tag:theconversation.com,2011:/uk/topics/soil-273/articlesSoil – The Conversation2024-03-26T17:01:48Ztag:theconversation.com,2011:article/2266432024-03-26T17:01:48Z2024-03-26T17:01:48ZThe ‘worm moon’ once marked the spring return of earthworms – until global warming kicked in<figure><img src="https://images.theconversation.com/files/584414/original/file-20240326-16-7psmz6.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5982%2C3970&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="source">Darkfoxelixir / shutterstock</span></span></figcaption></figure><p>The worm moon has risen. The final full moon of winter in the northern hemisphere appeared on <a href="https://www.theguardian.com/news/gallery/2024/mar/25/a-volcanic-eruption-and-a-worm-moon-photos-of-the-day">March 25</a> and owes its name to <a href="https://www.nationalgeographic.co.uk/2019/02/full-moon-names-explained">Native Americans</a> who noted winter’s end by the trails of earthworms it illuminated on the newly thawed soil. </p>
<p>Common names of full moons generally come from seasonal animals, colours or crops: wolf moon, pink moon, harvest moon. But the worm moon may be losing its significance, as climate change leads to wetter summers and milder winters in much of the world. I’ve been an earthworm scientist for more than three decades, and, of late, I’m seeing signs of worms at the surface in months when they used to be inactive.</p>
<p>To track how the worm moon might be changing we can look at a particular earthworm species (<em>Lumbricus terrestris</em>, aka the dew worm, nightcrawler or lob worm) which is unusually easy to track. Also sometimes called the common earthworm, if you see a big worm in the garden, it’s likely to be this species. </p>
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<p><em>Do the seasons feel increasingly weird to you? You’re not alone. Climate change is distorting nature’s calendar, causing plants to flower early and animals to emerge at the wrong time.</em></p>
<p><em>This article is part of a series, <a href="https://theconversation.com/uk/topics/wild-seasons-152175?utm_source=InArticleTop&utm_medium=TCUK&utm_campaign=WS">Wild Seasons</a>, on how the seasons are changing – and what they may eventually look like.</em></p>
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<p>Most worms spend most of their lives underground, but the dew worm almost completely leaves its deep burrow, with tail tip left in, as it ventures on to the soil surface every night to feed on dead leaves. These worms also mate on the soil surface. They may be hermaphrodite (both male and female) but still need to exchange sperm with a partner – each fertilising the other.</p>
<p>Such activities usually take place under the cover of darkness to avoid birds and other potential daytime predators. However, the worms are restricted by soil conditions at the top of the burrow. They cannot surface if the soil is baked dry (in summer) or frozen (in winter). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/584428/original/file-20240326-22-f8tpaz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Large worm in soil" src="https://images.theconversation.com/files/584428/original/file-20240326-22-f8tpaz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/584428/original/file-20240326-22-f8tpaz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/584428/original/file-20240326-22-f8tpaz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/584428/original/file-20240326-22-f8tpaz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/584428/original/file-20240326-22-f8tpaz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/584428/original/file-20240326-22-f8tpaz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/584428/original/file-20240326-22-f8tpaz.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>
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<span class="caption"><em>Lumbricus terrestris</em> is a large earthworm found across the world.</span>
<span class="attribution"><span class="source">D. Kucharski K. Kucharska / shutterstock</span></span>
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<p>In theory, the passing of winter would kickstart the surface activity (and therefore the worm moon). Yet if the winter isn’t that cold, we perhaps need to reconsider which moon should be termed the “worm moon”. Maybe a date earlier in the year would be better, or perhaps the term may cease to have any real meaning.</p>
<p>We can get a sense of how these earthworms can adapt to changing circumstances by looking at the northernmost populations, such as those in Finland, which are exposed to 24 hours of daylight in summer. These “white nights”, when the sky never gets dark, put additional stress on these worms as they cannot use darkness to hide from predators but must still feed and mate at the surface while conditions allow.</p>
<h2>Finland v Lancashire v Ohio</h2>
<p>A decade ago, colleagues and I set out to see if Finnish worms behaved any differently during the white night period to worms of the same species taken to Finland from lower latitudes. We <a href="https://www.sciencedirect.com/science/article/pii/S0038071714000248">compared native dew worms</a> from an area in south-west Finland at 60°N, with those from Lancashire in the UK (53°N) and Ohio in the US (40°N, more than 2,000km south of Finland), both of which have dark nights throughout the year.</p>
<p>We put these worms outdoors under ambient (white night) light in soil-filled drainpipes (1m deep) in a large, controlled temperature water bath (an old chest freezer with no lid). We looked at their feeding and mating, and, in parallel, repeated the experiment under darkened conditions at “night”. </p>
<p>In darkness, worms from all three origins were similarly very active in feeding and mating. </p>
<p>Under ambient conditions, the Finnish worms were generally the most active. They emerged earlier in the evening and ceased their activity later in the morning than those from the two more southerly populations. It seems the species had adapted to its conditions, with a normal reluctance to surface during daylight overtaken by a need to feed and mate.</p>
<p>Perhaps with warming soils, earthworms are becoming more active during traditionally colder or drier months. This will increase their effect on the soil – earthworms are ecosystem engineers and generally lead to increased soil fertility – which is generally positive, even if churning up the soil can lead to <a href="https://www.nature.com/articles/nclimate1692">further decomposition and greenhouse gas emissions</a>. </p>
<p>A worm moon and white nights would never normally appear in the same sentence. However, changes in the activities of worms as the global climate becomes less predictable means we may need to rethink at least one of our terms of reference that has marked time for hundreds or thousands of years. Enjoy the traditional worm moon while it lasts.</p><img src="https://counter.theconversation.com/content/226643/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Richard Butt 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>The last full moon of winter can illuminate earthworms in newly-thawed soil.Kevin Richard Butt, Reader in Ecology, University of Central LancashireLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2241522024-03-25T12:39:22Z2024-03-25T12:39:22ZWhat is dirt? There’s a whole wriggling world alive in the ground beneath our feet, as a soil scientist explains<figure><img src="https://images.theconversation.com/files/582688/original/file-20240318-24-77z9su.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C3110%2C2057&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Dig into soil and you'll find rock dust but also thousands of living species.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/little-childs-hands-digging-in-the-mud-royalty-free-image/619539728">ChristinLola/iStock/Getty Images Plus</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<blockquote>
<p><strong>What is dirt? – Belle and Ryatt, ages 7 and 5, Keystone, South Dakota</strong></p>
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<p>When you think about dirt, you’re probably picturing soil. There’s so much more going on under our feet than the rock dust, or “dirt,” that gets on your pants.</p>
<p>When <a href="https://arts-sciences.und.edu/academics/biology/brian-darby/index.html">I began studying soil</a>, I was amazed at how much of it is actually alive. Soil is teeming with life, and not just the earthworms that you see on rainy days.</p>
<p>Keeping this vibrant world healthy is <a href="https://www.youtube.com/watch?v=Qas9tPQKd8w">crucial for food, forests and flowers to grow</a> and for the animals that live in the ground to thrive. Here’s a closer look at what’s down there and how it all works together.</p>
<figure class="align-center ">
<img alt="Cupped hands holds soil against a dark background with a tendril of plant root dangling through the fingers." src="https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.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">
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<span class="caption">Soil is a vibrant ecosystem.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/bokeh-photography-of-person-carrying-soil-jin4W1HqgL4">Gabriel Jimenez via Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>The rocky part of soils</h2>
<p>If you scoop up a handful of dry soil, the basic dirt that you feel in your hand is actually very small pieces of <a href="https://passel2.unl.edu/view/lesson/c62dc027ae56/1">weathered rock</a>. These tiny bits eroded from larger rocks over millions of years.</p>
<p>The <a href="https://www.soils4teachers.org/physical-properties/">balance of these particles</a> is important for how well soil can hold water and nutrients that plants need to thrive. </p>
<p>For example, <a href="https://www.masterclass.com/articles/sandy-soil-guide">sandy soil</a> has larger rock grains, so it will be loose and can easily wash away. It won’t hold very much water. <a href="https://www.thespruce.com/understanding-and-improving-clay-soil-2539857">Soil with mostly clay</a> is finer and more compact, making it difficult for plants to access its moisture. In between the two in size is <a href="https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/what-is-silt.htm">silt, a mix of rock dust and minerals</a> often found in fertile flood plains.</p>
<p>Some of the most productive soils have a good balance of sand, clay and silt. <a href="https://www.masterclass.com/articles/how-to-create-loam-soil-for-your-garden">That combination</a>, along with the remnants of plants and animals that have died, helps the soil to retain water, allows plants to access that water and minimizes erosion from wind or rain.</p>
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<img alt="Three tipped over pots spill different types of soil – sandy is heavier grain, clay is finer grain and thicker, and loamy is darker." src="https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.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">
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<span class="caption">Loamy soil, ideal for gardens, is a mix of sand, clay and silt.</span>
<span class="attribution"><a class="source" href="https://www.nesdis.noaa.gov/learn-about-soil-types">NOAA</a></span>
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<h2>The wriggling, munching parts of soil</h2>
<p>Among all those rock particles is a <a href="https://doi.org/10.3390/app10113717">whole world of living things</a>, each busy doing its job.</p>
<p>To get a sense of just how many creatures are there, picture this: The zoo in Omaha, Nebraska, boasts <a href="https://www.omahazoo.com/">over 1,000 animal species</a>. But if you scooped up a small spoonful of soil in your backyard, it would likely contain <a href="https://www.ceh.ac.uk/our-science/case-studies/case-study-why-do-soil-microbes-matter">at least 10,000 species</a> and around a billion living microscopic cells.</p>
<p>Most of those species are <a href="https://www.westernsydney.edu.au/newscentre/news_centre/story_archive/2018/first_soil_atlas">still largely a mystery</a>. Scientists don’t know much about them or what they do in soil. In fact, most species in soil don’t even have a formal scientific name. But each plays some kind of role in the vast soil ecosystem, including generating the <a href="https://www.aces.edu/blog/topics/farming/essential-plant-elements/">nutrients that plants need to grow</a>.</p>
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<a href="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two centipede-like creatures caught on camera immediately after a rock is lifted." src="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=439&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=439&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=439&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=552&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=552&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=552&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">Lifting a rock reveals a symphylan, or garden centipede, left, and a poduromorph, or plump springtail, munching through the soil.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Symphylan_%26_poduromorph_springtail_(3406419924).jpg">Marshal Hedin via Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Imagine a leaf falling from a tree in late autumn.</p>
<p>Inside that leaf are a lot of nutrients that plants need, such as nitrogen, potassium and phosphorus. There is also a lot of <a href="https://scied.ucar.edu/learning-zone/earth-system/biogeochemical-cycles">carbon in that leaf</a>, which holds energy that can be used by other organisms such as bacteria and fungi.</p>
<p>The leaf itself is too large for a plant to take up through its roots, of course. But that leaf can be broken down into smaller and smaller pieces. This process of breaking down plant and animal tissue is <a href="https://youtu.be/IBvKKMzXYtY?feature=shared">known as decomposition</a>.</p>
<p>When the leaf first falls to the ground, <a href="https://doi.org/10.3390%2Finsects11010054">arthropods</a> – such as insects, mites and <a href="https://www.chaosofdelight.org/collembola-springtails">collembolans</a> – break the leaf down into smaller chunks by shredding the tissue. Then, an <a href="https://youtu.be/n3wsUYg3XV0?feature=shared">earthworm might come along</a> and eat one of the smaller chunks and break it down even more in <a href="https://www.pbs.org/video/how-do-worms-turn-garbage-into-compost-jwj6cm/">its digestive tract</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/2Pa1FwmKZcQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">PBS explores how earthworms help turn dead plants into fertile soil.</span></figcaption>
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<p>Now the broken-up leaf is small enough for microbes to come in. <a href="https://ohioline.osu.edu/factsheet/anr-36">Bacteria</a> and <a href="https://ohioline.osu.edu/factsheet/anr-37">fungi secrete enzymes</a> into the soil that further break down organic material into even smaller pieces. If enough microbes are active, eventually this organic material will be broken down enough that it can dissolve in water and be taken up by plants that need it.</p>
<p>To aid in this process, there are many small animals, such as <a href="https://www.canr.msu.edu/news/are_soil_nematodes_beneficial_or_harmful">nematodes</a> and <a href="https://www.livingsoil.net/protozoa">amoebae</a>, that consume bacteria and fungi. There are also predatory nematodes that feed on other nematodes to make sure they don’t become too abundant, so everything remains in balance as much as possible. </p>
<p>It’s quite a complicated food web of interacting species in a delicate balance.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/IBvKKMzXYtY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A time-lapse video filmed about 4 inches underground shows a leaf decomposing over 21 days in July. At the end, radish roots make their way down into the soil. Video by Josh Williams.</span></figcaption>
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<p>While some fungi and bacteria <a href="https://www.growingagreenerworld.com/bacteria-fungus-and-viruses-an-overview/">can harm plants</a>, there are many species that are considered beneficial. In fact, they <a href="https://www.nrcs.usda.gov/conservation-basics/natural-resource-concerns/soils/soil-health">may be the key</a> to figuring out how to grow enough crops to feed everyone without degrading and overburdening the soil.</p>
<h2>Figuring out your soil type</h2>
<p>Scientists have named <a href="https://www.nrcs.usda.gov/resources/education-and-teaching-materials/soil-facts">over 20,000 different types</a> of unique soils. If you’re curious about the <a href="https://www.nesdis.noaa.gov/learn-about-soil-types">soil and dirt in your area</a>, the University of California, Davis has a <a href="https://casoilresource.lawr.ucdavis.edu/gmap/">website where you can learn</a> more about local soils and their chemical and physical attributes.</p>
<p><a href="https://www.farmers.gov/conservation/soil-health">Caring for soil</a> to promote its living creatures’ benefits and minimize their harm takes work, but it’s essential for keeping the land healthy and growing food for the future.</p>
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<p class="fine-print"><em><span>Brian Darby receives funding from the United States Department of Agriculture. </span></em></p>Rock dust is only part of the story of soil. Living creatures, many of them too tiny to see, keep that soil healthy for growing everything from food to forests.Brian Darby, Associate Professor of Biology, University of North DakotaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2221082024-03-22T12:34:47Z2024-03-22T12:34:47ZClimate change is shifting the zones where plants grow – here’s what that could mean for your garden<figure><img src="https://images.theconversation.com/files/583569/original/file-20240321-20-wkg9tp.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C4019%2C2474&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Climate change complicates plant choices and care. Early flowering and late freezes can kill flowers like these magnolia blossoms.</span> <span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>With the <a href="https://www.pbs.org/newshour/science/the-vernal-equinox-marks-the-first-day-of-spring-what-does-that-mean">arrival of spring</a> in North America, many people are gravitating to the gardening and landscaping section of home improvement stores, where displays are overstocked with eye-catching seed packs and benches are filled with potted annuals and perennials. </p>
<p>But some plants that once thrived in your yard may not flourish there now. To understand why, look to the U.S. Department of Agriculture’s recent update of its <a href="https://planthardiness.ars.usda.gov/">plant hardiness zone map</a>, which has long helped gardeners and growers figure out which plants are most likely to thrive in a given location. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A U.S. map divided into colored geographic zones with a numbered key." src="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?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 2023 USDA plant hardiness zone map shows the areas where plants can be expected to grow, based on extreme winter temperatures. Darker shades (purple to blue) denote colder zones, phasing southward into temperate (green) and warm zones (yellow and orange).</span>
<span class="attribution"><a class="source" href="https://planthardiness.ars.usda.gov/">USDA</a></span>
</figcaption>
</figure>
<p>Comparing the 2023 map to the previous version from 2012 clearly shows that as climate change warms the Earth, plant hardiness zones are shifting northward. On average, the coldest days of winter in our current climate, based on temperature records from 1991 through 2020, are 5 degrees Fahrenheit (2.8 Celsius) warmer than they were between 1976 and 2005. </p>
<p>In some areas, including the central Appalachians, northern New England and north central Idaho, winter temperatures have warmed by 1.5 hardiness zones – 15 degrees F (8.3 C) – over the same 30-year window. This warming changes the zones in which plants, whether annual or perennial, will ultimately succeed in a climate on the move.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="U.S. map showing large areas colored tan, denoting a 5-degree increase in average winter minimum temperatures." src="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This map shows how plant hardiness zones have shifted northward from the 2012 to the 2023 USDA maps. A half-zone change corresponds to a tan area. Areas in white indicate zones that experienced minimal change.</span>
<span class="attribution"><a class="source" href="https://site.extension.uga.edu/climate/2023/11/new-usda-plant-hardiness-zone-map-shows-most-of-southeast-has-gotten-one-half-zone-warmer/">Prism Climate Group, Oregon State University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>As a <a href="https://scholar.google.com/citations?user=frEPl6IAAAAJ&hl=en">plant pathologist</a>, I have devoted my career to understanding and addressing plant health issues. Many stresses not only shorten the lives of plants, but also affect their growth and productivity. </p>
<p>I am also a gardener who has seen firsthand how warming temperatures, pests and disease affect my annual harvest. By understanding climate change impacts on plant communities, you can help your garden reach its full potential in a warming world.</p>
<h2>Hotter summers, warmer winters</h2>
<p>There’s no question that the temperature trend is upward. From 2014 through 2023, the world experienced the <a href="https://www.noaa.gov/news/world-just-sweltered-through-its-hottest-august-on-record">10 hottest summers ever recorded</a> in 174 years of climate data. Just a few months of sweltering, unrelenting heat can significantly affect plant health, especially <a href="https://extension.psu.edu/cool-season-vs-warm-season-vegetables">cool-season garden crops</a> like broccoli, carrots, radishes and kale. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Radishes sprouting in a garden bed." src="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.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"></a>
<figcaption>
<span class="caption">Radishes are cool-season garden crops that cannot withstand the hottest days of summer.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Winters are also warming, and this matters for plants. The USDA defines plant hardiness zones based on the coldest average annual temperature in winter at a given location. Each zone represents a 10-degree F range, with zones numbered from 1 (coldest) to 13 (warmest). Zones are divided into 5-degree F half zones, which are lettered “a” (northern) or “b” (southern). </p>
<p>For example, the coldest hardiness zone in the lower 48 states on <a href="https://planthardiness.ars.usda.gov/">the new map</a>, 3a, covers small pockets in the northernmost parts of Minnesota and has winter extreme temperatures of -40 F to -35 F. The warmest zone, 11b, is in Key West, Florida, where the coldest annual lows range from 45 F to 50 F. </p>
<p>On the <a href="https://planthardiness.ars.usda.gov/system/files/US_Map_2012.jpg">2012 map</a>, northern Minnesota had a much more extensive and continuous zone 3a. North Dakota also had areas designated in this same zone, but those regions now have shifted completely into Canada. Zone 10b once covered the southern tip of mainland Florida, including Miami and Fort Lauderdale, but has now been pushed northward by a rapidly encroaching zone 11a. </p>
<p>Many people buy seeds or seedlings without thinking about hardiness zones, planting dates or disease risks. But when plants have to contend with temperature shifts, heat stress and disease, they will eventually struggle to survive in areas where they once thrived. </p>
<p>Successful gardening is still possible, though. Here are some things to consider before you plant:</p>
<h2>Annuals versus perennials</h2>
<p>Hardiness zones matter far less for <a href="https://www.britannica.com/science/annual">annual plants</a>, which germinate, flower and die in a single growing season, than for <a href="https://www.britannica.com/science/perennial">perennial plants</a> that last for several years. Annuals typically avoid the lethal winter temperatures that define plant hardiness zones. </p>
<p>In fact, most annual seed packs don’t even list the plants’ hardiness zones. Instead, they provide sowing date guidelines by geographic region. It’s still important to follow those dates, which help ensure that frost-tender crops are not planted too early and that cool-season crops are not harvested too late in the year.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Orange flowers blooming with other plants and grasses." src="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.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">California poppies are typically grown as annuals in cool areas, but can survive for several years in hardiness zones 8-10.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/FWtHc">The Marmot/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>User-friendly perennials have broad hardiness zones</h2>
<p>Many perennials can grow across wide temperature ranges. For example, hardy fig and hardy kiwifruit grow well in zones 4-8, an area that includes most of the Northeast, Midwest and Plains states. Raspberries are hardy in zones 3-9, and blackberries are hardy in zones 5-9. This eliminates a lot of guesswork for most gardeners, since a majority of U.S. states are dominated by two or more of these zones. </p>
<p>Nevertheless, it’s important to pay attention to plant tags to avoid selecting a variety or cultivar with a restricted hardiness zone over another with greater flexibility. Also, pay attention to instructions about proper sun exposure and planting dates after the last frost in your area. </p>
<h2>Fruit trees are sensitive to temperature fluctuations</h2>
<p>Fruit trees have two parts, the rootstock and the scion wood, that are <a href="https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource003733_Rep5323.pdf">grafted together to form a single tree</a>. Rootstocks, which consist mainly of a root system, determine the tree’s size, timing of flowering and tolerance of soil-dwelling pests and pathogens. Scion wood, which supports the flowers and fruit, determines the fruit variety. </p>
<p>Most commercially available fruit trees can tolerate a wide range of hardiness zones. However, stone fruits like peaches, plums and cherries are more sensitive to temperature fluctuations within those zones – particularly abrupt swings in winter temperatures that create unpredictable freeze-thaw events. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Packages for hardy fig and kiwi seedlings." src="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=587&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=587&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=587&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Following planting instructions carefully can maximize plants’ chances of success.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>These seesaw weather episodes affect all types of fruit trees, but stone fruits appear to be more susceptible, possibly because they flower earlier in spring, have fewer hardy rootstock options, or have bark characteristics that make them more vulnerable to winter injury. </p>
