rb-1.1.0&rect=63%2C369%2C3142%2C1959&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When not hibernating, ground squirrels need to feast to store energy.</span> <span class="attribution"><a class="source" href="https://doi.org/10.1126/science.abh2950">Robert Streiffer</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Ground squirrels spend the end of summer gorging on food, preparing for hibernation. They need to store a lot of energy as fat, which becomes their primary fuel source underground in their hibernation burrows all winter long.</p>
<p>While hibernating, ground squirrels enter <a href="https://doi.org/10.1111/brv.12137">a state called torpor</a>. Their metabolism drops to as low as just 1% of summer levels and their body temperature can <a href="https://doi.org/10.1152/physrev.00008.2003">plummet to close to freezing</a>. Torpor greatly reduces how much energy the animal needs to stay alive until springtime.</p>
<p>That long fast comes with a downside: no new input of protein, which is crucial to maintain the body’s tissues and organs. This is a particular problem for muscles. In people, long periods of inactivity, like prolonged bed rest, <a href="https://doi.org/10.1186/s13728-015-0036-7">lead to muscle wasting</a>. But muscle wasting is minimal in hibernating animals. Despite as much as six to nine months of inactivity and no protein intake, they preserve muscle mass and performance remarkably well – a very handy adaptation that helps ensure a successful breeding season come spring.</p>
<p>How do hibernators pull this off? It’s been <a href="https://doi.org/10.1086/650471">a real head-scratcher</a> <a href="https://doi.org/10.1152/ajpregu.1991.261.5.R1214">for hibernation biologists for decades</a>. <a href="https://scholar.google.com/citations?user=TUVZbtcAAAAJ&hl=en&oi=ao">Our research</a> <a href="https://scholar.google.com/citations?user=zuJyGe8AAAAJ&hl=en&oi=ao">team tackled</a> this question by investigating how hibernating animals might be getting a major assist <a href="https://doi.org/10.1126/science.abh2950">from the microbes that live in their guts</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="small mammal curled into a ball, nestled in wood chips" src="https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/442827/original/file-20220126-23-o570i5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The 13-lined ground squirrel shows minimal signs of muscle wasting, even after hibernating for up to six months.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1126/science.abh2950">Robert Streiffer</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>A nitrogen-recycling system</h2>
<p>We knew from previous research that a hibernator’s <a href="https://doi.org/10.1016/j.cbpa.2020.110875">gastrointestinal system undergoes dramatic changes</a> in its structure and function from summer feeding to winter fasting. And it’s not only the animals who are fasting all winter long – their gut microbes are, too. Along with our microbiology collaborators, we figured out that <a href="https://doi.org/10.1146/annurev-nutr-071816-064740">winter fasting changes the gut microbiome</a> quite a bit.</p>
<p>And then we wondered … could gut microbes play a functional role in the process of hibernation itself? Could certain bacteria help keep muscle and other tissues working when the mostly immobile animals aren’t eating?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="brown cow munching grass" src="https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=671&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=671&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=671&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=843&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=843&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443024/original/file-20220127-6424-ql553k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=843&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microbes in their guts help ruminants, including cows, hold on to the nitrogen they need to build proteins.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/brown-cow-royalty-free-image/1219160750">Lemanieh/ iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Biologists had previously identified a clever trick in ruminant animals, such as cattle, that helps them survive times when protein intake in the diet is low or protein needs are especially high, such as during pregnancy. A process <a href="https://doi.org/10.1079/NRR200498">called urea nitrogen salvage</a> allows the animal to recoup nitrogen – a critical ingredient for building protein – that would otherwise be excreted in urine as the waste product urea. Instead, the urea’s nitrogen is retained in the body and used to make amino acids, the building blocks of proteins.</p>
<p>This salvage operation depends on the chemical breakdown of urea molecules to release their nitrogen. But here’s the kicker: Chemical breakdown of urea requires urease, an enzyme that animals do not produce. So how does a cow, for instance, get that nitrogen out of urea?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="ball and stick model of a chemical structure" src="https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/443025/original/file-20220127-16-1kqqp1u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A model of the urea molecule, with two nitrogen atoms (in blue) along with a carbon (gray), an oxygen (red) and four hydrogen (white) atoms.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/urea-molecule-royalty-free-illustration/147217473">LAGUNA DESIGN/Science Photo Library via Getty Images</a></span>
</figcaption>
</figure>
<p>It turns out certain microbes that are normal residents of animals’ guts can do just that. They make the urease enzyme and use it to chemically split urea molecules, freeing up the nitrogen, which becomes part of ammonia molecules. Microbes then absorb ammonia and use it to make new protein for themselves.</p>
<p>Peculiarities of the ruminant digestive system allow those animals to benefit greatly from this process. But for other animals – like hibernators and us – it was less clear whether and how the urea nitrogen could make its way into the animals’ bodies to support protein synthesis.</p>
<p>This was our challenge as scientists: Could we demonstrate urea nitrogen recycling in hibernators and show that it is particularly helpful to them the longer they fast?</p>
<h2>Our experimental game plan</h2>
<p>Using the 13-lined ground squirrel, <a href="https://doi.org/10.1126/science.abh2950">we designed experiments to investigate</a> key steps in urea nitrogen salvage.</p>
<p>First, we injected into the squirrel’s bloodstream urea molecules in which the two nitrogen atoms were replaced by a heavier form of nitrogen that naturally occurs only in tiny amounts in the body.</p>
<p>We were able to follow these heavier nitrogen atoms as the injected urea moved from the blood into the gut, then as microbial urease broke down the urea into its component parts, and finally into the squirrels’ tissue metabolites and proteins. Wherever we saw higher levels of the heavier form of nitrogen, we knew that urea was the source of the nitrogen, and therefore gut microbes had to be responsible for getting the urea nitrogen back into the animals’ bodies.</p>
<p>To confirm that the microbes were doing the nitrogen recycling, we compared squirrels that had normal gut microbiomes to squirrels that didn’t. We treated some animals with antibiotics to reduce gut microbes at three times of the year: summer; early winter, when they were one month into fasting and hibernation; and late winter, whwithen they were four months into fasting and hibernation.</p>
<p>In squirrels with normal microbiomes, we saw evidence of urea nitrogen salvage at each step of the process that we tested. But squirrels with depleted microbiomes displayed minimal urea nitrogen salvage. Our observations confirmed that this process was indeed dependent on the gut microbes’ ability to break down urea and liberate its nitrogen in the hibernators’ guts. Hibernators’ liver and muscle tissue incorporated the most urea nitrogen during late winter – that is, the longer they’d been hibernating and without food.</p>
<p>We also found that the ground squirrels contribute to this remarkable symbiosis. During hibernation, their gut cells increase production of proteins called urea transporters. These molecules are lodged in intestinal cell membranes and shepherd urea from the blood into the gut where the microbes that contain urease are found. This assist means that what little urea the animal makes during hibernation has an easier route to the gut.</p>
<p>Finally, we found that it wasn’t just squirrels who benefited from this process. The microbes too were using the urea nitrogen to build their own proteins, showing that urea nitrogen salvage provides both parties with this important molecular building block during the long winter fast.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Fal-vhNgxvs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Every few weeks, hibernating squirrels arouse temporarily, as seen in this time-lapse video. They don’t eat or drink or leave the burrow, but the short increase in body temperature lets enzymes like urease do their jobs.</span></figcaption>
</figure>
<h2>Could this kind of symbiosis help humans?</h2>
<p>This example of hibernator-microbe symbiosis has potential clinical applications. For example, undernourishment, which affects millions of people globally, leads to a progressive decline in muscle mass and compromises health. Sarcopenia, which is muscle wasting that is a natural part of aging, impairs mobility and makes people more susceptible to injury. A detailed understanding of how the hibernator nitrogen salvage system is most effective when the risk of tissue loss and muscle wasting is greatest could lead to new therapeutics to help people in similar situations.</p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>Another potential application is in human spaceflight, during which crew members experience <a href="https://doi.org/10.33549/physiolres.934550">high rates of muscle atrophy</a> because of a microgravity-induced suppression of muscle protein synthesis. Even the extensive exercise regime that astronauts undertake to offset this is insufficient. A microbiome-based countermeasure that facilitates muscle protein synthesis similar to the process we have observed in hibernators may be worth investigating.</p>
<p>These applications, though theoretically possible, are a long way from delivery. But studies in the 1990s demonstrated that humans are capable of <a href="https://doi.org/10.1097/01.mco.0000196142.72985.d3">recycling small amounts of urea nitrogen with the help of their gut microbes</a>. So the necessary machinery is in place – it just needs to be optimized.</p><img src="https://counter.theconversation.com/content/175610/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hannah V. Carey received funding from the U.S. National Science Foundation for this work.</span></em></p><p class="fine-print"><em><span>Matthew Regan receives funding from the Natural Sciences and Engineering Research Council of Canada and the Canadian Space Agency.</span></em></p>
Months not eating or moving don’t result in muscle wasting and loss of function for animals that hibernate. New research found gut microbes help their hosts hold onto and use nitrogen to build proteins.
Hannah V. Carey, Professor Emeritus of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison
Matthew Regan, Assistant Professor of Biological Sciences, Université de Montréal
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/170985
2021-11-03T16:44:45Z
2021-11-03T16:44:45Z
Why the fate of our planet’s environment depends on the state of its soil
<figure><img src="https://images.theconversation.com/files/429947/original/file-20211103-13-1x2dcvw.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C1276%2C848&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many of our planet's ecosystems depend on the health of soil.</span> <span class="attribution"><a class="source" href="https://pixabay.com/photos/greenhouse-planting-spring-beds-6226263/">Katya_Ershova/Pixabay</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>In 1937, Franklin Roosevelt, then president of the US, wrote to state governors in the wake of the “<a href="https://www.history.com/topics/great-depression/dust-bowl">dust bowl</a>” catastrophe, where drought across the <a href="https://www.drought.gov/dews/southern-plains">Southern Plains</a> led to catastrophic famine and dust storms. “The nation that destroys its soils destroys itself,” he wrote, highlighting what remains a fundamental truth: that the state of the Earth’s soil is a vital indicator of the planet’s health.</p>
<p>As a society, we do not place <a href="https://www.pnas.org/content/113/22/6105">sufficient value</a> on the ground beneath our feet. The use of the word “dirt” to denote inferiority is an example of this disrespect for our land. Yet societies succeed and fail as a direct <a href="https://digitalcommons.pepperdine.edu/cgi/viewcontent.cgi?article=1019&context=globaltides">consequence</a> of the value they place on their soils.</p>
<p>Our soil not only directly or indirectly provides most of our food, but it’s also central to our planet’s life-support system. Soil is an integral component of the <a href="https://theconversation.com/carbon-catch-22-the-pollution-in-our-soil-78718">carbon</a>, water and nutrient cycles, which allow organisms of all sizes to to thrive.</p>
<p>When plants and animals decompose, their bodies release nutrients into the soil for subsequent generations of organisms to use and recycle. Soils store, filter and purify our water, helping to protect against <a href="https://www.eea.europa.eu/highlights/forests-can-help-prevent-floods">flash flooding</a> through absorbing rainwater. And soils are critical for <a href="https://news.climate.columbia.edu/2018/02/21/can-soil-help-combat-climate-change/">carbon storage</a>, helping buffer our climate against the effects of human-driven carbon emissions. There is an estimated <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev.earth.35.031306.140057">three times</a> more carbon in our soils than in Earth’s atmosphere.</p>
<p>But these ecosystem services are fragile and can easily break down. By mistreating soil through <a href="https://ec.europa.eu/environment/integration/research/newsalert/pdf/14si5_en.pdf">deep ploughing</a> (which damages soil structure) and using <a href="https://www.fao.org/3/a0100e/a0100e0d.htm">harsh chemicals</a> (which kill important microbe communities), many of our soils are now degraded. It’s estimated that <a href="https://www.theguardian.com/environment/2015/dec/02/arable-land-soil-food-security-shortage#:%7E:text=5%20years%20old-,Earth%20has%20lost%20a%20third%20of%20arable,past%2040%20years%2C%20scientists%20say&text=The%20world%20has%20lost%20a,food%20soars%2C%20scientists%20have%20warned.">one-third</a> of our agricultural soils have been lost over the past 40 years.</p>
<p>This reduces our ability to produce high-quality food. Soils in poor condition can require more fertiliser, since they cannot trap nitrogen and phosphorus. Manufacturing nitrogen fertiliser to make up for this is a significant source of carbon emissions: nearly <a href="https://www.nature.com/articles/nplants201712">600g of CO₂</a> is produced in making an 800g loaf of bread, with 43% of these emissions arising from nitrogen fertiliser alone.</p>
<figure class="align-center ">
<img alt="A tractor ploughs a field" src="https://images.theconversation.com/files/430011/original/file-20211103-13-o0ft6e.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/430011/original/file-20211103-13-o0ft6e.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=606&fit=crop&dpr=1 600w, https://images.theconversation.com/files/430011/original/file-20211103-13-o0ft6e.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=606&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/430011/original/file-20211103-13-o0ft6e.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=606&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/430011/original/file-20211103-13-o0ft6e.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=761&fit=crop&dpr=1 754w, https://images.theconversation.com/files/430011/original/file-20211103-13-o0ft6e.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=761&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/430011/original/file-20211103-13-o0ft6e.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=761&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Deep ploughing disturbs the natural composition of soil and the organisms that inhabit it, leaving it vulnerable to erosion.</span>
<span class="attribution"><a class="source" href="https://pixabay.com/photos/gerridae-guerrido-aquatic-insect-1415382/">MemoryCatcher/Pixabay</a></span>
</figcaption>
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<p>On top of this, degradation can also lead to soils releasing their stored carbon as CO₂, amplifying the climate crisis. In 2015, when I spoke at the UN climate change conference <a href="https://www.fao.org/global-soil-partnership/resources/events/detail/en/c/330852/">COP21</a> in Paris, I warned of impending disaster if we don’t protect our soils from degradation with techniques which reduce soil erosion, such as planting cover crops. </p>
<p>At that time, I was <a href="https://digitalmedia.sheffield.ac.uk/media/Bright+Minds++-+Food+Sustainability/1_wei1otk8/199532763">described</a> as a “peddler of university disaster pornography” by climate change deniers. But my testimony was not some fanciful prediction. As studying the dust bowl reminds us, the <a href="https://www.pbs.org/kenburns/the-dust-bowl/legacy">repercussions</a> of soil degradation are still being felt today. </p>
<h2>Degradation</h2>
<p>Across the UK, soils have been degraded due to intensive agriculture, leaving them vulnerable to erosion by extreme weather. In the spring of 2014, when heavy rainfall across the UK saturated land, degraded soils were unable to store water, leading to <a href="https://www.theguardian.com/environment/2014/feb/11/englands-floods-everything-you-need-to-know">widespread flooding</a> and soil erosion. That month, the Earth observation centre <a href="https://www.neodaas.ac.uk/">NEODAAS</a> in Plymouth released a satellite image of the UK “<a href="https://ntplanning.wordpress.com/2018/06/13/taking-the-initiative-to-deliver-soil-health-for-uk-agricultural-soils/">bleeding</a>” its soils into the ocean. </p>
<p>We understand why this happens. Ploughing breaks down conglomerations of inorganic soil particles such as clay and sand, bound together by <a href="https://www.sare.org/publications/building-soils-for-better-crops/what-is-organic-matter-and-why-is-it-so-important/">organic material</a> such as dead roots, fungal filaments and bacterial and earthworm secretions. These store organic carbon and build soil structure. Without them, soils wash out more easily into our rivers and estuaries. </p>
<figure class="align-center ">
<img alt="An earthworm on moss" src="https://images.theconversation.com/files/429950/original/file-20211103-18-1s1naob.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/429950/original/file-20211103-18-1s1naob.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/429950/original/file-20211103-18-1s1naob.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/429950/original/file-20211103-18-1s1naob.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/429950/original/file-20211103-18-1s1naob.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/429950/original/file-20211103-18-1s1naob.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/429950/original/file-20211103-18-1s1naob.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Organisms such as earthworms contribute to soil health, but are negatively affected by fertilisers and ploughing.</span>
<span class="attribution"><a class="source" href="https://pixabay.com/photos/earthworms-the-frog-s-perspective-2773457/">Catarina132/Pixabay</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Recent research at the universities of Sheffield, York and Leeds has shown how we might fix this problem: by using no or shallow ploughing, rotating land used for farming, and planting cover crops, all of which allow our soils to <a href="https://eprints.whiterose.ac.uk/172056/">rest and recover</a>. Coupled with limiting fertilisers, this allows populations of beneficial soil organisms like earthworms, fungi and bacteria to increase. </p>
<h2>Regeneration</h2>
<p>This evidence supports growing calls to embrace <a href="https://www.climaterealityproject.org/blog/what-regenerative-agriculture">regenerative agriculture</a>, which calls for supporting – rather than fighting – biodiversity within the agricultural landscape. </p>
<p>In South America, for example, the popular method of “slash, burn and move on” agriculture – where forests are felled, burned to release nutrients and then farmed until those nutrients are depleted – has been criticised for its destruction of biodiversity. In contrast, regenerative agriculture’s focus on increasing biodiversity has been shown to be a <a href="https://www.nature.org/en-us/about-us/where-we-work/latin-america/stories-in-latin-america/transforming-agriculture-to-unleash-the-regenerative-power-of-na/">success</a> in terms of protecting and even increasing soil health in the region. </p>
<figure class="align-center ">
<img alt="Plants grow in an urban greenhouse" src="https://images.theconversation.com/files/429951/original/file-20211103-27-1mq8oto.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/429951/original/file-20211103-27-1mq8oto.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/429951/original/file-20211103-27-1mq8oto.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/429951/original/file-20211103-27-1mq8oto.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/429951/original/file-20211103-27-1mq8oto.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/429951/original/file-20211103-27-1mq8oto.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/429951/original/file-20211103-27-1mq8oto.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Growing food in urban spaces could help protect our planet’s remaining arable land and feed rising populations.</span>
<span class="attribution"><a class="source" href="https://pixabay.com/photos/greenhouse-agriculture-farm-3247181/">WiselyWoven/Pixabay</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Part of regenerative agriculture involves taking pressure off our soils, which might appear tricky in light of the need to feed a growing global population. <a href="https://www.sheffield.ac.uk/sustainable-food">Our research</a> has shown that producing more food in the <a href="https://www.sciencedaily.com/releases/2020/03/200317130713.htm">urban environment</a> could help achieve this.</p>
<p>Crops can be grown in <a href="https://www.telegraph.co.uk/news/2020/03/19/cities-should-grow-fruit-vegetables-roadside-verges-study-claims/">crowded cities</a> using highly efficient hydroponic systems, which use less water, less fertiliser and require no soil. These can operate on top of flat-roofed buildings – or even in <a href="https://www.youtube.com/watch?v=5TP65QA3Vhc&ab_channel=WorldFoodForum">refugee camps</a>, where farming enhances food security and community resilience. By growing crops close to where people live, we can remove the need to ship food around the globe, making our food systems much more sustainable.</p>
<p><a href="https://www.fao.org/3/cb3808en/cb3808en.pdf">Almost 20%</a> of greenhouse gas emissions currently arise from agriculture: meaning that carbon is effectively leaking out of our soils across the world. That means we urgently need to embrace technologies that take a soil-centric view of food production if we are to leave a functional agricultural ecosystem for future generations.</p><img src="https://counter.theconversation.com/content/170985/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duncan Cameron receives funding from BBSRC, NERC and the Royal Society.</span></em></p>
If we want to reduce carbon emissions and preserve planetary ecosystems, we need to protect our soils.