<p>Perennial plants’ hardiness increases through the seasons in a process called <a href="https://extension.umd.edu/resource/hardening-vegetable-seedlings-home-garden/">hardening off</a>, which conditions them for harsher temperatures, moisture loss in sun and wind, and full sun exposure. But a too-sudden autumn temperature drop can cause plants to die back in winter, an event known as <a href="https://extension.psu.edu/winterkill-of-turfgrasses">winter kill</a>. Similarly, a sudden spring temperature spike can lead to premature flowering and subsequent frost kill.</p>
<h2>Pests are moving north too</h2>
<p>Plants aren’t the only organisms constrained by temperature. With milder winters, southern insect pests and plant pathogens are expanding their ranges northward. </p>
<p>One example is <a href="https://www.britannica.com/science/blight">Southern blight</a>, a stem and root rot disease that affects 500 plant species and is caused by a fungus, <em>Agroathelia rolfsii</em>. It’s often thought of as affecting hot Southern gardens, but has become more commonplace recently in the Northeast U.S. on tomatoes, <a href="https://theconversation.com/how-to-keep-your-jack-o-lantern-from-turning-into-moldy-maggoty-mush-before-halloween-190526">pumpkins and squash</a>, and other crops, including <a href="https://extension.psu.edu/apple-disease-southern-blight">apples in Pennsylvania</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A stem dotted with small round growths." src="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.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">Southern blight (small round fungal structures) at the base of a tomato plant.</span>
<span class="attribution"><a class="source" href="https://ag.purdue.edu/department/arge/swpap/southern-blight-tomato.html">Purdue University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Other plant pathogens may take advantage of milder winter temperatures, which leads to prolonged saturation of soils instead of freezing. Both plants and microbes are less active when soil is frozen, but in wet soil, microbes have an opportunity to colonize dormant perennial plant roots, leading to more disease.</p>
<p>It can be challenging to accept that climate change is stressing some of your garden favorites, but there are thousands of varieties of plants to suit both your interests and your hardiness zone. Growing plants is an opportunity to <a href="https://theconversation.com/take-a-break-from-your-screen-and-look-at-plants-botanizing-is-a-great-way-to-engage-with-life-around-you-210616">admire their flexibility</a> and the features that enable many of them to thrive in a world of change.</p><img src="https://counter.theconversation.com/content/222108/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matt Kasson receives funding from the US Department of Agriculture.</span></em></p>The US Department of Agriculture has updated its plant hardiness zone map, which shows where various plants will grow across the country. Gardeners should take note.Matt Kasson, Associate Professor of Mycology and Plant Pathology, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2243372024-03-08T05:37:23Z2024-03-08T05:37:23ZCultural burning is better for Australian soils than prescribed burning, or no burning at all<figure><img src="https://images.theconversation.com/files/580328/original/file-20240307-10578-g6monm.jpeg?ixlib=rb-1.1.0&rect=28%2C5%2C3805%2C2149&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Ulladulla Local Aboriginal Land Council and Mane Collective</span></span></figcaption></figure><p>Imagine a landscape shaped by fire, not as a destructive force but as a life-giving tool. That’s the reality in Australia, where Indigenous communities have long understood the intricate relationship between fire, soil and life. <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/emr.12592?saml_referrer">Cultural burning</a>
has been used for millennia to care for landscapes and nurture biodiversity. In contrast, government agencies conduct “<a href="https://knowledge.aidr.org.au/media/4893/overview-of-prescribed-burning-in-australasia.pdf">prescribed burning</a>” mainly to reduce fuel loads.</p>
<p>In <a href="https://www.mdpi.com/2571-6255/7/3/75">our new research</a>, we compared cultural burning to agency-led prescribed burning or no burning. We studied the effects on soil properties such as moisture content, density and nutrient levels.</p>
<p>Both fire treatments increased soil moisture and organic matter, while reducing soil density. That means burning improved soil health overall. But cultural burning was the best way to boost soil carbon and nitrogen while also reducing soil density, which improves the soil’s ability to nurture plants.</p>
<p>Understanding the effects of different fire management techniques is crucial for developing more sustainable land management practices. By studying what happens to the soil, we can work out how best to promote healthy, resilient ecosystems while also reducing risks of uncontrolled bushfires. </p>
<figure>
<iframe src="https://player.vimeo.com/video/603712505" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Cultural Burning for Resilience (2021), a mini documentary featuring coauthors Vic Channell, Leanne Brook and Katharine Haynes.</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/before-the-colonists-came-we-burned-small-and-burned-often-to-avoid-big-fires-its-time-to-relearn-cultural-burning-201475">Before the colonists came, we burned small and burned often to avoid big fires. It's time to relearn cultural burning</a>
</strong>
</em>
</p>
<hr>
<h2>The vital role of fire</h2>
<p>Fire has shaped Australian landscapes for millions of years, transforming ecosystems and influencing biodiversity.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/580338/original/file-20240307-22-oaacq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People standing around a slow-burning patch of bracken" src="https://images.theconversation.com/files/580338/original/file-20240307-22-oaacq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/580338/original/file-20240307-22-oaacq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580338/original/file-20240307-22-oaacq9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580338/original/file-20240307-22-oaacq9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580338/original/file-20240307-22-oaacq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580338/original/file-20240307-22-oaacq9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580338/original/file-20240307-22-oaacq9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Slow, cool burns are safe for onlookers.</span>
<span class="attribution"><span class="source">Ulladulla Local Aboriginal Land Council</span></span>
</figcaption>
</figure>
<p>For Indigenous Australians, fire is not just a tool but a way of life. Fire is used to care for Country, for cultural purposes including ceremonies, to promote new plant growth and food resources, and to facilitate hunting and gathering. </p>
<p>Cultural burning is only ever conducted when it will benefit the health of Country. It is a practice deeply rooted in Indigenous knowledge and traditions. Fires are small, slow and cool. Practitioners read signs in the environment in relation to the local flora and fauna that provide guidance on the right time to burn. </p>
<p>In comparison, prescribed burning, conducted by government agencies, is principally conducted to reduce fuel loads and minimise the risk of wildfires. Fires are often larger and burn hotter than cultural burning. </p>
<p>In recent times, bushfires have become <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0242484">more frequent and severe</a> in parts of Australia. So understanding and <a href="https://www.publish.csiro.au/wf/pdf/WFv29n11_BR">supporting Indigenous-led fire management practices</a> is becoming increasingly important for sustainable land management. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-1970s-conservation-laws-turned-this-paradise-on-earth-into-a-tinderbox-192401">How 1970s conservation laws turned this ‘paradise on Earth’ into a tinderbox</a>
</strong>
</em>
</p>
<hr>
<h2>Unlocking the secrets of soil health</h2>
<p>Our new research sheds light on the impact of fire management techniques on soil properties. The study was conducted on the south coast of New South Wales, on land managed by the Ulladulla Local Aboriginal Land Council. At this plot, one area of land experienced no burn, another was burnt by NSW Rural Fire Service and another experienced a cultural burn. </p>
<p>While the area burnt was relatively small, about 5,000 square metres for each plot, it can still help shed a light on the effect of fire treatments on soil properties.</p>
<p>We found both agency-led prescribed burning and cultural burning increased soil moisture levels. There may be different reasons for this. For soils that experienced the cultural burn, the extra moisture could be explained by the reduction in soil density, which promotes water flow. For soils that experienced the agency-led prescribed burn, where density didn’t decrease much, it’s possible the hotter fire removed the water-repellant layer of soil that sometimes develops following a fire, allowing more moisture to soak in.</p>
<p>Cultural burning had a more pronounced effect on reducing soil density and increasing organic matter content. Having more organic matter in the soil means more nutrients such as carbon and nitrogen are available to plants. Lower density improves soil structure. Both improve the capacity of ecosystems to withstand environmental stress such as drought and wildfire. </p>
<p>These findings suggest cultural burning not only benefits soil health but also helps make ecosystems more resilient, by providing more water and nutrients that native plants need. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/580352/original/file-20240307-16-a0d19p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Research student Jessica Davis measuring carbon dioxide emissions from soil" src="https://images.theconversation.com/files/580352/original/file-20240307-16-a0d19p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580352/original/file-20240307-16-a0d19p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580352/original/file-20240307-16-a0d19p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580352/original/file-20240307-16-a0d19p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580352/original/file-20240307-16-a0d19p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580352/original/file-20240307-16-a0d19p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580352/original/file-20240307-16-a0d19p.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">Carbon dioxide emissions from soil can be measured in the field.</span>
<span class="attribution"><span class="source">Jessica Davis</span></span>
</figcaption>
</figure>
<h2>Embracing Indigenous wisdom</h2>
<p>Indigenous communities use cultural land management practices, of which cultural burning is one tool, to care for Country as kin. They do not see themselves as separate to the environment. Instead their practices are guided by place-based knowledge that weaves human, spiritual and ecological needs together in a symbiotic relationship where one cannot thrive without the other. </p>
<p>Supporting Indigenous-led fire practices is not just about what it can do for the environment. It’s also a recognition of the deep cultural and spiritual connections Indigenous communities have with the land. </p>
<p>By learning from and working with Indigenous communities, we can foster a more harmonious relationship with Country, one that benefits both people and the environment.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/580335/original/file-20240307-24-m4ckp4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A group of people standing in the bush during a controlled burn, with the sun in the background peeking through the smoke" src="https://images.theconversation.com/files/580335/original/file-20240307-24-m4ckp4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/580335/original/file-20240307-24-m4ckp4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580335/original/file-20240307-24-m4ckp4.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580335/original/file-20240307-24-m4ckp4.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580335/original/file-20240307-24-m4ckp4.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580335/original/file-20240307-24-m4ckp4.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580335/original/file-20240307-24-m4ckp4.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cultural burning is a team effort.</span>
<span class="attribution"><span class="source">Ulladulla Local Aboriginal Land Council</span></span>
</figcaption>
</figure>
<h2>Rekindling our relationships</h2>
<p>Indigenous fire management practices offer invaluable wisdom and the potential to transform our approach to land stewardship. </p>
<p>By embracing these practices, we can nurture healthier soils, promote biodiversity, and foster more resilient ecosystems. </p>
<p>Practically, to make this possible, ongoing investment is required to build the capacity of Indigenous communities to fulfil their obligations to care for Country. Policies must be updated to allow greater access to Country and to reduce red tape and bureaucracy.</p>
<p>There is a danger here. Government agencies often want to incorporate or take on some of the principles of cool burns themselves, forgetting the cultural aspects and the need for this to be Indigenous-led. We must understand this is not just about managing fires, it’s about rekindling our relationship with the land and learning from those who have lived in harmony with it for thousands of years. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-research-in-arnhem-land-reveals-why-institutional-fire-management-is-inferior-to-cultural-burning-184562">New research in Arnhem Land reveals why institutional fire management is inferior to cultural burning</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/224337/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anthony Dosseto receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Katharine Haynes, Leanne Brook, and Victor Channell do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>What does fire management do to soils? We compared prescribed burning to cultural burning and looked at how soil properties changed after fire. Cultural burning was better.Anthony Dosseto, Professor, University of WollongongKatharine Haynes, Honorary Senior Research Fellow, University of WollongongLeanne Brook, CEO, Ulladulla Local Aboriginal Land Council, Indigenous KnowledgeVictor Channell, Murramarang and Walbunga Elder, Indigenous KnowledgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2248692024-03-05T15:02:19Z2024-03-05T15:02:19ZArctic rivers face big changes with a warming climate, permafrost thaw and an accelerating water cycle − the effects will have global consequences<figure><img src="https://images.theconversation.com/files/579392/original/file-20240303-24-mmw6cz.jpg?ixlib=rb-1.1.0&rect=0%2C1333%2C9000%2C6157&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Water from the Mackenzie River, seen from a satellite, carries silt and nutrients from land to the Arctic Ocean.</span> <span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/images/90703/mackenzie-meets-beaufort">Jesse Allen/NASA Earth Observatory</a></span></figcaption></figure><p>As the Arctic warms, its mighty rivers are changing in ways that could have vast consequences – not only for the Arctic region but for the world.</p>
<p>Rivers represent the land branch of the earth’s hydrological cycle. As rain and snow fall, rivers transport freshwater runoff along with dissolved organic and particulate materials, including carbon, to coastal areas. With the Arctic now warming nearly <a href="https://theconversation.com/arctic-is-warming-nearly-four-times-faster-than-the-rest-of-the-world-new-research-188474">four times faster</a> than the rest of the world, the region <a href="https://doi.org/10.1175/2010JCLI3421.1">is seeing more precipitation</a> and the permafrost is thawing, leading to stronger river flows.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows major rivers and their water sheds, primarily in Russia, Alaska and Canada." src="https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=596&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=596&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=596&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=749&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=749&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579353/original/file-20240303-28-rq37ng.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=749&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Major river basins of the Arctic region.</span>
<span class="attribution"><a class="source" href="https://www.pmel.noaa.gov/arctic-zone/detect/land-river.shtml">NOAA Arctic Report Card</a></span>
</figcaption>
</figure>
<p>We’re climate scientists who study how warming is influencing the water cycle and ecosystems. <a href="https://doi.org/10.5194/tc-18-1033-2024">In a new study</a> using historical data and sophisticated computer models of Earth’s climate and hydrology, we explored how climate change is altering Arctic rivers. </p>
<p>We found that thawing permafrost and intensifying storms will change how water moves into and through Arctic rivers. These changes will affect coastal regions, the Arctic Ocean and, potentially, the North Atlantic, as well as the climate.</p>
<h2>Thawing permafrost: Big changes in Arctic soils</h2>
<p>Permafrost thaw is one of the most consequential changes that the Arctic is experiencing as temperatures rise. </p>
<p>Permafrost is soil that has been <a href="https://climate.mit.edu/explainers/permafrost">frozen for at least two years</a> and often for millennia. It covers approximately 8.8 million square miles (about 22.8 million square kilometers) in Earth’s Northern Hemisphere, but that area is shrinking as the permafrost thaws.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two people stand on a cliff with permafrost evident." src="https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579355/original/file-20240303-22-s4w5f9.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">Erosion reveals ice-rich permafrost near Teshekpuk Lake, Alaska.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/usgeologicalsurvey/12116729705">Brandt Meixell/USGS</a></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows where permafrost is found, both in ground and below the ocean." src="https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=425&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=425&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=425&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=534&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=534&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564666/original/file-20231210-25-jz5ezj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=534&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Known permafrost zones in the Northern Hemisphere.</span>
<span class="attribution"><a class="source" href="https://www.grida.no/resources/13519">GRID-Arendal/Nunataryuk</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Historically, most water going into Arctic rivers flows atop frozen permafrost soils in spring. Scientists call this “overland runoff.” </p>
<p>However, our results suggest that as warming continues, an increasing fraction of annual river flow will come from under the surface, through thawed soils in the degrading permafrost. As the overall flow increases with more precipitation, as much as 30% more of it could be moving underground by the end of this century as subsurface pathways expand.</p>
<p>When water flows through soil, it picks up different chemicals and metals. As a result, water coming into rivers will likely have a different chemical character. For example, it may carry more nutrients and dissolved carbon that can affect coastal zones and the global climate. The fate of that mobilized carbon is an active area of study.</p>
<p>More carbon in river water could end up “outgassed” upon reaching placid coastal waters, increasing the amount of carbon dioxide released into the atmosphere, which further drives <a href="https://doi.org/10.1038/nature14338">climate warming</a>. The thaw is also revealing other nasty surprises, such as the <a href="https://www.usatoday.com/story/news/politics/2023/11/18/arctic-permafrost-thawing-deadly-pathogens/71581668007/">emergence of long-frozen viruses</a>. </p>
<h2>More rain and snow, more runoff</h2>
<p>The Arctic’s water cycle is also ramping up as temperatures rise, meaning more precipitation, evaporation, plant transpiration and river discharge. This is primarily due to a warmer atmosphere’s inherent ability to hold more moisture. It’s the same reason that <a href="https://theconversation.com/why-a-warming-climate-can-bring-bigger-snowstorms-176201">bigger snowstorms are occurring</a> as the climate warms. </p>
<p>Our study found that the bulk of the additional precipitation will occur across far northern parts of the Arctic basin. As sea ice disappears in a warming climate, computer models agree that a more open Arctic Ocean will feed more water to the atmosphere, where it will be transported to adjacent land areas to fall as precipitation. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two maps show increasing snow and rainfall" src="https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=326&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=326&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=326&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=410&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=410&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579640/original/file-20240304-28-gtrh1a.gif?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">Changes projected this century in annual rainfall and snowfall simulated by the computer model used in the study. Red areas represent increases.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.5194/tc-18-1033-2024">Rawlins and Karmalkar, 2024</a></span>
</figcaption>
</figure>
<p>More snow in northern Alaska, Siberia and Canada will lead to more water flowing in rivers, potentially up to 25% more under a high-warming scenario based on our research. There is more carbon in the soil in northern parts of the Arctic compared with the south. With permafrost thaw, those regions will also see more water coming into rivers from below the surface, where additional soil carbon can leach into the water and become dissolved organic carbon.</p>
<p>More <a href="https://doi.org/10.1088/1748-9326/aaa1fe">old carbon is already showing up</a> in samples gathered from Arctic rivers, attributed to permafrost thaw. Carbon dating shows that some of this carbon has been frozen for thousands of years. </p>
<h2>Impacts will cascade through Arctic ecosystems</h2>
<p>So, what does the future hold? </p>
<p>One of the most notable changes expected involves the transport of fresh water and associated materials, such as dissolved organic carbon and heat energy, to Arctic coastal zones. </p>
<figure class="align-center ">
<img alt="A scientist in a rain jacket and cap holds up a water sample in a jar." src="https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579395/original/file-20240303-28-uto6m1.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">James McClelland of the Beaufort Lagoon Ecosystems Long Term Ecological Research program examines a water sample from a stream near Utqiagvik on Alaska’s North Slope. The brown tint is dissolved organic matter.</span>
<span class="attribution"><span class="source">Michael A. Rawlins</span></span>
</figcaption>
</figure>
<p><a href="https://ble.lternet.edu/">Coastal lagoons</a> may become fresher. This change would affect organisms up and down the food chain, though <a href="https://doi.org/10.3389/fmars.2022.738363">our current understanding</a> of the potential affects of changes in fresh water and dissolved organic carbon is still murky.</p>
<p>River water will also be warmer as the climate heats up and has the potential to melt coastal sea ice earlier in the season. Scientists <a href="https://theconversation.com/arctic-report-card-2023-from-wildfires-to-melting-sea-ice-the-warmest-summer-on-record-had-cascading-impacts-across-the-arctic-218872">observed this in spring 2023</a>, when unusually warm water in Canada’s Mackenzie River carried heat to the Beaufort Sea, contributing to early coastal sea ice melting.</p>
<figure class="align-center ">
<img alt="A satellite view of the Arctic coast showing a river and sea ice breaking up." src="https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579397/original/file-20240303-20-8tx0p.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">
<figcaption>
<span class="caption">Fresh water flowing from rivers such as Canada’s Mackenzie River, at the bottom center of the satellite image, into the Beaufort Sea can break up sea ice early.</span>
<span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/images/83271/river-discharge-alters-arctic-sea-ice">NASA Earth Observatory</a></span>
</figcaption>
</figure>
<p>Finally, more river water reaching the coast has the potential to freshen the Arctic Ocean, particularly along northern Eurasia, where big Russian rivers export massive amounts of fresh water each year. </p>
<p>There are concerns that <a href="https://arctic.noaa.gov/report-card/report-card-2021/river-discharge/">rising river flows in that region</a> are influencing the Atlantic Meridional Overturning Circulation, the currents that circulate heat from the tropics, up along the U.S. East Coast and toward Europe. Evidence is mounting that these currents <a href="https://theconversation.com/the-atlantic-oceans-major-current-system-is-slowing-down-but-a-21st-century-collapse-is-unlikely-214647">have been slowing in recent years</a> as more fresh water enters the North Atlantic. If the circulation shuts down, it would <a href="https://theconversation.com/atlantic-ocean-is-headed-for-a-tipping-point-once-melting-glaciers-shut-down-the-gulf-stream-we-would-see-extreme-climate-change-within-decades-study-shows-222834">significantly affect temperatures</a> across North America and Europe.</p>
<p>At the coast, changing river flows will also affect the plants, animals and Indigenous populations that call the region home. For them and for the global climate, our study’s findings highlight the need to closely watch how the Arctic is being transformed and take steps to mitigate the effects.</p><img src="https://counter.theconversation.com/content/224869/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael A. Rawlins receives funding from The Department of Energy, the National Aeronautics and Space Administration and the U.S. National Science Foundation. </span></em></p><p class="fine-print"><em><span>Ambarish Karmalkar receives funding from the Department of Energy and the United States Geological Survey. </span></em></p>A new study shows how thawing permafrost and intensifying storms will change how water moves into and through Arctic rivers.Michael A. Rawlins, Associate Director, Climate System Research Center and Associate Professor of Climatology, UMass AmherstAmbarish Karmalkar, Assistant Professor of Geosciences, University of Rhode IslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2220952024-02-12T16:31:43Z2024-02-12T16:31:43ZForever chemicals in ski wax are being spread on snowy slopes<figure><img src="https://images.theconversation.com/files/574955/original/file-20240212-16-zludm6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A study of the Austrian slopes has found that forever chemicals in ski wax end up on the slopes, in soil and snow.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/skiing-jumping-skier-extreme-winter-sports-1187224183">Artur Didyk/Shutterstock</a></span></figcaption></figure><p>Every February half-term, I think back to the French ski trips I went on as a teenager. I remember the freshness of the cold, crisp air as I snow-ploughed my way down the slopes. Escaping to somewhere seemingly so pristine felt like a world away from where I grew up in London. </p>
<p>Back then, I never considered that snow could be a potential source of exposure to a harmful chemical. However, recent evidence suggests that persistent, synthetic chemicals are being transferred into snow and soil from waxes applied to the surfaces of skis to enhance performance.</p>
<p>Nicknamed forever chemicals, per- and poly-fluoroalkyl substances (PFAS) are a class of more than <a href="https://www.oecd.org/chemicalsafety/portal-perfluorinated-chemicals/aboutpfass/">10,000 different chemicals</a>, many of which have been used since the 1950s. They repel water and oil so they make great waterproof coatings for clothing, greaseproof paper and construction materials. </p>
<p>Some act as surfactants, allowing different liquids to mix more easily. Many resist high temperatures, so they’re ideal for making non-stick frying pans and firefighting foams. </p>
<p>Certain PFAS are used in ski wax applied to skis and snowboards as lubrication. By making surfaces of ski kit more slippery, skiers can speed up and make smoother turns as they travel from piste to piste. A <a href="https://pubs.rsc.org/en/content/articlelanding/2023/EM/D3EM00375B">new study</a> has found high PFAS concentrations in ski waxes and in the snow and soil sampled from popular skiing areas in Austria.</p>
<h2>The problem with persistence</h2>
<p>PFAS are organoflourine compounds – their super strong carbon-flourine bonds make them incredibly stable. Because PFAS don’t <a href="https://echa.europa.eu/hot-topics/perfluoroalkyl-chemicals-pfas">break down easily</a>, they can persist inside our bodies or in the environment for <a href="https://www.health.pa.gov/topics/Documents/Environmental%20Health/PFAS%20Fact%20Sheet.pdf">many years</a>. </p>
<p>A single dose of perfluorooctanoic acid or PFOA, one of the most well-studied PFAS, could take between three and seven years to reduce by half inside the body – that means it could take 100 years to eliminate 99.9% of that dose. </p>
<p>Some PFAS can be toxic to humans and wildlife, with links to <a href="https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(23)00397-3/fulltext#:%7E:text=This%20study%20supports%20the%20hypothesis,plastic%20packaging%2C%20etc.">cancers</a>, <a href="https://www.sciencedirect.com/science/article/pii/S0160412022003117">developmental</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/36334833/#:%7E:text=Conclusion%3A%20Based%20on%20the%20evidence,in%20odds%20ratio%20for%20infertility">reproductive problems</a>, <a href="https://www.sciencedirect.com/science/article/abs/pii/S1438463918300476?via%3Dihub">hormone disruption</a>, <a href="https://www.sciencedirect.com/science/article/pii/S0013935123003171#:%7E:text=May%202023%2C%20115525-,Exposure%20to%20high%20levels%20of%20PFAS%20through%20drinking%20water%20is,based%20study%20in%20Ronneby%2C%20Sweden">diabetes</a> and <a href="https://doi.org/10.1002/etc.4890;%20https://doi.org/10.1016/j.scitotenv.2020.144795">obesity</a>. </p>
<figure class="align-center ">
<img alt="Woman in yellow jackets applies wax to four yellow skis laid out on wooden table" src="https://images.theconversation.com/files/574960/original/file-20240212-28-bro51v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574960/original/file-20240212-28-bro51v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574960/original/file-20240212-28-bro51v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574960/original/file-20240212-28-bro51v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574960/original/file-20240212-28-bro51v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574960/original/file-20240212-28-bro51v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574960/original/file-20240212-28-bro51v.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">The presence of PFAS in ski wax is widely understood - now research shows that the chemicals transfer from ski wax to the environment and end up in snow and soil on the white slopes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/japanese-senior-woman-waxing-skis-1620325474">Rammy_Rammy/Shutterstock</a></span>
</figcaption>
</figure>
<h2>A slippery slope?</h2>
<p>The presence of PFAS in ski waxes is not a new discovery. In 2010, a Swedish study, found high levels of various PFAS in ski wax and in the blood of <a href="https://doi.org/10.1021/es9034733">ski-waxing technicians</a>. </p>
<p>The fascinating thing about the new study is the potential for these chemicals to transfer into the environment from recreational and professional skiing equipment. She reveals that PFAS levels in the snow and soil from skiing areas are consistently higher than in those from the control sample collected away from skiing areas, indicating that skiing can act as a source. </p>
<p>The researchers highlight how the PFAS profiles (the combination of different PFAS found in each sample) differed between locations and sample types. This variability was attributed to differences between ski waxes that had been manufactured at different times or in different places. </p>
<p>I would suggest that additional sources of PFAS are likely in these areas, particularly as PFAS were still sometimes detected in areas of no skiing. They are present in some waterproof clothing, which is worn in abundance by skiers, and in food packaging, paints and cabling – all of which will be found in these areas. These products are likely to display different PFAS profiles. </p>
<p>The new study highlights the difficulty of assessing PFAS globally. There are so many different individual PFAS chemicals. So much so that there’s still uncertainty over the true number that <a href="https://time.com/6281242/pfas-forever-chemicals-home-beauty-body-products/">exist</a>. With PFAS in so many products, it’s hard to identify a singular source.</p>
<p>With so many PFAS in circulation, it’s hard to know which ones to test for. The researchers in the new study searched for 34 PFAS chemicals – that’s no easy task. For every PFAS measured, analysis takes more time and money and gets more complicated.</p>
<p>The sum of the concentrations of these 34 PFAS represented less than 1% of the total organofluorine present in the same samples, so the true PFAS concentration could be even higher. </p>
<h2>A class-based approach</h2>
<p>Historically, individual chemicals have been banned depending on toxicity, persistence and resistance to degradation. This has invariably led to the replacement of banned chemicals with structurally similar ones. </p>
<p>Assessing 10,000 PFAS individually would be impossible. PFAS display varying levels of toxicity and persistence with some breaking down <a href="https://doi.org/10.1016/j.yrtph.2022.105226">quite readily</a>, but in recent years, environmental chemists have called for PFAS to be regulated together as a <a href="https://doi.org/10.1039%2Fd0em00147c">group or class</a>. </p>
<p>The European Chemicals Agency is considering a <a href="https://echa.europa.eu/-/echa-publishes-pfas-restriction-proposal">proposed restriction</a> to ban the manufacture and use of PFAS, with some exemptions for essential use where no alternatives exist. If accepted by member states, it could prove a significant step towards the beginning of the end for forever chemicals. Meanwhile, UK legislation <a href="https://www.dwi.gov.uk/pfas-and-forever-chemicals/">falls behind</a> by focusing on individual PFAS, with delays in implementing new restrictions. </p>
<p>Interestingly, PFAS-containing waxes were banned by the International Ski and Snowboard Federation at the start of the 2023 – 2024 season. Norwegian Olympic silver medallist Ragnhild Mowinckel was disqualified last October for competing with fluorinated wax. </p>
<p>But a ban that only applies to professional competition won’t stop PFAS chemicals from reaching the slopes. A ban on the manufacture of PFAS-containing products is crucial. Only then can we prevent PFAS reaching the mountains, and even with a comprehensive ban now, PFAS already in the snow won’t disappear within my lifetime.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
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<p class="fine-print"><em><span>Daniel Drage has previously worked on projects funded by the Natural Environment Research Council and the Environmental Protection Agency of Ireland. He is a Lecturer in Environmental Health at the University of Birmingham, and an Honorary Research Fellow at the University of Queensland (Australia). </span></em></p>Synthetic chemicals found in ski wax have been found in the snow and soil on ski slopes and could pose a toxic threat to the environment.Daniel Drage, Lecturer in Environmental Health, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2221002024-02-08T21:32:00Z2024-02-08T21:32:00ZSecrets of soil-enriching pulses could transform future of sustainable agriculture<figure><img src="https://images.theconversation.com/files/574321/original/file-20240208-20-86knbn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Root nodules of legumes such as soybeans help fix nitrogen into the soil. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/development-soybean-root-1248864754">Lidiane Miotto/Shutterstock</a></span></figcaption></figure><p>From lentils to chickpeas, and even the humble baked bean, pulses are perhaps best known as an alternative, plant-based source of protein. These plants are environmental heroes: they work together with soil microbes to “fix” nitrogen from the air, enriching the soil with nutrients to allow them to thrive.</p>
<p>As their nitrogen-fixing capacity is becoming better understood, scientists are hoping to find ways to increase productivity, and eventually apply some of these effective soil-enriching characteristics to other crops such as cereals. With the ability to fix nitrogen, crops would need less nitrogen fertiliser and soil health would simultaneously improve.</p>
<p>Pulses, the edible dry seeds of legume plants, are staple foods in the diets of both people and livestock around the world. Across Europe and the US, they are <a href="https://www.cbi.eu/market-information/grains-pulses-oilseeds/dried-beans/market-potential">commonly eaten</a> as tinned beans, chickpeas and lentils, while in sub-Saharan Africa, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7794592/">cowpea</a> is among the most important legumes. </p>
<p>High in protein, carbohydrates, dietary fibres, vitamins and minerals, pulses play a fundamental role in <a href="https://www.frontiersin.org/articles/10.3389/fsufs.2022.878269/full">nutritious healthy diets</a>. Both the seeds and leaves are also used as <a href="https://www.un-ilibrary.org/content/books/9789210472579">feed for livestock</a>. For smallholder farmers in developing nations, nutritious pulses are a cost-effective substitute for animal protein and make up a large proportion of typical diets.</p>
<p>In Western Kenya, Rwanda and Burundi, people eat <a href="https://cgspace.cgiar.org/handle/10568/121077">more than 30kg beans a year</a> on average, while many African countries recommend pulses as a meat alternative in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9370574/">dietary guidelines</a>. Pulses can also be stored for <a href="https://www.sciencedirect.com/science/article/abs/pii/S0022474X14000496">extended periods</a> without affecting their nutritional content.</p>
<h2>The magic inside root nodules</h2>
<p>Some <a href="https://doi.org/10.1016/j.jplph.2022.153765">100 million years ago</a>, legumes developed the natural ability to house beneficial bacteria inside dedicated structures called root nodules. Here, bacteria convert gaseous nitrogen from the air and soil into a form that’s accessible to the plant as nutrients.</p>
<p>So, legumes need less nitrogen fertiliser than cereal and other vegetable crops. A high-performing legume can fix up to <a href="https://www.frontiersin.org/articles/10.3389/fsufs.2021.767998/full">300kg of nitrogen per hectare</a>, which would otherwise cost farmers around $1 per kg in fertiliser to meet the nutrient needs of the plant. </p>
<p>At the <a href="https://www.ensa.ac.uk/">Enabling Nutrient Symbioses in Agriculture</a> project, we are trying to understand how exactly legumes do this. We are exploring how these nitrogen-fixing root nodules evolved in only legumes in the first place. With that knowledge, we hope to find ways to increase the efficiency of nitrogen fixation inside the root nodules and maximise the growth and yield of legume crops.</p>
<figure class="align-center ">
<img alt="microscopic image of pink cells - bacteria inside root nodules close up" src="https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574454/original/file-20240208-18-zvrb8w.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">Under the microscope, the nitrogen-fixing bacteria inside root nodules of a bean plant can be seen.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/root-bacteria-nodules-bean-under-microscope-1114612907">ChWeiss/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Beneficial bacteria</h2>
<p>My research group is investigating how legumes can engage with beneficial bacteria and avoid disease-causing microbes. While bacteria like the rhizobia in these root nodules help plants source nutrients, other soil microbes including bacteria and fungi could cause disease and prevent plants from converting as much nitrogen. So the plant must have a defence mechanism that keeps disease-causing microbes at bay. This may also prevent it from fully engaging with beneficial bacteria. </p>
<p>Our team of researchers has identified potential factors that limit nitrogen fixation in the nodules of <em>Medicago</em>, also known as barrel medic or barrel clover. This legume is frequently used for research and not grown for consumption. By studying these limiting factors, we hope to improve the efficiency of nitrogen fixation without affecting the crop’s in-built defence mechanisms to protect it from disease.</p>
<p>Having studied this mechanism in the research legume, researchers are now studying a few relevant crop legumes such as soybean and cowpea to understand how widespread and applicable the underlying biological mechanisms are, and whether they can be harnessed to improve other pulses in the future.</p>
<p>Despite being some of the oldest domesticated crops, many legumes are much less adapted to farming and so have significant potential for further improvement through breeding and genetic engineering, making them more suitable and sustainable for modern food systems.</p>
<p>The benefits of more efficient nitrogen fixing in legumes would include greater growth and biomass and, we hope, higher protein content in the seeds or pulses. This would increase the nutritional value per crop, meaning more high-quality nutrient-rich food could be produced per hectare.</p>
<p>Higher yields would create new opportunities for small-scale and subsistence farmers to grow and benefit from legumes – such as soybean – as cash crops to improve rural livelihoods. More productive legumes could be more effective as a <a href="https://link.springer.com/article/10.1007/s41130-018-0063-z">rotation crop</a> that improves soil health, which is especially important for farmers dealing with degraded soil, such as those found across sub-Saharan Africa. </p>
<p>The more we know about this unique ability of legumes, the greater our chance of successfully developing other crops with a similar ability. Such a development, though some years away, could transform sustainable agriculture, especially in areas where access to synthetic fertiliser is already limited by cost and availability.</p>
<p>Extending nitrogen fixing to other crops has long been an ambition of crop scientists around the world and as the study of plant biology advances, the pulse of progress is quickening.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/222100/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sebastian Schornack receives funding from Bill and Melinda Gates Agricultural Innovations. He is also listed as an inventor on a patent filed by the University of Cambridge on a gene that seems to limit nitrogen fixation.</span></em></p>New technology could unlock the soil-enriching nitrogen-fixing ability of legumes…and one day apply this to other crops too.Sebastian Schornack, Senior research group leader in the Enabling Nutrient Symbioses in Agriculture (ENSA) project, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2166402024-01-29T05:26:27Z2024-01-29T05:26:27ZAustralia’s soils are notoriously poor. Here’s how scientists are working to improve them<p>Most things you eat grew in soil or ate plants growing in soil. We don’t think much about it, but soil is essential to life. </p>
<p>During the last Ice Age, much of the northern hemisphere was covered in glaciers. As they moved, glaciers eroded away the top layer of rock and left a fresh layer of rock, ready to weather into soil. </p>
<p>But Australia didn’t have this renewal of soil from grinding ice – or from volcanoes, which dredge up minerals vital to plant life from deep below. As a result, our soils are famously very poor – heavily weathered, old, and short on nutrients. This is one reason why we have so much land devoted to grazing animals (crops need more nutrients than grass does), a heavy reliance on fertilisers and a <a href="https://www.soilscienceaustralia.org.au/about/about-soil/state-soils/">detailed knowledge</a> of fertile soils where they exist. </p>
<p>Unfortunately, our soils – <a href="https://link.springer.com/chapter/10.1007/978-3-319-43394-3_20">valued at A$930 billion</a> – are under threat. The latest <a href="https://soe.dcceew.gov.au/land/environment/soil">State of the Environment report</a> rated the health of our soils as “poor” and declining. Late last year, the government <a href="https://www.agriculture.gov.au/agriculture-land/farm-food-drought/natural-resources/soils/national-soil-action-plan">released a national plan</a> to improve our soils. </p>
<p>Researchers are working on ways of improving Australian soils to make agriculture more sustainable and less reliant on fertilisers. Here are some examples. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="black soil in hands" src="https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571820/original/file-20240129-29-84yv2w.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>
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<span class="caption">Good soil is hard to come by.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>From farm to food</h2>
<p>You might wonder what the problem is. Aren’t we growing and exporting more food than ever? Farm productivity and incomes are at <a href="https://www.agriculture.gov.au/abares/products/insights/snapshot-of-australian-agriculture#farm-incomes-at-record-highs">record highs</a> and many farmers are adopting more efficient practices informed by research to help manage their soil amid new risks such as shifting rainfall and <a href="https://theconversation.com/what-is-a-flash-drought-an-earth-scientist-explains-194141">flash droughts</a>. </p>
<p><iframe id="S6lxv" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/S6lxv/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>But many of our soils are fundamentally vulnerable because they function in old and weathered landscapes. To keep the food coming, farmers have had to resort to clearing more land and increasing <a href="https://soe.dcceew.gov.au/land/environment/soil#soil-health">fertilisers, pesticides and herbicides</a>. That works short term. But there are <a href="https://theconversation.com/intensive-farming-is-eating-up-the-australian-continent-but-theres-another-way-130877">increasing concerns</a> this intensive approach ends up making soil worse – more eroded, more saline and more acidic. All three of these are worsened by our changing climate.</p>
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<strong>
Read more:
<a href="https://theconversation.com/regenerative-agriculture-is-all-the-rage-but-its-not-going-to-fix-our-food-system-203922">'Regenerative agriculture' is all the rage – but it's not going to fix our food system</a>
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<h2>What can be done?</h2>
<p>Soil scientists have long worked on ways to get more out of our soils. The Green Revolution of the 1960s led to huge increases in yield – but required huge increases in application of fertilisers and other chemicals. </p>
<p>In Australia, farmers will likely have to rely on fertiliser for the foreseeable future as a way to correct soils which are naturally short on nutrients. </p>
<p>What we can do is learn to apply fertiliser only when it’s needed. That’s good for farmers – fertiliser is expensive – and good for the health of soil and nearby waterways. </p>
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<strong>
Read more:
<a href="https://theconversation.com/what-sub-sahara-can-learn-from-indias-green-revolution-the-good-and-the-bad-78868">What sub-Sahara can learn from India's 'Green revolution': the good and the bad</a>
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<p>In southwest Western Australia, for example, soil scientists are <a href="https://soilswest.org.au/project-npk/">working to understand</a> how best to dose the soil with nitrogen, potassium and phosphorus – and how much to use. </p>
<p><iframe id="BxKje" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/BxKje/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>In <a href="https://estuaries.dwer.wa.gov.au/soil-wise">another project</a>, scientists are working with farmers and land managers to sample and test their soil and interpret the data together. The goal is to pare back fertiliser use, which improves water quality in nearby waterways and estuaries, as unused fertiliser runs off and can trigger algal blooms. </p>
<p>Precision application of fertiliser is one method. But there are many other innovative soil projects across Australia. </p>
<p>For instance, fungi do vital work in cycling soil nutrients. And mycorrhizal fungi go one step further and live in symbiotic relationships with plants. What if we could use these fungi as a kind of living biofertiliser for grain crops? Scientists <a href="https://groundcover.grdc.com.au/agronomy/soil-and-nutrition/biofertiliser-potential-in-native-fungus">are exploring</a> the potential for one such species, the ridge-stemmed bolete (<em>Austroboletus occidentalis</em>), to play this role. </p>
<h2>It’s alive!</h2>
<p>Researchers recently estimated <a href="https://doi.org/10.1073/pnas.2304663120">soil contains</a> about three-fifths of all species on the planet, including bacteria, fungi, viruses, nematodes, mites, worms and insects.</p>
<p>Soil is, in short, teeming with life. Some underground lifeforms are pests to farmers, chewing on the roots of crops. But many others are beneficial. </p>
<p>If we <a href="https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(23)00211-2">improve our understanding</a> and measurement of soil microorganisms, we could use them to speed up recovery of degraded landscapes, such as former mine sites or unproductive farmland. </p>
<p>Our understanding of how things living in soil impact environments and respond to change is rapidly growing, but we are still scratching the surface. For example, more than 90% of the estimated 5 million species of fungi are <a href="https://www.theguardian.com/environment/2023/aug/30/flora-fauna-and-funga-un-backs-new-term-for-conservation-discussions">currently unknown</a>.</p>
<h2>Digging deeper</h2>
<p>Australia has the <a href="https://doi.org/10.1073/pnas.1706103114">world’s third highest loss</a> of soil carbon over the last 250 years, caused largely by very high rates of land clearing. We risk releasing even more soil carbon in the future, as climate change is expected to worsen erosion and bushfire intensity. </p>
<p>One response by the government has been to create a market for soil carbon credits, the first of which went on sale last year. The market-based approach has been <a href="https://doi.org/10.1016/j.jenvman.2023.119146">widely criticised</a>. Soil experts <a href="https://theconversation.com/heres-how-to-fix-australias-approach-to-soil-carbon-credits-so-they-really-count-towards-our-climate-goals-210880">have called</a> for the credit system to be much more robust to ensure it actually works.</p>
<p>Research into the problems facing our soil is important, but we’ll need government and industry backing to better coordinate the response. </p>
<p>That’s why last year’s action plan has been broadly welcomed, despite being 18 months overdue. The joint federal-state plan indicates governments at both levels recognise the danger to our soil. Framed around securing soil as a “national asset”, the plan envisages standardising soil data collection and sharing, accelerating uptake of best-practice soil management, among other things. </p>
<p>Will it stop the damage done to our lifegiving soils? That remains to be seen. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/heres-how-to-fix-australias-approach-to-soil-carbon-credits-so-they-really-count-towards-our-climate-goals-210880">Here's how to fix Australia's approach to soil carbon credits so they really count towards our climate goals</a>