Duncan Cameron, Professor of Plant and Soil Biology, University of Sheffield
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/159067
2021-04-23T16:11:56Z
2021-04-23T16:11:56Z
Why the humble legume could be the answer to Europe’s fertiliser addiction
<figure><img src="https://images.theconversation.com/files/396801/original/file-20210423-17-z40fft.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5628%2C3757&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An assortment of legumes.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/variety-legumes-glass-jars-zero-waste-1426134863">Morinka/Shutterstock</a></span></figcaption></figure><p>Peas, lentils, chickpeas, beans and peanuts: if it comes in a pod then chances are it’s a legume. These unassuming food crops have a special ability that makes them fairly unique in the plant kingdom. </p>
<p>They can convert nitrogen gas – which is abundant in the air – to something altogether more rare and important to plants: ammonia. Ammonia can be immediately converted to proteins within a plant, helping it grow. That’s why legume crops don’t need nitrogen fertiliser, and they even leave some of the nitrogen they produce in the soil for other plants to use.</p>
<p>Most modern farms add nitrogen to fields in synthetic fertilisers. Since the 1960s, annual nitrogen fertiliser production worldwide has increased by a staggering 458%, boosting cereal production in Europe to <a href="http://www.fao.org/faostat/en/#data/QC">more than 188 million tonnes</a> a year. At best, <a href="https://www.mdpi.com/2071-1050/13/4/2400">half of the nitrogen</a> fertiliser applied to farmland will be taken up and used by the crop. Much of the remainder is lost to the atmosphere, often in the form of nitrous oxide – a greenhouse gas <a href="https://www.epa.gov/ghgemissions/overview-greenhouse-gases">300 times more potent</a> than CO₂. Some of it leaches into freshwater stored deep underground, predominantly as nitrate.</p>
<p>The <a href="http://www.nine-esf.org/node/204/ENA.html">most comprehensive study</a> to date found that in the early 2000s, nitrate pollution in drinking water had shortened the lifespan of the average European by six months by promoting conditions such as <a href="https://www.healthline.com/health/methemoglobinemia#acquired-methemoglobinemia">methemoglobinemia</a>, <a href="https://www.tandfonline.com/doi/full/10.1080/09603123.2020.1815664">thyroid disorders</a>, and <a href="https://iwaponline.com/jwh/article/15/4/602/28585/The-risk-of-cancer-as-a-result-of-elevated-levels">gastric cancer</a>.</p>
<p>Globally, <a href="https://theconversation.com/global-food-system-emissions-alone-threaten-warming-beyond-1-5-c-but-we-can-act-now-to-stop-it-149312">nitrous oxide emissions</a> from fertilisers and methane from livestock contribute most of agriculture’s greenhouse gases – a sector responsible for <a href="https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data">about a quarter</a> of all human activity’s planet-warming gases. The EU has set itself <a href="https://ec.europa.eu/info/strategy/priorities-2019-2024/european-green-deal_en">a 2030 target</a> for reducing agricultural greenhouse gas emissions and chemical pesticide use by 50%, and synthetic fertiliser use by 20%. </p>
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Read more:
<a href="https://theconversation.com/global-food-system-emissions-alone-threaten-warming-beyond-1-5-c-but-we-can-act-now-to-stop-it-149312">Global food system emissions alone threaten warming beyond 1.5°C – but we can act now to stop it</a>
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<p>Sometimes, the simplest solution is the best one. By reintroducing an age-old system of growing legumes in rotation with other crops, farms could slash the amount of fertiliser they use while producing nutritious and wildlife-friendly food.</p>
<h2>The wonder crop</h2>
<p><a href="https://doi.org/10.3389/fsufs.2021.656005">In a recent study</a>, we found that using legumes in conventional cereal crop rotations can deliver the same amount of nutrition but at a markedly lower environmental cost. That’s because some of the nitrogen that cereal crops need is provided by the previous year’s cropping of legumes on the same field.</p>
<p>As grain legumes such as beans, peas and lentils have more protein and fibre by weight than cereal crops such as wheat, barley and oats, we calculated that an average cereal farm in Scotland could grow a legume crop for one year in a five-year cycle and reduce the amount of nitrogen fertiliser needed over the entire rotation cycle by nearly 50%, while producing the same nutritional output.</p>
<p>By using substantially less fertiliser, greenhouse gas emissions would be expected to fall by as much as 43% over the same period. Grain legumes can also be used as animal feed along with cereals – providing more digestible protein at lower environmental cost.</p>
<p>Scientists only discovered the process by which legumes take nitrogen from the air in the late 19th century, nearly a hundred years after they discovered elemental nitrogen. Special tissues on the roots of legume plants provide a safe haven for thousands of nitrogen-fixing bacteria. In return for a steady supply of sugars, which the legume generates in its leaves using photosynthesis, these bacteria provide ample nitrogen in a form that’s most useful for plant growth. </p>
<p>After the crop is harvested, the legume residues decompose and deliver the useful nitrogen to the soil so that other plants can use it. These crops even work as green manure, by ploughing the still growing plants into the soil to give it more nitrogen.</p>
<figure class="align-center ">
<img alt="Rows of peanut crops." src="https://images.theconversation.com/files/396803/original/file-20210423-17-1jg5ihs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/396803/original/file-20210423-17-1jg5ihs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/396803/original/file-20210423-17-1jg5ihs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/396803/original/file-20210423-17-1jg5ihs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/396803/original/file-20210423-17-1jg5ihs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/396803/original/file-20210423-17-1jg5ihs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/396803/original/file-20210423-17-1jg5ihs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Peanuts – not just a tasty snack.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/peanuts-field-lush-growth-1110101516">Zhengzaishuru/Shutterstock</a></span>
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<p>But legumes crops offer many more benefits beyond reducing how much farms rely on fertiliser. Diversifying crop rotations with legumes can reduce the incidence of cereal pests and disease by cutting off their life cycle between years and reducing the need for pesticides. </p>
<p>By virtue of their deep roots, many legumes are also more resistant to drought than conventional crops. Legume flowers provide an <a href="https://www.kew.org/read-and-watch/pollen-and-pollinators-legumes#:%7E:text=Most%20legumes%20are%20pollinated%20by,of%20remote%20or%20inaccessible%20species.">excellent source</a> of nectar and pollen for pollinating insects too, and consuming more legumes in the human diet offers a wide variety of health benefits.</p>
<p>Despite all these positives, legumes are not widely cultivated in Europe, covering only 1.5% of European arable land, compared to <a href="https://www.sciencedirect.com/science/article/pii/S0065211317300202">14.5% worldwide</a>. In fact, Europe imports a lot of its protein-rich crops from South America, where booming demand for soya beans is <a href="https://theconversation.com/demand-for-meat-is-driving-deforestation-in-brazil-changing-the-soy-industry-could-stop-it-151060">driving deforestation</a>. It’s high time farmers in Europe restored these wonder crops to their fields – for less pollution and more nutritious food.</p><img src="https://counter.theconversation.com/content/159067/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Williams receives funding from the TRUE project, funded by the EU Framework Programme for Research and Innovation H2020, Grant Agreement number 727973.</span></em></p><p class="fine-print"><em><span>David Styles receives funding from the TRUE project, funded by the EU Framework Programme for Research and Innovation H2020, Grant Agreement number 727973.</span></em></p><p class="fine-print"><em><span>Marcela Porto Costa receives funding from the TRUE project, funded by the EU Framework Programme for Research and Innovation H2020, Grant Agreement number 727973.</span></em></p>
Legumes have a superpower: they can convert nitrogen in the air into a form plants can use to grow.
Michael Williams, Assistant Professor of Botany, Trinity College Dublin
David Styles, Lecturer in Carbon Footprinting, Bangor University
Marcela Porto Costa, PhD Candidate in Sustainable Agriculture, Bangor University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/158555
2021-04-19T14:52:10Z
2021-04-19T14:52:10Z
Revealed: true cost of Britain’s addiction to factory-farmed chicken
<p>The first time I encountered an intensive “chicken shed” up close I was taken aback by just how massive it was – the huge industrial-looking metal clad building was well over 100 metres long by 25 metres wide. And there wasn’t just one, there were seven of these colossal sheds, the sun glinting off their roofs and adjacent clusters of tall silos. A constant hum emanated from them and periodically a strange clattering sound, possibly of grain being sprayed automatically from a silo into a shed. </p>
<p>There was a large, immaculately clean concrete yard and an almost uncanny lack of human activity. Finally, overwhelmingly, was the all-pervading smell. The malty, almost sweetish odour became increasingly unpleasant as I stood to take in the scene, making me feel slightly sick. </p>
<p>The distinctive stink followed me as I continued down the footpath. I began to develop a headache. I felt jumpy despite being on a public right of way – should I be this close to what I knew was an intensive poultry unit? Were there biosecurity risks? </p>
<p>And when the path veered close to the building I began to actually hear the birds inside. That triggered other emotions. I knew that the chickens were on a life trajectory of a mere six weeks (eight weeks for “slow grow birds”) before they would be loaded onto lorries to be taken to the processing factory. </p>
<figure class="align-center ">
<img alt="Sun shines on multiple metal sheds by field." src="https://images.theconversation.com/files/394829/original/file-20210413-17-83dpcw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/394829/original/file-20210413-17-83dpcw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=232&fit=crop&dpr=1 600w, https://images.theconversation.com/files/394829/original/file-20210413-17-83dpcw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=232&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/394829/original/file-20210413-17-83dpcw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=232&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/394829/original/file-20210413-17-83dpcw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=292&fit=crop&dpr=1 754w, https://images.theconversation.com/files/394829/original/file-20210413-17-83dpcw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=292&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/394829/original/file-20210413-17-83dpcw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=292&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An ‘intensive poultry unit’ near the author’s home.</span>
<span class="attribution"><span class="source">© Alison Caffyn</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Later, several farmers showed me round their sheds. Inside one, I stood rather stunned at the sheer scale of the building stretching in front of me and the 45,000 chickens crowded into the space. They pecked at plastic feeders or the occasional small bale of hay providing “environmental enrichment”.</p>
<p>This is how <a href="https://www.eating-better.org/uploads/Documents/2020/EB_WeNeedToTalkAboutChicken_Feb20_A4_Final.pdf">95%</a> of the one billion chickens raised in the UK each year are grown: chicken is the country’s most popular meat and these massive sheds are why it’s so cheap.</p>
<p>The premises which produce much of the UK’s meat are relatively hidden from view. Not only do most people not want to think about how meat is raised, it is in the interests of the intensive livestock industry to keep a low profile. Many meat eaters understandably <a href="https://www.bbc.com/future/article/20190206-what-the-meat-paradox-reveals-about-moral-decision-making">tend to avoid</a> watching documentaries and reading about the horrors of factory farming. Out of sight, out of mind. The meat industry knows this too, and tries hard to keep the realities of the conditions that industrially farmed animals are kept in divorced from the product people buy in supermarkets.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-arent-we-more-outraged-about-eating-chicken-82284">Why aren't we more outraged about eating chicken?</a>
</strong>
</em>
</p>
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<p>But this article isn’t about animal welfare realities. It’s about how the poultry industry has managed to keep a low profile while undergoing a massive expansion to supply all the supermarkets and fast food chains. There has been an intensive poultry industry in the UK for over 60 years, but it has been upscaling in recent decades, becoming more like North America’s <a href="https://www.theguardian.com/environment/2017/jul/18/rise-of-mega-farms-how-the-us-model-of-intensive-farming-is-invading-the-world">mega farms</a>.</p>
<p>For the last four years, I have been investigating how <a href="https://www.sciencedirect.com/science/article/pii/S0264837721001381?via%3Dihub">intensive poultry units have been allowed to multiply</a> across certain parts of the UK. I have discovered that the poultry industry has taken advantage of weak regulatory and planning regimes in order to expand what is a very profitable business. I have traced how local people have become increasingly angry about the myriad impacts they face from the intensive chicken sheds – and how they have mobilised to fight the industry’s expansion.</p>
<h2>Chicken hub</h2>
<p>I live in Ludlow, Shropshire, close to the Herefordshire border. These two counties are at the heart of the UK’s chicken industry. My attention was first drawn to the issue in 2014, when I began to notice frequent articles and angry letters in my local papers, the Hereford Times and the Shropshire Star. The headlines read things like: “Stench from broiler units is inescapable”; “Protesters mass to fight ‘terrible’ chicken farm”. </p>
<p>Campaigns against several planning applications for what are known in the business as intensive poultry units (IPUs) had been launched in the Shropshire Hills (an Area of Outstanding Natural Beauty) and scenic and tranquil parts of Herefordshire. A significant controversy had kicked off. Some planning applications had hundreds of letters submitted objecting to the proposals. I wanted to know what had prompted the levels of outrage in an area where there has been commercial chicken farming since the 1950s, and set about researching the issue for my PhD.</p>
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<img alt="" src="https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><strong><em>This article is part of Conversation Insights</em></strong>
<br><em>The Insights team generates <a href="https://theconversation.com/uk/topics/insights-series-71218">long-form journalism</a> derived from interdisciplinary research. The team is working with academics from different backgrounds who have been engaged in projects aimed at tackling societal and scientific challenges.</em> </p>
<hr>
<p>When I began to trace the pattern of planning applications across Herefordshire and Shropshire, trawling through the records for each county, it became clear that the industry had expanded steadily over the 1990s and 2000s, with more and more farms investing in poultry and IPUs becoming progressively bigger. Where the average broiler (meat chicken) shed held 25,000 birds in 1990 and 40,000 birds in the 2000s, the new applications were for sheds to hold 50,000-55,000 birds at a time. By 2010 there were at least <a href="https://authors.elsevier.com/a/1cqhjyDvMI8sb">800 chicken sheds</a>, for meat and also many for eggs, across the two counties, which I estimate to be around 20% of the UK total.</p>
<p>I found there had been a sudden surge in applications in the early 2010s, partly as a result of supermarkets wanting to source more chicken from the UK in the wake of the <a href="https://theconversation.com/horsemeat-scandal-was-a-damning-indictment-of-the-state-of-our-food-21490">horsemeat scandal</a>. In 2013-14 for example, the huge chicken processing plants in Hereford, run by multinational <a href="https://theconversation.com/the-most-powerful-companies-youve-never-heard-of-cargill-3191">Cargill</a>, took on a new contract with Tesco to provide an additional <a href="https://www.thepoultrysite.com/news/2013/11/cargill-to-upgrade-and-enhance-uk-poultry-processing-business">million chickens a week</a>. This required a further 90 chicken sheds within an hour’s drive of the plants and many farmers were keen to become suppliers.</p>
<figure class="align-center ">
<img alt="Graph showing growing number of IPU farms in Herefordshire (orange) and Shropshire (blue)." src="https://images.theconversation.com/files/394827/original/file-20210413-17-1hvjxw9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/394827/original/file-20210413-17-1hvjxw9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=362&fit=crop&dpr=1 600w, https://images.theconversation.com/files/394827/original/file-20210413-17-1hvjxw9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=362&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/394827/original/file-20210413-17-1hvjxw9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=362&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/394827/original/file-20210413-17-1hvjxw9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=455&fit=crop&dpr=1 754w, https://images.theconversation.com/files/394827/original/file-20210413-17-1hvjxw9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=455&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/394827/original/file-20210413-17-1hvjxw9.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=455&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The number of poultry farms has been steadily rising.</span>
<span class="attribution"><span class="source">Alison Caffyn</span>, <span class="license">Author provided</span></span>
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</figure>
<p>I started to interview as many people as I could: farmers, planners, local authority and environmental agency staff, councillors, objectors, campaigners and other local businesses; and began to understand why the controversy had erupted. </p>
<h2>The pull of poultry</h2>
<p>Going into poultry is an attractive proposition for farmers. Consistently the <a href="https://www.nao.org.uk/report/early-review-of-the-new-farming-programme/">most profitable</a> UK agricultural sector, poultry provides a steady income and is not dependent on subsidy, <a href="https://fullfact.org/economy/farming-subsidies-uk/">unlike most UK farming</a>. The farmers I spoke to wanted the “certainty” that a contract with a poultry processor gave them. Several wanted to expand and create a job for a member of the next generation and to make the farm more resilient, particularly given the uncertainties over Brexit.</p>
<p>Expanding into poultry is a big investment; in the region of £2.5 million for a four shed broiler unit. But I was told farms can pay off their investment within 10-15 years and more quickly if they also installed <a href="https://www.gov.uk/non-domestic-renewable-heat-incentive">renewable energy systems</a> such as solar, biomass and anaerobic digestion (AD) units, all of which receive government subsidies. </p>
<figure class="align-center ">
<img alt="More massive chicken sheds in rural landscape." src="https://images.theconversation.com/files/394830/original/file-20210413-17-1sg3ik8.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/394830/original/file-20210413-17-1sg3ik8.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/394830/original/file-20210413-17-1sg3ik8.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/394830/original/file-20210413-17-1sg3ik8.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/394830/original/file-20210413-17-1sg3ik8.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/394830/original/file-20210413-17-1sg3ik8.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/394830/original/file-20210413-17-1sg3ik8.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Another IPU in the Shropshire hills.</span>
<span class="attribution"><span class="source">© Alison Caffyn</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>But once the system is up and running, it doesn’t require much physical effort (at least compared to traditional farming methods). The vast majority of chicken farming in the UK has joined other forms of “precision farming” that uses smart technology within an integrated system owned and organised by a processing company. </p>
<p>Day-old chicks are delivered from the hatchery. The processor (such as Cargill) provides the feed and sends in “catching gangs” and lorries to pick up the birds after six weeks. The farmer never actually owns the birds but carries the risk if more than the normal <a href="https://www.ciwf.org.uk/research/species-meat-chickens/the-welfare-of-broiler-chickens-in-the-european-union/">5%</a> die before reaching the processing plant. </p>
<p>The farmer is able to monitor the shed temperature, humidity and check on feed, water and so on on their computer or phone. All it requires is for someone to walk through each shed daily picking up the dead and sick birds. This means the intensive chicken production provides only about 1.5 workers on each average farm of four to six sheds (although some of the operations have ten or 15 sheds). A poultry farmer told me that these larger businesses can make in the region of £1 million profit a year.</p>
<p>The justifications for IPUs I heard at planning committee meetings mainly revolved around the need for affordable, healthy protein to feed the nation. The UK is <a href="https://www.fwi.co.uk/business/markets-and-trends/outlook-2018-poultry-sector-is-well-placed-for-growth">about 75%</a> self-sufficient in poultry (according to figures published by the Agriculture and Horticulture Development Board in 2018, although little recent data has been made available). Emphasis was placed on how raising chicken in the UK is better in terms of food miles and animal welfare as the UK has higher welfare regulations than in many parts of the world. </p>
<p>Farmers applying for planning permission for new units stressed the supply chain and economic benefits as well as the jobs in the processing factory. They accused objectors of being incomers to the area; “NIMBYs” or “down-from-Londoners” who didn’t understand the realities of modern farming and who had unrealistic, idyllic ideas of what rural life is like. </p>
<p>They denied the IPUs would cause any environmental problems, saying that they had to meet environmental permit standards and that the Environment Agency would address any inadvertent pollution. They denied that IPUs smell and ridiculed those who complain about agricultural smells or noises in rural areas. </p>
<p>It is true that these intensive chicken units vary considerably. There is a huge difference between the larger sites, some owned directly by the processing company, where there may be ten or more sheds and very little other farming activities, and at the other extreme small farms that have diversified into free range eggs because their beef or sheep enterprise has struggled to make a profit. But both types can be controversial. </p>
<p>(Most UK eggs are also produced in intensive units; standard free-range units house 16,000 or 32,000 hens in systems where the birds have theoretical access to the outdoors, while in contrast conventional systems may house millions of hens).</p>
<p>The surge in applications to supply Cargill in 2014 included some in particularly scenic and biodiverse environments. This created a PR disaster. Local people who had always been largely tolerant of agricultural activities felt the expansion of the poultry industry had become “something other”, as one officer described. Resistance crystallised and a range of local people began to mobilise to fight the proliferation of further poultry units.</p>
<h2>The other side of the story</h2>
<p>So were these objectors really just retired NIMBYs and ignorant townies?</p>
<p>I interviewed numerous people who objected to the IPU proposals and followed one group of campaigners that formed in a small, historic village not far from my home. The farming family who own much of the land around the village was proposing to build a new poultry site, close to residents’ houses. I attended the campaign group’s meetings in the back room of the village pub. </p>
<p>I listened to them discussing what was meant by the scientific terminology used in the various odour, noise, ecology and visual impact assessments. They became increasingly expert in understanding the planning process and the technical information used. I heard their frustrated complaints about the unfairness of the process, the profits made by the interconnected farming families and the influence such landowners had on the parish council and local planning committee.</p>
<p>There was a sense of injustice that one business could inflict such change on the local area and community. Unlike with some invasive developments such as wind turbines, electricity pylons or housing developments, there are no financial payback mechanisms which would fund community projects or facilities in recompense. I regularly heard objectors mention the fact that farmers do not even pay business rates on their poultry operations as they are deemed agricultural developments. </p>
<p>The campaign group reached out to local experts to learn more about the impacts. They learned how the ammonia gas from the chicken faeces is pumped out of sheds into the air and damages <a href="https://www.plantlife.org.uk/uk/our-work/publications/we-need-to-talk-about-nitrogen">local habitats</a> and <a href="https://www.woodlandtrust.org.uk/media/1687/ammonia-impacts-on-ancient-woodland.pdf">ancient woodland</a>, and how excess manure spreading has been found to cause illegal levels of <a href="https://consult.environment-agency.gov.uk/++preview++/environment-and-business/challenges-and-choices/user_uploads/phosphorus-pressure-rbmp-2021.pdf">pollution in local rivers</a>. I joined the group on a visit to a nearby Site of Special Scientific Interest to see breathtaking swards of orchids and other rare plants in stunning wildflower meadows – also vulnerable to cumulative ammonia emissions.</p>
<figure class="align-center ">
<img alt="Long grass and wildflowers beneath blue sky and tree." src="https://images.theconversation.com/files/395238/original/file-20210415-15-2ugi9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395238/original/file-20210415-15-2ugi9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395238/original/file-20210415-15-2ugi9w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395238/original/file-20210415-15-2ugi9w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395238/original/file-20210415-15-2ugi9w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395238/original/file-20210415-15-2ugi9w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395238/original/file-20210415-15-2ugi9w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">One of the threatened meadows.</span>
<span class="attribution"><span class="source">© Alison Caffyn</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This group was typical of the objectors I met: a mix of some people who had moved to the area to work or retire, alongside long-time residents. Some were older but there were many middle-aged people, some professionals who developed the expertise in planning processes but also many others who supplied local knowledge, contacts and who simply cared about what was changing in their local countryside and how it impacted on their families and friends. </p>
<p>I also met several farmers who objected to intensive poultry. One told a friend of mine, while contemplating his neighbour’s new IPU, “That’s not farming.” Others voiced concerns and misgivings to me, but few felt able to disrupt relations within the farming community and go on the record against other farmers. </p>
<p>While each planning application was different, there were a number of concerns consistently voiced by objectors. These were the foul smell, the visual impact of the IPU on the landscape, noise from the units and from the associated HGV traffic, road safety concerns, water pollution affecting local rivers, biodiversity loss from ammonia and that the proliferating industrial buildings would damage the local tourism industry, which was economically much more valuable to the economy of the area than agriculture.</p>
<p>One issue which tended to creep up on objectors as they researched the impacts of IPUs was the uncertainty over health impacts – the ammonia and dangerous particulates <a href="https://pubmed.ncbi.nlm.nih.gov/29133137/">in the air</a>, which can cause serious respiratory problems, the potential for spread of <a href="https://www.ciwf.org.uk/research/animal-diseases/zoonotic-diseases/">livestock-related infections</a>, whether <a href="https://amr-review.org/sites/default/files/160518_Final%20paper_with%20cover.pdf">antimicrobial resistance</a>, of which intensive animal farms are a major source, could linger in the local environment and the existential threat of a bird flu outbreak which might cross the species barrier. This particular concern has hardly lessened in the last year.</p>
<p>And yes, people were also concerned about whether a large IPU built near their house might affect the value of their property or deter future business customers. Others were vociferous about animal welfare issues or the evils of <a href="https://www.thebureauinvestigates.com/stories/2020-11-25/british-chicken-driving-deforestation-in-brazil">importing soya from South America</a> for the bird feed. But overall I found that most people had multiple concerns – for themselves, their family, their health and their finances but also for the community, other people, local businesses, plus concerns about farming systems, planning procedures, democracy and justice. </p>
<h2>Increasing awareness</h2>
<p>Clearly there are extremely polarised values and concerns involved in these arguments. Planning officers and committees have difficult decisions to make, particularly as there are almost no planning policies that govern where intensive livestock operations can be sited. There is a policy void. The repercussions of allowing intensive poultry units to proliferate have been ignored in favour of facilitating the expansion of agribusiness.</p>
<p>Local plans for both counties have almost no reference to poultry businesses despite the numbers of sheds now nearing 1,150 and the number of birds in the counties at any one time approaching 38 million <a href="https://authors.elsevier.com/a/1cqhjyDvMI8sb">in my estimate</a>. I found that the local authorities had neglected (intentionally or not) to develop supplementary planning guidance which would have clarified the situation for everyone. </p>
<p>Decisions were therefore made largely with reference to vague objectives in national planning policy such as “<a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/810197/NPPF_Feb_2019_revised.pdf">sustainable development</a>” and boosting rural economies, and over 95% of applications between 2000 and 2020 were given permission. I found that the planning committees have been dominated by local politicians who are embedded in local agricultural networks and tend to accept the farming lobby’s arguments or be cowed by the dominance of major economic actors such as Cargill.</p>
<p>The application the group I followed were fighting, like most others, was approved. But the campaigners did not give up. There is no third party right of appeal in the UK so they could not challenge the decision directly, but they applied for, and secured, a judicial review of the decision-making process. At this point the county council ceded the case, accepting that they had made errors when assessing some of the likely impacts of the IPU. This has happened in several <a href="https://www.crowdjustice.com/case/help-stop-industrial-chicken-f/">cases</a> now. Local communities have lost trust in the planning system and local authorities’ <a href="https://www.shropshirestar.com/news/farming/2019/05/29/planning-consent-for-poultry-farm-near-bridgnorth-is-quashed-by-judges/">ability to make sound decisions</a>. </p>
<p>Ultimately, Cargill (now a joint venture renamed Avara) succeeded in having its 90 additional sheds built, although it took much longer than anticipated and there were many battles along the way. In the process, local awareness about the range of cumulative negative impacts has been raised. In Herefordshire, the increased nutrient pollution and algal blooms in the rivers Wye and Lugg has finally woken up the council to the links with <a href="https://www.herefordtimes.com/news/18503597.river-wye-turns-green-amid-chicken-farm-manure-claims/">vastly increased amounts</a> of poultry manure being spread on agricultural land.</p>
<p>In Shropshire, concerns over ammonia pollution of protected habitats now mean recent applications for IPUs must include technical fixes, such as expensive <a href="https://shropshire.gov.uk/environment/biodiversity-ecology-and-planning/new-interim-guidance-for-livestock-unit-lsu-applications/">ammonia scrubbers</a>. There is a better understanding of how local people, communities, environments and tax payers are paying the true costs of the <a href="https://sustainablefoodtrust.org/articles/hidden-cost-uk-food/">externalities</a> from the poultry industry, which avoids picking up the bill.</p>
<p>The situation also raises broader questions such as whether intensive livestock operations should be treated in planning law as agriculture or industry. The scale, intensity and impacts have changed dramatically since the last relevant planning act in 1990. One councillor told me: “If these sheds were producing spring coils they wouldn’t be allowed. They’d be encouraged to go to enterprise zones and business parks, but because this is, in policy terms, deemed to be agriculture, that’s a real problem.”</p>
<p>What this all brings home is the wildly unnatural price of chicken in the UK. Why can you buy a whole chicken at Tesco for under £3? The actual, but largely hidden, costs associated with the production of cheap chicken are not passed on to consumers. Neither are they paid by the owners of multinational meat processing conglomerates, Tesco shareholders or poultry farmers. </p>
<p>The costs are being paid by local communities and environments in the damage to the landscape, air and water pollution and quality of life. They are also being paid by the taxpayer, in terms of health costs or pollution clean-up costs, or renewable energy subsidy costs. </p>
<p>Chicken is viewed as a healthy and convenient source of protein, but there are other more sustainable, cheaper and healthier protein options which could also be grown in the UK. These include peas, beans, nuts and lentils, some of which have the advantage of fixing nitrogen in the soil rather than increasing nutrients in the environment. People could substitute such plant-based protein for chicken in many meals.</p>
<p>So don’t wince when you see the price of chickens raised in better conditions – there are many reasons it’s more expensive and it’s not just the better environment the animals experience. You’ll be paying farmers who resist the dominance of multinational agri-industry and who are inflicting less harm on rural communities and localities. </p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=112&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=112&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=112&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=140&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=140&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=140&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>For you: more from our <a href="https://theconversation.com/uk/topics/insights-series-71218?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Insights series</a>:</em></p>
<ul>
<li><p><em><a href="https://theconversation.com/how-we-discovered-a-hidden-world-of-fungi-inside-the-worlds-biggest-seed-bank-156051?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">How we discovered a hidden world of fungi inside the world’s biggest seed bank</a></em></p></li>
<li><p><em><a href="https://theconversation.com/rewilding-rare-birds-return-when-livestock-grazing-has-stopped-137948?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Rewilding: rare birds return when livestock grazing has stopped</a></em></p></li>
<li><p><em><a href="https://theconversation.com/for-a-sustainable-future-we-need-to-reconnect-with-what-were-eating-and-each-other-123490?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">For a sustainable future, we need to reconnect with what we’re eating – and each other</a></em></p></li>
</ul>
<p><em>To hear about new Insights articles, join the hundreds of thousands of people who value The Conversation’s evidence-based news. <a href="https://theconversation.com/uk/newsletters/the-daily-newsletter-2?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK"><strong>Subscribe to our newsletter</strong></a>.</em></p><img src="https://counter.theconversation.com/content/158555/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alison Caffyn received grant funding from the Economic Social Research Council. </span></em></p>
A lack of policy has allowed industrial chicken farms to multiply in certain parts of the UK – with a lack of consideration of the environmental and social impacts.
Alison Caffyn, Research Affiliate, Geography and Planning, Cardiff University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/158100
2021-04-16T14:43:52Z
2021-04-16T14:43:52Z
UK land now stores 7% more carbon than 300 years ago – what that means for the environment
<figure><img src="https://images.theconversation.com/files/395460/original/file-20210416-23-qpwjh5.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6720%2C4466&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/golden-sunset-sunrise-light-on-lone-1938816559">Stephen Bridger/Shutterstock</a></span></figcaption></figure><p>Limiting global warming to 1.5°C and avoiding the worst effects of climate change will take more than eliminating greenhouse gas emissions. The world will also need to capture and store a lot of carbon dioxide (CO₂) from the atmosphere. </p>
<p>Land offers one natural way of doing this. The soil and everything that grows in it, including all plants and trees, represents <a href="https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter06_FINAL.pdf">about half of all</a> organic carbon globally. This is the carbon that’s bound up in living and decaying matter, as opposed to rocks and minerals. Depending on how humans treat it, the land can act as a net sink or source of carbon, either slowing or accelerating climate change. Planting trees can lock carbon away while deforestation and tilling the soil in agriculture can release it. </p>
<p>Since the dawn of the Industrial Revolution, the UK has emitted about <a href="https://ourworldindata.org/co2/country/united-kingdom?country=%7EGBR">77 billion tonnes of CO₂</a>. But how much has the country’s land area absorbed over the same period? <a href="https://www.sciencedirect.com/science/article/pii/S2213305421000126#bib0030">Our new study</a> set out to find an estimate by modelling natural cycles of carbon, nitrogen and phosphorus. </p>
<p>We found that over the last 300 years, the UK’s land carbon store has grown by about 7%, with vegetation storing 13% more carbon and soil 5% more than it did in the 18th century. Carbon storage increased most in forests and heathlands, and fell by the greatest amount in areas which were converted to arable farmland. </p>
<p>So the UK’s land carbon sink is working harder today than it was three centuries ago. Is that a good thing? As it turns out, not really. </p>
<h2>Right direction, wrong reason</h2>
<p>Since 1700, land carbon storage in the UK has increased by 233 million tonnes. That’s equivalent to 855 million tonnes of CO₂. The UK is one of the world’s largest historical emitters of carbon, so this only equates to 1.1% of the nation’s estimated emissions over the same period. But there’s a bigger problem: land-based carbon stores in the UK are unlikely to continue growing in the future for several reasons. </p>
<p>The biggest driver of the increase was pollution. When fertilisers are used in agriculture or fossil fuels are burned, these processes release reactive forms of nitrogen into the atmosphere. This is deposited on the land when it rains. </p>
<p>Since the availability of nitrogen normally limits how much plants can grow, this additional nitrogen <a href="https://theconversation.com/carbon-catch-22-the-pollution-in-our-soil-78718">acts like extra fertiliser</a>, boosting the amount of carbon that vegetation can capture. More leaf and plant litter is produced, which rots and delivers carbon to the soil.</p>
<p>But areas which were converted to farmland showed steep declines in the size of their carbon stores. When land is cleared of vegetation, the carbon stored in it is lost. Even though farmers add more nitrogen to arable land through fertilisers, the crop plants that grow are harvested, and so their carbon doesn’t end up stored in the soil.</p>
<p>The net increase in the carbon that the UK’s land is storing came from the gains across natural habitats fertilised by nitrogen. These were only slightly larger than the carbon losses from land converted for agriculture. And plants won’t continue to respond to all the extra nitrogen from atmospheric pollution forever. Other factors, such as sunlight, or the availability of phosphorus and other important nutrients, will come into play and limit growth, restricting how much more carbon can be stored in vegetation. </p>
<p>To keep the land soaking up carbon this way, we’d need to continue releasing nitrogen into the atmosphere by burning fossil fuels and applying fertilisers to crops at the current rate. This isn’t a good solution. All that nitrogen seeps into waterways where it can deplete oxygen and kill aquatic wildlife. It also contributes to <a href="https://doi.org/10.1016/j.envpol.2021.117017">plant biodiversity loss</a>, as few plant species are adapted to cope with the extra nitrogen, which also increases the acidity of the soil.</p>
<p>Soil on arable farmland is still losing carbon, while gains in natural habitats are slowing. If these trends continue, the small net gain in carbon storage that we’ve observed across the UK since the 18th century could be reversed.</p>
<figure class="align-center ">
<img alt="Gnarled oak trees grow out of mossy boulders." src="https://images.theconversation.com/files/395459/original/file-20210416-19-oz8sj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395459/original/file-20210416-19-oz8sj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395459/original/file-20210416-19-oz8sj1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395459/original/file-20210416-19-oz8sj1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395459/original/file-20210416-19-oz8sj1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395459/original/file-20210416-19-oz8sj1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395459/original/file-20210416-19-oz8sj1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A recent report suggested that just 7% of the UK’s woodlands are in a good condition.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/ancient-gnarled-stunted-oak-tree-trunks-213662014">Helen Hotson/Shutterstock</a></span>
</figcaption>
</figure>
<p>Continuing to pollute just to maintain this thin advantage is not an option. But the news isn’t all bad. Changing the way people manage the land by reducing or preventing soil tillage, switching crops grown regularly and adding ones which can fix nitrogen like legumes and using manure-based fertilisers that add organic matter can <a href="https://www.4p1000.org/">sequester carbon in agricultural soils</a>.</p>
<p>Housing, food and energy production: the demands on the world’s land are high, but they’re particularly acute in a small country like the UK. Practices like <a href="https://theconversation.com/britain-needs-to-grow-more-trees-are-sheep-farms-the-answer-145872">rewilding</a> – where land ecosystems are allowed to naturally regenerate – can help permanently shift more carbon into the land without polluting the environment. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-crisis-the-countryside-could-be-our-greatest-ally-if-we-can-reform-farming-126304">Climate crisis: the countryside could be our greatest ally – if we can reform farming</a>
</strong>
</em>
</p>
<hr>
<p>The country has a long way to go to meet its 2050 net zero emissions target, but taking better care of the UK’s soil is a critical first step.</p><img src="https://counter.theconversation.com/content/158100/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jess Davies receives funding from UKRI, Defra and the EU Commission. </span></em></p><p class="fine-print"><em><span>Victoria Janes-Bassett does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Scientists need to know how much we can rely on the land to offset our emissions.
Victoria Janes-Bassett, Senior Research Associate in Sustainable Land Management, Lancaster University
Jess Davies, Chair Professor in Sustainability, Lancaster University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/158995
2021-04-15T20:23:10Z
2021-04-15T20:23:10Z
As extreme fires transform Alaska’s boreal forest, deciduous trees put a brake on carbon loss and how fast the forest burns
<figure><img src="https://images.theconversation.com/files/395019/original/file-20210414-19-8bk5bx.jpg?ixlib=rb-1.1.0&rect=0%2C17%2C3834%2C2535&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A helicopter drops water on a forest fire in Alaska.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/thenationalguard/48233324007/">Michael Risinger/U.S. Army National Guard</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Fire is a hot topic these days, particularly when it comes to the boreal forest, the vast expanse of trees that stretches across Alaska, Canada and other cold northern regions. <a href="https://doi.org/10.1029/2006GL025677">Large fires</a> have been <a href="https://doi.org/10.1073/pnas.1305069110">burning more frequently and severely</a> in these remote landscapes, driven by <a href="https://doi.org/10.1111/ecog.02205">longer seasons of hot, dry weather</a> and <a href="https://doi.org/10.1038/nclimate3329">more lightning strikes</a> as the climate warms. </p>
<p>As forests burn, they <a href="https://doi.org/10.1111/gcb.14287">release organic carbon</a> that has accumulated in tree trunks, leaves and roots and in soils. This sets up a potentially dangerous climate feedback loop: More fires release more carbon from the land, which further exacerbates global warming, which means more hot, dry weather that can fuel more fire activity.</p>
<p>It’s enough to keep scientists like ourselves awake at night. However, <a href="https://science.sciencemag.org/content/372/6539/280">new results</a> from our research team published in the journal Science on April 15, 2021, suggest there may be a natural brake on the system.</p>
<p>We found that when black spruce forests that had recently burned in interior Alaska began regrowing, <a href="https://doi.org/10.1111/j.1365-2486.2009.02051.x">more aspen and birch</a> trees were mixed in with the spruce. In fact, broadleaf deciduous trees like these were becoming the dominant species.</p>
<p>This has two important effects when it comes to climate change and wildfires: The deciduous trees store more carbon, and they don’t burn as quickly or a severely as dry, resinous black spruces and their needles do.</p>
<p>The result is that these changing forests could mitigate the fire-climate feedback loop, and maybe even reverse it – at least for now.</p>
<figure class="align-center ">
<img alt="A river runs through a forest of yellow broadleaf trees with spruce mixed in." src="https://images.theconversation.com/files/395147/original/file-20210414-13-1hwt0i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395147/original/file-20210414-13-1hwt0i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395147/original/file-20210414-13-1hwt0i5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395147/original/file-20210414-13-1hwt0i5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395147/original/file-20210414-13-1hwt0i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395147/original/file-20210414-13-1hwt0i5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395147/original/file-20210414-13-1hwt0i5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Deciduous forests have been taking over historic black spruce forests in Alaska after severe fires.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/paxson_woelber/29758817875">Paxson Woelber/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Deciduous trees take over</h2>
<p>When severe fires in black spruce forests <a href="https://doi.org/10.1038/ngeo1027">burn deep into the soil organic layer</a>, more carbon is lost during the blaze. But something else happens as well: Instead of spruce trees regrowing after these severe fires, they are often replaced by deciduous broadleaf trees that make up for that carbon loss when they regrow.</p>
<p>Severely burned black spruce stands, or groups of trees, lose the most carbon during a fire, but once these forests transition to aspen and birch, they store carbon at a rate that is four times faster than in similarly aged black spruce stands. By 50 years, they have compensated for fire-driven carbon losses.</p>
<p>By the time deciduous forests are 100 years old, the typical interval between burns in this region, <a href="https://doi.org/10.1126/science.abf3903">carbon pools are 1.6 times larger</a> than in black spruce forests, according to our calculations. The net effect is an increase in stored carbon that more than compensates for the increased carbon lost during the previous fire. </p>
<p><iframe id="6orkR" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/6orkR/4/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<figure class="align-center ">
<img alt="Illustration of forests and carbon storage above and below ground" src="https://images.theconversation.com/files/395361/original/file-20210415-18-1sc6u03.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395361/original/file-20210415-18-1sc6u03.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=459&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395361/original/file-20210415-18-1sc6u03.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=459&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395361/original/file-20210415-18-1sc6u03.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=459&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395361/original/file-20210415-18-1sc6u03.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=577&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395361/original/file-20210415-18-1sc6u03.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=577&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395361/original/file-20210415-18-1sc6u03.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=577&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Deciduous forests store more carbon above ground, while spruce forests store more in the soil.</span>
<span class="attribution"><a class="source" href="https://nau.edu/nau-research/category/ecosystem-science-and-society/">Victor O. Leshyk, Center for Ecosystem Science and Society, Northern Arizona University</a></span>
</figcaption>
</figure>
<p>Most of the carbon stored in deciduous stands is in the trees’ biomass above ground – woody trunks and branches – not in soils like in spruce stands. This is because trees like birch and aspen grow much more rapidly than spruce and are more effective at cycling nutrients and sequestering carbon in wood.</p>
<h2>15 years of changing forests</h2>
<p>Our research began over 15 years ago, when <a href="https://doi.org/10.1007/s00704-010-0357-9">an intense fire season in 2004</a> burned a record 6.7 million acres across Alaska.</p>
<p>We suspected then that the worsening fires carried the <a href="https://doi.org/10.1093/biosci/biz088">fingerprint of contemporary climate change</a>, and we wondered what it might mean for patterns of forest recovery.</p>
<figure class="align-right ">
<img alt="Map showing boreal forest regions" src="https://images.theconversation.com/files/395146/original/file-20210414-17-1im7ab2.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/395146/original/file-20210414-17-1im7ab2.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395146/original/file-20210414-17-1im7ab2.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395146/original/file-20210414-17-1im7ab2.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395146/original/file-20210414-17-1im7ab2.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395146/original/file-20210414-17-1im7ab2.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395146/original/file-20210414-17-1im7ab2.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Boreal forests stretch across Alaska and Canada, Europe and Russia.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Boreal_forest_of_Canada#/media/File:Taiga_ecoregion.png">Wikimedia/Mark Baldwin-Smith</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>After the fires, we established a broad network of research sites in burned black spruce forests across the region. In each, we measured the amount of carbon in the ecosystems as they recovered. </p>
<p>We discovered that recent fires had burned deeper into the soil, <a href="https://doi.org/10.1111/j.1365-2486.2009.02051.x">disrupting the relatively shallow burn patterns</a> that had allowed black spruce to dominate the landscape. The severe burning resulted from the warmer climate and consequently drier, more flammable fuels. Once deciduous seedlings become established after a fire, they quickly dominate the forest canopy.</p>
<p>It is still too early to know how widespread these changes may be, but recent <a href="https://www.doi.org/10.1111/gcb.14804">estimates from remote sensing</a> suggest that deciduous forests could replace conifer forests at a rate as high as 5% per decade, mostly due to fire.</p>
<p><iframe id="8puLy" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/8puLy/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p><a href="https://science.sciencemag.org/content/372/6539/280">Putting all those pieces together</a>, we now understand that such rapid shifts in forest composition and their effects on carbon storage patterns could shape the long-term feedback loops between boreal forests and the Earth’s atmosphere.</p>
<h2>Less flammable trees, but that may not last</h2>
<p>There’s more to the story about the potential for deciduous trees to mitigate fire and climate feedbacks in the boreal forest.</p>
<p>Importantly, wildfire studies indicate deciduous broadleaf forests often <a href="https://doi.org/10.1007/s10021-011-9474-2">burn less easily</a> when a fire ignites, and fires in deciduous forests are more easily put out by rainfall or human efforts. Although not immune to fire, aspen stands burn more slowly and less severely than black spruce stands, which have dry, resinous and highly flammable fuels. </p>
<p>The result is that more deciduous stands across boreal forests are likely to translate into smaller, less severe fires.</p>
<figure class="align-center ">
<img alt="View of a burning forest from a helicopter with a soldier sitting in the open helicopter door" src="https://images.theconversation.com/files/395148/original/file-20210414-17-1tdu17p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/395148/original/file-20210414-17-1tdu17p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/395148/original/file-20210414-17-1tdu17p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/395148/original/file-20210414-17-1tdu17p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/395148/original/file-20210414-17-1tdu17p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/395148/original/file-20210414-17-1tdu17p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/395148/original/file-20210414-17-1tdu17p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Alaska fires are much harder to control in the rugged, remote landscape, and often left to burn.</span>
<span class="attribution"><a class="source" href="https://www.dvidshub.net/image/2036301/alaska-national-guard-fights-alaska-wildfires">Sherman Hogue/U.S. Army</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>However, we do not know how long deciduous forests’ lower flammability will persist as the climate warms. There likely is a threshold at which even resistant trees will readily burn. Other ecological changes as the forests transform could also influence their long-term carbon storage.</p>
<p>The ability of deciduous forests to slow climate warming will depend on both the local landscape and the choices people make about their carbon emissions. For the time being, it is welcome news that natural shifts in forest ecosystems have the potential to be important players in bolstering the resilience of the Earth system to climate warming.</p>
<p><em>This article was updated to change the illustration credit.</em></p><img src="https://counter.theconversation.com/content/158995/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jill Johnstone acknowledges funding from the Natural Sciences and Engineering Research Council in Canada and in the United States from the Long Term Ecological Research Program (National Science Foundation and US Forest Service), the Joint Fire Science Program, and the Strategic Environmental Research and Development Program. </span></em></p><p class="fine-print"><em><span>Heather Dawn Alexander receives funding from the National Science Foundation and the US Forest Service. </span></em></p><p class="fine-print"><em><span>Michelle C. Mack acknowledges funding from the NASA Arctic Boreal Vulnerability Experiment, the Bonanza Creek Long Term Ecological Research Program funded by the National Science Foundation and US Forest Service, the Interagency Joint Fire Sciences Program, and the Department of Defense Strategic Environmental Research and Development Program.</span></em></p><p class="fine-print"><em><span>Xanthe Walker acknowledges funding from NASA Arctic Boreal Vulnerability Experiment, Long Term Ecological Research Program (National Science Foundation and US Forest Service), Joint Fire Science Program, and Strategic Environmental Research and Development Program</span></em></p>
A new study finds more deciduous trees like aspen are growing in after severe fires in the region, and that has some unexpected impacts.