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<img src="https://counter.theconversation.com/content/216640/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ryan Borrett is part of SoilsWest and collaborates on projects that receive funding from Murdoch University, the Western Australian Department of Primary Industries and Regional Development, and the Grains Research and Development Corporation. </span></em></p>The health of our soils is poor – and getting worse. Here’s why that matters and what we can do about itRyan Borrett, Science Communications Coordinator, Murdoch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2175822024-01-21T08:55:58Z2024-01-21T08:55:58ZCongo’s blackwater Ruki River is a major transporter of forest carbon - new study<figure><img src="https://images.theconversation.com/files/559590/original/file-20231115-29-kv00ye.jpg?ixlib=rb-1.1.0&rect=0%2C17%2C3888%2C2892&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">River Ruki. </span> <span class="attribution"><span class="source">Photo by Matti Barthel</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The Congo Basin of central Africa is well known for its network of rivers that drain a variety of <a href="https://www.britannica.com/place/Congo-Basin">landscapes</a>, from dense tropical forests to more arid and wooded savannas. Among the Congo River’s large tributaries, the Ruki is unique in its extremely <a href="https://www.iflscience.com/why-the-ruki-may-be-the-worlds-darkest-river-71206">dark colour</a>, which renders the water opaque below a few centimetres’ depth. </p>
<p>This large blackwater river caught the attention of our carbon biogeochemistry research team when we visited its confluence with the Congo River at the city of Mbandaka. Mbandaka is a small city in the Democratic Republic of Congo, located about 600km upstream from Kinshasa on the Congo River. The area around Mbandaka is known as the Cuvette Centrale and is characterised by its vast low-lying topography, much of which floods during the rainy season and results in extensive swamp forests.</p>
<p>As we watched the placid dark water of the Ruki flow by, we wondered just how much carbon this river was transporting and where it came from. To answer these questions, we decided to measure the carbon in the Ruki for one year to account for seasonal changes. </p>
<p>The results of this <a href="https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.12436">study</a> show that the Ruki is a major contributor of dissolved carbon to the Congo River, and that the majority of this carbon is sourced from the leaching of forest vegetation and soils. These results also suggest that the way in which calculations are made about how much carbon tropical forests accumulate might be off the mark – perhaps slightly overestimated.</p>
<p>These findings are important because rivers are major conduits of carbon from land to ocean and atmosphere, supplying organic matter to downstream ecosystems and carbon dioxide to the air. It is important to quantify how much carbon they are moving, where it is coming from, and where it ends up. Such accounting helps scientists understand how different ecosystems function, what role they play in the <a href="https://en.wikipedia.org/wiki/Carbon_cycle">carbon cycle</a>, and how they might respond to future or ongoing human perturbations such as climate or land-use change.</p>
<h2>The heart of the forest</h2>
<p>The Ruki River lies at the centre of the Congo Basin. It drains a uniquely homogeneous 188,800km² of pristine lowland and swamp forests. Since climate, vegetation, soils, geology and the concentration of human impacts vary widely across Earth’s surface, it’s uncommon for a watershed of this size to have such uniform land cover. There are likely no other such uniform watersheds of this size on earth.</p>
<p>This means we had an opportunity to pinpoint how a specific land cover influences the quantity and composition of organic material leached from decomposing plants and soils and carried by rainwater to river channels. Knowing this, we can “unmix” the signals measured in the Congo River and better ascertain the differences in carbon export between the many tributaries and land covers of the basin.</p>
<p>We <a href="https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.12436">found</a> that Ruki supplies 20% of the dissolved carbon in the Congo River though it makes up only 5% of the Congo’s watershed by area. This contribution is so high because the Ruki’s water is extremely concentrated in dissolved organic matter. In fact, it is significantly richer in dissolved carbon than even the Amazon’s Rio Negro (“Black River”), which is famous for its black colour also stemming from <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/hyp.1291">high concentration of organics</a>. </p>
<p>Water with very high concentrations of organic matter signals neither a good nor bad thing. It just means lots of carbon is contained in the water.</p>
<p>Because the Ruki watershed is so flat, rainwater drains slowly and has plenty of time to leach organic material from its dense vegetation. It’s like leaving multiple bags of tea to steep in water over a long period of time. </p>
<p>One of the reasons we wanted to know where these organic compounds were originating from is that large areas of the Ruki are underlain by enormous tracts of peat-like soils. These organic-rich soils have accumulated over hundreds to thousands of years from the buildup of partially decomposed plant matter. </p>
<p>If this peat was being leached or eroded into the river, through some form of disturbance, it could be <a href="https://peatlands.org/peatlands/peatlands-and-climate/">released</a> as carbon dioxide into the atmosphere and compound the greenhouse effect, much like the unearthing and combustion of fossil fuels. </p>
<p>Our radiocarbon isotopic measurements of the dissolved carbon indicate that there is very little peat carbon entering the river (none of it is very old), and that the dissolved carbon is sourced instead from forest vegetation and recently formed soil.</p>
<p>This is good news for now, but it’s something to keep an eye on if periods of drought or human activity disturb these carbon-rich peat soils. </p>
<h2>Balancing the forest sink</h2>
<p>Why does it matter if the Ruki transports a large amount of carbon?</p>
<p>One answer is that the carbon lost from terrestrial ecosystems to rivers can determine whether forests are taking up more carbon from the atmosphere (sinks) than releasing it (source) to the atmosphere. Most assessments of the balance (carbon coming in versus carbon going out of a forest) fail to account for the carbon that moves laterally to rivers. </p>
<p>In the case of the Ruki, the high amount of carbon that is contained in the river per unit area of the watershed suggests that this lateral movement of carbon from the Congo’s lowland forests comprises a significant proportion of the carbon balance, that is, the difference between what is coming in from photosynthesis and what is returned via respiration. </p>
<p>Thus, tropical forests like those around the Ruki might not accumulate quite as much carbon as we once thought. Further research is required to pin down whether this is the case. But our work on the Ruki already indicates that areas drained by such blackwater rivers may be particularly prone to carbon accounting errors like this.</p><img src="https://counter.theconversation.com/content/217582/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Travis Drake received funding from the Swiss National Science Fund.</span></em></p><p class="fine-print"><em><span>Johan Six received funding from Swiss National Science Fund. </span></em></p><p class="fine-print"><em><span>Matti Barthel receives funding from Swiss National Science Fund.</span></em></p>The Ruki River supplies dissolved carbon from forest vegetation and soils to the Congo River.Travis Drake, Postdoctoral Researcher, Swiss Federal Institute of Technology ZurichJohan Six, Professor of Sustainable Agrosystems, Swiss Federal Institute of Technology ZurichMatti Barthel, Research Technician, Swiss Federal Institute of Technology ZurichLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163552024-01-16T19:15:14Z2024-01-16T19:15:14ZSpace travel taxes astronauts’ brains. But microbes on the menu could help in unexpected ways<figure><img src="https://images.theconversation.com/files/565638/original/file-20231213-27-4xr8mj.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5991%2C3000&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-vector/smiling-man-astronaut-presents-shawarma-kebab-1128088580">studiostoks/Shutterstock</a></span></figcaption></figure><p>Feeding astronauts on a long mission to Mars goes well beyond ensuring they have enough nutrients and calories to survive their multi-year journey.</p>
<p>Providing astronauts with the right diet is also paramount in supporting their <a href="https://www.frontiersin.org/articles/10.3389/fncir.2023.1170395/full?trk=public_post_comment-text">mental and cognitive health</a>, in a way unlike previous missions.</p>
<p>So we need to radically rethink how we feed astronauts not only on a challenging mission to Mars, which could be on the cards in the late 2030s or early 2040s, but to prepare for possible settlement on the red planet. </p>
<p>That includes acknowledging the role of microbes in mental health and wellbeing, and providing astronauts with the right foods and conditions for a variety of these beneficial microbes to grow. Our research aims to do just that.</p>
<p>Here’s why a healthy balance of microbes is important under such challenging conditions, and how we could put microbes on the menu.</p>
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Read more:
<a href="https://theconversation.com/was-going-to-space-a-good-idea-218235">Was going to space a good idea?</a>
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<hr>
<h2>Why are missions to Mars so challenging?</h2>
<p>Deep space missions will expose humans to immense physical and psychological challenges. These include prolonged isolation from loved ones, extreme space and resource constraints, and the difficulties of microgravity. </p>
<p>Disruption to astronauts’ circadian rhythms, prolonged radiation exposure and dietary changes can also lower their cognitive performance and wellbeing. </p>
<p>The hazardous conditions, combined with the psychological toll of potential spacecraft failures, can all contribute to mental health problems.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-live-in-space-what-weve-learned-from-20-years-of-the-international-space-station-144851">How to live in space: what we've learned from 20 years of the International Space Station</a>
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<h2>Why is diet important for mental health?</h2>
<p>We already know the quality of people’s diet not only influences their physical health, but also their mental and brain health. </p>
<p>Diet quality is <a href="https://www.nature.com/articles/s41380-018-0237-8">consistently and independently linked</a> to the risk of depression or anxiety. Clinical trials <a href="https://pubmed.ncbi.nlm.nih.gov/35441666/">show</a> improving diet quality <a href="https://www.ncbi.nlm.nih.gov/pubmed/30720698">can lead to</a> profound improvements in depression and anxiety symptoms. </p>
<p>Diet also affects the size and function of a specific brain region – the hippocampus – that is crucial to learning and memory, as well as for maintaining <a href="https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-015-0461-x?report=reader">mental health</a>. When even young healthy adults eat “junk” foods, aspects of cognition linked to the hippocampus quickly <a href="https://royalsocietypublishing.org/doi/abs/10.1098/rsos.191338">decline</a>.</p>
<p>On the other hand, research shows a diet containing more and varied plant foods and seafood (which are rich in components called long-chain omega-3 fatty acids and flavonoids) leads to <a href="https://www.nature.com/articles/s41598-022-21927-5">better cognitive performance</a>. This study was conducted in a closed chamber for 45 days, designed to mimic conditions in space.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Plate of salmon on bed of green salad, with lemon slices, on blue wood table" src="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565649/original/file-20231213-23-owo81l.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 diet rich in plant food and seafood might help your brain, but how do you turn that into space food that will go the distance?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/grilled-salmon-vegetables-366852431">Jacek Chabraszewski/Shutterstock</a></span>
</figcaption>
</figure>
<p>Diet can have such consequences by <a href="https://www.ncbi.nlm.nih.gov/pubmed/33144709">altering</a>:</p>
<ul>
<li>immune function</li>
<li>the size and functioning of the hippocampus </li>
<li>chemical messenger (neurotransmitter) systems</li>
<li>how our bodies respond to stress.</li>
</ul>
<p>Diet can also influence the many ways microbes in the gut affect the brain, a link known as the <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">microbiota gut-brain axis</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/essays-on-health-microbes-arent-the-enemy-theyre-a-big-part-of-who-we-are-79116">Essays on health: microbes aren't the enemy, they're a big part of who we are</a>
</strong>
</em>
</p>
<hr>
<h2>Not all foods make the grade</h2>
<p>Space foods need to appeal to a diverse crew and stay nutritious for an extremely long time (likely a three- to five-year mission). They also need to be lightweight and compact enough to fit on the spacecraft.</p>
<p>Once on Mars, challenges include growing fresh food and culturing protein sources. Beyond providing nutrients, we also need to consider providing more recently identified factors including phytonutrients (such as polyphenols), fermentation products and microbes. These will likely be crucial to sustain health and, indeed, life on deep space missions.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/humans-are-going-back-to-the-moon-and-beyond-but-how-will-we-feed-them-189794">Humans are going back to the Moon, and beyond – but how will we feed them?</a>
</strong>
</em>
</p>
<hr>
<h2>Why are microbes so important?</h2>
<p>If you’ve seen the film <a href="https://theconversation.com/the-martian-review-science-fiction-that-respects-science-fact-48373">The Martian</a>, you’ll know microbes are a crucial aspect of growing food, and are essential for keeping humans alive and functioning. </p>
<p>We have co-evolved with, and are hosts to, trillions of different microbes that live on our skin and in all our niches and cavities. This includes our mouths, nose, vagina, lungs and – crucially – our gut.</p>
<p>Most of these microbes are bacteria. The largest number are in the gut, where they influence our digestion, metabolism, and immune, endocrine (hormone) and nervous systems.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/YB-8JEo_0bI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What is the human microbiome?</span></figcaption>
</figure>
<p>The relationship between gut microbes and <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">mental health and behaviour</a> goes both ways. Gut microbes influence our mental health and behaviour, and these, in turn, influence our gut microbes. </p>
<p>Other components of our microbiomes – viruses, fungi and even parasites – and the oral and lung microbiome are also linked to mental and <a href="https://journals.physiology.org/doi/full/10.1152/physrev.00018.2018?rfr_dat=cr_pub">brain health</a>. </p>
<p>Importantly, we <a href="https://www.nature.com/articles/s41586-022-05620-1">share microbes</a> with others, including via the exchange of air, which is highly relevant in closed-environment systems such as inside spacecrafts.</p>
<p>So ensuring all astronauts have the healthiest and most diverse of microbes for the whole of the mission is vital.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-some-farts-smell-and-some-dont-and-why-do-some-farts-feel-hot-215064">Curious Kids: why do some farts smell and some don’t? And why do some farts feel hot?</a>
</strong>
</em>
</p>
<hr>
<h2>How could we encourage healthy microbes?</h2>
<p>It’s not just the food itself we have to think about. We also need to think about how we grow the food if we are to support healthy microbiomes. </p>
<p>Indeed, microbes play an essential role in the nutrient and phytochemical content of plants, and the microbes in soil, plants and humans are interconnected. Research published in 2023 confirms bacteria on vegetables and other plant foods find a home in the <a href="https://www.tandfonline.com/doi/abs/10.1080/19490976.2023.2258565">human gut</a>, enhancing microbe diversity. </p>
<p>But current ways of growing foods on spacecraft don’t use natural soil. Standard “vertical farming” methods grow plants in an alternative growth medium – imagine a next-generation hydroponics system. So we may need to add an optimised microbial cocktail to these systems to enhance the health properties of the foods astronauts grow and eat.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Growing tending plants in a vertical farm" src="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565654/original/file-20231213-19-kwbbo1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This closed chamber mimics how astronauts will grow fresh crops in space.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/technology/tech-transfer-spinoffs/nasa-research-launches-a-new-generation-of-indoor-farming/">NASA</a></span>
</figcaption>
</figure>
<p><a href="https://www.cell.com/cell/fulltext/S0092-8674(22)01515-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS009286742201515X%3Fshowall%3Dtrue">Fermented protein</a> from microbes can be quickly produced in a bioreactor on board the spacecraft, even from food waste. Some types have a meat-like flavour and texture, and can provide all the amino acids humans need as well as useful byproducts from the microbes themselves. </p>
<p>Fermentation itself creates thousands of different bioactive molecules, including some vitamins, that have diverse <a href="https://www.tandfonline.com/doi/abs/10.1080/1028415X.2018.1544332">beneficial effects on health</a>, including possible benefits to mental health.</p>
<p>While we don’t yet know what types of fermented foods are possible in space, we could include fermented foods, such as kimchi and sauerkraut, in astronauts’ diets on Earth.</p>
<p>Probiotics and prebiotics as supplements may also be essential. Probiotics are live microbes that have demonstrated health benefits and prebiotics are food for these healthy microbes.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-kombucha-and-how-do-the-health-claims-stack-up-87180">What is kombucha and how do the health claims stack up?</a>
</strong>
</em>
</p>
<hr>
<h2>Benefits on Earth too</h2>
<p>We’re only at the start of learning how to optimise microbes to keep space crews healthy, which is crucial for long space flights and for possible settlement on other planets. </p>
<p>However, this research could have many other applications. We can use what we learn to help create self-sustaining and <a href="https://www.nasa.gov/technology/tech-transfer-spinoffs/nasa-research-launches-a-new-generation-of-indoor-farming/">sustainable food systems</a> on Earth to improve the environment and human health.</p><img src="https://counter.theconversation.com/content/216355/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Felice N Jacka is supported by a National Health and Medical Research Council investigator grant (#1194982). She has received: (1) competitive grant/research support from the Brain and Behaviour Research Institute, the National Health and Medical Research Council, Australian Rotary Health, the Geelong Medical Research Foundation, the Ian Potter Foundation, The University of Melbourne; (2) industry support for research from Meat and Livestock Australia, Woolworths Limited, the A2 Milk Company, Be Fit Foods, Bega Cheese; (3) philanthropic support from the Fernwood Foundation, Wilson Foundation, the JTM Foundation, the Serp Hills Foundation, the Roberts Family Foundation, the Waterloo Foundation and; (4) travel support and speakers honoraria from Sanofi-Synthelabo, Janssen Cilag, Servier, Pfizer, Network Nutrition, Angelini Farmaceutica, Eli Lilly, Metagenics, and The Beauty Chef. She is on the Scientific Advisory Board of the Dauten Family Centre for Bipolar Treatment Innovation and Zoe Limited. Felice Jacka has written two books for commercial publication.</span></em></p><p class="fine-print"><em><span>Dorit Donoviel is Executive Director, NASA-Funded Translational (moving products from lab-bench to practice) Research Institute for Space Health at Baylor College of Medicine. Dorit receives funding from NASA through Cooperative Agreement NNX16AO69A and disburses this funding to research groups and companies performing work to safeguard the health of humans in deep space.</span></em></p>Here’s why a healthy balance of microbes is important for astronauts when they travel to Mars and beyond.Felice Jacka, Alfred Deakin Professor, Deakin UniversityDorit Donoviel, Executive Director/Associate Professor, Baylor College of Medicine Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2183972023-11-27T20:33:32Z2023-11-27T20:33:32ZQuébec’s hardwood trees could move north. Here’s how that could affect the boreal forest landscape<figure><img src="https://images.theconversation.com/files/561078/original/file-20231101-23-x790gm.jpg?ixlib=rb-1.1.0&rect=2%2C2%2C994%2C663&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The combined impact of increasing temperatures (2 to 8°C by 2100) and forest development in the mixed boreal forest could modify the growth and distribution of temperate species.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>In Québec, there are two distinct types of forest: the northern temperate forest in the south, and the boreal forest in the north.</p>
<p>These forest ecosystems provide <a href="https://doi.org/10.1126/science.abf3903">many different and essential services</a> to the overall functioning of the planet, and to our economy. For example, the storage of large quantities of atmospheric carbon and habitats for many species, as well as a supply of raw materials to the wood industry, which is a pillar of the economies of both Québec and Canada.</p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524152/original/file-20230503-20-rp105s.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>
</figcaption>
</figure>
<p><strong>This article is part of <em>La Conversation Canada’s</em> series <a href="https://theconversation.com/ca-fr/topics/foret-boreale-138017">The boreal forest: A thousand secrets, a thousand dangers</a></strong></p>
<p><br><em>La Conversation Canada invites you to take a virtual walk in the heart of the boreal forest. In this series, our experts focus on management and sustainable development issues, natural disturbances, the ecology of terrestrial wildlife and aquatic ecosystems, northern agriculture and the cultural and economic importance of the boreal forest for Indigenous peoples. We hope you have a pleasant — and informative — walk through the forest!</em></p>
<hr>
<p>As a doctoral student at Université du Québec en Abitibi-Témiscamingue (UQAT), I work on the colonization potential of sugar maple, yellow birch and red maple north of their range, in the mixed boreal forest. These three emblematic species of North American forests are of capital economic importance (for lumber, manufacture of plywood, pulp, or maple syrup for sugar maple) and contribute to the diversity of Québec’s forests.</p>
<h2>The mixed forest, between the temperate and boreal biomes</h2>
<p>The mixed forest is located in the transition zone (ecotone) between the boreal and temperate forests. </p>
<p>It refers to the region where these two forests meet, creating an area in which the <a href="https://www.researchgate.net/figure/Quebecs-vegetation-zones-subzones-and-bioclimatic-domains_fig16_269095315">characteristics of these two types of forest intermingle</a>. This amalgam is characterized by a complex coexistence between temperate hardwood species and the conifers typical of the boreal forest. </p>
<p>It is in this ecotone that temperate hardwoods reach the northern limit of their distribution. </p>
<h2>An uncertain future for the mixed boreal forest</h2>
<p>The combined impact of rising temperatures (2-8°C by 2100) and forest management in the boreal mixedwood forest could <a href="https://doi.org/10.1111/gcb.16014">alter the growth and distribution of temperate species</a>. The ecosystem services provided by these species could then be altered.</p>
<p>This transformation could be profound. Temperate hardwood species could migrate northwards and even become <a href="https://doi.org/10.1111/ecog.06525">dominant species</a> in boreal mixedwood <a href="https://cfs.nrcan.gc.ca/terms/read/1106">stands</a>.</p>
<p>Such a change in the forest composition of the boreal mixedwood forest could have major consequences for the forest industry, natural disturbance regimes and the biodiversity associated with the dominant tree species in the forests. However, there is still considerable uncertainty surrounding the factors that influence the successful establishment and growth of temperate hardwoods in the boreal mixedwood forest. </p>
<p>In order to get a complete picture of the future of the boreal mixedwood forest, it is essential to understand how the growth and establishment of temperate hardwoods within mixedwood stands is influenced by factors such as climate, soil characteristics and competitive interactions between trees.</p>
<h2>Hardwoods in the mixed boreal forest?</h2>
<p>As part of my doctoral work, we attempted to model competitive interactions between trees by taking into account the effects of climate change on their growth. This model simulates each tree in a stand. Each year, trees grow, reproduce and eventually die. The growth of each tree depends on the light the tree receives, competition for nutrients and space, and climate.</p>
<p>In our study, <a href="https://doi.org/10.1111/ecog.06525">published in the journal <em>Ecography</em></a>, we used this model to evaluate the capacity of temperate deciduous trees to establish themselves within mixed species stands in the boreal forest. To do this, we modelled typical mixed stands of the boreal forest, then integrated temperate deciduous species into these, giving the trees the opportunity to colonize these stands.</p>
<p>We showed that the three species of temperate hardwoods could colonize the stand. Yellow birch had a better colonization capacity, with its more numerous and lighter seeds which can disperse further. Red maple and sugar maple had similar abilities when it came to colonizing boreal mixed stands. However, sugar maple showed a better ability to colonize older forests, due to its superior growth under a closed canopy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/557904/original/file-20231106-27-ukk16g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="snowy forest" src="https://images.theconversation.com/files/557904/original/file-20231106-27-ukk16g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557904/original/file-20231106-27-ukk16g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557904/original/file-20231106-27-ukk16g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557904/original/file-20231106-27-ukk16g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557904/original/file-20231106-27-ukk16g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557904/original/file-20231106-27-ukk16g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557904/original/file-20231106-27-ukk16g.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">Temperate hardwood species could migrate north and even become dominant species within the forest’s stands.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The establishment capacity of temperate hardwoods in the boreal mixed forest was higher in the youngest stands, as well as in stands after clear-cutting. Therefore, forest management and forest fires, by rejuvenating boreal mixed forest landscapes, could accelerate the northward migration of temperate tree species.</p>