Jill Johnstone, Adjunct Professor of Biology, University of Saskatchewan
Heather Dawn Alexander, Assistant Professor of Forest Ecology, Auburn University
Michelle C. Mack, Professor of Ecosystem Ecology, Northern Arizona University
Xanthe Walker, Assistant Research Professor, Northern Arizona University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/158568
2021-04-08T17:48:03Z
2021-04-08T17:48:03Z
Water being pumped into Tampa Bay could cause a massive algae bloom, putting fragile manatee and fish habitats at risk
<figure><img src="https://images.theconversation.com/files/393869/original/file-20210407-17-brnypt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Tampa Bay's sea grass meadows need sunlight to thrive. Algae blooms block that light and can be toxic to marine life.</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/btsAoomBCeM">Joe Whalen Caulerpa/Tampa Bay Estuary Program via Unsplash</a></span></figcaption></figure><p>Millions of gallons of water laced with fertilizer ingredients are being pumped into Florida’s Tampa Bay from a <a href="https://protectingfloridatogether.gov/PineyPointUpdate">leaking reservoir</a> at an abandoned phosphate plant at Piney Point. As the water spreads into the bay, it carries phosphorus and nitrogen – nutrients that under the right conditions can <a href="https://www.noaa.gov/what-is-harmful-algal-bloom">fuel dangerous algae blooms</a> that can suffocate sea grass beds and kill fish, dolphins and manatees.</p>
<p>It’s the kind of risk no one wants to see, but officials believed the other options were worse.</p>
<p>About 300 homes sit downstream from the 480-million-gallon reservoir, which began leaking in late March 2021. State officials determined that <a href="https://protectingfloridatogether.gov/PineyPointUpdate">pumping out the water</a> was the only way to prevent the reservoir’s walls from collapsing. They decided the safest location for all that water would be out <a href="https://www.usatoday.com/in-depth/news/2021/04/05/piney-point-florida-reservoir-breach-flood-tampa-bay-palmetto-evacuation/7088307002/">through Port Manatee</a> and into the bay.</p>
<p>Florida’s coast is dotted with <a href="https://www.fws.gov/southeast/gulf-restoration/next-steps/focal-area/tampa-bay/">fragile marine sanctuaries</a> and <a href="https://www.pewtrusts.org/en/research-and-analysis/issue-briefs/2019/10/healthy-seagrass-forms-underwater-meadows-that-harbor-diverse-marine-life">sea grass beds</a> that help nurture the state’s thriving <a href="https://coast.noaa.gov/enowexplorer/#/employment/total/2017/12081">marine and tourism economy</a>. Those near Port Manatee now face a risk of algal blooms over the next few weeks. Once algae blooms get started, little can be done to clean them up.</p>
<p>The phosphate mining industry around Tampa is just one source of nutrients that can fuel dangerous algae blooms, which I study <a href="https://people.miami.edu/profile/l.brand@miami.edu#panelResearch">as a marine biologist</a>. The sugarcane industry, cattle ranches, dairy farms and citrus groves <a href="https://iwaponline.com/wp/article/20/5/919/41575">all release</a> <a href="http://doi.org/10.1016/j.hal.2006.08.005">nutrients</a> that often flow into rivers and eventually into bays and the ocean. Sewage is another problem – Miami and Fort Lauderdale, for example, have <a href="https://www.theguardian.com/us-news/2020/sep/10/florida-sewage-spill-waterways-infrastructure">old sewage treatment systems with frequent pipe breaks</a> that leak sewage into canals and coastal waters.</p>
<p>All can <a href="https://iwaponline.com/wp/article/20/5/919/41575">fuel harmful algal blooms</a> that harm marine life and people. Overall, blooms are <a href="https://www.jstor.org/stable/24897842">getting worse locally</a> and <a href="https://doi.org/10.1038/s41586-019-1648-7">globally</a>. </p>
<figure class="align-center ">
<img alt="Two manatees swimming underwater" src="https://images.theconversation.com/files/394065/original/file-20210408-21-19rm9jk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/394065/original/file-20210408-21-19rm9jk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/394065/original/file-20210408-21-19rm9jk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/394065/original/file-20210408-21-19rm9jk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/394065/original/file-20210408-21-19rm9jk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/394065/original/file-20210408-21-19rm9jk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/394065/original/file-20210408-21-19rm9jk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Red tide in recent years has killed large numbers of Florida’s manatees, a threatened species.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/usfwsendsp/5104977481/">David Hinkel/U.S. Fish and Wildlife Service</a></span>
</figcaption>
</figure>
<h2>The problem with algae blooms</h2>
<p>Just down the coast from Port Manatee, the next three counties to the south have had algae blooms in recent weeks, including red tide, which <a href="https://doi.org/10.1016/j.hal.2009.08.005">produces a neurotoxin</a> that feels like pepper spray if you breathe it in. <em>Karenia brevis</em>, a dinoflagellate, is the organism in red tide and produces the toxin.</p>
<p>This part of Florida’s Gulf Coast is a <a href="https://doi.org/10.1016/j.hal.2006.08.005">hot spot for red tide</a>, often fueled by agricultural runoff. A persistent red tide in 2017 and 2018 <a href="https://wusfnews.wusf.usf.edu/2020-01-02/2019-was-not-a-good-year-for-manatees-boat-strikes-and-red-tide-took-a-toll">killed at least 177 manatees</a> and left a trail of dead fish along the coast and into Tampa Bay. If the coastal currents carry today’s red tide father north and into Tampa Bay, the toxic algae could thrive on the nutrients from Piney Point. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/394043/original/file-20210408-13-1dg5rae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two maps with dots showing locations of reports." src="https://images.theconversation.com/files/394043/original/file-20210408-13-1dg5rae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/394043/original/file-20210408-13-1dg5rae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=270&fit=crop&dpr=1 600w, https://images.theconversation.com/files/394043/original/file-20210408-13-1dg5rae.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=270&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/394043/original/file-20210408-13-1dg5rae.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=270&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/394043/original/file-20210408-13-1dg5rae.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=340&fit=crop&dpr=1 754w, https://images.theconversation.com/files/394043/original/file-20210408-13-1dg5rae.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=340&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/394043/original/file-20210408-13-1dg5rae.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=340&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A map shows red tide reports just south of Tampa Bay.</span>
<span class="attribution"><a class="source" href="https://myfwc.com/research/redtide/statewide/">Florida Fish and Wildlife Conservation Commission</a></span>
</figcaption>
</figure>
<p>Even blooms that are not toxic are <a href="https://www.noaa.gov/what-is-harmful-algal-bloom">still dangerous to ecosystems</a>. They cloud the water, cutting off light and killing the plants below. A large enough bloom can also reduce oxygen in the water. A lack of oxygen can kill off everything in the water, including the fish.</p>
<p>This part of Florida has extensive sea grass meadows, <a href="https://floridadep.gov/rcp/seagrass">about 2.2 million acres (8.9 billion square meters) in all</a>, which are important habitat for lots of species and serve as nurseries for shrimp, crabs and fish. Scientists have argued that sea grass is also a <a href="https://doi.org/10.1038/ngeo1477">major carbon sink</a> – the grass sucks up carbon and pumps it down into the sediments.</p>
<p>Once the nutrients are in a large body of water, there isn’t much that can be done to stop algae growth. Killing the algae would only release the nutrients again, putting the bay back where it started. Algae blooms can remain a problem for years, finally declining when a predator population develops to eats them, a viral disease spreads through the bloom or strong currents and mixing disperse the bloom.</p>
<h2>Agriculture runoff poses risks to marine life</h2>
<p>The phosphate mining industry around Tampa is a large source of nutrient-rich waste. On average, <a href="https://www.epa.gov/radiation/tenorm-fertilizer-and-fertilizer-production-wastes#fertilizer">more than 5 tons</a> of phosphogypsum waste are produced for every ton of phosphoric acid created for fertilizer. In Florida, that adds up to <a href="https://fipr.floridapoly.edu/about-us/phosphate-primer/phosphogypsum-stacks.php">over 1 billion tons</a> of radioactive waste material that can’t be used, so it’s stacked up and turned into reservoirs like the one now leaking at Piney Point.</p>
<p>The reservoirs are obvious in satellite photos of the region, and they can be highly acidic. To get the phosphate out of the minerals, the industry uses sulfuric acid, and it leaves behind a highly acid wastewater. There have been at least <a href="https://www.theguardian.com/us-news/2016/sep/17/florida-sinkhole-wastewater-leak-drinking-water">two cases where it ate through the limestone below a reservoir</a>, creating huge sinkholes hundreds of feet deep and draining wastewater into the aquifer.</p>
<p>Since <a href="https://protectingfloridatogether.gov/PineyPointUpdate">saltwater had previously been pumped into</a> the Piney Point reservoir, acidity is less of an issue. That’s because the seawater would buffer the pH. There is some radioactivity, but <a href="https://protectingfloridatogether.gov/PineyPointUpdate">only slightly above regulatory standards</a>, according to state Department of Environmental Protection, and probably not much of a health hazard.</p>
<p>But the nutrients are a risk. In 2004, water releases from the Piney Point reservoir <a href="https://www.wtsp.com/article/news/local/piney-point-dumping-causes-algae-bloom-in-bishop-harbor/67-396514258">contributed to an algae bloom</a> in Bishop Harbor, just south of the current release site. In 2011, it released over <a href="https://thebradentontimes.com/piney-point-a-retrospective-p6328-158.htm">170 million gallons</a> into Bishop Harbor again after a liner broke.</p>
<p><iframe id="J5e50" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/J5e50/5/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Another significant source of algae-feeding nutrients is agriculture, particularly cattle ranching and the sugarcane industry. Nutrient runoff from cattle ranches and dairy farms north of Lake Okeechobee end up in the lake. South of the lake, much of the <a href="https://doi.org/10.4000/miranda.2881">northern third of the Everglades</a> was converted to sugarcane farms, and those fields back-pumped runoff into the lake for decades until the state started cracking down in the 1980s. Their legacy nutrients are still in the lake. </p>
<p>The nutrient-rich water in the lake then pours down the Caloosahatchee River and into the Gulf of Mexico near Fort Myers, south of Tampa. That’s likely feeding the current red tide off the mouth of the Caloosahatchee River.</p>
<p>When water from the Everglades region’s agriculture is pumped south instead, huge blooms tend to appear in Florida Bay at the southern tip of the state. Some scientists believe it <a href="http://doi.org/10.1007/s00227-019-3538-9">may be damaging coral reefs</a> there, though there’s debate about it. During times that flow of water from the farms increased, reefs throughout the Florida Keys have been harmed. Those reefs have become overgrown with algae.</p>
<p>With the current red tide, the coastal currents have carried it north as far as Sarasota already. If they carry it farther north, it will run into the Piney Point area.</p>
<p>[<em>Get our best science, health and technology stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-best">Sign up for The Conversation’s science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/158568/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Larry Brand has received funding from the National Science Foundation, National Institutes of Health, Environmental Protection Agency, National Oceanic and Atmospheric Association, National Park Service, Department of Energy, Office of Naval Research, Army Corps of Engineers, Florida Department of Health, Dade County Department of Environmental Resources Management, Cove Point Foundation, and Hoover Foundation. </span></em></p>
Harmful algae blooms are an increasing problem in Florida. Once nutrients are in the water to fuel them, little can be done to stop the growth, and the results can be devastating for marine life.
Larry Brand, Professor of Marine Biology and Ecology, University of Miami
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/152652
2021-01-21T13:13:27Z
2021-01-21T13:13:27Z
Invasive tawny crazy ants have an intense craving for calcium – with implications for their spread in the US
<figure><img src="https://images.theconversation.com/files/378340/original/file-20210112-23-1duz31c.png?ixlib=rb-1.1.0&rect=6%2C6%2C4019%2C3011&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Multiple queens ensure colonies have a steady output of workers.</span> <span class="attribution"><span class="source">Ryan Reihart</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>In a recent study, <a href="https://chelseprather.wordpress.com/">my colleagues</a> and <a href="https://scholar.google.com/citations?hl=en&user=6GBgzO8AAAAJ">I</a> discovered micronutrients in the ground <a href="https://www.doi.org/10.1002/ECY.3263">can control populations of invasive crazy ants</a> (<em>Nylanderia fulva</em>). </p>
<p>Tawny crazy ants – named for their fast, erratic movements – can blanket the ground by the millions. Originating in South America and now established in parts of the southern U.S., they <a href="https://www.nytimes.com/2013/12/08/magazine/crazy-ants.html">harm other insects, asphyxiate chickens and even short-circuit electronics in homes</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/378389/original/file-20210112-23-1urj0n3.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close up photo of a golden-colored ant against a blue background." src="https://images.theconversation.com/files/378389/original/file-20210112-23-1urj0n3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378389/original/file-20210112-23-1urj0n3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378389/original/file-20210112-23-1urj0n3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378389/original/file-20210112-23-1urj0n3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378389/original/file-20210112-23-1urj0n3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378389/original/file-20210112-23-1urj0n3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378389/original/file-20210112-23-1urj0n3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">At only 0.125 inches (3.2 mm) long, crazy ants are tiny but mighty.</span>
<span class="attribution"><span class="source">Ryan Reihart</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Crazy ants are <a href="https://doi.org/10.1146/annurev.ecolsys.33.010802.150444">liquid feeders</a> <a href="https://doi.org/10.1653/024.096.0219">that consume nectar from plants – and honeydew (or secretions) from certain insects</a>. Ants crave these sugary resources, which <a href="https://doi.org/10.1073/pnas.1115263108">boost their colony growth</a>, enabling them to outcompete native species and ultimately spread. </p>
<p>The nutritional content of nectar and honeydew vary widely, however, <a href="https://www.britishecologicalsociety.org/ant-cravings-sugar-salt-vary-across-us/">depending on the nutrients available in a particular ecosystem</a>. There are 25 chemical elements required to build life – too much or too little of one may cause disease. So far, ecologists only really know about the importance of macronutrients, like nitrogen and phosphorus, that are abundant in living tissue. My team wanted to learn more about what micronutrients might be important to crazy ants.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/377606/original/file-20210107-20-1t2ehyf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man kneeling over a small hole dug in the grass." src="https://images.theconversation.com/files/377606/original/file-20210107-20-1t2ehyf.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/377606/original/file-20210107-20-1t2ehyf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=801&fit=crop&dpr=1 600w, https://images.theconversation.com/files/377606/original/file-20210107-20-1t2ehyf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=801&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/377606/original/file-20210107-20-1t2ehyf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=801&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/377606/original/file-20210107-20-1t2ehyf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1007&fit=crop&dpr=1 754w, https://images.theconversation.com/files/377606/original/file-20210107-20-1t2ehyf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1007&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/377606/original/file-20210107-20-1t2ehyf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1007&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Installing a pitfall trap in one of the 128 fertilized study plots.</span>
<span class="attribution"><span class="source">Kiersten Angelos</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We conducted a fertilization experiment at the <a href="http://www.eih.uh.edu/">University of Houston’s Coastal Center</a> and were able to demonstrate that the abundance of tawny crazy ants decreased 24% where there was more potassium and 45% where there was more sodium and potassium. </p>
<p>What greatly surprised our team was the discovery that ants were 13% more abundant in areas where there was more calcium – even in areas that had more sodium and potassium. This finding, <a href="https://www.doi.org/10.1002/ECY.3263">published in the journal Ecology</a>, could have big implications for the continued spread of crazy ants. </p>
<h2>Why it matters</h2>
<p>Ours is the first study showing calcium is important to an invasive ant, which is somewhat surprising given ants don’t have bones. It turns out, though, calcium is important in their <a href="https://doi.org/10.1016/j.ceca.2012.11.008">egg production</a>, <a href="https://doi.org/10.1080/00218839.2015.1035074">larval development</a> and <a href="https://doi.org/10.1093/aesa/51.2.142">physiological regulation</a>. </p>
<p><a href="https://doi.org/10.1002/ece3.1737">If the spread of crazy ants continues north</a>, the calcium-rich limestone bedrock of the lower U.S. Midwest may provide ideal conditions for populations to explode. Farmlands may be at risk because calcium is found in many fertilizers. Additionally, cities often have <a href="https://doi.org/10.1007/s10980-008-9288-6">more calcium than surrounding areas</a>, thanks to heavy cement use, limestone quarrying and destruction of buildings.</p>
<p>Tawny crazy ants not only are a major threat to the biodiversity and conservation of ecosystems but also <a href="https://doi.org/10.1038/ncomms12986">cost the U.S. billions of dollars in damage annually</a>. </p>
<h2>What still isn’t known</h2>
<p>Our results add to a small but <a href="https://doi.org/10.1111/geb.13196">growing list</a> <a href="https://doi.org/10.1111/ele.13517">of other experiments</a> <a href="https://doi.org/10.1111/ele.13127">that show the importance of micronutrients</a> to insects. </p>
<p>How far will tawny crazy ants make it in the United States? Will calcium influence their spread? Could other micronutrients like magnesium or iron be important to crazy ants?</p>
<p>In a world where <a href="https://doi.org/10.1126/science.1259855">humans are changing the “ingredients” of Earth’s surface soils</a> at an alarming rate, people may be unwittingly creating more favorable habitats for some invasive species. Figuring out which elements are most important to invasive species will be key to predicting, preventing and managing their spread.</p><img src="https://counter.theconversation.com/content/152652/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan Reihart receives funding from the National Science Foundation (NSF) Division of Environmental Biology (DEB) grants 1457114 and 1724663 and from the University of Dayton Office for Graduate Academic Affairs through the Graduate Student Summer Fellowship Program. </span></em></p>
The spread of tawny crazy ants may be driven, in part, by their need for calcium. The calcium-rich limestone bedrock of the lower U.S. Midwest may provide ideal conditions for populations to explode.
Ryan Reihart, Teaching Assistant and Ph.D. Candidate of Ecology, University of Dayton
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/148877
2020-11-06T14:30:47Z
2020-11-06T14:30:47Z
We found a way to turn urine into solid fertiliser – it could make farming more sustainable
<figure><img src="https://images.theconversation.com/files/367925/original/file-20201106-23-1uqu5iu.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3865%2C2575&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/gardener-blending-organic-fertiliser-humic-granules-1364887628">Zlikovec/Shutterstock</a></span></figcaption></figure><p>It’s likely that most of the food you’ll eat today was not farmed sustainably. </p>
<p>The global system of food production is the largest human influence on the planet’s <a href="https://science.sciencemag.org/content/347/6223/1259855.abstract">natural cycles</a> of nitrogen and phosphorus. How much crops can grow is limited by the amount of these two elements in the soil, so they’re applied as fertilisers. </p>
<p>But the majority of fertilisers are either made by converting nitrogen in the air to ammonia, which alone consumes <a href="http://www.iipinetwork.org/wp-content/Ietd/content/ammonia.html#key-data">2% of the world’s energy</a> and relies heavily on fossil fuels, or by mining finite resources, like <a href="https://www.sciencedirect.com/science/article/pii/S095937800800099X">phosphate rock</a>. </p>
<p><a href="https://doi.org/10.2166/9781780401072">A solution</a> to this problem could be much closer than people realise. Most of the nutrients we consume in food are passed in our urine, because our bodies already have enough. But instead of being recaptured, these nutrients are flushed, diluted, and sent to wastewater treatment plants where they’re scrubbed out, leaving effluents that can be safely released into the environment. </p>
<p>The most nutrient-rich part of wastewater is <a href="https://www.sciencedirect.com/science/article/pii/S0960852409002806">human urine</a>, which makes up less than 1% of the total volume but contains 80% of the nitrogen and 50% of the phosphorus. We discovered how to recycle this urine into valuable – and sustainable – farmland fertiliser.</p>
<figure class="align-center ">
<img alt="A pair of gloved hands hold a pot containing a urine sample." src="https://images.theconversation.com/files/367922/original/file-20201106-13-8ngh5x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/367922/original/file-20201106-13-8ngh5x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/367922/original/file-20201106-13-8ngh5x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/367922/original/file-20201106-13-8ngh5x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/367922/original/file-20201106-13-8ngh5x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/367922/original/file-20201106-13-8ngh5x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/367922/original/file-20201106-13-8ngh5x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Urine is surprisingly rich in the nutrients needed for growing food.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/preparation-urine-samples-laboratory-hospital-study-1257550750">Tati9/Shutterstock</a></span>
</figcaption>
</figure>
<h2>How to recycle urine</h2>
<p>You can capture urine with <a href="https://www.treehugger.com/urine-separating-toilets-are-not-quite-wonderful-we-keep-saying-they-are-4858530">special toilets</a> that separate it from faeces after you flush. But because urine is mostly water, farmers would have to spread 15,000kg of it just to fertilise a hectare of land. If there was a way to remove the water and extract just the nutrients, farmers would only need to apply 400kg of it for the same effect.</p>
<p>Evaporating the water from urine is surprisingly difficult, as urine is a complex chemical solution. Almost all of the valuable nitrogen in urine is in the form of urea, a chemical that is used as the world’s <a href="http://nmsp.cals.cornell.edu/publications/factsheets/factsheet80.pdf">most commonly applied</a> nitrogen fertiliser. </p>
<p>But a fast-acting enzyme called urease is invariably present inside wastewater pipes and <a href="https://www.sciencedirect.com/science/article/pii/S0043135418304457">converts urea to ammonia</a>. When exposed to air, the ammonia quickly evaporates, taking the nitrogen from the urine with it and giving off a very pungent odour – think the stale urine smell of public toilets. </p>
<p>Fortunately, we’ve discovered that <a href="https://iwaponline.com/wst/article-abstract/74/6/1436/19385">increasing the pH of urine</a> to make it alkaline ensures the urea doesn’t break down or end up smelling really bad. Using this technique, we’ve developed a process that can reduce the volume of urine and transform it into a solid fertiliser. We call this process <a href="https://www.sciencedirect.com/science/article/pii/B978044464309400009X">alkaline urine dehydration</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/366976/original/file-20201102-23-17rt15y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A petri dish full of a dry, soil-like powder." src="https://images.theconversation.com/files/366976/original/file-20201102-23-17rt15y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366976/original/file-20201102-23-17rt15y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=326&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366976/original/file-20201102-23-17rt15y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=326&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366976/original/file-20201102-23-17rt15y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=326&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366976/original/file-20201102-23-17rt15y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=410&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366976/original/file-20201102-23-17rt15y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=410&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366976/original/file-20201102-23-17rt15y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=410&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some of the fertiliser produced by drying human urine.</span>
<span class="attribution"><span class="source">Prithvi Simha</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The idea behind it is rather simple. Fresh urine is collected from urinals or <a href="https://www.sciencedirect.com/science/article/pii/S2352710219308460">specially designed toilets</a> and channelled into a dryer, where an alkalising agent, such as <a href="https://www.sciencedirect.com/science/article/pii/S0048969720328308">calcium or magnesium hydroxide</a>, raises its pH. Any water in the now alkaline urine is evaporated and only the nutrients are left behind. We can even <a href="https://www.frontiersin.org/articles/10.3389/fenvs.2020.570637/full">condense the evaporated water</a> and reuse it for flushing toilets or washing hands. </p>
<h2>A circular pee-conomy</h2>
<p>Doing this is quite easy: you just fill a urine dryer with an alkalising agent, connect it to your toilet, pee as usual and the urine is converted into dried fertiliser. A smart design could even make the dryer fit below the toilet so it doesn’t take up a lot of bathroom space. While electricity would be needed for evaporating the water, the dryer could be <a href="https://www.sciencedirect.com/science/article/pii/S0048969717302796">coupled with solar energy</a> to take its energy use off the grid.</p>
<p>We estimate that it would cost just US$5 (£4.20) to supply an average family of four with a year’s supply of alkalising agent. The output from the dryer is a solid fertiliser containing 10% nitrogen, 1% phosphorus and 4% potassium – a similar combination to <a href="https://doi.org/10.1016/j.scitotenv.2020.139313">blended mineral fertilisers</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/367238/original/file-20201103-15-qoz66f.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Left: a scientist spreads fertiliser on soil. Right: the same area with short, green crops growing." src="https://images.theconversation.com/files/367238/original/file-20201103-15-qoz66f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/367238/original/file-20201103-15-qoz66f.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=226&fit=crop&dpr=1 600w, https://images.theconversation.com/files/367238/original/file-20201103-15-qoz66f.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=226&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/367238/original/file-20201103-15-qoz66f.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=226&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/367238/original/file-20201103-15-qoz66f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=283&fit=crop&dpr=1 754w, https://images.theconversation.com/files/367238/original/file-20201103-15-qoz66f.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=283&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/367238/original/file-20201103-15-qoz66f.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=283&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Field trials on farmland outside Paris revealed that dried urine works as well as synthetic crop fertilisers.</span>
<span class="attribution"><span class="source">Tristan Martin</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p><a href="https://www.baus.org.uk/museum/164/a_brief_history_of_the_flush_toilet">The first flush toilet</a>, invented by Alexander Cummings in 1775, revolutionised sanitation. Drying urine could kickstart a second revolution in how we manage wastewater. If implemented worldwide, recycled urine could replace nearly a quarter of all the synthetic nitrogen fertiliser used in agriculture. </p>
<p>But that would require <a href="https://www.sciencedirect.com/science/article/pii/B978044464309400009X">a service chain</a> capable of supplying homes with alkalising agent, collecting the dried urine and processing it into fertiliser for farmers to use. A similar service chain already exists for the recycling of plastics, metals, paper and glass – dried urine could simply be another component. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/366972/original/file-20201102-19-nvrah4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A world map highlighted to show where urine could replace more synthetic fertiliser use." src="https://images.theconversation.com/files/366972/original/file-20201102-19-nvrah4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366972/original/file-20201102-19-nvrah4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=296&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366972/original/file-20201102-19-nvrah4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=296&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366972/original/file-20201102-19-nvrah4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=296&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366972/original/file-20201102-19-nvrah4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=372&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366972/original/file-20201102-19-nvrah4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=372&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366972/original/file-20201102-19-nvrah4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=372&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Countries with large populations and low rates of fertiliser use are most suitable for replacing synthetic fertilisers with urine.</span>
<span class="attribution"><span class="source">Prithvi Simha/Datawrapper and FAOSTAT</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p><a href="https://www.sciencedirect.com/science/article/pii/S004896971730044X">Research</a> suggests that people are <a href="https://www.sciencedirect.com/science/article/pii/S0043135418305384">open to the idea</a> of recycling urine. A survey of nearly 3,800 people across 16 countries even revealed that people would buy and eat <a href="https://data.mendeley.com/datasets/kccc8m9pn9/1">food grown using human urine</a>. With technology like this, ordinary people would have a safe and convenient way to make modern life more sustainable every time they go to the bathroom.</p><img src="https://counter.theconversation.com/content/148877/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Prithvi Simha owns shares in Sanitation360, a company which aims to commercialise urine dehydration technology.</span></em></p><p class="fine-print"><em><span>Björn Vinnerås owns shares in Sanitation360 AB. He receives funding from the Swedish Research Council Vetenskapsrådet, Formas, VINNOVA (the Swedish Innovation agency), and the EU H2020 projects Run4Life and REWAISE. </span></em></p><p class="fine-print"><em><span> Jenna Senecal is CEO of Sanitation360, a company which aims to commercialise urine dehydration technology.</span></em></p>
If rolled out worldwide, our method could replace a quarter of all the synthetic nitrogen fertiliser used in agriculture.
Prithvi Simha, PhD Candidate in Environmental Engineering, Swedish University of Agricultural Sciences
Björn Vinnerås, Professor of Environmental Engineering, Swedish University of Agricultural Sciences
Jenna Senecal, Postdoctoral Researcher in Environmental Engineering, Swedish University of Agricultural Sciences
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/146980
2020-11-02T13:24:50Z
2020-11-02T13:24:50Z
A few heavy storms cause a big chunk of nitrogen pollution from Midwest farms
<figure><img src="https://images.theconversation.com/files/364813/original/file-20201021-23-1sop9qc.jpg?ixlib=rb-1.1.0&rect=26%2C0%2C3000%2C1998&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Corn plants in a flooded field near Emden, Ill., May 29, 2019.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.ie/detail/news-photo/corn-grows-in-a-saturated-farm-field-on-may-29-2019-near-news-photo/1152539969?adppopup=true">Scott Olson/Getty Images</a></span></figcaption></figure><p>Some effects of extreme weather are visible – like <a href="https://www.marketwatch.com/story/devastating-august-derecho-prompts-usda-to-cut-iowa-corn-acres-by-550-000-11599849936">half a million acres of flattened corn in Iowa</a> left behind after a <a href="https://theconversation.com/what-is-a-derecho-an-atmospheric-scientist-explains-these-rare-but-dangerous-storm-systems-140319">derecho</a> that hit the Midwestern United States on Aug. 10. </p>
<p>Other effects are harder to measure, but can be just as harmful. One example is agricultural nitrogen runoff from farmlands in the Mississippi River Basin. It mainly comes from fertilizer that farmers apply to <a href="https://pubs.usgs.gov/fs/old.2003/fs-105-03/">millions of acres of crops</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/366499/original/file-20201029-19-1c171bd.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of Mississippi River basin" src="https://images.theconversation.com/files/366499/original/file-20201029-19-1c171bd.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/366499/original/file-20201029-19-1c171bd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=550&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366499/original/file-20201029-19-1c171bd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=550&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366499/original/file-20201029-19-1c171bd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=550&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366499/original/file-20201029-19-1c171bd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=691&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366499/original/file-20201029-19-1c171bd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=691&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366499/original/file-20201029-19-1c171bd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=691&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Mississippi River Basin covers over 1.245 million square miles across 32 U.S. states and two Canadian provinces.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Mississippi_River_System#/media/File:Mississippiriver-new-01.png">Shannon1/Wikipedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Plants can’t use all of the nitrogen in fertilizer because fertilizers are usually applied in excess. This excess can wash off farm fields into local rivers and lakes, degrading water quality and <a href="https://theconversation.com/how-your-diet-contributes-to-nutrient-pollution-and-dead-zones-in-lakes-and-bays-118902">stimulating algae blooms</a>. Traveling down the Mississippi River, it contributes to the yearly formation of a <a href="https://coastalscience.noaa.gov/news/large-dead-zone-measured-in-gulf-of-mexico/">dead zone in the northern Gulf of Mexico</a>, covering several thousand square miles; oxygen levels there are so low that fish and shellfish cannot survive. </p>
<p>Excess nitrogen in drinking water also <a href="https://www.wsj.com/articles/farms-more-productive-than-ever-are-poisoning-drinking-water-in-rural-america-11547826031">threatens public health</a>. Ingesting high levels of nitrate, a nitrogen compound, can <a href="https://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=1186&tid=258">reduce red blood cells’ ability to transport oxygen</a>, a condition that is especially dangerous for infants. </p>
<p>My work as a <a href="https://scholar.google.com/citations?user=VI_Lb-YAAAAJ&hl=en">quantitative ecologist</a> examines how ecosystems respond to external factors such as adding nitrogen. In a recently published study, I worked with colleagues to quantify nitrogen runoff from land into rivers and streams. We found that infrequent but heavy rainfall events account for <a href="https://doi.org/10.1038/s43247-020-00020-7">one-third of annual total runoff and nitrogen leaching from soils</a> across the Mississippi Basin. This tells us that managing nitrogen is likely to be more challenging if climate change continues to make heavy rains more frequent.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/OQFjmWGONCA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">To use nitrogen fertilizer efficiently, farmers need to consider factors including yield goals, soil quality, chemistry and weather.</span></figcaption>
</figure>
<h2>Too much of a good thing</h2>
<p>Plants can’t grow without nitrogen, but using too much or applying it improperly can cause problems. In the U.S. Midwest, one of the <a href="https://pubs.usgs.gov/fs/fs155-99/fs155-99.html">most intensively farmed areas in the world</a>, farmers have added <a href="https://doi.org/10.5194/essd-10-969-2018">large amounts of synthetic nitrogen fertilizer</a> to the land to boost crop yields. </p>
<p>Long-term monitoring data from river gauges shows large year-to-year variations in the quantity of nitrogen that flows down from the Mississippi River Basin into the Gulf of Mexico. Yearly changes in farmers’ fertilizer use are not large enough to explain these fluctuations.</p>
<p>Studies show that annual total precipitation is a <a href="https://carnegiescience.edu/news/projected-precipitation-increases-are-bad-news-water-quality">significant factor in these changes</a>. But we know less about the role of daily rainfall – particularly heavy rains – in mobilizing and transporting nitrogen. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/366164/original/file-20201028-19-1obdcnf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph showing nitrogen runoff from Midwest states to the Gulf of Mexico, 1980-2017." src="https://images.theconversation.com/files/366164/original/file-20201028-19-1obdcnf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366164/original/file-20201028-19-1obdcnf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=381&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366164/original/file-20201028-19-1obdcnf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=381&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366164/original/file-20201028-19-1obdcnf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=381&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366164/original/file-20201028-19-1obdcnf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=479&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366164/original/file-20201028-19-1obdcnf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=479&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366164/original/file-20201028-19-1obdcnf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=479&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Stream gauge measurements show that the amount of dissolved inorganic nitrogen (DIN) moving from Mississippi River Basin states to the Gulf of Mexico fluctuates dramatically from year to year. Heavy rainfalls can produce higher nitrogen levels.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s43247-020-00020-7">Modified from Lu et al., 2020</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Heavy rains have an outsized impact</h2>
<p>My collaborators and I wanted to assess the impacts of extreme rainfall events in the Midwest. In this region, many cropped fields are laced with buried networks of drainage channels, known locally as <a href="https://en.wikipedia.org/wiki/Tile_drainage">tile drainage</a>. These pipelines are designed to move excess moisture out of fields. But they can also channel large surges of water and nutrients into rivers and streams after heavy rainfalls.</p>
<p>It is challenging to determine how individual rainfall events affect nitrogen leaching and movement within a <a href="https://www.britannica.com/science/drainage-basin">drainage basin</a>. Rain happens here and there, so it’s hard to distinguish a single storm’s impact from river gauge monitoring data. Rainfall events also vary a lot by season and intensity. </p>
<p>Our study used a well-tested model to quantify how much nitrogen is washed out by each rainfall event, as well as total nitrogen delivered to the Gulf of Mexico. We looked closely at heavy rainfall events, which we defined as the top 10% of historical daily precipitation amounts for any location in a given month. </p>
<p>Climate records show that over the past 20 years, a growing share of annual precipitation has come in heavy rainfall events across two-thirds of the Mississippi River Basin’s land area. The region that receives a total of more than 15.7 inches (400 millimeters) of heavy rain per year has expanded from areas in Louisiana and Arkansas northward to Corn Belt states like Illinois and Indiana, where nitrogen fertilizer is heavily used.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/366496/original/file-20201029-21-1uua7k7.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="U.S. map showing more precipitation falling during very heavy events" src="https://images.theconversation.com/files/366496/original/file-20201029-21-1uua7k7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366496/original/file-20201029-21-1uua7k7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=541&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366496/original/file-20201029-21-1uua7k7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=541&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366496/original/file-20201029-21-1uua7k7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=541&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366496/original/file-20201029-21-1uua7k7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=679&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366496/original/file-20201029-21-1uua7k7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=679&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366496/original/file-20201029-21-1uua7k7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=679&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Percentage increases in the amount of precipitation falling in very heavy events (defined as the heaviest 1% of all daily events) from 1958 to 2012.</span>
<span class="attribution"><a class="source" href="https://nca2014.globalchange.gov/report/our-changing-climate/heavy-downpours-increasing#:~:text=National%20Climate%20Assessment%20Home&text=Heavy%20downpours%20are%20increasing%20nationally,Explore%20extreme%20precipitation.">Globalchange.gov</a></span>
</figcaption>
</figure>
<p>We found that one-third of annual total runoff and nitrogen leaching loss come from heavy rainfall events, which happen on only about nine days per year on average across the basin. Nearly half to three-quarters of heavy rainfall in the basin occurs in spring and summer, with a monthly peak in May. </p>
<p>This timing coincides with the planting and seed germinating stages of corn, when the plants are using <a href="http://nmsp.cals.cornell.edu/publications/factsheets/factsheet98.pdf">minimal amounts of nitrogen</a>. We wondered whether changing when and how farmers apply fertilizer could reduce nitrogen runoff.</p>
<h2>When to fertilize</h2>
<p>When during the year to apply fertilizer is a long-standing question in both <a href="https://theconversation.com/farmers-of-the-future-will-utilize-drones-robots-and-gps-37739">precision agriculture</a> and environmental science. Midwest farmers apply over 90% of nitrogen fertilizer before crops germinate in springtime and after harvesting. This means that a fair amount of available nitrogen accumulates in the soil before crops start taking it up. When heavy rainfalls occur, it is likely to be washed out. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1318214328403767303"}"></div></p>
<p>We set up modeling experiments to test whether postponing fertilizer application could make the water running off of farmlands cleaner. In our alternative fertilizer management scenario, we assumed fertilizer was applied only twice, after crops developed. We expected this would reduce the amount of unused nitrogen accumulating in soils.</p>
<p>Our results predicted that this modification could reduce nitrogen loading to the Gulf of Mexico by up to 16%. This would be a significant step toward goals set by the U.S. Environmental Protection Agency, which is working with states to reduce nutrient loads entering the Gulf of Mexico by <a href="https://archive.epa.gov/epa/newsreleases/states-develop-new-strategies-reduce-nutrient-levels-mississippi-river-gulf-mexico.html">20% by 2025 and 45% by 2035</a>. </p>
<p>However, even under the postponed fertilizer application scenario, we still found the frequent heavy rains in the recent decade could enhance nitrogen loss during summer and early fall. Scientists predict that if climate change continues at its current rate, it will cause <a href="https://nca2014.globalchange.gov/highlights/regions/midwest#intro-section-2">more extreme rainfall events in the Midwest</a>, which, we think, would reduce environmental benefits from alternative nitrogen management practices. </p>
<p>Reducing the amount of nitrogen that escapes from land into water bodies while maintaining food production is a significant challenge. Our study complements the well-known <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/ia/technical/ecoscience/nutrient/nrcs142p2_008196/">4R concept</a> for managing nutrients: Using the right fertilizer product, at the right rate, at the right time, and in the right place. To get that timing right, our research shows that along with crop nitrogen demand, farmers should also consider the occurrence of heavy rainfall.</p>
<p>[<em>Get our best science, health and technology stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-best">Sign up for The Conversation’s science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/146980/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chaoqun Lu receives funding from the National Science Foundation, Iowa State University, and the Iowa Nutrient Research Center.</span></em></p>
New research shows that one-third of yearly nitrogen runoff from Midwest farms to the Gulf of Mexico occurs during a few heavy rainstorms. New fertilizing schedules could reduce nitrogen pollution.