<p>Increased temperatures due to climate change are not expected to increase the ability of temperate hardwoods to colonize boreal mixedwood forest stands, either in the current climate or under high climate forcing scenarios. This means that climate would not be a factor influencing the northern limit of distribution of temperate hardwood species, and therefore, that climate change should not have an immediate effect on the northern distribution of temperate hardwoods.</p>
<p>The soil types of the boreal mixed forest could, however, be a limit to the growth of temperate hardwoods. In clay soils, the growth of red maple and sugar maple would be poor and would not allow them to be competitive with the species already present, which tolerate clay very well.</p>
<p>Factors governing tree growth such as climate, soil and competition interact together and can <a href="https://cdnsciencepub.com/doi/10.1139/cjfr-2019-0319">make predictions about the future distribution of different tree species very complex</a>.</p>
<h2>Both positive and negative effects</h2>
<p>The establishment of temperate hardwoods in the boreal mixed forest could increase the complexity and diversity in stands. This could strengthen the <a href="https://doi.org/10.1111/1365-2435.13257">resistance and resilience of the boreal mixed forest to disturbances</a>.</p>
<p>The presence of temperate deciduous trees in mixed boreal forests could, in particular, attenuate spruce budworm epidemics, because the proportion of fir and spruce trees would be lower and these species would be <a href="http://link.springer.com/10.1007/s004420050441">more dispersed in the stands</a>.</p>
<p>The establishment of temperate deciduous trees will cause an increase in the proportion of deciduous trees in the landscape. This phenomenon, known as enfoliation, has been observed in the mixed boreal forest for the last 100 years and is mainly due to forest management. This envelopment could make epidemics of <a href="https://open.canada.ca/data/en/dataset/663c3ba7-9d26-4243-a6f4-de6866d1685b">forest livery</a> more severe. This defoliating insect attacks deciduous trees and especially aspen, paper birch and sugar maple.</p>
<p>Finally, wildfire regimes could be modified by the differences in flammability of hardwoods and conifers. The presence of temperate deciduous trees, which are less flammable than conifers, could lengthen fire cycles. This positive effect will, however, be associated with a major challenge for the forestry industry which manages the mixed boreal forest, since the industry is currently focused mainly on conifers.</p>
<h2>We can’t stop there</h2>
<p>Further modelling studies are needed to explore the impact of other factors that may influence the ability of temperate hardwoods to colonize boreal mixedwood forest.</p>
<p>In particular, we can think of the impact of soil and mycorrhizae (symbiosis between the roots of plants and fungi) on the germination and growth of trees, but also the effect of weather phenomena, such as late frosts, which can affect the survival and growth of young temperate trees.</p>
<p>Additionally, landscape scale modeling would be beneficial in order to be able to consider the topography of the land, a potentially influential factor on the ability of temperate hardwoods to establish further north.</p><img src="https://counter.theconversation.com/content/218397/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fabio Gennaretti received funding from the Canada Research Chair in Dendroecology and Dendroclimatology (CRC-2021-00368) and from the Ministère des Ressources Naturelles et des Forêts (contract no. 142332177-D), and the Natural Sciences and Engineering Research Council of Canada (Discovery Grant no. RGPIN-2021-03553 and Alliance Grant no. ALLRP 557148-20, obtained in partnership with the MRNF and Resolute Forest Products).</span></em></p><p class="fine-print"><em><span>Maxence Soubeyrand ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Research shows that the distribution of temperate hardwoods (sugar maple, red maple and yellow birch) could be shifting northward, which would have serious consequences for the boreal forest.Maxence Soubeyrand, Doctorant en écologie forestière, Université du Québec en Abitibi-Témiscamingue (UQAT)Fabio Gennaretti, Professeur en sciences forestière, Université du Québec en Abitibi-Témiscamingue (UQAT)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2172272023-11-13T16:25:47Z2023-11-13T16:25:47ZEarthworms are our friends – but they will make the climate crisis worse if we’re not careful<figure><img src="https://images.theconversation.com/files/559077/original/file-20231113-22-x1gfqr.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6720%2C4476&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/two-earthworms-on-wet-soil-space-2331008495">New Africa/Shutterstock</a></span></figcaption></figure><p>Earthworms are revered for the way they nourish healthy soils, and scientific evidence validates the affection gardeners feel for these industrious invertebrates. Nevertheless, research has shown that our soil-dwelling friends may be less benevolent as the climate crisis escalates and grants them access to recently defrosted northern soils.</p>
<p>Historically, earthworms were viewed alongside slugs and snails as garden pests and thought to eat flower and vegetable roots from beneath the soil surface. They were killed and removed from gardens until more informed naturalists like Charles Darwin made observations that showed their worth. </p>
<p>Sometimes referred to as “Darwin’s plough”, earthworms naturally till the soil and increase its fertility by pulling leaves underground where they rot and enrich the soil. </p>
<p>Earthworms are considered ecosystem engineers too – species with an outsized influence on their environment. As such, they carry out numerous activities that are beneficial to us, including the formation, drainage and aeration of soils. They are also a protein-rich food source for birds and mammals. </p>
<figure class="align-center ">
<img alt="A bird with earthworms in its beak." src="https://images.theconversation.com/files/559078/original/file-20231113-23-4d70qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559078/original/file-20231113-23-4d70qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=433&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559078/original/file-20231113-23-4d70qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=433&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559078/original/file-20231113-23-4d70qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=433&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559078/original/file-20231113-23-4d70qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=544&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559078/original/file-20231113-23-4d70qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=544&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559078/original/file-20231113-23-4d70qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=544&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A firm favourite of feathered friends.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/a-bird-with-a-worm-in-its-mouth-standing-in-the-grass-FBWpkk20hoc">Jack Blueberry/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Unfortunately, they now have what may be perceived as a darker side.</p>
<h2>Globetrotters without feet</h2>
<p>European earthworms, such as the well-known lobworm (<em>Lumbricus terrestris</em>), the large and darkly pigmented worm you’ve probably seen writhing in a patch of upturned soil, are now found worldwide. Centuries ago they travelled in the soil of crop and fruit-bearing plants as they were taken by settlers to new lands. On newly ploughed farms this was seen as a bonus and these introduced worms bolstered food production. </p>
<p>More recently, these introduced earthworms have established themselves in more natural habitats, such as the temperate forests of North America. More often than not, their arrival in these forests has been as discarded fishing bait. There, the earthworm’s tendency to bury fallen leaves and till the soil has <a href="https://www.jstor.org/stable/3868431?searchText=&searchUri=&ab_segments=&searchKey=&refreqid=fastly-default%3A184c54dd2618c074f41c077ce668985c&seq=1">caused problems</a>, severely altering the nutrient status of the soil, exposing tree roots and reducing cover for ground nesting birds. </p>
<p>Earthworms are now viewed as invasive alien species in such ecosystems. Further north, in the boreal forests of Arctic and sub-Arctic Canada, an even greater problem is growing</p>
<p>Arctic soils are thought to store <a href="https://bg.copernicus.org/articles/11/6573/2014/bg-11-6573-2014.pdf">around half</a> of all the carbon locked up in soil globally. The greatest risk to the carbon storage of boreal forests was always assumed to be forest fires, which <a href="https://cdnsciencepub.com/doi/10.1139/er-2021-0074">may be increasing</a> as a result of rising global temperatures. </p>
<p>But earthworms may actually pose as great a threat. As land that was once covered with ice or in a semi-permanent frozen state thaws, the carbon-rich nutrients it held for thousands of years become accessible to microorganisms and soil-dwelling animals. </p>
<p>After the last ice age, no earthworms were present in northern soils. Since these creatures spread through the earth at a rate of only <a href="https://link.springer.com/article/10.1007/BF00317626">10 metres per year</a> under normal circumstances, even if they could survive, they wouldn’t be expected to reach such regions for centuries. </p>
<h2>Heading north</h2>
<p>But by building roads and pursuing recreational activities like freshwater angling, people are accidentally transporting ecosystem-engineering earthworms into areas where recently defrosted soil awaits. Again, it is abandoned, living fishing bait that creates a new invasion front.</p>
<p>By exercising their natural behaviour, earthworms are unlocking carbon from this soil and much of it is being released into the atmosphere as carbon dioxide. A study published in 2015 <a href="https://doi.org/10.1016/j.soilbio.2015.05.020">predicted</a> average losses of 10g of carbon per square metre of forest floor per year – a similar figure to that released by wildfires or the removal of trees for timber.</p>
<p>You might think earthworms would struggle to survive Arctic winters, but some, such as the octagonal worm (<em>Dendrobaena octaedra</em>) are relatively freeze-tolerant and their eggs can <a href="https://cdnsciencepub.com/doi/10.1139/er-2021-0074">survive temperatures of -35°C</a>. Others, such as the lobworm, can burrow deep to survive freezing temperatures above. Such species, once established, are not easily eradicated. </p>
<figure class="align-center ">
<img alt="A worm in soil." src="https://images.theconversation.com/files/559120/original/file-20231113-15-e1twa2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559120/original/file-20231113-15-e1twa2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559120/original/file-20231113-15-e1twa2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559120/original/file-20231113-15-e1twa2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559120/original/file-20231113-15-e1twa2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559120/original/file-20231113-15-e1twa2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559120/original/file-20231113-15-e1twa2.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">The lobworm, once confined to western Europe, is now globally distributed.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/common-earthworm-lumbricus-terrestris-nightcrawler-1581313723">Liz Weber/Shutterstock</a></span>
</figcaption>
</figure>
<p>In these newly available soils, earthworms are interacting with a range of microorganisms and enabling them to more easily decompose plant matter which was <a href="https://pub.epsilon.slu.se/31133/1/blume-werry-g-et-al-20230619.pdf">previously locked up in ice</a>, generating large volumes of carbon dioxide, methane and other greenhouse gases in the process.</p>
<p>This creates a positive feedback loop as the further release of greenhouse gases accelerates temperature rise. This is probably an unstoppable process and the best action with respect to earthworms is to prevent their accidental introduction at further sites in the sub-Arctic through education and, potentially, the policing of recreational areas.</p>
<p>Earthworms are vital in most soils, but in extremely northern latitudes, a massive shift has occurred in our view of these exceptional animals. Globally, we – the general public, governments, industry and scientists – must begin to address the issues of the climate crisis that affect us, earthworms, and indeed all living things on Earth.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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">
<figcaption>
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<p class="fine-print"><em><span>Kevin Richard Butt 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>Thawing permafrost in the far north is an inviting prospect for invertebrate burrowers.Kevin Richard Butt, Reader in Ecology, University of Central LancashireLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2149702023-11-05T09:27:02Z2023-11-05T09:27:02ZGrowing African vegetables on buildings can save space and feed cities – new study<figure><img src="https://images.theconversation.com/files/554793/original/file-20231019-21-c6blch.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4771%2C3183&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Eco Green Wall is an example of a sustainable living wall system.</span> <span class="attribution"><span class="source">Karen Botes</span></span></figcaption></figure><p><em>As cities grow, more people <a href="https://globalaffairs.org/sites/default/files/2021-02/report_growing-food-for-growing-cities.pdf#page=13">need</a> food. However, space for farming is <a href="https://www.focusingfuture.com/eco-city/urban-farming-solves-lack-of-agriculture-space/">limited</a> in cities. Building facades can offer a solution for growing food. We asked landscape architect Karen Botes to tell us about her research – cultivating traditional African vegetables on walls.</em> </p>
<h2>What are ‘living wall systems’ and why did you study them?</h2>
<p><a href="https://www.ajlajournal.org/articles/traditional-african-vegetables-living-walls">Living wall systems</a> are vertical growing platforms which usually form part of a building façade. Some are <a href="https://www.sciencedirect.com/science/article/pii/S1364032114006637">continuous, others modular</a>.</p>
<p><a href="https://journals.ufs.ac.za/index.php/as/article/view/5801/4204#page=147">Continuous systems</a> are lightweight screens with pockets that can contain wet <a href="https://www.sciencedirect.com/science/article/pii/S0360132316305108">felted substrate layers</a>, or rock wool, for the plants to grow in, or the plants’ exposed roots are kept wet with nutrient-rich fluids. An example of a continuous system is <a href="https://www.nal.usda.gov/farms-and-agricultural-production-systems/hydroponics#:%7E:text=Hydroponics%20is%20the%20technique%20of,%2C%20coconut%20coir%2C%20or%20perlite.">hydroponics</a>.</p>
<p><a href="https://journals.ufs.ac.za/index.php/as/article/view/5801/4204">Modular living wall systems</a> are irrigated plant trays or pots containing soil and fixed onto a supporting structure on the building’s vertical surface. Modular systems are widely used because they make an immediate aesthetic impact. The plants are pre-grown offsite and individual plants are easily replaced. </p>
<p>To learn more about which modular living wall systems work best, I compared two during the 2021/2022 growing season in Pretoria, South Africa. My <a href="https://www.ajlajournal.org/articles/traditional-african-vegetables-living-walls#:%7E:text=Living%20wall%20food%20systems%20involving,social%2Cenvironmental%20and%20educational%20benefits.">six-month study</a> also compared traditional African vegetable crops with a mainstream crop. </p>
<h2>What are the benefits of living walls?</h2>
<p>Benefits of living walls include <a href="https://iopscience.iop.org/article/10.1088/1755-1315/1101/2/022051">food production</a>, <a href="https://repository.up.ac.za/handle/2263/61145">biodiversity, cooling, air purification and noise reduction</a>. They also have aesthetic value and are known to <a href="https://www.sciencedirect.com/science/article/pii/S1618866719302894?casa_token=y4OCy-Fm0QYAAAAA:4Hw1JE3WdPN-jq2yt_7N_hN2-eYsWPvqLe99lWUuDpW2SkKxS0do0OjFmI5a8_qi3MckNMAN">reduce stress and improve productivity and wellbeing</a>. </p>
<p>When households grow edible crops in living walls, it reduces the environmental impact of food because it doesn’t have to come from far away. And it reduces waste. Growing vegetables has also been found to encourage urban gardeners to eat a more balanced diet in <a href="https://journals.openedition.org/factsreports/5610">Honduras</a>, <a href="https://www.jstage.jst.go.jp/article/jrm/13/2/13_2960/_article/-char/ja/">Japan</a>, <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/hpja.207?casa_token=RbOlOoyUaUoAAAAA%3AkFEtqYg4Q4KR5MfSlWne6LfeJZZjLb4VKiaU6TIv69QABUjGd7m55KQz-12bDaa1HxgxJpMX2NBuSYo">Australia and elsewhere</a>.</p>
<p>I’m interested in whether <a href="https://iopscience.iop.org/article/10.1088/1755-1315/1101/2/022051">living walls with traditional African vegetables</a> could improve local household food production and contribute to dealing with climate change, <a href="https://theconversation.com/the-loss-of-vegetation-is-creating-a-dangerous-heat-island-over-nairobi-150622">urban heat islands</a> and urban <a href="https://theconversation.com/how-buildings-in-johannesburg-could-benefit-from-green-roofs-122877">microclimates</a>.</p>
<h2>What did you discover in your study in Pretoria?</h2>
<p>The study compared the performance of traditional African vegetable crops in two types of living wall system, the Vicinity wall and the Eco Green Wall, in terms of crop yields and health. </p>
<p>The <a href="https://www.modularverticalgarden.com/">Vicinity</a> wall is an all-in-one system, with water tanks at the bottom, a pump and a filter. The top row of pots is drip irrigated and the water gravitates into each row, before circulating back to the top row. The Vicinity pots are clipped onto an aluminium rail fixed to the building. </p>
<p>The <a href="https://journals.ufs.ac.za/index.php/as/article/view/5801/4204">Eco Green Wall</a> comprises interlocking, lightweight blocks made out of recycled polystyrene aggregate-and-cement mixture, and plant pots with a soil volume of roughly 1.5 litres. It is designed with economic feasibility and sustainability in mind. </p>
<p>I compared the living wall systems’ performance to traditional soil-based agriculture. Variables included minimum and maximum daily temperatures, relative humidity, precipitation, soil temperature, water content and electrical conductivity, leaf biomass yield and plant stress. </p>
<p>The <a href="https://iopscience.iop.org/articlesystem's%20components/10.1088/1755-1315/1101/2/022051">study</a> found that local production of the living wall components reduced their cost and carbon footprint. </p>
<p><a href="https://www.ajlajournal.org/articles/traditional-african-vegetables-living-walls#:%7E:text=Living%20wall%20food%20systems%20involving,social%2Cenvironmental%20and%20educational%20benefits.">Low technology</a> that requires basic assembly, and a basic irrigation system to limit dependency on electricity and water, can enhance performance.</p>
<p>An <a href="https://iopscience.iop.org/article/10.1088/1755-1315/1101/2/022051/meta">appropriate plant selection</a> can further improve the living wall’s resilience, feasibility and sustainability. The study identified seven <a href="https://link.springer.com/article/10.1007/s12231-019-09448-1">traditional African vegetable</a> species suitable for household food production in living wall systems: creeping foxglove, Indian borage, jute plant, pink ribbons, water mint, dwarf elephant’s food and black-eyed pea. </p>
<h2>How feasible is it? What are the biggest barriers?</h2>
<p><a href="https://link.springer.com/article/10.1007/s11252-008-0063-x">Building facades</a> make up roughly double the area of building footprints in urban areas. This means that walls have more potential for local food production than traditional soil-based urban agriculture. They also have environmental benefits. </p>
<p>But the efficiency, resilience and sustainability of current living wall systems have been <a href="https://iopscience.iop.org/article/10.1088/1755-1315/1101/2/022051">questioned</a> globally and need improvement. </p>
<ul>
<li><p>They are costly to install and maintain. </p></li>
<li><p>They seldom provide optimal conditions for plants to flourish. </p></li>
<li><p>They rely on electricity and water.</p></li>
<li><p>Some systems require specialised skills and technology.</p></li>
</ul>
<h2>What could make it work for cities on the continent?</h2>
<p>Sun exposure of plant pots should be limited so that the soil doesn’t get too hot. The <a href="https://journals.ufs.ac.za/index.php/as/article/view/5801/4204">Eco Green Wall</a> system is an example where sun exposure is limited and the structure protects the crops.</p>
<p>Pots need to have at least three litres of <a href="https://www.publish.csiro.au/fp/FP12028">soil</a> with a depth of 200mm. This increases yield and reduces plant stress. The soil must be lightweight and meet the plant’s requirements. Aeration, texture and drainage must be right. The pots’ drainage holes must limit blockages. </p>
<p>A drip or wick irrigation system for each plant level reduces maintenance and increases resilience.</p>
<p>Selecting <a href="https://www.ajlajournal.org/articles/traditional-african-vegetables-living-walls#:%7E:text=Living%20wall%20food%20systems%20involving,social%2Cenvironmental%20and%20educational%20benefits.">traditional African vegetables</a> increases the feasibility and resilience of crop performance. These crops can tolerate sub-Saharan Africa’s harsh climate conditions. </p>
<p><a href="https://iopscience.iop.org/article/10.1088/1755-1315/1101/2/022051">Traditional African vegetables</a> also have a high nutritional value, don’t need much irrigation or chemicals, and are resistant to disease. </p>
<p>These vegetables prefer full sun and no frost. Well-drained, aerated potting soil that allows for movement of air, water and nutrients works well for them. They require moderate irrigation.</p>
<p>The system should be positioned to avoid possible contamination of crops by <a href="https://iopscience.iop.org/article/10.1088/1755-1315/1101/2/022051">polluted environments</a>. It must be orientated to provide <a href="https://www.sciencedirect.com/science/article/abs/pii/S1618866717304156">efficient sun exposure</a> for the selected plants.</p>
<h2>So, are living wall systems worth considering to grow vegetables?</h2>
<p>I concluded from my research that growing traditional African vegetables in modular living walls saves space compared to standard soil-based food production on a household scale. Considering the horizontal footprint area occupied in terms of yield per square metre, living wall systems with larger pot volumes produced over four times the yield of conventional soil-based agriculture. And they use space that would otherwise not have been used productively.</p>
<p>I also concluded that <a href="https://www.ajlajournal.org/articles/traditional-african-vegetables-living-walls#:%7E:text=Living%20wall%20food%20systems%20involving,social%2Cenvironmental%20and%20educational%20benefits.">outdoor modular living wall systems with selected traditional African vegetable crops</a> might be one way of improving food security and urban environments in sub-Saharan Africa.</p><img src="https://counter.theconversation.com/content/214970/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Botes 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>Growing traditional African vegetables on building facades is feasible and can improve food supply in cities.Karen Botes, Lecturer in Landscape Architecture, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2140482023-09-28T12:28:11Z2023-09-28T12:28:11ZYour microbes live on after you die − a microbiologist explains how your necrobiome recycles your body to nourish new life<figure><img src="https://images.theconversation.com/files/550423/original/file-20230926-27-qpnpj4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1794%2C1668&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">After you die, bacteria harvest your body for the nutrients that help push daisies.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/embroidery-skull-and-roses-grapes-humming-royalty-free-illustration/931298520">Matriyoshka/iStock via Getty Images Plus</a></span></figcaption></figure><p>Each human body contains a <a href="https://www.hmpdacc.org/overview/">complex community of trillions of microorganisms</a> that are important for your health while you’re alive. These <a href="https://open.oregonstate.education/generalmicrobiology/chapter/microbial-symbioses/">microbial symbionts</a> help you digest food, produce essential vitamins, protect you from infection and serve many other critical functions. In turn, the microbes, which are mostly concentrated in your gut, get to live in a relatively stable, warm environment with a steady supply of food.</p>
<p>But what happens to these symbiotic allies after you die? </p>
<p>As an <a href="https://scholar.google.com/citations?user=U_xOnjEAAAAJ&hl=en">environmental microbiologist</a> who studies <a href="https://doi.org/10.1093/femsec/fiad006">the necrobiome</a> – the microbes that live in, on and around a decomposing body – I’ve been curious about our postmortem microbial legacy. You might assume that your microbes die with you – once your body breaks down and your microbes are flushed into the environment, they won’t survive out in the real world. </p>
<p>In our September 2023 study, my research team and I share evidence that not only do your microbes continue to live on after you die, they actually play an important role in <a href="https://doi.org/10.1186/s13717-023-00451-y">recycling your body</a> so that new life can flourish.</p>
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<figcaption><span class="caption">Your microbes accompany you from cradle to grave.</span></figcaption>
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<h2>Microbial life after death</h2>