Chaoqun Lu, Assistant Professor of Ecology, Evolution and Organismal Biology, Iowa State University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/147208
2020-10-07T19:09:47Z
2020-10-07T19:09:47Z
New research: nitrous oxide emissions 300 times more powerful than CO₂ are jeopardising Earth’s future
<figure><img src="https://images.theconversation.com/files/361788/original/file-20201006-20-162nmfy.jpg?ixlib=rb-1.1.0&rect=25%2C0%2C3359%2C2211&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Nitrous oxide from agriculture and other sources is accumulating in the atmosphere so quickly it puts Earth on track for a dangerous 3°C warming this century, <a href="https://doi.org/10.1038/s41586-020-2780-0">our new research</a> has found.</p>
<p>Each year, <a href="http://www.fao.org/faostat/en/#data/RFN/visualize">more than 100 million tonnes of nitrogen</a> are spread on crops in the form of synthetic fertiliser. The same amount again is put onto pastures and crops in manure from livestock.</p>
<p>This colossal amount of nitrogen makes crops and pastures grow more abundantly. But it also releases nitrous oxide (N₂O), a greenhouse gas. </p>
<p>Agriculture is the main cause of the increasing concentrations, and is likely to remain so this century. N₂O emissions from agriculture and industry can be reduced, and we must take urgent action if we hope to stabilise Earth’s climate.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/361458/original/file-20201004-14-8imsmp.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/361458/original/file-20201004-14-8imsmp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361458/original/file-20201004-14-8imsmp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361458/original/file-20201004-14-8imsmp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361458/original/file-20201004-14-8imsmp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361458/original/file-20201004-14-8imsmp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361458/original/file-20201004-14-8imsmp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361458/original/file-20201004-14-8imsmp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">2000 years of atmospheric nitrous oxide concentrations. Observations taken from ice cores and atmosphere. Source: BoM/CSIRO/AAD.</span>
</figcaption>
</figure>
<h2>Where does nitrous oxide come from?</h2>
<p>We found that N₂O emissions from natural sources, such as soils and oceans, have not changed much in recent decades. But emissions from human sources have increased rapidly.</p>
<p>Atmospheric concentrations of N₂O reached 331 parts per billion <a href="https://library.wmo.int/index.php?lvl=notice_display&id=21761#.X3kJstMzZuU">in 2018</a>, 22% above levels around the year 1750, before the industrial era began.</p>
<p>Agriculture caused <a href="https://doi.org/10.1038/s41586-020-2780-0">almost 70%</a> of global N₂O emissions in the decade to 2016. The emissions are created through <a href="https://www.agriculture.gov.au/ag-farm-food/climatechange/australias-farming-future/n2o-emissions">microbial processes</a> in soils. The use of nitrogen in synthetic fertilisers and manure is a key driver of this process.</p>
<p>Other human sources of N₂O include the chemical industry, waste water and the burning of fossil fuels. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/intensive-farming-is-eating-up-the-australian-continent-but-theres-another-way-130877">Intensive farming is eating up the Australian continent – but there's another way</a>
</strong>
</em>
</p>
<hr>
<p>N₂O is destroyed in the upper atmosphere, primarily by <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/photolysis">solar radiation</a>. But humans are emitting N₂O faster than it’s being destroyed, so it’s accumulating in the atmosphere.</p>
<p>N₂O both depletes the ozone layer and contributes to global warming. </p>
<p>As a greenhouse gas, N₂O has 300 times the warming potential of carbon dioxide (CO₂) and stays in the atmosphere for an average 116 years. It’s the third most important greenhouse gas after CO₂ (which lasts up to thousands of years in the atmosphere) and methane.</p>
<p>N₂O depletes the ozone layer when it interacts with ozone gas in the stratosphere. Other ozone-depleting substances, such as chemicals containing chlorine and bromine, have been banned under the United Nations <a href="https://ozone.unep.org/treaties/montreal-protocol">Montreal Protocol</a>. N₂O is not banned under the protocol, although the Paris Agreement seeks to reduce its concentrations. </p>
<figure class="align-center ">
<img alt="A farmer emptying fertiliser into machinery" src="https://images.theconversation.com/files/361790/original/file-20201006-22-117gmcc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361790/original/file-20201006-22-117gmcc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361790/original/file-20201006-22-117gmcc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361790/original/file-20201006-22-117gmcc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361790/original/file-20201006-22-117gmcc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361790/original/file-20201006-22-117gmcc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361790/original/file-20201006-22-117gmcc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Reducing fertiliser use on farms is critical to reducing N₂O emissions.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What we found</h2>
<p>The Intergovernmental Panel on Climate Change has developed <a href="https://www.carbonbrief.org/explainer-how-shared-socioeconomic-pathways-explore-future-climate-change">scenarios</a> for the future, outlining the different pathways the world could take on emission reduction by 2100. <a href="https://doi.org/10.1038/s41586-020-2780-0">Our research</a> found N₂O concentrations have begun to exceed the levels predicted across all scenarios.</p>
<p>The current concentrations are in line with a global average temperature increase of well above 3°C this century.</p>
<p>We found that global human-caused N₂O emissions have grown by 30% over the past three decades. Emissions from agriculture mostly came from synthetic nitrogen fertiliser used in East Asia, Europe, South Asia and North America. Emissions from Africa and South America are dominated by emissions from livestock manure.</p>
<p>In terms of emissions growth, the highest contributions come from emerging economies – particularly Brazil, China, and India – where crop production and livestock numbers have increased rapidly in recent decades. </p>
<p>N₂O emissions <a href="https://ageis.climatechange.gov.au">from Australia</a> have been stable over the past decade. Increase in emissions from agriculture and waste have been offset by a decline in emissions from industry and fossil fuels.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/361459/original/file-20201004-21-1vgc283.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/361459/original/file-20201004-21-1vgc283.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361459/original/file-20201004-21-1vgc283.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361459/original/file-20201004-21-1vgc283.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361459/original/file-20201004-21-1vgc283.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361459/original/file-20201004-21-1vgc283.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=548&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361459/original/file-20201004-21-1vgc283.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=548&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361459/original/file-20201004-21-1vgc283.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=548&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Regional changes in N₂O emissions from human activities, from 1980 to 2016, in million tons of nitrogen per year. Data from: Tian et al. 2020, Nature. Source: Global Carbon Project & International Nitrogen Initiative.</span>
</figcaption>
</figure>
<h2>What to do?</h2>
<p>N₂O must be part of efforts to reduce greenhouse gas emissions, and there is already work being done. Since the late 1990s, for example, efforts to reduce emissions from the chemicals industry have been successful, particularly in the production of <a href="https://www.sciencedirect.com/science/article/pii/S1465997200000246">nylon</a>, in the <a href="https://www.eia.gov/environment/emissions/ghg_report/ghg_nitrous.php">United States</a>, Europe and Japan.</p>
<p>Reducing emissions from agriculture is more difficult – food production must be maintained and there is no simple alternative to nitrogen fertilisers. But some options do exist.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/emissions-of-methane-a-greenhouse-gas-far-more-potent-than-carbon-dioxide-are-rising-dangerously-142522">Emissions of methane – a greenhouse gas far more potent than carbon dioxide – are rising dangerously</a>
</strong>
</em>
</p>
<hr>
<p>In Europe over the past two decades, N₂O emissions have fallen as agricultural productivity increased. This was largely achieved through <a href="https://www.eea.europa.eu/archived/archived-content-water-topic/water-pollution/prevention-strategies/nitrate-directive">government policies</a> to reduce pollution in waterways and drinking water, which encouraged <a href="https://ec.europa.eu/eurostat/statistics-explained/pdfscache/16817.pdf">more efficient fertiliser use</a>.</p>
<p>Other ways to reduce N₂O emissions from agriculture include:</p>
<ul>
<li><p>better management of animal manure</p></li>
<li><p>applying fertiliser in a way that better matches the needs of growing plants</p></li>
<li><p>alternating crops to include those that produce their own nitrogen, such as legumes, to reduce the need for fertiliser</p></li>
<li><p>enhanced efficiency fertilisers that lower N₂O production.</p></li>
</ul>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/361457/original/file-20201003-18-1ixjovk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/361457/original/file-20201003-18-1ixjovk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361457/original/file-20201003-18-1ixjovk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361457/original/file-20201003-18-1ixjovk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361457/original/file-20201003-18-1ixjovk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361457/original/file-20201003-18-1ixjovk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361457/original/file-20201003-18-1ixjovk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361457/original/file-20201003-18-1ixjovk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Global nitrous oxide budget 2007-16. Adopted from Tian et al. 2020. Nature. Source: Global Carbon Project & International Nitrogen Initiative.</span>
</figcaption>
</figure>
<h2>Getting to net-zero emissions</h2>
<p>Stopping the overuse of nitrogen fertilisers is not just good for the climate. It can also reduce water pollution and increase <a href="https://ccafs.cgiar.org/research-highlight/farmers-and-climate-profit-more-precise-fertilizer-management#.X30NaNMzZuU">farm profitability</a>.</p>
<p>Even with the right agricultural policies and actions, synthetic and manure fertilisers will be needed. To bring the sector to net-zero greenhouse gas emissions, as needed to stabilise the climate, <a href="https://theconversation.com/turning-methane-into-carbon-dioxide-could-help-us-fight-climate-change-117317">new technologies</a> will be <a href="https://theconversation.com/the-morrison-government-wants-to-suck-co-out-of-the-atmosphere-here-are-7-ways-to-do-it-144941">required</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/earth-may-temporarily-pass-dangerous-1-5-warming-limit-by-2024-major-new-report-says-145450">Earth may temporarily pass dangerous 1.5℃ warming limit by 2024, major new report says</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/147208/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Pep Canadell receives funding from The Australian National Environmental Science Program, and the Gordon and Betty Moore Foundation.</span></em></p><p class="fine-print"><em><span>Eric Davidson receives funding from the U.S. Department of Agriculture. </span></em></p><p class="fine-print"><em><span>Glen Peters receives funding from the European Commission (Horizon 2020) and the Research Council of Norway. </span></em></p><p class="fine-print"><em><span>Hanqin Tian receives funding from US National Science Foundation, National Oceanic and Atmospheric Administration, National Aeronautics and Space Administration and Andrew Carnegie Fellowship Program. </span></em></p><p class="fine-print"><em><span>Michael Prather is an employee of the University of California at Irvine; currently has received research funding from NASA, NSF, US DOE, and private donors; and is a consultant for the Citizens Climate Lobby. </span></em></p><p class="fine-print"><em><span>Paul Krummel is employed by CSIRO and receives funding from MIT, NASA, Australian Bureau of Meteorology, Department of Agriculture, Water and the Environment, and Refrigerant Reclaim Australia.</span></em></p><p class="fine-print"><em><span>Rob Jackson receives funding from the Gordon and Betty Moore Foundation. </span></em></p><p class="fine-print"><em><span>Rona Thompson receives funding from the European Commission (Horizon 2020) and the Research Council of Norway.</span></em></p><p class="fine-print"><em><span>Wilfried Winiwarter currently receives funding from the Austrian national foundations for science (FWF) and applied research (FFG), from the Polish national foundation for applied research (NCBiR), and from UNEP via the Global Environment Fund. </span></em></p>
Agriculture is the dominant cause for the increasing N₂O concentrations. Emissions must be reduced if we hope to stabilise Earth’s climate.
Pep Canadell, Chief research scientist, Climate Science Centre, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO
Eric Davidson, Director, Appalachian Laboratory and Professor, University of Maryland, Baltimore
Glen Peters, Research Director, Center for International Climate and Environment Research - Oslo
Hanqin Tian, Director, International Center for Climate and Global Change Research, Auburn University
Michael Prather, Distinguished Professor of Earth System Science, University of California, Irvine
Paul Krummel, Research Group Leader, CSIRO
Rob Jackson, Professor, Department of Earth System Science, and Chair of the Global Carbon Project, Stanford University
Rona Thompson, Senior scientist, Norwegian Institute for Air Research
Wilfried Winiwarter, International Institute for Applied Systems Analysis (IIASA)
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/145181
2020-10-05T04:19:50Z
2020-10-05T04:19:50Z
Curious Kids: what happens if you breathe pure oxygen?
<figure><img src="https://images.theconversation.com/files/358790/original/file-20200918-14-19ewyu1.jpg?ixlib=rb-1.1.0&rect=1%2C4%2C997%2C582&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Breathing pure oxygen would be like fireworks exploding in your body. And that's not always a good thing.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/abstract-colored-firework-background-free-space-516676762">Shutterstock</a></span></figcaption></figure><blockquote>
<p><strong>What happens if you breathe pure oxygen and why? Stephen, age 9, Muntinlupa City, The Philippines</strong></p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>Hi Stephen!</p>
<p>That’s a great question. We can’t live without <a href="https://kids.britannica.com/kids/article/oxygen/353585">oxygen</a>. But too much can harm us. Let’s find out why.</p>
<p>Our bodies make the energy we need to run around, play and do schoolwork, by burning the food we eat. Think of this a bit like a candle burning. To burn our food, we need oxygen, which we get from breathing in the air around us.</p>
<p>Oxygen isn’t the only gas in the air. In fact, air’s mostly made of <a href="https://kids.britannica.com/kids/article/nitrogen/353537">nitrogen</a>. This has a very important job. Nitrogen slows down the burning process so you get enough energy through the day, bit by bit.</p>
<p>If you breathed pure oxygen, the energy from your food would be released all at once. So forget candles. This is more like a firework exploding. Bang! If you breathed pure oxygen, you wouldn’t actually explode. But you would damage your body.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-when-i-swipe-a-matchstick-how-does-it-make-fire-116673">Curious Kids: when I swipe a matchstick how does it make fire?</a>
</strong>
</em>
</p>
<hr>
<p>Breathing pure oxygen sets off a series of runaway chemical reactions. That’s when some of that oxygen turns into its dangerous, unstable cousin called a “radical”. Oxygen radicals harm the fats, protein and DNA in your body. This damages your eyes so you can’t see properly, and your lungs, so you can’t breathe normally.</p>
<p>So breathing pure oxygen is quite dangerous.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/m6haYrvAQ5s?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Food, oxygen and explosions!</span></figcaption>
</figure>
<p>But breathing pure oxygen can sometimes be necessary. <a href="https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-a-spacewalk-k4.html">Astronauts</a> and <a href="https://www.scubadoctor.com.au/scuba-diving-gas-analysis.htm">deep-sea scuba divers</a> sometimes breathe pure oxygen because they work in very dangerous places.</p>
<p>The length of time they breathe pure oxygen, and how much they breathe, is carefully controlled so they’re not harmed.</p>
<p>Sick people, including <a href="https://medlineplus.gov/ency/article/007242.htm">premature babies in hospital</a> or people in hospital <a href="https://theconversation.com/how-are-the-most-serious-covid-19-cases-treated-and-does-the-coronavirus-cause-lasting-damage-134398">with the coronavirus</a>, might also need some extra help breathing. They might be given a bit of extra oxygen on top of what’s in the air. It acts like a medicine to help calm and settle their breathing. </p>
<p>Again, too much oxygen can be dangerous. That’s why doctors and nurses keep a close eye to make sure people get just the right amount they need.</p>
<p>So we need oxygen to help us get energy from our food. We might also need a little extra if we’re sick in hospital, or if we’re an astronaut or deep-sea diver. But too much oxygen can harm us.</p>
<hr>
<p><em>Hello, Curious Kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p><img src="https://counter.theconversation.com/content/145181/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Lynch does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
You might think the more oxygen you breathe in the better. But too much oxygen can make you sick.
Mark Lynch, Lecturer in Chemistry, University of Southern Queensland
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/130877
2020-07-07T02:47:33Z
2020-07-07T02:47:33Z
Intensive farming is eating up the Australian continent – but there’s another way
<figure><img src="https://images.theconversation.com/files/344552/original/file-20200629-155353-18mmn1c.jpeg?ixlib=rb-1.1.0&rect=0%2C0%2C3264%2C1886&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Sue McIntyre</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Last week <a href="https://www.smh.com.au/environment/sustainability/nsw-farmers-accelerate-land-clearing-rates-doubling-previous-decade-20200701-p5581j.html">we learned</a> woody vegetation in New South Wales is being cleared at more than double the rate of the previous decade – and agriculture was responsible for more than half the destruction.</p>
<p>Farming <a href="https://www.agriculture.gov.au/abares/publications/insights/snapshot-of-australian-agriculture-2020#agricultural-production-is-growing">now covers</a> 58% of Australia, or 385 million hectares, and accounts for 59% of water extracted.</p>
<p>It’s painfully clear <a href="https://www.wenfo.org/aer/">nature is buckling</a> under the weight of farming’s demands. In the past decade, the federal government has <a href="http://www.environment.gov.au/cgi-bin/sprat/public/publiclookupcommunities.pl">listed</a> ten ecological communities as endangered, or critically endangered, as a result of farming development and practices.</p>
<p>So how can we accommodate the needs of both farming and nature? Research shows us how – but it means accepting land as a finite resource, and operating within its limits. In doing so, farmers will also reap benefits.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/325446/original/file-20200404-74220-5bgtta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325446/original/file-20200404-74220-5bgtta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=405&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325446/original/file-20200404-74220-5bgtta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=405&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325446/original/file-20200404-74220-5bgtta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=405&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325446/original/file-20200404-74220-5bgtta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=509&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325446/original/file-20200404-74220-5bgtta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=509&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325446/original/file-20200404-74220-5bgtta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=509&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Grassy eucalypt woodlands used for cattle farming in subtropical Queensland.</span>
<span class="attribution"><span class="source">Tara Martin. Author provided.</span></span>
</figcaption>
</figure>
<h2>Healthy grazing landscapes</h2>
<p>In the 1990s, I worked as a research ecologist in the cattle country of sub-tropical Queensland. The prevailing culture valued agricultural development over conservation. Yet many of these producers lived on viable farms that supported a wealth of native plants and animals.</p>
<p>They made a living from the native grassy eucalypt woodlands, an ecosystem that extends from Cape York to Tasmania. In these healthy landscapes, vigorous pastures of tall perennial grasses protected the soil, enriched it with carbon and fed the cattle.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ipccs-land-report-shows-the-problem-with-farming-based-around-oil-not-soil-121643">IPCC's land report shows the problem with farming based around oil, not soil</a>
</strong>
</em>
</p>
<hr>
<p>NSW and Victoria have similar eucalypt grassy vegetation, but <a href="https://trove.nla.gov.au/work/16380796?q=pasture+improvement+in+australia&c=book&sort=holdings+desc&_=1586924950730&versionId=196760124">farming here has taken a very different path</a>. </p>
<p>Fertilised legumes and grasses grown for livestock fodder have replaced hundreds of native grassland plants. Over time, native trees and shrubs <a href="http://www.environment.gov.au/system/files/resources/386f395f-b2c6-4e10-8fc3-e937ad277bfe/files/white-and-yellow-box.pdf">stopped regenerating</a> and remaining trees became unhealthy, <a href="http://www.environment.gov.au/system/files/resources/386f395f-b2c6-4e10-8fc3-e937ad277bfe/files/white-and-yellow-box.pdf">destroying wildlife habitat</a>. The transformation was hastened by <a href="https://trove.nla.gov.au/work/16380796?q=pasture+improvement+in+australia&c=book&sort=holdings+desc&_=1586924950730&versionId=196760124">aerial applications of fertiliser and herbicide</a>. </p>
<p>By 2006, 4.5 million hectares of box-gum grassy woodland – or 90% – in temperate Australia had been <a href="http://www.environment.gov.au/system/files/pages/dcad3aa6-2230-44cb-9a2f-5e1dca33db6b/files/box-gum.pdf">destroyed</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/325450/original/file-20200404-74220-lu4kpp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325450/original/file-20200404-74220-lu4kpp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325450/original/file-20200404-74220-lu4kpp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325450/original/file-20200404-74220-lu4kpp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325450/original/file-20200404-74220-lu4kpp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325450/original/file-20200404-74220-lu4kpp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325450/original/file-20200404-74220-lu4kpp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Aerial delivery of fertiliser, seed and herbicide transformed grassy woodlands in NSW.</span>
<span class="attribution"><span class="source">F. G. Swain. Author provided.</span></span>
</figcaption>
</figure>
<h2>A template for sustainability</h2>
<p>Back in Queensland in the 1990s, my colleagues and I devised a <a href="https://www.publish.csiro.au/book/4749">template</a> for sustainable land use. Funded by the livestock industry and a now-defunct federal corporation, we worked with producers and government agencies to find the right balance between farm production and conserving natural resources. </p>
<p>Our research concluded that for farming to be sustainable, <a href="https://www.youtube.com/watch?v=YG0I8nVXcbg">intensive land uses</a> must be limited. Such intensive uses include crops and non-native pastures. They are “high input”, typically requiring fertilisers, herbicides and pesticides, and some form of cultivation. They return greater yields but kill native plants, and are prone to soil and nutrient runoff into waterways.</p>
<p>But our template was not adopted as conventional farming practice. In the past 20 years, Australia’s cropping area has <a href="https://www.agriculture.gov.au/abares/aclump/land-use-change-overview/national-scale-examples">increased</a> by 18,200 square kilometres.</p>
<p>By 2019, 38,000 square kilometres of poplar box grassy woodland in Australia had been cleared – more than half the size of Tasmania. The ecosystem was listed as <a href="http://www.environment.gov.au/cgi-bin/sprat/public/publiclookupcommunities.pl">endangered in 2019</a>. Until that point, it had been considered <a href="http://www.environment.gov.au/biodiversity/threatened/communities/pubs/141pb-conservation-advice.pdf">invasive native scrub in NSW</a> – exempting it from clearing regulations – and was systematically cleared for agriculture in Queensland. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/345299/original/file-20200702-111353-10i55s3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345299/original/file-20200702-111353-10i55s3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=367&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345299/original/file-20200702-111353-10i55s3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=367&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345299/original/file-20200702-111353-10i55s3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=367&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345299/original/file-20200702-111353-10i55s3.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=461&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345299/original/file-20200702-111353-10i55s3.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=461&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345299/original/file-20200702-111353-10i55s3.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=461&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Farmers should conserve sufficient areas of landscape to support native plants and animals.</span>
<span class="attribution"><span class="source">Sue McIntyre</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Regenerating the land</h2>
<p>Hearteningly, our research was recently <a href="https://www.vbs.net.au/long-term-research/">revived</a> in a multidisciplinary study of regenerative grazing on the grassy woodlands of NSW. The template was used to assess the ecological condition of participating farms.</p>
<p>The study examined differences in profitability between graziers who had adopted regenerative techniques such as low-input pasture management, and all other sheep, sheep-beef and mixed cropping-grazing farmers in their region. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/three-ways-farms-of-the-future-can-feed-the-planet-and-heal-it-too-128853">Three ways farms of the future can feed the planet and heal it too</a>
</strong>
</em>
</p>
<hr>
<p>It found regenerative grazing was often more profitable than other types of farming, especially in dry years. Regenerative farmers also experienced significantly higher than average well-being compared with other NSW farmers.</p>
<p>So what does our <a href="https://www.sciencedirect.com/science/article/abs/pii/S0167880912000291?via%3Dihub">template involve</a>? First, it identifies four types of land use relevant to farmed grassy woodland regions.</p>
<p>Second, it specifies the proportion of land that should be allocated to each use, in order to achieve landscape health (see pie chart below). The proportions can be applied to single farm, or entire districts or regions.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/325448/original/file-20200404-74220-ojf0wk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325448/original/file-20200404-74220-ojf0wk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=587&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325448/original/file-20200404-74220-ojf0wk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=587&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325448/original/file-20200404-74220-ojf0wk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=587&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325448/original/file-20200404-74220-ojf0wk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=737&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325448/original/file-20200404-74220-ojf0wk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=737&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325448/original/file-20200404-74220-ojf0wk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=737&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">How to sustain production, natural resources and native flora and fauna on a landscape or farm.</span>
<span class="attribution"><span class="source">Sue McIntyre</span></span>
</figcaption>
</figure>
<p>Intensive land use involves activities that replace nearly all native species. If these activities occupy more than 30% of the landscape, there’s insufficient habitat to maintain many native species, especially plants. </p>
<p>At least 10% of land must be devoted to nature conservation. The remaining 60% of the land should involve low-intensity activity such as grazed native pasture and timber production. If managed well, these land uses can support human livelihoods and a diversity of native species.</p>
<p>Within that split of land use, total native woodland should be no less than 30%. This guarantees connected habitats for native plants and animals, enabling movement and breeding opportunities.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/345522/original/file-20200703-33913-149u3o2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/345522/original/file-20200703-33913-149u3o2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/345522/original/file-20200703-33913-149u3o2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/345522/original/file-20200703-33913-149u3o2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/345522/original/file-20200703-33913-149u3o2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/345522/original/file-20200703-33913-149u3o2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/345522/original/file-20200703-33913-149u3o2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Retaining grassy woodland ensures habitat for native animals.</span>
<span class="attribution"><span class="source">Duncan McCaskill/Flickr</span></span>
</figcaption>
</figure>
<h2>Respect the land’s limits</h2>
<p>Australians ask a lot of our land. It must make space for our houses, businesses, and roads. It should support all species to prevent extinctions. And it must produce our food and fibre.</p>
<p>Global population growth demands a rapid rise in <a href="https://www.wri.org/blog/2018/12/how-sustainably-feed-10-billion-people-2050-21-charts">food production</a>. But relying on intensive agriculture to achieve this is unsustainable. Aside from damaging the land, it increases greenhouse gas emissions though mechanisation, fertilisation, chemical use and tree clearing. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australian-farmers-are-adapting-to-climate-change-76939">Australian farmers are adapting to climate change</a>
</strong>
</em>
</p>
<hr>
<p>To meet the challenges of the future we must ensure farmed landscapes retain their <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.12689">ecological functions</a>. In particular, maintaining biodiversity is <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.12689">key to climate adaptation</a>. And as many of Australia’s plants and animals march towards extinction, the need to reverse biodiversity loss has never been greater.</p>
<p>Farmers can be profitable while maintaining and improving the ecological health of their land. It’s time to look harder at farming models that respect the limits of nature, and recognise that less can be more.</p><img src="https://counter.theconversation.com/content/130877/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sue McIntyre is a member of Bush Heritage Australia and volunteers for Landcare Australia. </span></em></p>
It’s painfully clear nature is buckling under the weight of farming’s demands. There’s another way – but it involves accepting nature’s limits.
Sue McIntyre, Honorary Professor, Australian National University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/129175
2020-02-06T13:45:39Z
2020-02-06T13:45:39Z
Soil carbon is a valuable resource, but all soil carbon is not created equal
<figure><img src="https://images.theconversation.com/files/313401/original/file-20200203-41490-e2t1q4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4031%2C3024&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Planting cover crops, like this red clover in Sussex County, Delaware, can help return carbon to farm fields.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/2i9AvF4">Michele Dorsey Walfred/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Human society is literally built on soil. It feeds the world and produces vital fuel and fiber. But most people rarely give soil a second thought.</p>
<p>Recently, though, soil has been getting some well-deserved attention from environmental organizations, policymakers and industry leaders. It has been covered in <a href="https://www.nytimes.com/2018/04/18/magazine/dirt-save-earth-carbon-farming-climate-change.html">news articles</a>, argued over in policy debates and has even received an international <a href="http://www.fao.org/world-soil-day/en/">day of recognition</a>. </p>
<p>Why all this attention? Because the world urgently needs ways to keep carbon out of the atmosphere, and to build food security for a rapidly growing global population. Soil can do both. </p>
<p>However, current efforts to promote carbon storage in soil miss a key point: Not all soil carbon is the same. As scientists focusing on <a href="https://scholar.google.com/citations?user=Jg8EQ28AAAAJ&hl=en">soil ecology</a> and <a href="https://scholar.google.com/citations?user=1rl-6DIAAAAJ&hl=en">sustainability</a>, we believe that managing soil carbon effectively requires taking its differences into account.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/313841/original/file-20200205-149789-ahxxv8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/313841/original/file-20200205-149789-ahxxv8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313841/original/file-20200205-149789-ahxxv8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=671&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313841/original/file-20200205-149789-ahxxv8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=671&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313841/original/file-20200205-149789-ahxxv8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=671&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313841/original/file-20200205-149789-ahxxv8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=843&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313841/original/file-20200205-149789-ahxxv8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=843&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313841/original/file-20200205-149789-ahxxv8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=843&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">How carbon cycles into and out of soil.</span>
<span class="attribution"><span class="source">Jocelyn Lavallee</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Soil carbon is amazingly complex</h2>
<p>Building up soil carbon can help cut greenhouse gas concentrations in the air. It also improves soil quality in many ways: It gives soil structure, stores water and nutrients that plants need and feeds <a href="https://theconversation.com/to-restore-our-soils-feed-the-microbes-79616">vital soil organisms</a>.</p>
<p>But carbon in soil doesn’t exist on its own. It is combined with oxygen, hydrogen, nitrogen and other elements, in compounds that scientists collectively call soil organic matter. This material is amazingly complex stuff, made of thousands of different chemical compounds that remain from the decomposition and transformation of plants, animals and microorganisms. </p>
<p>Adding to this complexity, carbon can be found in different physical states within soil. It can be dissolved in water, present as larger chunks or “particulates,” enveloped by soil particles or bonded to minerals. These various forms all behave differently, and ultimately have very different impacts on plant growth, soil structure and carbon sequestration.</p>
<p>The challenge is how to conceptually divide up all of these different forms without getting completely lost in the muck. The soil science community – yes, we are out there! – has been studying this question for decades. As we discuss in a recent study, one key distinction can provide an underlying <a href="https://doi.org/10.1111/gcb.14859">framework for soil carbon management</a>: particulate organic matter versus mineral-associated organic matter.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ykgEwEOA25w?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The world’s soils are rapidly deteriorating due to soil erosion, nutrient depletion, loss of soil organic carbon and other threats.</span></figcaption>
</figure>
<h2>Like money in the bank</h2>
<p>Particulate organic matter is the stuff you generally can see. It contains partially decomposed organic fragments, such as tiny bits of leaves or roots. Mineral-associated organic matter consists mostly of microscopic coatings on soil particles, derived mainly from the bodies and byproducts of microorganisms and certain plant compounds.</p>
<p>One key difference between the two is that mineral-associated organic matter is stuck to soil particles, so it tends to stay there for a long time. Particulate organic matter, on the other hand, is freely available to microorganisms, so it gets broken down much faster. It’s also more vulnerable to agricultural practices like tillage that disturb the soil.</p>
<p>A second key difference is their <a href="https://doi.org/10.1038/s41561-019-0484-6">nutrient contents</a>. Remember that organic matter contains not just carbon but lots of other elements, including nitrogen, a natural fertilizer that plants need to thrive.</p>
<p>Mineral-associated organic matter contains more nitrogen per unit of carbon than particulate organic matter, but because mineral-associated organic matter is less available and cycles more slowly, that nitrogen isn’t all usable. Particulate organic matter, meanwhile, contains less nitrogen relatively speaking, but that nitrogen is more readily available.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/313585/original/file-20200204-41503-6nwiel.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/313585/original/file-20200204-41503-6nwiel.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313585/original/file-20200204-41503-6nwiel.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=587&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313585/original/file-20200204-41503-6nwiel.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=587&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313585/original/file-20200204-41503-6nwiel.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=587&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313585/original/file-20200204-41503-6nwiel.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=737&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313585/original/file-20200204-41503-6nwiel.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=737&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313585/original/file-20200204-41503-6nwiel.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=737&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Overview of how particulate and mineral-associated organic matter form and function.</span>
<span class="attribution"><span class="source">Jocelyn Lavallee</span></span>
</figcaption>
</figure>
<p>It helps to think about these two types of soil carbon like <a href="https://landinstitute.org/video-audio/soil-organic-matter-humanitys-true-capital/">a checking and a savings account</a>. Particulate organic matter is the checking account: It receives money every payday, but gets spent pretty quickly to cover everyday expenses. Mineral-associated organic matter is the savings account. It usually receives less money from each paycheck, but that money isn’t spent as quickly. </p>
<p>When humans face a big unexpected expense, they typically will drain their checking accounts and may also dip into their savings accounts. If this happens over and over, eventually both accounts go broke. </p>
<p>This is exactly what happens when an ecosystem loses lots of soil carbon – for example, when a meadow is plowed and converted to crop fields. Plowing causes faster carbon breakdown, so the existing particulate organic matter is lost rapidly. Mineral-associated organic matter is often the only thing left to help sustain soil life and plant growth. </p>
<p>To make matters worse, annual crops tend to have tiny roots that do not add much carbon into the soil; put another way, they have very low paychecks. This means that particulate organic matter and mineral-associated organic matter aren’t replenished and continue to decline. Without a boost of “cash,” in the form of more decomposing plant matter, soils will go broke and become less healthy and productive.</p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/B29bR8kAKQ3","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p>
<h2>Managing soil carbon for climate change and food security</h2>
<p>Initiatives such as “<a href="https://www.4p1000.org/">4 per mille</a>” and <a href="https://terraton.indigoag.com/">Terraton</a> aim to sequester huge amounts of carbon in soil. The <a href="https://agfundernews.com/senate-passes-farm-bill-with-incentives-for-farmers-to-build">2018 U.S. Farm Bill</a> includes the first-ever incentives for farmers to adopt practices aimed at improving soil health and sequestering carbon. But these initiatives are missing a key point: not all soil carbon is the same.</p>
<p>The very different lifetimes of particulate organic matter and mineral-associated organic matter have important implications for these efforts. For example, adding low-quality crop residues to agricultural fields would likely create more particulate organic matter than mineral-associated organic matter. This could increase soil carbon in the short term – but if that field later is disturbed by tilling, a lot of it would decompose and the benefit would be quickly reversed. The best practices focus on building up mineral-associated organic matter for longer-term carbon storage, while also producing high-quality particulate organic matter with lots of nitrogen to help boost crop productivity. </p>
<p>Natural healthy soils show us that providing continuous and diverse plant inputs that reach all the way to deep soil are key for achieving both high mineral-associated organic matter storage and particulate organic matter recycling. There are many promising ways to do this, such as maintaining <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/climatechange/?cid=stelprdb1077238">plant cover</a> on fields year-round; growing diverse crops that include high-nitrogen legumes and <a href="https://landinstitute.org/video-audio/soil-organic-matter-humanitys-true-capital/">perennials with deep roots</a>; and minimizing tillage.</p>
<p>However, not all soils can accumulate both mineral-associated organic matter and particulate organic matter. Before implementing any management practices for carbon sequestration, participants should first assess the <a href="https://doi.org/10.1038/s41561-019-0484-6">carbon storage potential of the local soil</a>, much as a doctor studies a patient before prescribing a cure.</p>
<p>Sequestering soil carbon effectively requires an understanding of how particulate organic matter and mineral-associated organic matter work, how human actions affect them, and how to build up both types to meet our planet’s climate and food security needs.</p>
<p>[ <em>Insight, in your inbox each day.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=insight">You can get it with The Conversation’s email newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/129175/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Francesca Cotrufo receives funding from NSF, USDA, DOE, FFAR, Shell, McDonalds. </span></em></p><p class="fine-print"><em><span>Jocelyn Lavallee does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Storing more carbon in soil helps slow climate change and makes croplands more productive. But there are two kinds of soil carbon that are both important, but function very differently.