<p>When you die, your heart stops circulating the blood that has carried oxygen throughout your body. Cells deprived of oxygen start digesting themselves in a <a href="https://en.wikipedia.org/wiki/Autolysis_(biology)">process called autolysis</a>. Enzymes in those cells – which normally digest carbohydrates, proteins and fats for energy or growth in a controlled way – start to work on the membranes, proteins, DNA and other components that make up the cells. </p>
<p>The products of this cellular breakdown make excellent food for your symbiotic bacteria, and without your immune system to keep them in check and a steady supply of food from your digestive system, they turn to this new source of nutrition. </p>
<p><a href="https://doi.org/10.7717/peerj.3437">Gut bacteria</a>, especially a class of microbes called <a href="https://doi.org/10.3389/fmicb.2017.02096"><em>Clostridia</em></a>, <a href="https://doi.org/10.1016/j.forsciint.2016.03.019">spread through your organs</a> and digest you from the inside out in a process called <a href="https://www.ncbi.nlm.nih.gov/books/NBK539741/">putrefaction</a>. Without oxygen inside the body, your anaerobic bacteria rely on energy-producing processes that don’t require oxygen, such as fermentation. These create the distinctly odorous-gases signature to decomposition.</p>
<p>From an <a href="https://doi.org/10.1016/j.meegid.2017.09.006">evolutionary standpoint</a>, it makes sense that your microbes would have evolved ways to adapt to a dying body. Like rats on a sinking ship, your bacteria will soon have to abandon their host and survive out in the world long enough to find a new host to colonize. Taking advantage of the carbon and nutrients of your body allows them to increase their numbers. A bigger population means a higher probability that at least a few will survive out in the harsher environment and successfully find a new body.</p>
<h2>A microbial invasion</h2>
<p>If you’re buried in the ground, your microbes are flushed into the soil along with a soup of decomposition fluids as your body breaks down. They’re entering an entirely new environment and encountering a whole new microbial community in the soil.</p>
<p>The <a href="https://doi.org/10.1016/j.tree.2015.06.004">mixing or coalescence</a> of two distinct microbial communities happens frequently in nature. Coalescence happens when the roots of two plants grow together, when wastewater is emptied into a river or even when two people kiss.</p>
<p>The outcome of mixing – which community dominates and which microbes are active – depends on several factors, such as how much environmental change the microbes experience and who was there first. Your microbes are adapted to the stable, warm environment inside your body where they receive a steady supply of food. In contrast, soil is a particularly <a href="https://doi.org/10.1016/B978-0-12-820202-9.00002-2">harsh place to live</a> – it’s a highly variable environment with steep chemical and physical gradients and big swings in temperature, moisture and nutrients. Furthermore, soil already hosts an exceptionally diverse microbial community full of decomposers that are well adapted to that environment and would presumably outcompete any newcomers. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of Clostridium septicum" src="https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=501&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=501&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=501&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=629&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=629&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=629&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Clostridium septicum</em> is one species of bacteria involved in putrefaction.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/2n1hVng">Joseph E. Rubin/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
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<p>It’s easy to assume that your microbes will die off once they are outside your body. However, my research team’s previous studies have shown that the DNA signatures of host-associated microbes can be detected in the soil below a decomposing body, <a href="https://doi.org/10.1371/journal.pone.0130201">on the soil surface</a> and <a href="https://doi.org/10.1371/journal.pone.0208845">in graves</a> for months or years after the soft tissues of the body have decomposed. This raised the question of whether these microbes are still alive and active or if they are merely in a dormant state waiting for the next host.</p>
<p>Our newest study suggests that your microbes are not only living in the soil but also <a href="https://doi.org/10.1186/s13717-023-00451-y">cooperating with native soil microbes</a> to help decompose your body. In the lab, we showed that mixing soil and decomposition fluids filled with host-associated microbes increased decomposition rates beyond that of the soil communities alone.</p>
<p>We also found that host-associated microbes <a href="https://doi.org/10.1186/s13717-023-00451-y">enhanced nitrogen cycling</a>. Nitrogen is an essential nutrient for life, but most of the nitrogen on Earth is tied up as atmospheric gas that organisms can’t use. Decomposers play a critical role recycling organic forms of nitrogen such as proteins <a href="https://doi.org/10.1016/j.soilbio.2018.03.005">into inorganic forms</a> such as ammonium and nitrate that microbes and plants can use. </p>
<p>Our new findings suggest that our microbes are likely <a href="https://doi.org/10.1186/s13717-023-00451-y">playing a part</a> in this recycling process by converting large nitrogen-containing molecules like proteins and nucleic acids into ammonium. Nitrifying microbes in the soil can then convert the ammonium into nitrate. </p>
<h2>Next generation of life</h2>
<p>The recycling of nutrients from detritus, or nonliving organic matter, is a <a href="https://doi.org/10.2307/1930126">core process in all ecosystems</a>. In terrestrial ecosystems, decomposition of dead animals, or carrion, <a href="https://doi.org/10.1007/s00442-012-2460-3">fuels biodiversity</a> and is an important <a href="https://doi.org/10.1002/ece3.7542">link in food webs</a>.</p>
<p>Living animals are a bottleneck for the carbon and nutrient cycles of an ecosystem. They slowly accumulate nutrients and carbon from large areas of the landscape throughout their lives then deposit it all at once in a small, localized spot when they die. One dead animal can support a whole pop-up food web of <a href="https://doi.org/10.1093/femsec/fiad006">microbes</a>, <a href="https://doi.org/10.1371/journal.pone.0241777">soil fauna</a> and <a href="https://doi.org/10.1007/978-3-642-88448-1_6">arthropods</a> that make their living off carcasses. </p>
<p><a href="https://theconversation.com/life-after-death-how-insects-rise-from-the-dead-and-transform-corpses-into-skeletons-148847">Insect</a> and <a href="https://doi.org/10.1890/09-0292.1">animal scavengers</a> help further redistribute nutrients in the ecosystem. Decomposer microbes convert the concentrated pools of nutrient-rich organic molecules from our bodies into <a href="https://doi.org/10.1371/journal.pone.0287094">smaller, more bioavailable forms</a> that other organisms can use to support new life. It’s not uncommon to see <a href="https://doi.org/10.1002/ecs2.1537">plant life flourishing near a decomposing animal</a>, visible evidence that nutrients in bodies are being recycled back into the ecosystem.</p>
<p>That our own microbes play an important role in this cycle is one microscopic way we live on after death.</p><img src="https://counter.theconversation.com/content/214048/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer DeBruyn receives funding from the United States Department of Agriculture, National Science Foundation, Department of Justice, and Defense Advanced Research Projects Agency.</span></em></p>With the help of the microbes that once played an essential role in keeping you alive, the building blocks of your body go on to become a part of other living things.Jennifer DeBruyn, Professor of Environmental Microbiology, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2127002023-09-14T02:50:47Z2023-09-14T02:50:47ZHealthy soil can help grow more food and cut emissions – but government inaction means too much soil is being degraded<figure><img src="https://images.theconversation.com/files/546150/original/file-20230904-29-iz3bq6.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">(Volodymyr Shtun/Shutterstock)</span></span></figcaption></figure><p>The soil beneath our feet is a living entity. It is home to many microbes on Earth responsible for crucial processes such as decomposition and supporting plant health.</p>
<p>Organic compounds in the soil, such as humus – made from decomposed plant and animal matter – play a crucial role in maintaining soil’s structure, by acting as a bonding agent between soil particles. Similar to the walls of a building, healthy soil acts as a structure that allows water to flow, prevents erosion and provides habitats for organisms.</p>
<p>Healthy soil also helps people get safe and nutritious food, and is especially important for people including farmers and indigenous communities in developing nations.</p>
<p>Yet, more than a third of the soil worldwide is <a href="https://www.fao.org/about/meetings/soil-erosion-symposium/key-messages/en/">now degraded</a>, or facing issues such as hardening, erosion, nutrient degradation and increased salinity.</p>
<p>Degraded soil <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil-degradation">can result</a> in lower crop yields and poorer food quality. It also reduces water supply and increases drought risks. It may also increase the risks for floods, as the soil loses its ability to hold and filter water.</p>
<p>This article will share major factors behind soil degradation, and why we need governments worldwide to do more to take better care of our soil. </p>
<h2>Soil destroyers</h2>
<p>The global agriculture industry’s excessive use of fertiliser seriously damages the microbiological ecosystem in soil. This in turn makes the industry more dependent on expensive fertiliser and pesticides.</p>
<p>Modern ways of growing crops such as corns and potatoes often prioritise maximising high yields by using more nitrogen fertiliser than necessary. This releases nitrous oxide – a greenhouse gas <a href="https://www.bbc.com/future/article/20210603-nitrous-oxide-the-worlds-forgotten-greenhouse-gas">300 times more potent</a> than carbon dioxide at trapping heat in the atmosphere.</p>
<p>In addition, aggressive soil cultivation practices – such as deep plowing with heavy machinery – have risen significantly <a href="https://www.nytimes.com/1998/04/05/us/deep-plowing-is-halted-by-many-to-protect-soil.html">over recent decades</a>. These practices crush organic matter hidden within soil clumps, resulting in serious loss of biodiversity.</p>
<p>Human activities are putting too much stress on soil resources, and we are reaching a point where the soil can <a href="https://www.unccd.int/sites/default/files/2018-06/17.%20Threats%2Bto%2BSoils__Pierzynski_Brajendra.pdf">no longer sustain us</a>. This not only endangering biodiversity but also disrupting food supplies, potentially pushing millions into poverty.</p>
<h2>The global significance of healthy soil</h2>
<p><a href="https://www.iucn.org/news/ecosystem-management/202009/farmers-could-substantially-boost-productivity-conserving-soil-biodiversity-iucn-report">A 2020 study</a> by the International Union for Conservation of Nature found that healthy soils and landscapes can enhance crops’ ability to withstand the detrimental effects of climate change, such as drought or flood. </p>
<p>Improving our understanding of soil can also advance economic and climate goals.</p>
<p><a href="https://portals.iucn.org/library/node/49094">The IUCN report</a> found that increasing soil organic carbon by 0.4% annually in the first 30-40cm of soil may increase global production of major food crops, such as corn, rice and wheat, in some cases between 20-40% per year. </p>
<p>Boosting soil organic carbon in the world’s agricultural land by that much could increase carbon capture by croplands and grasslands by approximately <a href="https://portals.iucn.org/library/node/49094">1 gigatonne</a> per year over the next 30 years. That would be equivalent to capturing 10% of the world’s greenhouse gas emissions from human activity in 2017. </p>
<p>However, enhancing soil fertility is not as simple as pouring fertiliser out of a bag. Governments need to work together at the global, regional, and national levels to collectively improve soil health.</p>
<h2>Better policies to soil museums: how governments can help</h2>
<p>There are many existing soil initiatives around the world that governments can learn from. </p>
<p><strong>First,</strong> governments need to create policies that encourage farmers or land managers to implement environmentally friendly practices.</p>
<p>One example is the <a href="https://agriculture.ec.europa.eu/common-agricultural-policy/cap-overview/cap-glance_en">“carbon farming” policy</a> implemented by the European Union, which provides financial incentives to farmers or land managers who adopt eco-friendly practices. These practices include diversifying crops, planting leguminous plants, such as peanuts or lentils, and practising agroforestry (integrating trees and shrubs with crops or livestock).</p>
<p>These actions help to increase carbon sequestration in soils and support a healthy ecosystem with beneficial organisms, such as bacteria, fungi, protozoa and nematodes.</p>
<p>Brazil, China, India, Indonesia and Thailand <a href="https://web.kominfo.go.id/sites/default/files/G20%20Bali%20Leaders%27%20Declaration%2C%2015-16%20November%202022%2C%20incl%20Annex.pdf">have led globally</a> in reducing chemical fertiliser subsidies. To improve soil fertility and biodiversity, governments need to direct subsidies towards a biological solution that involves using bio-fertilisers and science-based composting.</p>
<p><strong>Second,</strong> governments can participate in global initiatives aimed at improving soil quality.</p>
<p>International organisations, such as the UN Sustainable Development Solutions Network, bring together experts, governments, the private sector and environmental organisations to emphasise critical environmental issues, including the significance of soil health. </p>
<p>The upcoming UN SDG Summit and UN Climate Change Conference (<a href="https://unfccc.int/cop28">COP28</a>) later in the year present opportunities for governments to recognise the feasibility and economic viability of large-scale soil ecosystem restoration.</p>
<p><strong>Third</strong>, educating the general public about soil science is also essential.</p>
<p>For instance, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0065211320301024">soil museums</a> – located in various regions around the world – serve as an effective means of educating people about different types of soil, how they are formed, their uses and threats, as well as ways to protect it.</p>
<p>Nurturing the symbiotic relationship between human and life in soil requires a mindset change. Doing so will improve citizens’ understanding and respect for the nutrient recycling mechanisms that nature itself has developed and relies on.</p><img src="https://counter.theconversation.com/content/212700/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yuen Yoong Leong, Director of Sustainability Studies, UN Sustainable Development Solutions Network (SDSN); Professor, Sunway University, and Michael James Platts (1945-2022), University of Cambridge</span></em></p>From policies to support carbon farming, to setting up local ‘soil museums’, governments need to do much more to protect the soil we rely on for growing food and a healthier life on Earth.Yuen Yoong Leong, Director of Sustainability Studies, UN Sustainable Development Solutions Network (SDSN); Professor, Sunway University, Sunway UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2114552023-08-16T14:52:16Z2023-08-16T14:52:16ZMore than half of life on Earth is found in soil – here’s why that’s important<figure><img src="https://images.theconversation.com/files/542806/original/file-20230815-17-8wyoa2.jpeg?ixlib=rb-1.1.0&rect=93%2C67%2C1501%2C831&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Springtails (Fasciosminthurus quinquefasciatus) are found in any damp soil.</span> <span class="attribution"><a class="source" href="https://www.chaosofdelight.org/gallery/5kispkk47gfjazdxskbw7m04mgvga3">Andy Murray/chaosofdelight.org</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>A <a href="https://www.pnas.org/doi/abs/10.1073/pnas.2304663120">recent study</a> has found that soil is home to 59% of all life on Earth, from an insect feeding on the soil surface to a tiny microbe nestled in a soil pore. This discovery crowns soil as the most biodiverse habitat on the planet.</p>
<p>The paper estimates that around 2 million species of <a href="https://www.britannica.com/animal/arthropod">arthropod</a> (think insects and spiders) inhabit the soil – some 30% of all known arthropod species. There are far fewer species of soil specialists such as <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/enchytraeidae"><em>enchytraeidae</em></a> (resembling mini earthworms) and <a href="https://www.britannica.com/animal/oligochaete"><em>oligochaeta</em></a> (worms), with only 770 and 6,000 species respectively. That might not seem like a lot, but it still represents around 98% and 63% of these animal groups.</p>
<p>The variety of mammals living in soil is, by comparison, quite limited. Only 3.8% of mammal species are associated with this habitat. On the other hand, 85% of plants have their roots buried in the soil and around 43% of <a href="https://www.britannica.com/animal/nematode"><em>nematode</em></a> (tiny worms) species call soil their home, or reside within the plants and animals that inhabit it.</p>
<p>However, the number of animal and plant species that live in soil are dwarfed by microscopic organisms. The researchers estimate that a mind-blowing 430 million species (or more than 50%) of bacteria and 5.6 million species (or 90%) of fungi have made soil their home.</p>
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Read more:
<a href="https://theconversation.com/the-melting-arctic-is-a-crime-scene-the-microbes-i-study-have-long-warned-us-of-this-catastrophe-but-they-are-also-driving-it-207785">The melting Arctic is a crime scene. The microbes I study have long warned us of this catastrophe – but they are also driving it</a>
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<p>But perhaps more important than the raw numbers are the functions that this biodiversity performs. The life within the soil not only helps to produce the food we eat, it also plays a crucial role in holding the soil together and even gives us potential sources for new antibiotics and medicines.</p>
<h2>Helping plants grow</h2>
<p>Small animals, including <a href="https://www.britannica.com/animal/earthworm">earthworms</a> and <a href="https://www.britannica.com/animal/springtail">springtails</a>, break down plant material and other forms of organic matter, such as dead insects, and incorporate them into the soil. This process releases the nutrients that most plants rely on to grow. But it’s not the only way that soil organisms <a href="https://theconversation.com/tapping-the-plant-microbiome-to-improve-farming-and-plant-health-36288">help plants gain more nutrition</a>. </p>
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<figcaption><span class="caption">How soil organisms break down plant remains and create soil pores.</span></figcaption>
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<p><a href="https://www.rhs.org.uk/biodiversity/mycorrhizal-fungi"><em>Mycorrhizal</em> fungi</a> (a species of fungi that grow in association with plant roots), for instance, embed themselves in the roots of plants where they extract energy-rich compounds. In return, the fungi help plants expand their reach in the soil, allowing them to access a greater amount of nutrients.</p>
<p>Other species that are vital for food production include <a href="https://www.britannica.com/science/nitrogen-fixing-bacteria">nitrogen-fixing bacteria</a>. They are commonly associated with legumes such as beans and clover. These bacteria convert nitrogen gas from the atmosphere into compounds that the plants can use – an undertaking that can otherwise only be done synthetically, using vast amounts of energy.</p>
<h2>Holding soil together</h2>
<p>As organisms penetrate the soil, whether by burrowing, creating nests or as a means of anchoring themselves, they engineer pathways through the soil and contribute to its structure. Notable examples include <a href="https://www.britannica.com/animal/termite">termites</a> rearranging the soil to create channels for air and water to filter through, as well as <a href="https://doi.org/10.1093/aob/mcab029">roots and root hairs enmeshing soil</a>.</p>
<p>The incorporation of decomposed plant material into the soil serves a similarly crucial purpose. It helps to hold the soil together and creates pores that protect the soil from erosion and increase its capacity to store water.</p>
<p>Some of this organic material is also locked away with soil minerals, leading to the <a href="https://theconversation.com/france-has-a-great-plan-for-its-soil-and-its-not-just-about-wine-47335">storage of carbon</a>. In fact, <a href="https://www.ipcc.ch/site/assets/uploads/2018/03/WGI_TAR_full_report.pdf">soils hold</a> three times as much carbon as vegetation and twice as much as the atmosphere. </p>
<figure class="align-center ">
<img alt="A termite mound on the Savanna." src="https://images.theconversation.com/files/542774/original/file-20230815-19-a37hww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542774/original/file-20230815-19-a37hww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=434&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542774/original/file-20230815-19-a37hww.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=434&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542774/original/file-20230815-19-a37hww.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=434&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542774/original/file-20230815-19-a37hww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=546&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542774/original/file-20230815-19-a37hww.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=546&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542774/original/file-20230815-19-a37hww.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=546&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Termites create structures above and below ground for air and water to move through.</span>
<span class="attribution"><span class="source">John Quinton</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Biodiversity increases resilience</h2>
<p>In many cases, these functions involve a variety of species. Having multiple species perform the same function offers a safety net if conditions change, such as during a drought or a flood. </p>
<p>Some species are more resilient to these events than others. When conditions change, unaffected organisms within the soil can step in to fulfil the same functions as those that might have suffered – a process ecologists call “functional redundancy”. This improves the ability of an ecosystem, such as soil, to withstand and recover from environmental shocks. </p>
<p>Soil biodiversity is also a key reservoir for new drugs. Soil bacteria have produced <a href="https://doi.org/10.1016/j.cub.2009.04.001">most of our antibiotics</a>, including streptomycin, chloramphenicol and tetracycline. Unfortunately, the rise of antibiotic resistance has rendered many early antibiotics ineffective. However, searching through different soils is <a href="https://www.nature.com/articles/d41586-018-01931-4">yielding promising new antibiotics</a> with the potential to kill “superbugs” that are resistant to existing drugs.</p>
<figure class="align-center ">
<img alt="A soil animal eating mould." src="https://images.theconversation.com/files/542612/original/file-20230814-25671-a5b8tl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542612/original/file-20230814-25671-a5b8tl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542612/original/file-20230814-25671-a5b8tl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542612/original/file-20230814-25671-a5b8tl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542612/original/file-20230814-25671-a5b8tl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542612/original/file-20230814-25671-a5b8tl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542612/original/file-20230814-25671-a5b8tl.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">A peeudachorutes species eating a slime mould.</span>
<span class="attribution"><a class="source" href="https://www.chaosofdelight.org/gallery/m5bftdf81d97p7ib5tgiais5dymfb8">Andy Murray/ChaosofDelight.org</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Soil biodiversity plays an important role in producing the food we eat, sustaining soil health and helping to deliver a range of other services, from sourcing medicines to reducing the impact of floods and droughts. The importance of protecting our soils for future generations becomes ever clearer.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
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<p class="fine-print"><em><span>John Quinton receives research funding from the Natural Environment Research Council, The Engineering and Physical Sciences Research Council and the European Commission</span></em></p>With more than one species for every person on the planet, soils are the most diverse habitat on Earth.John Quinton, Professor of Soil Science, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2062812023-08-07T12:06:44Z2023-08-07T12:06:44ZSuccessfully managing forests must include stewarding the hidden life belowground<figure><img src="https://images.theconversation.com/files/531843/original/file-20230614-27-m8n5el.jpg?ixlib=rb-1.1.0&rect=3%2C0%2C1717%2C1092&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Forest-harvesting practices that retain living trees throughout the harvested area sustain belowground life.</span> <span class="attribution"><span class="source">(John L. Innes)</span>, <span class="license">Author provided</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/successfully-managing-forests-must-include-stewarding-the-hidden-life-belowground" width="100%" height="400"></iframe>
<p>Half of the biodiversity in forests is unseen because it lives belowground. These organisms are miniscule in size, but their importance to the ecosystem is enormous. </p>
<p>In a single teaspoon of forest soil there are <a href="https://doi.org/10.1038/nature13855">thousands of species</a> and billions of individual organisms. These include microorganisms such as bacteria and archaea, soil animals like the microscopic protozoa, nematodes, tardigrades, collembolan and mites, and larger fauna such as millipedes, centipedes and worms. </p>