Jocelyn Lavallee, Research Scientist, Colorado State University
Francesca Cotrufo, Professor of Soil and Crop Sciences and Senior Scientist, Natural Resource Ecology Laboratory, Colorado State University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/108807
2019-05-07T11:20:36Z
2019-05-07T11:20:36Z
The deadly, life-giving and transient elements that make up group 15 of the periodic table
<figure><img src="https://images.theconversation.com/files/253989/original/file-20190115-152977-vkt7qa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The red tip on these matches contains phosphorus, which ignites when in contact with oxygen.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/group-red-wooden-matches-standing-burning-288725405?src=eYSqUzfy1HG_Jkkm4ApeAg-1-14">Andrew Rafalsky/Shutterstock.com</a></span></figcaption></figure><p>When you see the periodic table, what comes to mind? The pieces on a scrabble board? Maybe you think about your high school chemistry class. Maybe you think of the colorful table plastered on the wall of a lecture hall in college. Maybe you remember your favorite teacher setting something on fire in the front of the classroom. I am <a href="https://blog.richmond.edu/pollocklab/">an assistant professor of chemistry at University of Richmond</a> and when I hear the phrase “the periodic table,” I think about life. </p>
<p>I think about how the molecules and chemicals that surround us and dictate our everyday activities are made up of the elements on that table – they sustain our life, they bring beauty to the world and they are vital in medicine.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=320&fit=crop&dpr=1 600w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=320&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=320&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=402&fit=crop&dpr=1 754w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=402&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/252876/original/file-20190108-32136-l3sinu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=402&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Here is the periodic table with all the elements blocked excepted for the ones in group 15.</span>
<span class="attribution"><span class="source">Julie Pollock</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Each column of the periodic table is called a group. Every member of the group has a similar arrangement of electrons which can result in similar chemical properties. The group 15 elements – nitrogen, phosphorus, arsenic, antimony, bismuth and moscovium – are interesting to me because of their pivotal role in life, as well as in <a href="https://blog.richmond.edu/pollocklab/">my research lab</a>. One element we study is phosphorus because of its integral role in the fate of cells. </p>
<p>But before we get into those details, let’s take a brief look at each of the group 15 elements. They are a unique set in their history, uses and properties. </p>
<h2>Group 15 – giving life and causing death</h2>
<p>Nitrogen (N) in its atmospheric form (N₂) makes up approximately 78% of the air we breathe. When bacteria living within plant roots convert it into a usable form through a process called nitrogen fixation, this elemental form of nitrogen gets incorporated into many compounds that are <a href="https://www.wiley.com/en-us/Essential+Biochemistry%2C+3rd+Edition-p-9781118441688">necessary for life – proteins and DNA, for example</a>. At the bottom of the column is Moscovium (Mc), which is interesting because it doesn’t really exist in nature. It’s a radioactive element that can only be generated in a laboratory and <a href="https://doi.org/10.1038/s41557-018-0185-6">survives for less than a second</a>.</p>
<p>Arsenic (As) may be familiar to you because of its association with poisonings. In 1494, Pico della Mirandola, an Italian humanist philosopher during the Renaissance, was poisoned by arsenic, although the details surrounding his <a href="https://doi.org/10.1016/j.jflm.2018.03.016">early death are still debated</a>. For a long time it was believed that Napoleon Bonaparte died of arsenic exposure in 1821, but after <a href="https://doi.org/10.1373/clinchem.2008.117358">extensive comparisons of preserved hair samples</a> from different stages of his life, researchers concluded the increased levels of arsenic were most likely due to preservation techniques of the time. More recently, the World Health Organization estimated arsenic-contaminated drinking water in Bangladesh <a href="https://www.who.int/ipcs/assessment/public_health/arsenic/en/">resulted in over 9,000 deaths in 2001</a>. How arsenic poisons and kills isn’t completely understood, but there is no doubt that the element causes destruction of vital organs in the human body.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/271601/original/file-20190429-194612-1scvjok.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A woman from Sonargaon, Bangladesh, shows palms affected by years of drinking arsenic-laced water.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/a8a68bf484aa458c94cf5ad9bc639ac6/a8a68bf484aa458c94cf5ad9bc639ac6/3/1">AP Photo/ A.M. Ahad</a></span>
</figcaption>
</figure>
<p>When the element antimony (Sb) is combined with three oxygen atoms to form antimony trioxide, it is used extensively as a flame retardant for furniture, carpets, drapes, rubber, plastics and adhesives. Quantities of this molecule in these household products tend to be very small, <a href="http://doi.org/10.17226/9841">and these levels of antimony are regarded as safe</a>. </p>
<p>Bismuth (Bi) is a metal found in the same row of the periodic table as a number of toxic metals; however, compounds containing bismuth are harmless. Bismuth compounds can be found in cosmetics due to their distinctive and desirable silvery shimmer. Even if you haven’t used bismuth-containing personal care products, you have probably encountered it in the well-known antacid Peptobismol®, which is <a href="https://doi.org/10.1038/nchem.609">used to treat upset stomachs</a>, or on the Fourth of July when you are watching fireworks. It is a bismuth compound that causes the crackling sounds of the <a href="https://www.youtube.com/watch?reload=9&v=ix8uHBtxxcE">dragon egg fireworks</a>.</p>
<p>Last, but not least, of the group 15 elements is phosphorus (P). It was discovered in 1669 by the alchemist Hennig Brandt and named from the Greek word “phosphoros,” meaning <a href="https://doi.org/10.1007/s11837-007-0071-y">bringer of light</a>. That’s because when the elemental form interacts with atmospheric oxygen it produces a brilliant light. Chemists figured out how to harness the power of this reaction for the development of matches. The red tip on a match still contains a form of phosphorus today.</p>
<h2>Phosphates – regulating cancer cell fate</h2>
<p>In addition to sparks generated by the element, phosphorus is found in a compound known as a phosphate: phosphorus linked to four oxygen atoms. In cells, when a phosphate molecule is attached to a protein, it can turn on, or activate, the protein so that it can perform its function in the cell – like stimulating growth. </p>
<p>When the phosphate is no longer attached to the protein, the cells stop growing. You can think of it almost like the matches described above – when the phosphate is there, the match can ignite and business can proceed. When the phosphate is removed, the match is just a stick and no light is provided; not as much work can happen in the dark. </p>
<p>In cancerous cells, the <a href="https://doi.org/10.1046/j.0014-2956.2001.02473.x">phosphate status is out of control</a>. Imagine a lot of lit matches and a very bright room that can result in a flurry of activity. This activity can have severe consequences for cells. For example, unregulated growth and migration can lead to cancer. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=303&fit=crop&dpr=1 600w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=303&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=303&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/252877/original/file-20190108-32154-1cpc0s5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Phosphorylation in cancer cells: When a protein is phosphorylated, it is like a lit match in a room that leads to cancer cell growth. If the phosphate is removed, the match is extinguished and the cells don’t grow as much.</span>
</figcaption>
</figure>
<p>In <a href="https://blog.richmond.edu/pollocklab/">my laboratory</a> at the University of Richmond, we are interested in understanding these phosphates and one protein in particular that interacts with them. This protein, called MEMO1, is found in high quantities in breast cancer patients and helps the phosphates to always stay attached to proteins. We are trying to understand <a href="https://doi.org/10.1021/acs.biochem.8b00582">how MEMO1 interacts with these phosphates</a> and are developing strategies to disrupt those interactions. </p>
<p>We hope that our work reveals a way to help remove the phosphates to stop the unchecked growth of cells – in other words, to blow out the matches.</p>
<p>So next time you hear the words “periodic table,” please think of life. Think of the molecules that you encounter every moment of every day, think of the medicine that keeps you healthy and think of those of us who are working to understand how to keep you that way.</p><img src="https://counter.theconversation.com/content/108807/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julie Pollock receives research funding from the University of Richmond, the Mary Louise Andrews Award for Cancer Research from the Virginia Academy of Sciences, the Jeffress Memorial Trust and the Beckman Foundation. </span></em></p>
The elements that make up each column of the periodic table share a set of common traits. Here, a chemist describes group 15 and the crucial role phosphorus, in particular, plays in cancer.
Julie Pollock, Assistant Professor of Chemistry, University of Richmond
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/113264
2019-03-19T10:44:06Z
2019-03-19T10:44:06Z
Wastewater is an asset – it contains nutrients, energy and precious metals, and scientists are learning how to recover them
<figure><img src="https://images.theconversation.com/files/264422/original/file-20190318-28479-189zeqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Aeration tanks at the Oaks wastewater treatment plant in New Providence, Penn.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/2aA2E9C">Montgomery County Planning Commission</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Most people think as little as possible about the wastewater that is produced daily from their showers, bathtubs, sinks, dishwashers and toilets. But with the right techniques, it can become a valuable resource.</p>
<p>On average, every Americans uses <a href="http://www.waterrf.org/PublicReportLibrary/4309A.pdf">about 60 gallons of water per day</a> for purposes that include flushing toilets, showering and doing laundry. This figure can easily double if outdoor uses, such as watering lawns and filling swimming pools, are also included. </p>
<p>Most of the used water will eventually become wastewater that must be <a href="https://water.usgs.gov/edu/wuww.html">treated before it can be discharged into nature</a>. And that treatment uses a lot of energy. According to the U.S. Environmental Protection Agency, water and wastewater facilities account for <a href="https://www.epa.gov/sites/production/files/2015-08/documents/wastewater-guide.pdf">more than a third of municipal energy budgets</a>. </p>
<p>My research focuses on <a href="https://scholar.google.com/citations?user=5Zv3mM0AAAAJ&hl=en">recovering resources from wastewater</a>. This process is difficult because wastewater contains many different types of contaminants. But researchers in our fields are exploring many creative ways to make valuable products from them. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/264424/original/file-20190318-28496-cvbo9s.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264424/original/file-20190318-28496-cvbo9s.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264424/original/file-20190318-28496-cvbo9s.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264424/original/file-20190318-28496-cvbo9s.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264424/original/file-20190318-28496-cvbo9s.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264424/original/file-20190318-28496-cvbo9s.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264424/original/file-20190318-28496-cvbo9s.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264424/original/file-20190318-28496-cvbo9s.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="source" href="https://www.epa.gov/watersense/how-we-use-water">EPA</a></span>
</figcaption>
</figure>
<h2>Energy from organic materials</h2>
<p>Diehard wastewater engineers understand the value of wastewater, which they view as an asset rather than a waste. That’s why some of them call it “used water” instead, and refer to what most people call wastewater treatment plants as water resource recovery facilities. </p>
<p>In fact, wastewater can contain <a href="http://dx.doi.org/10.1021/es2014264">more than three times the amount of energy needed to treat it</a>. One simple and mature technique for recovering part of this energy is <a href="https://www.epa.gov/anaerobic-digestion/basic-information-about-anaerobic-digestion-ad">anaerobic digestion</a>, a natural process in which microorganisms feed on grease and other organic materials in wastewater and produce biogas, just as yeast can eat up barley and spit out beer. Biogas contains <a href="https://www.epa.gov/agstar/benefits-anaerobic-digestion">roughly 50 percent methane</a>, which can be used as a renewable fuel for boilers, furnaces and heating systems or to turn turbines and generate electricity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/264431/original/file-20190318-28499-104k6ig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264431/original/file-20190318-28499-104k6ig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264431/original/file-20190318-28499-104k6ig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264431/original/file-20190318-28499-104k6ig.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264431/original/file-20190318-28499-104k6ig.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264431/original/file-20190318-28499-104k6ig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264431/original/file-20190318-28499-104k6ig.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264431/original/file-20190318-28499-104k6ig.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Inside these anaerobic ‘egg’ digesters at the Deer Island Treatment Plant on Boston Harbor, microbes break down sewage sludge and scum into methane gas, carbon dioxide, water and organic solids that are processed into fertilizer.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Deer_Island_Waste_Water_Treatment_Plant#/media/File:Deerislandeggs.jpg">Frank Hebbert/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>More advanced techniques, such as <a href="http://www.genifuel.com/process.html">hydrothermal processes</a>, take sewage sludge – the solids removed from wastewater during treatment – and convert it into biobased fuels that can be used to replace gasoline and diesel fuel. This process is currently at the <a href="https://www.thesourcemagazine.org/genifuel-to-pilot-biofuel-processing-technology-in-vancouver/">demonstration stage</a>. </p>
<p>In additional to sewage sludge, many researchers – including me – are very interested in microalgae. Microalgae are <a href="https://www.energy.gov/sites/prod/files/2016/06/f33/national_algal_biofuels_technology_review.pdf">promising feedstocks for biofuels</a>, and some of them can grow in wastewater. My colleagues and I have designed hydrothermal systems to <a href="http://dx.doi.org/10.1021/acs.est.8b04035">turn wastewater-grown microalgae into biofuels</a>. They are still being tested in the lab, but we hope to scale them up in the near future.</p>
<h2>Mining nutrients from wastewater</h2>
<p>Wastewater also contains nutrients like nitrogen and phosphorus, which are essential elements that plants need to grow. In current wastewater treatment processes, we use energy to <a href="https://www.barnstablecountyhealth.org/resources/publications/compendium-of-information-on-alternative-onsite-septic-system-technology/basics-of-wastewater-treatment">convert ammonia in the wastewater</a>, which comes <a href="https://pubs.acs.org/doi/abs/10.1021/es0301018">mostly from urine</a>, into nitrogen gas. However, industries then use large quantities of natural gas to convert nitrogen gas back into ammonia, predominantly for producing fertilizer, through the <a href="https://web.archive.org/web/20080424083111/http://www.fertilizer.org/ifa/statistics/indicators/ind_reserves.asp">Haber-Bosch process</a>. </p>
<p>Clearly, it would be much more efficient to directly extract the ammonia from wastewater without converting it. One way is to use urine-diverting toilets, which already are <a href="https://www.toilettech.com/udseats">commercially available</a>, to <a href="https://theconversation.com/reinventing-the-toilet-urine-diversion-where-its-needed-most-9576">separate urine from other sources of wastewater</a>. Then the collected urine could be used as fertilizer after sanitizing it to remove pathogens. </p>
<p>Sanitized urine also contains other nutrients like phosphorus and potassium. The <a href="http://richearthinstitute.org/our-work/">Rich Earth Institute</a>, a Vermont-based nonprofit supported by federal agencies and foundations, is researching ways to turn human urine into fertilizer. The institute is testing harvested urine on real crops, and has found that <a href="https://www.npr.org/2018/02/01/582338635/could-harvesting-urine-ease-demand-for-phosphorus">it works effectively</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/xAUL8ySO1l8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Using pasteurized urine as fertilizer reduces waste and resource extraction.</span></figcaption>
</figure>
<p>Alternatively, we can recover these nutrients as <a href="https://en.wikipedia.org/wiki/Struvite">struvite</a>, or magnesium ammonium phosphate, a mineral that contains magnesium, nitrogen and phosphorus. Struvite can naturally form during wastewater treatment processes, but tends to deposit in tanks and pipes and will damage the equipment if left unattended. By controlling the formation of struvite, it can be recovered in separate reactors. </p>
<p>Researchers have tested recovered struvite on crops in laboratories and achieved yields <a href="https://phosphorusplatform.eu/scope-in-print/scope-in-press/1346-scope-struvite-as-fertiliser">comparable to commercial fertilizers</a>. The technique is still maturing, but companies are developing <a href="http://www.veoliawatertech.com/news-resources/datasheets/53931.htm">commercial versions for wastewater treatment plants</a>.</p>
<h2>More possibilities</h2>
<p>Want more valuable stuff? Wastewater is <a href="https://theconversation.com/mining-for-metals-in-societys-waste-43766">literally a gold mine</a>. It contains metals <a href="http://dx.doi.org/%2010.1021/es505329q">valued up to millions of U.S. dollars per year</a>. These metals are often toxic to aquatic life, so they need to be removed. But conventional removal technologies <a href="https://doi.org/10.1016/j.arabjc.2010.07.019">require a lot of energy and produce toxic sludge</a>. </p>
<p>Researchers are developing new ways to remove and reuse these metals, including membrane systems that can <a href="https://doi.org/10.1038/nnano.2015.310">selectively remove precious metals from water</a> and biosystems that <a href="http://dx.doi.org/10.1088/1757-899X/358/1/012024">use microorganisms to recover them</a>. These techniques are at a very early stage and it is not clear yet whether they will make economic sense, but they have the potential to make wastewater more valuable.</p>
<p>In addition, wastewater is generally warmer than natural water supplies, especially in the winter, so it can serve as a heat source. This technique is <a href="https://en.wikipedia.org/wiki/Water_heat_recycling">well-established</a> and is not limited to commercial scale. You can install <a href="https://www.energy.gov/energysaver/water-heating/drain-water-heat-recovery">drain-water heat recovery systems</a> at home to lower your energy bill.</p>
<p>To me, this is just a beginning. With proper techniques, “wastewater” can offer us much more – and I very much look forward to the day when there is no “wastewater,” just “used water.”</p><img src="https://counter.theconversation.com/content/113264/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yalin Li does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
The ‘used water’ that flows from our showers, dishwashers and toilets isn’t a waste to engineers – it contains valuable materials. The challenge is recovering them and turning them into products.
Yalin Li, Ph.D. Candidate/Research Assistant, Colorado School of Mines
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/111161
2019-02-07T22:22:20Z
2019-02-07T22:22:20Z
Benefits of pulses: Good for you and the planet
<figure><img src="https://images.theconversation.com/files/257774/original/file-20190207-174890-1e1cr4n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The benefits of beans, lentils and other pulses go beyond the belly.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>An illogical revolution has swept the Canadian Prairies and can take over the world. Farmland is now never rested — it is planted and harvested every year — and yet soil health has improved. </p>
<p>Food production from this continually cropped land has skyrocketed — and its nutritional value has increased. Today’s production of more, better food from the same amount of healthier land means that tomorrow’s population may not go hungry. But is there logical science behind this illogical revolution?</p>
<p>Science, like revolutions, has many complexities, but key to this major change is a trio of farming tactics: planting pulses (beans, lentils and chickpeas, for example), rotating crops and embracing zero-till farming. </p>
<p>In simple gardeners’ terms that means we plant pulses one year, a cereal such as wheat or barley the next year and then an oil seed such as canola in the third year. And we never clean up the mess! After harvesting the grain or seeds, we leave the rest of the plant bits in the field, and we sow the next year’s crop directly into the field in amongst all that leftover plant residue. </p>
<p>It doesn’t look tidy, and it takes special equipment — but oh, the benefits!</p>
<h2>Why a pulse?</h2>
<p>Pulses naturally produce their own nitrogen. They take nitrogen from air in soil and get the bacteria living in specialized pockets in their roots to “fix,” or trap, the nitrogen so that it stays in the soil in a form that is readily available for plants to use. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/257783/original/file-20190207-174857-p2ymp3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/257783/original/file-20190207-174857-p2ymp3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=214&fit=crop&dpr=1 600w, https://images.theconversation.com/files/257783/original/file-20190207-174857-p2ymp3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=214&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/257783/original/file-20190207-174857-p2ymp3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=214&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/257783/original/file-20190207-174857-p2ymp3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=269&fit=crop&dpr=1 754w, https://images.theconversation.com/files/257783/original/file-20190207-174857-p2ymp3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=269&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/257783/original/file-20190207-174857-p2ymp3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=269&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Canada’s Food Guide has put an emphasis on lentils, chickpeas and other pulses.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Since nitrogen is a primary component of fertilizer, pulses basically produce their own fertilizer. Their roots, left in the ground after the crop has been harvested, leave nitrogen behind for the next crop so it doesn’t need as much fertilizer. </p>
<p>Over a nine-year test in the prairies, <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ldr.3172">planting a sequence of pulse-pulse-durum wheat every three years yielded 13 per cent more wheat than did planting grain-grain-durum wheat</a>. Planting pulses also reduced the carbon footprint of the durum wheat by 34 percent: the farmers used less fertilizer and less fuel, and saved more carbon. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-carbon-farming-can-help-solve-climate-change-86087">How carbon farming can help solve climate change</a>
</strong>
</em>
</p>
<hr>
<p>The <a href="http://www.bioline.org.br/pdf?ja05067">pulses are also highly nutritious</a>. They contain vitamins and micronutrients, and are incredibly rich in protein, with two-to-four times the protein content of cereal grains and significantly more iron, folate and zinc, which are crucial for good health and eyesight. </p>
<p>A <a href="https://doi.org/10.1080/03670244.2014.974593">diet of nutrient-dense pulses can benefit young and adolescent girls</a>. Pulses can be especially valuable to children who suffer from stunted growth, are underweight and malnourished because of insufficient amounts of a diet largely based on cereals with limited nutrients. </p>
<p><a href="https://food-guide.canada.ca/en/">Canada’s new Food Guide</a> also celebrates the value of pulses, advising people to eat more beans, peas and lentils. The combination of disease-preventing micronutrients and high protein content of pulses, along with their relatively easy, cheap cultivation, truly merit the term “superfood.”</p>
<h2>Working the soil</h2>
<p>And let’s not forget the benefits of leaving all our plant trash in the field. <a href="https://www.researchgate.net/publication/255583266_Direct_Seeding_and_Soil_Quality_on_the_Prairies">It makes the soil healthier, more productive and turns it into a better carbon sink</a>. As the plant residue decomposes, it gets incorporated into the soil. All the carbon in the plant material enters the soil and doesn’t contribute to airborne carbon dioxide. Plant residue helps the soil trap water better, and the water moves deeper into the ground so soil moisture increases. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/257778/original/file-20190207-174870-1a1a9ne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/257778/original/file-20190207-174870-1a1a9ne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/257778/original/file-20190207-174870-1a1a9ne.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/257778/original/file-20190207-174870-1a1a9ne.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/257778/original/file-20190207-174870-1a1a9ne.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/257778/original/file-20190207-174870-1a1a9ne.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/257778/original/file-20190207-174870-1a1a9ne.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Cut and fallen stalks from last-year’s harvest lay scattered on a field to improve soil quality.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<p>Couple that with zero-till, where we do not plough and clear the land but rather punch seeds in with special drills. All that carbon, water and nitrogen stay trapped in the soil and do not enter the atmosphere, and <a href="https://doi.org/10.1007/s13593-016-0404-8">reduce emissions by 25 per cent to 50 per cent</a>.</p>
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Read more:
<a href="https://theconversation.com/organic-agriculture-is-going-mainstream-but-not-the-way-you-think-it-is-92156">Organic agriculture is going mainstream, but not the way you think it is</a>
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<p>Now add in the benefits of pulses to those of trash and no-till. This triple whammy combination <a href="https://www.doi.org/10.1016/j.agsy.2013.08.009">improves every measure of environmental impact tested</a> — from the resources invested to ecosystem health to greenhouse gas emissions — some by as much as 35 per cent. Strikingly, the impact on human health also increases between three per cent to 28 per cent. </p>
<p>This year, the <a href="http://www.fao.org/news/story/en/item/1175295/icode/">United Nations declared Feb. 10 as the first-ever World Pulses Day</a>. Truly, that is important and worth celebrating. But revolutionary integration of pulses, agroecosystem management — the best combination of crops, animals, fertilizer, pest and water management — the very best land management technologies, and all the other knowledge we have and are learning, THAT is the revolution that will help us feed the world.</p><img src="https://counter.theconversation.com/content/111161/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mary Buhr is a member of Agriculture & Agrifood's Pulse Industry Roundtable. </span></em></p>
Today’s production of more, better food from the same amount land means that tomorrow’s population may not go hungry.
Mary Buhr, Dean and Professor, College of Agriculture & Bioresources, University of Saskatchewan
Licensed as Creative Commons – attribution, no derivatives.