<p>A cubic centimetre of forest soil can also harbour more than a kilometre of <a href="https://doi.org/10.1111/gcb.16073">fungal hyphae</a>, the mass of thread-like cords running through the soil and forming mycelia. </p>
<p>This astonishing diversity of belowground life is arranged into complex food webs, with many of the larger animals feeding on smaller animals and microorganisms. This complex network has been largely ignored in forest management, but could be a key ally in making our forests resilient to stresses imposed by global climate change. </p>
<h2>Life belowground</h2>
<p>All life belowground ultimately relies on plants for nourishment. Some soil organisms feed on dead leaves and roots, which they <a href="https://doi.org/10.1016/j.foreco.2021.119522">transform into soil organic matter</a>. This matter is critical for soil fertility and water retention, and is the primary reservoir for soil carbon.</p>
<p>Other belowground organisms rely on the <a href="https://doi.org/10.1016/j.soilbio.2012.02.001">simple sugars</a> released from the roots of living trees to survive and grow. In tree needles and leaves, atmospheric carbon dioxide is converted into sugars and other metabolites via photosynthesis. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1623745635546718208"}"></div></p>
<p>Up to half of the sugars produced in leaves are conveyed belowground to tree roots. A portion of these sugars are <a href="https://doi.org/10.1111/gcb.13850">exuded from root tips</a> or transferred to mycorrhizal fungi that live in and around the roots.</p>
<p>Mycorrhizal fungal hyphae extend from root tips further into the soil and also <a href="https://doi.org/10.3389/fmicb.2019.00168">exude sugars</a> and metabolites. These compounds support abundant <a href="https://doi.org/10.1016/j.soilbio.2003.10.015">soil microorganisms</a> and form the basis of a vast food web belowground. </p>
<p><a href="https://doi.org/10.1111/j.1469-8137.2007.02238.x">Within hours or days</a> of carbon dioxide being taken up by tree leaves, some of the carbon is released from roots and fungal hyphae and distributed throughout the <a href="https://doi.org/10.1002/rcm.6368">belowground food web</a>. </p>
<p>The <a href="https://doi.org/10.1016/j.soilbio.2020.107929">dead bodies</a> of, and metabolites released by, the soil microorganisms are also an important source of soil organic matter.</p>
<h2>Managing the whole forest</h2>
<p>This new appreciation of the importance of living roots in sustaining life belowground should prompt us to rethink forest management.</p>
<p>Harvesting trees severs the critical flow of resources belowground, directly reducing the abundance and diversity of soil life. However, harvesting practices that <a href="https://doi.org/10.1016/j.foreco.2023.120848">retain living trees</a> within 15 metres of each other, can maintain soil life throughout the harvested area. </p>
<p>Forest harvesting practices that retain a portion of the living trees, such as continuous cover forestry and <a href="https://doi.org/10.1111/1365-2664.12289">retention forestry</a> can help keep the soil alive in harvested forests.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541294/original/file-20230804-33657-ldda9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A forest patch" src="https://images.theconversation.com/files/541294/original/file-20230804-33657-ldda9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541294/original/file-20230804-33657-ldda9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541294/original/file-20230804-33657-ldda9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541294/original/file-20230804-33657-ldda9c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541294/original/file-20230804-33657-ldda9c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541294/original/file-20230804-33657-ldda9c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541294/original/file-20230804-33657-ldda9c.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">Retention forestry in a Douglas-fir forest on Vancouver Island, in which 40 mature living trees were retained per hectare.</span>
<span class="attribution"><a class="source" href="https://www2.gov.bc.ca/gov/content/industry/forestry/managing-our-forest-resources/silviculture/silviculture-research/silvicultural-systems-research/stems/uniform-dispersed-retention">(Government of British Columbia)</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Plant diversity also matters, as species differ in the variety of compounds released by their roots, which influences <a href="https://doi.org/10.1002/ece3.2454">microbial diversity</a> in the soil. </p>
<p>Soil biodiversity can be promoted by establishing forests with more than one tree species. In particular, forests that contain <a href="https://doi.org/10.1111/ele.13651">broadleaf tree species</a> and tree species with <a href="https://doi.org/10.1016/j.foreco.2020.118127">nitrogen-fixing</a> microbial associates promote soil biodiversity and replenishment of soil organic matter.</p>
<h2>Twenty-first century forestry</h2>
<p>In the face of the twin crises of climate change and biodiversity collapse, we need forests that are resilient and diverse. Soil organisms are critical allies in this endeavour.</p>
<p><a href="https://doi.org/10.1038/nature13855">Soil organisms</a> contribute half of the biodiversity of forests and regulate the processes that govern soil fertility, water retention and greenhouse gas emissions. Forestry practices that foster soil biodiversity can assist in making our forests resilient and diverse.</p>
<p>The vital role of inputs from living roots for sustaining soil organic matter and belowground life has been recognized in agriculture and is a central principle of <a href="https://doi.org/10.2489/jswc.2021.0920A">regenerative agriculture</a>, a suite of practices that actively restore soil quality, biodiversity, ecosystems health and water quality while producing sufficient food of high nutritional quality. </p>
<p>Forestry could also be regenerative, particularly if we apply practices such as continuous cover and species mixtures, and intentionally conserve life belowground.</p><img src="https://counter.theconversation.com/content/206281/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sue Grayston receives funding from Mitacs. </span></em></p><p class="fine-print"><em><span>Cindy Prescott 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>The important role living roots play for sustaining life belowground should prompt us to rethink forest management.Cindy Prescott, Professor of Forest Ecology, University of British ColumbiaSue Grayston, Professor of Soil Microbial Ecology, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2054572023-07-04T22:14:59Z2023-07-04T22:14:59ZWhat listening to the soil can tell us about our relationship with the land<p>How often do you think about the soil beneath our feet? We humans rely on the soil to provide us with a stable supply of <a href="https://www.theguardian.com/environment/2022/may/07/secret-world-beneath-our-feet-mind-blowing-key-to-planets-future">food, clean water and clean air</a>. Soils have lived histories and stories to tell. They are alive. <a href="https://openpress.usask.ca/soilscience/">Soil exists as a varied continuum across Earth’s surface</a> reflecting the intersection of air, water, rock and life linked by the passage of time. </p>
<p>The soil can tell stories of their past to anyone who takes the time to listen.
Yet despite our reliance on soil, humans entrenched in colonial mindset and systems have been poor soil stewards and generally ignorant to <a href="https://www.taylorfrancis.com/chapters/edit/10.4324/9781315685366-8/colonialism-development-degradation-piers-blaikie-harold-brookfield">the destructive and extractive practices</a> we inflict on soil.</p>
<p>If we do not listen to the stories of the soil, we as humans might destroy the soil which supports countless lives. Only by understanding our past and current relationship with soil can we reflect and change our partnership with soil from extraction and exploitation to respect, relationality and reciprocity.</p>
<p>Whether we know it or not, soils are the silent partner that sustains us. In the years and decades to come, what will our lasting legacy be in the story the soil tells?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/533604/original/file-20230623-26366-dohtac.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Some soil in the palm of a hand." src="https://images.theconversation.com/files/533604/original/file-20230623-26366-dohtac.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/533604/original/file-20230623-26366-dohtac.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533604/original/file-20230623-26366-dohtac.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533604/original/file-20230623-26366-dohtac.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533604/original/file-20230623-26366-dohtac.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533604/original/file-20230623-26366-dohtac.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533604/original/file-20230623-26366-dohtac.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">We must listen to the stories the soil tells, and repair our relationship with it.</span>
<span class="attribution"><span class="source">(Author provided)</span></span>
</figcaption>
</figure>
<h2>Impacts of human activity</h2>
<p>Over the past three years, <a href="http://hdl.handle.net/1880/113973">we have worked</a> with our community partner, <a href="https://www.cbc.ca/news/canada/calgary/land-of-dreams-indigenous-garden-farm-newcomer-families-1.5574833">Land of Dreams</a>, a 30-acre community urban farm in southeast Calgary. The region has traditionally been stewarded by the Niitsitapi, Îethka Nakoda and Tsuut’ina Nations, and more recently Métis Nation Region 3. </p>
<p>The vision of Land of Dreams is to create a place where communities who are forcefully displaced from their land gather and reconnect to the soil through small-scale agricultural practices, while learning about <a href="https://open.spotify.com/show/0uGuMvlde8aEuntOaeGmhK">Indigenous ways of stewarding the land</a>. Our goal is to use <a href="https://doi.org/10.1093/acrefore/9780190264093.013.1655">STEM education to press for social justice and environmental protection</a>.</p>
<p>Enacting this vision requires using Indigenous knowledge to <a href="https://doi.org/10.1007/s11422-020-09983-7">carefully listen to the stories the soil reveals</a>. </p>
<p>Digging deeper into this land, we encounter various faces of the soil shaped by <a href="https://soilsofcanada.ca/soil-formation/factors.php">climate, topography, parent material and time</a>. </p>
<p>The Prairie Pothole region, where Land of Dreams is located, is typified by a mosaic of grasslands and wetlands. </p>
<p>Before European colonization, Indigenous communities had <a href="https://www.aupress.ca/books/120256-living-on-the-land/">long histories of stewarding the land</a> and <a href="https://nativesoilnerd.com/invited-talks-webinars">living reciprocally with the soil</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/533605/original/file-20230623-20-vmahw2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533605/original/file-20230623-20-vmahw2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533605/original/file-20230623-20-vmahw2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533605/original/file-20230623-20-vmahw2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533605/original/file-20230623-20-vmahw2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533605/original/file-20230623-20-vmahw2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533605/original/file-20230623-20-vmahw2.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 tipi on the Land of Dreams site. Indigenous communities have long histories of stewarding the land and living reciprocally with the soil.</span>
<span class="attribution"><span class="source">(University of Calgary/Fritz Tolentino)</span></span>
</figcaption>
</figure>
<p>We try to imagine, from the soil’s point of view, how detrimental the impacts of human activity have been. Until 2009, the soil experienced the cycle of harvest which involved the disruptive effects of annual soil tillage, vehicle traffic and the application of biocides for plants and animals deemed pests. </p>
<p>In 2010, the soil’s life-rich surface was stripped away and it was then pressed for the construction of a highway. This caused <a href="https://doi.org/10.1016/j.still.2004.08.009">soil compaction</a>, where the soil pores are pressed together and the soil becomes more rock-like. In this single event, human activity undid the thousands of years it took for the soil to be a space where life could thrive in harmony with the local climate.</p>
<h2>Repairing our relationship with the soil</h2>
<p>However, this is not the end of the soil’s story. Despite compaction causing the soil’s surface to become dry and dusty, some plants still grow. Ironically, plants such as dandelions and thistles that were carried here <a href="https://anpc.ab.ca/wp-content/uploads/2015/01/dandelion.pdf">alongside European colonization</a> also thrive on the soil impacted by <a href="https://theconversation.com/decolonize-your-garden-this-long-weekend-dig-into-the-complicated-roots-of-gardening-listen-205720">colonial legacy</a>. </p>
<p>Our observations show how some of the pasture soil continues to act as a refuge of native plants and animals, patiently watching the dandelions and thistles and waiting for a time when the compacted soil will be able to welcome them back.</p>
<p>Despite years of being forced into agricultural production, the soil of the nearby wetland quickly resumes its place as a home and provider to countless insects, birds, frogs, plants and mammals when left to be itself.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/534635/original/file-20230628-17-tqziv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two young boys throwing seeds in a feild." src="https://images.theconversation.com/files/534635/original/file-20230628-17-tqziv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/534635/original/file-20230628-17-tqziv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=780&fit=crop&dpr=1 600w, https://images.theconversation.com/files/534635/original/file-20230628-17-tqziv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=780&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/534635/original/file-20230628-17-tqziv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=780&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/534635/original/file-20230628-17-tqziv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=981&fit=crop&dpr=1 754w, https://images.theconversation.com/files/534635/original/file-20230628-17-tqziv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=981&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/534635/original/file-20230628-17-tqziv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=981&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Soil Campers throwing native plant seed balls onto the land.</span>
<span class="attribution"><span class="source">(Author provided)</span></span>
</figcaption>
</figure>
<p>Over time the compacted soil will recover, but it will never be the same. It will carry the stories of disturbance and compaction, and of resilience and recovery. </p>
<p>As we envisage our future relationships with the soil, we should let the land guide us. We should listen to <a href="https://jps.library.utoronto.ca/index.php/des/article/view/22170">the soil as our teacher</a> and relative. Despite the central role that soils play in the ecosystem and our food security, school curricula do not fully teach young minds about the soil. We run the <a href="https://www.soilcamp.ca/">Soil Camp</a>, an educational project that explores what more soil-centric relationships could look like in action. </p>
<p>The next time you are walking on a sidewalk, a well-used trail in an urban park or your backyard, take a moment to think about the land and soil. Imagine what it was like five, 50 or 5,000 years ago. What or who has impacted and changed it? Is the soil still connected with its surrounding natural habitat? Asking these questions can help us take action to be a better partner to the soil beneath our feet.</p><img src="https://counter.theconversation.com/content/205457/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mathew Swallow is supported by funding from Social Sciences and Humanities Research Council and Environmental and Climate Change Canada.</span></em></p><p class="fine-print"><em><span>Kori Czuy is works for the the TELUS Spark Science Centre.</span></em></p><p class="fine-print"><em><span>Miwa A. Takeuchi receives funding from Social Sciences and Humanities Research Council and Environmental and Climate Change Canada. </span></em></p>Only by understanding our past and current relationship with soil can we reflect and change our partnership with soil from extraction and exploitation to respect, relationality and reciprocity.Mathew Swallow, Associate Professor, Department of Earth and Environmental Sciences, Mount Royal UniversityKori Czuy, Manager, Indigenous Science Connections, TELUS Spark Science CentreMiwa Aoki Takeuchi, Associate Professor, Learning Sciences, University of CalgaryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2070322023-06-07T20:08:16Z2023-06-07T20:08:16ZMore than 60 billion leaf litter invertebrates died in the Black Summer fires. Here’s what that did to ecosystems<figure><img src="https://images.theconversation.com/files/530506/original/file-20230607-22-vp1de5.jpg?ixlib=rb-1.1.0&rect=5%2C2%2C992%2C663&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The predatory beetle Eurylychnus blagravei</span> <span class="attribution"><span class="source">Nick Porch</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The Black Summer megafires engulfing south-eastern Australia in 2019–2020 were so intense they burned habitats rarely exposed to fire, such as southern warm temperate rainforest.</p>
<p>These rainforests range from East Gippsland in Victoria up to just south of Sydney. Usually, they stay moist enough to prevent major fires. But in that unprecedented summer of fire, 80,000 hectares burned. Our <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/aec.13375">new research</a> estimates more than 60 billion invertebrates in the soil and leaf litter died too. </p>
<p>While our hearts went out to the burned koalas and kangaroos, this was a silent tragedy. These tiny creatures are enormously important in ecosystems. They eat dead leaves, create rich soil, and provide a key food source for bandicoots and lyrebirds. Many species have very small ranges, putting them at real risk of decline or even extinction from fire. </p>
<p>As renowned naturalist E. O. Wilson once said, invertebrates are the “the little things that run the world”. But because they are small and out of sight, we still underestimate their significance in ecosystems and their contribution to Australia’s biodiversity. They’re all but forgotten when ecological disasters strike. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/530516/original/file-20230607-27-zjfgrl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The aftermath of high severity burn" src="https://images.theconversation.com/files/530516/original/file-20230607-27-zjfgrl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/530516/original/file-20230607-27-zjfgrl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=190&fit=crop&dpr=1 600w, https://images.theconversation.com/files/530516/original/file-20230607-27-zjfgrl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=190&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/530516/original/file-20230607-27-zjfgrl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=190&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/530516/original/file-20230607-27-zjfgrl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=239&fit=crop&dpr=1 754w, https://images.theconversation.com/files/530516/original/file-20230607-27-zjfgrl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=239&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/530516/original/file-20230607-27-zjfgrl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=239&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Temperate rainforests such as those in East Gippsland are not used to intense fire.</span>
<span class="attribution"><span class="source">Joshua Grubb</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>How did we find out how many invertebrates died?</h2>
<p>In warm temperate rainforests, there’s a layer of moist leaf litter which is home to an abundance of <a href="https://theconversation.com/photos-from-the-field-zooming-in-on-australias-hidden-world-of-exquisite-mites-snails-and-beetles-147576">ancient lifeforms</a>. These include the macroinvertebrates big enough to see with the naked eye, such as velvet worms, snails, land hoppers, millipedes, slaters and beetles. </p>
<p>Many of these groups include species with very small ranges, putting them at particular risk from bushfire and other changes to their environments. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/530482/original/file-20230607-15-2nlkye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="macroinvertebrates of Australia" src="https://images.theconversation.com/files/530482/original/file-20230607-15-2nlkye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/530482/original/file-20230607-15-2nlkye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=602&fit=crop&dpr=1 600w, https://images.theconversation.com/files/530482/original/file-20230607-15-2nlkye.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=602&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/530482/original/file-20230607-15-2nlkye.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=602&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/530482/original/file-20230607-15-2nlkye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=756&fit=crop&dpr=1 754w, https://images.theconversation.com/files/530482/original/file-20230607-15-2nlkye.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=756&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/530482/original/file-20230607-15-2nlkye.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=756&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Common macroinvertebrates of these rainforests include velvet worms, snails, slaters, beetles, millipedes and land hoppers (clockwise from left)</span>
<span class="attribution"><span class="source">Nick Porch</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The fires incinerated much of the leaf litter and its inhabitants. To find out the toll on these creatures, a year after the fires we set out to collect leaf litter samples from 52 temperate rainforest sites ranging from Buchan in East Gippsland, Victoria, to Nowra in New South Wales, across the lands of the Kurnai, Bidawal and Yuin people. Then we compared sites subject to medium and high severity fires with those that had escaped the fire.</p>
<p>Back in the lab, we ran the samples through Tullgren funnels, which sort leaves from creatures, then counted the macroinvertebrates. We excluded the tiny springtails and mites, which are hugely abundant mesoinvertebrates. We found every hectare of unburnt rainforest had 2.5 million litter macroinvertebrates, while severely burnt forests had a quarter as many. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/530503/original/file-20230607-23-ankbf7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="tullgren funnels" src="https://images.theconversation.com/files/530503/original/file-20230607-23-ankbf7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/530503/original/file-20230607-23-ankbf7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/530503/original/file-20230607-23-ankbf7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/530503/original/file-20230607-23-ankbf7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/530503/original/file-20230607-23-ankbf7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/530503/original/file-20230607-23-ankbf7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/530503/original/file-20230607-23-ankbf7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">We used Tullgren funnels to sort leaf litter fron its inhabitants.</span>
<span class="attribution"><span class="source">Heloise Gibb</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>If we look at all temperate rainforest burned at different severities across the south-east that means 60 billion tiny deaths. But of all the forest that burned during that summer, rainforests made up only about 1%. The total loss might be closer to 6 trillion individuals. Then to get to truly extraordinary numbers, we can include mites and springtails which account for around 95% of individual invertebrates. That would give us an estimate of 120 trillion. </p>
<h2>Why are these tiny creatures so important?</h2>
<p>Invertebrates account for fully 99% of all animal species and most of the weight of animals on the planet. Renowned Australian scientist Baron Robert May is famously quoted as saying “to a good approximation, all species are insects”. Even now, an estimated 70% of all Australian invertebrate species <a href="https://www.taxonomyaustralia.org.au/about-taxonomy-australia">remain undescribed</a>. Many will go extinct before we have time to document them.</p>
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Read more:
<a href="https://theconversation.com/surprisingly-few-animals-die-in-wildfires-and-that-means-we-can-help-more-in-the-aftermath-174392">Surprisingly few animals die in wildfires – and that means we can help more in the aftermath</a>
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<p>Although we know little of the ecology of most invertebrate species, collectively we know they play crucial roles in ecosystems. Losing this rich food source is likely to slow the recovery of key ecosystem engineers such as lyrebirds and bandicoots, which turn over large volumes of dirt in search of them. </p>
<p>When we try to replant forests without invertebrates, many plants and trees struggle. That’s why conservationists are using <a href="https://www.abc.net.au/news/2022-12-08/land-revegetation-habitat-renewal-strathbogie-ranges-la-trobe/101742752">leaf litter transplants</a> to move vital invertebrates from healthy forests to new ones. </p>
<p>These critters are a vital way nutrients cycle through our forests by breaking down leaves and other organic matter. Globally, they’re directly responsible for converting about 40% of all leaf litter into soil. By turning over leaves or shredding them into pieces, they make it possible for microbes to help decompose organic matter. Without this work, leaf litter would begin to pile up, setting the scene for more fires. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/530504/original/file-20230607-23-gmoxtg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="mite eating springtail" src="https://images.theconversation.com/files/530504/original/file-20230607-23-gmoxtg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/530504/original/file-20230607-23-gmoxtg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/530504/original/file-20230607-23-gmoxtg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/530504/original/file-20230607-23-gmoxtg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/530504/original/file-20230607-23-gmoxtg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/530504/original/file-20230607-23-gmoxtg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/530504/original/file-20230607-23-gmoxtg.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">Springtails and mites are by far the most abundant invertebrates in leaf litter, with thousands in an average square metre. On the right is a predatory snout mite (Bdellidae) feeding on a purple springtail (Collembola).</span>
<span class="attribution"><span class="source">Nick Porch</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>When we lose billions or trillions of invertebrates, we may see the area become more susceptible to <a href="https://www.publish.csiro.au/wf/WF21112">future fires</a>. </p>
<p>More frequent fires means <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2486.2009.02011.x">slower decomposition</a>, which means leaf litter builds up more rapidly. This might be a direct effect of the loss of invertebrates due to fire.</p>
<p>We found the most damaging fires were those where almost all of the canopy was burned. These intense treetop fires killed off three to four times as many invertebrates as fires where only half of the canopy burned. </p>
<p>That’s good news, as it suggests species can tolerate fires, as long as some litter habitat is left. Recovery efforts should focus on the sites where the most canopy burned. </p>
<p>In the wake of fires, rainforest species risk getting pushed out by surrounding eucalyptus trees, which are better at tolerating fire – and encourage more fires by dropping large volumes of litter. </p>
<p>You might think bugs can easily bounce back as the rainforest regrows. But recolonisation doesn’t always happen. Land hoppers, millipedes and isopods (slaters) can be extremely abundant in leaf litter, but none of them can fly to a new location. The dry forest between two sheltered rainforest gullies is so hostile to invertebrates like land hoppers that they can die in minutes when removed from their moist homes. </p>
<h2>What can we do?</h2>
<p>The future holds <a href="https://theconversation.com/climate-change-wildfire-risk-has-grown-nearly-everywhere-but-we-can-still-influence-where-and-how-fires-strike-185465">more fire</a>, as the world heats up. How can we protect these vital invertebrates? One method is to make their habitats better connected wherever possible. Another is to <a href="https://theconversation.com/they-might-not-have-a-spine-but-invertebrates-are-the-backbone-of-our-ecosystems-lets-help-them-out-193447">rewild with minibeasts</a>, seeding severely burnt sites with healthy litter invertebrates from nearby unburnt rainforests. </p>
<p>While we can calculate the numbers of individuals lost to fire, we don’t know much about whether the fires caused extinctions because many species are still unknown to science. </p>
<p>We can no longer overlook these minibeasts and the vital roles they play in ecosystems. We would miss them if they were gone. </p>
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<strong>
Read more:
<a href="https://theconversation.com/photos-from-the-field-zooming-in-on-australias-hidden-world-of-exquisite-mites-snails-and-beetles-147576">Photos from the field: zooming in on Australia's hidden world of exquisite mites, snails and beetles</a>
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<img src="https://counter.theconversation.com/content/207032/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Heloise Gibb receives funding from the Australian Research Council, the Bushfire Wildlife and Habitat Recovery Scheme (Federal Department of Agriculture, Water and the Environment), the NSW Environment Trust and the Hermon Slade Foundation. </span></em></p><p class="fine-print"><em><span>Nick Porch receives funding from the Australian Research Council, the Australian Nuclear Science and Technology Organisation, the Plomley Foundation, the Marsden Fund, National Geographic, The Hermon Slade Foundation and the Wildlife and Habitat Bushfire Recovery Program (Department of Agriculture, Water and the Environment).</span></em></p>When the rainforests burned, the leaf litter did too – and with it, billions of invertebrates vital to healthy ecosystems.Heloise Gibb, Professor, La Trobe UniversityNick Porch, Senior Lecturer in Environmental Earth Science, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2052232023-05-23T00:15:39Z2023-05-23T00:15:39ZGood vibrations: how listening to the sounds of soil helps us monitor and restore forest health<figure><img src="https://images.theconversation.com/files/526930/original/file-20230518-12204-6wif25.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4307%2C2851&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pxfuel.com/en/free-photo-xnwfk">pxfuel</a></span></figcaption></figure><p>Nurturing a forest ecosystem back to life after it’s been logged is not always easy. </p>
<p>It can take a lot of hard work and careful monitoring to ensure biodiversity thrives again. But monitoring biodiversity can be costly, intrusive and resource-intensive. That’s where ecological acoustic survey methods, or “ecoacoustics”, come into play. </p>
<p>Indeed, the planet sings. Think of birds calling, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0169534706000218?casa_token=o5SOujsJEcMAAAAA:DGMMfg-Le6QaVPY756llqYodbVZi5hlji-MQ8wNdOFn7dMBOOeT9emo8flURI6x3c7GMLKtx3A">bats echolocating</a>, tree leaves fluttering in the breeze, frogs croaking and bush crickets <a href="https://link.springer.com/article/10.1007/s00114-021-01749-7">stridulating</a>. We live in a euphonious theatre of life. </p>
<p>Even the creatures in the soil beneath our feet emit unique vibrations as they navigate through the earth to commute, hunt, feed and mate.</p>
<p>Eavesdropping on this subterranean cacophony using special microphones can provide researchers with important insights into ecosystem health. Our <a href="https://onlinelibrary.wiley.com/doi/10.1111/rec.13934">new study</a> published in Restoration Ecology shows ecoacoustics can provide an effective way of monitoring biodiversity in soil and in the forest it supports. </p>
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<strong>
Read more:
<a href="https://theconversation.com/restoring-forests-often-falls-to-landholders-heres-how-to-do-it-cheaply-and-well-204123">Restoring forests often falls to landholders. Here's how to do it cheaply and well</a>
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<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/525045/original/file-20230509-15-uslr52.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525045/original/file-20230509-15-uslr52.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525045/original/file-20230509-15-uslr52.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525045/original/file-20230509-15-uslr52.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525045/original/file-20230509-15-uslr52.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525045/original/file-20230509-15-uslr52.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525045/original/file-20230509-15-uslr52.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">
<figcaption>
<span class="caption">Setting up the ecoacoustics field trial.</span>
<span class="attribution"><span class="source">Jake M. Robinson</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>What did the study do?</h2>
<p>Acoustic technology is widely used to survey bats, birds and other creatures. However, scientists who restore degraded ecosystems have yet to make full use of soil ecoacoustics. This is despite its demonstrable effectiveness at detecting small animal vibrations.</p>
<p>Our study applied ecoacoustic tools to measure biodiversity above and below ground in a UK forest. We hypothesised that the soils of forests restored to a healthier state would have a higher diversity of sounds than the soils of recently deforested plots. This is because we assumed more creatures would live in the restored and “healthier” soils, producing a greater variety of sounds that we would detect. </p>
<p>Think of two symphony orchestras. Half of one orchestra’s musicians have fallen ill and can’t play at the concert. This is analogous to a degraded ecosystem. In contrast, the other orchestra has all its members and will therefore be louder, with more complex and diverse sounds.</p>
<p>During the spring and summer of 2022, we collected 378 samples from three recently deforested and three restored forest plots. We created a recording system with special “contact” microphones that we inserted into the ground. </p>
<p>We used a chamber with sound-dampening foam inside to record soil creatures such as earthworms and beetles. This chamber allowed us to block out unwanted signals such as mechanical noise, wind and human activity. The chamber housed the microphone and a 5 litre sample of the soil at each plot.</p>
<p>Our results were exciting. The diversity of sounds was much higher in the soil from the restored plots. This finding confirmed our suspicions that healthier soil would be more tuneful. </p>
<figure class="align-center ">
<img alt="Earthworms making tunnels through soil" src="https://images.theconversation.com/files/526433/original/file-20230516-23-ofar3e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/526433/original/file-20230516-23-ofar3e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526433/original/file-20230516-23-ofar3e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526433/original/file-20230516-23-ofar3e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526433/original/file-20230516-23-ofar3e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526433/original/file-20230516-23-ofar3e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526433/original/file-20230516-23-ofar3e.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">Earthworms make sounds as they digest organic matter and tunnel through the soil.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-technology-allows-us-to-reveal-secrets-of-amazonian-biodiversity-182077">How technology allows us to reveal secrets of Amazonian biodiversity</a>
</strong>
</em>
</p>
<hr>
<h2>Why is monitoring soil health important?</h2>
<p>Our preliminary findings suggest ecoacoustics can monitor life underground. But why is monitoring soil biodiversity so important? Soil health is the foundation of our food systems and supports all other <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/rec.13453?casa_token=7c9REV8s7m0AAAAA%3A8hfzqCbk1BIhUrRZSuqjsj442JnhcIPBGkNT3XmMZRbfi43XbIhLkfFmx47HEaDBTeEsS7finQnOEII">life on land</a>. It should be a global priority.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/526439/original/file-20230516-15-mt7dsp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Australian magpie cocking its head to one side as it listens for worms in the soil" src="https://images.theconversation.com/files/526439/original/file-20230516-15-mt7dsp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/526439/original/file-20230516-15-mt7dsp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=901&fit=crop&dpr=1 600w, https://images.theconversation.com/files/526439/original/file-20230516-15-mt7dsp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=901&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/526439/original/file-20230516-15-mt7dsp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=901&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/526439/original/file-20230516-15-mt7dsp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1133&fit=crop&dpr=1 754w, https://images.theconversation.com/files/526439/original/file-20230516-15-mt7dsp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1133&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/526439/original/file-20230516-15-mt7dsp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1133&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Birds, including Australian magpies, are known to listen for worms. Scientists can also use the sounds of the soil to assess its health.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The “unseen” and “unheard” organisms living in the soil maintain its health. Below-ground organisms, such as earthworms and beetles, play a crucial role in <a href="https://link.springer.com/chapter/10.1007/978-0-387-74943-3_8">nutrient cycling</a> and soil health. Without them, forests can’t thrive. </p>
<p>By using ecoacoustics to monitor below-ground biodiversity, ecologists can better assess the effectiveness of restoration efforts. This will allow them to make more informed decisions about the best ways to protect nature.</p>
<p>Using ecoacoustics in restoration efforts could also have important implications for climate change mitigation. Forests are crucial <a href="https://www.nature.com/articles/s41467-021-22459-8">carbon sinks</a>. They absorb CO₂ from the atmosphere and store it in their woody biomass and soils. </p>
<p>In contrast, degraded or deforested areas are significant sources of <a href="https://www.lse.ac.uk/granthaminstitute/explainers/whats-redd-and-will-it-help-tackle-climate-change/#:%7E:text=When%20deforestation%20occurs%2C%20much%20of,Africa%2C%20followed%20by%20South%20America.">carbon emissions</a>. Restoring these areas and monitoring subterranean life can help reduce carbon emissions and improve our ability to reduce the effects of a changing climate.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-more-excuses-restoring-nature-is-not-a-silver-bullet-for-global-warming-we-must-cut-emissions-outright-186048">No more excuses: restoring nature is not a silver bullet for global warming, we must cut emissions outright</a>
</strong>
</em>
</p>
<hr>
<h2>It’s still an emerging science</h2>
<p>The use of ecoacoustics in restoration efforts is still relatively new, but it’s an important step towards a more holistic and effective approach to ecosystem recovery. By embracing new technologies and approaches, we can work towards a healthier and more sustainable planet.</p>
<p>Of course, there are challenges we still have to overcome. For instance, accurately identifying the sources of acoustic signals in a complex soundscape can be challenging. However, as technologies and methods continue to improve, the potential benefits of ecoacoustics are immense.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/525048/original/file-20230509-23-oxr0m9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/525048/original/file-20230509-23-oxr0m9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/525048/original/file-20230509-23-oxr0m9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/525048/original/file-20230509-23-oxr0m9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/525048/original/file-20230509-23-oxr0m9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/525048/original/file-20230509-23-oxr0m9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/525048/original/file-20230509-23-oxr0m9.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">When a forest like this temperate woodland in the UK is healthy, it acts as a carbon sink.</span>
<span class="attribution"><a class="source" href="https://pixabay.com/photos/bluebell-woods-bluebells-oak-forest-5069304/">Pixabay</a></span>
</figcaption>
</figure>
<p>By monitoring life underground in a non-intrusive and efficient way, we can better understand the effectiveness of our restoration efforts. This will help us make more informed decisions about how to protect nature. </p>
<p>We’ve only just begun to scratch the surface when it comes to the possibilities of ecoacoustics in restoration efforts. It’s an exciting time for those working in this field, as we discover new ways to use sound to heal our planet.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/soil-abounds-with-life-and-supports-all-life-above-it-but-australian-soils-need-urgent-repair-187280">Soil abounds with life – and supports all life above it. But Australian soils need urgent repair</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/205223/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jake M Robinson is affiliated with the UNFCCC Resilience Frontiers think tank. </span></em></p><p class="fine-print"><em><span>Carlos Abrahams works for Baker Consultants, an ecological consultancy that specialises in ecoacoustics. He currently receives research funding from the UK Government.</span></em></p><p class="fine-print"><em><span>Martin Breed receives funding from the Australian Research Council, Cooperative Research Centre for Transformations in Mining Economies (CRC TiME), Australian Academy of Science, and New Zealand Ministry of Business, Innovation & Employment.</span></em></p>Acoustic technology allows us to listen to the sounds produced by the creatures in forest soils. A new study shows it’s a reliable way to monitor the biodiversity and health of the soil and forest.Jake M Robinson, Ecologist and Researcher, Flinders UniversityCarlos Abrahams, Senior Lecturer in Environmental Biology - Director of Bioacoustics, Nottingham Trent UniversityMartin Breed, Associate Professor in Biology, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2031412023-05-01T20:00:42Z2023-05-01T20:00:42ZAn epic global study of moss reveals it is far more vital to Earth’s ecosystems than we knew<figure><img src="https://images.theconversation.com/files/523382/original/file-20230428-14-xrem6f.jpg?ixlib=rb-1.1.0&rect=38%2C12%2C4137%2C2830&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/UxyWwU6n_ts">Dylan Shaw/Unsplash</a></span></figcaption></figure><p>Mosses are some of the <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev.ecolsys.39.110707.173526">oldest land plants</a>. They are found all over the world, from lush tropical rainforests to the driest deserts, and even the wind-swept hills of Antarctica. </p>
<p>They are everywhere; growing in cracks along roads and pathways, on the trunks of trees, on rocks and buildings, and importantly, on the soil.</p>
<p>Yet despite this ubiquity, we have a relatively poor understanding of how important they are, particularly the types of moss that thrive on soil. </p>
<p>New global research on soil mosses <a href="https://doi.org/10.1038/s41561-023-01170-x">published today in Nature Geoscience</a> reveals they play critical roles in sustaining life on our planet. Without soil mosses, Earth’s ability to produce healthy soils, provide habitat for microbes and fight pathogens would be greatly diminished. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/520000/original/file-20230410-14-agkvcs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/520000/original/file-20230410-14-agkvcs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/520000/original/file-20230410-14-agkvcs.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/520000/original/file-20230410-14-agkvcs.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/520000/original/file-20230410-14-agkvcs.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/520000/original/file-20230410-14-agkvcs.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/520000/original/file-20230410-14-agkvcs.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">
<figcaption>
<span class="caption">Soil moss with fruiting bodies (capsules). David Eldridge, Author provided.</span>
</figcaption>
</figure>
<h2>A global survey of soil mosses</h2>
<p>The results of the new study indicate we have probably underestimated just how important soil mosses are.</p>
<p>Using data from 123 sites across all continents including Antarctica, we show that the soil beneath mosses has more nitrogen, phosphorus and magnesium, and a greater activity of soil enzymes than bare surfaces with no plants. </p>
<p>In fact, mosses affect all major soil functions, increasing carbon sequestration, nutrient cycling and the breakdown of organic matter. These processes are critical for sustaining life on Earth. </p>
<p>Our modelling revealed that soil mosses cover a huge area of the planet, about 9 million square kilometres – equivalent to the area of China. And that’s not counting mosses from boreal forests, which were not included in the study.</p>
<p>The strength of the effect mosses have on soil depends on their growing conditions. They have the strongest effect in natural low productivity environments, such as deserts. They are also more important on sandy and salty soils, and where rainfall is highly variable. </p>
<p>Not unexpectedly, mosses have the strongest effects on soils where <a href="https://www.britannica.com/plant/plant/Vascular-plants">vascular plants</a> – those that contain specialised tissues to conduct water and minerals – are sparse. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/silver-moss-is-a-rugged-survivor-in-the-city-landscape-113459">Silver moss is a rugged survivor in the city landscape</a>
</strong>
</em>
</p>
<hr>
<h2>An intimate connection</h2>
<p>Mosses lack the plumbing that allows vascular plants to grow tall and pull water from beneath the soil. This keeps them relatively short, and means they develop an intimate connection with the uppermost soil layers.</p>
<p>Mosses are extremely absorbent and <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/esp.3290160206">can attract airborne dust</a> particles. Some of these particles are incorporated into the soil below. It is not surprising then that they have such a strong effect on soils. </p>
<p>Our modelling shows that, across the globe, mosses store 6.4 gigatonnes more carbon than soils without plant cover. </p>
<p>Losing just 15% of the global cover of soil mosses would be equivalent to global emissions of carbon dioxide from all land use changes over a year, such as clearing and overgrazing.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523383/original/file-20230428-14-jckx3t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A forest floor with rich green moss cover seen in the foreground" src="https://images.theconversation.com/files/523383/original/file-20230428-14-jckx3t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523383/original/file-20230428-14-jckx3t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523383/original/file-20230428-14-jckx3t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523383/original/file-20230428-14-jckx3t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523383/original/file-20230428-14-jckx3t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523383/original/file-20230428-14-jckx3t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523383/original/file-20230428-14-jckx3t.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">Without mosses, the world’s ecosystems wouldn’t thrive nearly as well.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/n2tAkKqtmqc">Eric Prouzet/Unsplash</a></span>
</figcaption>
</figure>
<h2>Not all mosses are equal</h2>
<p>We also found some mosses are more effective at promoting healthy soils than others. Long-lived mosses tended to be associated with more carbon and greater control of soil pathogens.</p>
<p>The ability of mosses to provide ecosystem services and support a diverse community of microbes, fungi and invertebrates was strongest in locations with a high cover of mat- and turf-forming mosses such as <a href="https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2012.04254.x"><em>Sphagnum</em></a>, which are widely distributed in boreal forests. </p>
<p>Soils are a huge reservoir of <a href="https://sci-hub.se/10.1351/pac200779040557">soil pathogens</a>, yet the soil beneath mosses had a lower proportion of plant pathogens. Mosses can help to reduce the pathogen load in soils. This ability may have originated when mosses <a href="https://www.frontiersin.org/articles/10.3389/fpls.2017.00366/full#B75">evolved</a> as land plants.</p>
<h2>A special group in the desert</h2>
<p>A special type of moss flourishes in deserts. They either live hard (perennial mosses) or die young (annual mosses).</p>
<p>Mosses in the family <a href="http://www.jstor.org/stable/3243765">Pottiaceae</a> are uniquely suited to life under dry and inhospitable conditions. Many have specialised structures that allow them to survive when water is scarce. These include boat-shaped leaves with long hairy tips that help to funnel water into the centre of the plant. Some mosses twist around their stem to reduce the area exposed to the sun and conserve moisture.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/519983/original/file-20230409-24-oxavpy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519983/original/file-20230409-24-oxavpy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519983/original/file-20230409-24-oxavpy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519983/original/file-20230409-24-oxavpy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519983/original/file-20230409-24-oxavpy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=487&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519983/original/file-20230409-24-oxavpy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=487&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519983/original/file-20230409-24-oxavpy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=487&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Long hair points on the leaves of <em>Campylopus</em> sp.</span>
<span class="attribution"><span class="source">David Eldridge</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Desert mosses also protect the soil against erosion, influence <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15232">how much water</a> moves through the upper layers and even alter <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.13269">the survival chances of plant seedlings</a>. </p>
<p>Other mosses have special moisture-absorbing cells (papillae) that swell up and provide them with a moisture reserve when conditions are dry.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/519982/original/file-20230409-28-kyly8k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519982/original/file-20230409-28-kyly8k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519982/original/file-20230409-28-kyly8k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519982/original/file-20230409-28-kyly8k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519982/original/file-20230409-28-kyly8k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519982/original/file-20230409-28-kyly8k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519982/original/file-20230409-28-kyly8k.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">Papillae on the leaf of the moss <em>Crossidium davidai</em>.</span>
<span class="attribution"><span class="source">David Eldridge, Author provided</span></span>
</figcaption>
</figure>
<p>Our global study showed that mat- and turf-forming mosses such as <em>Sphagnum</em> had the strongest positive effects on the diversity of microbes, fungi and invertebrates, and on critical services such as nutrient supply. Predictably, longer-lived mosses supported more soil carbon and had greater control of plant pathogens than short-lived mosses.</p>
<h2>Protect the mosses</h2>
<p>Overall, our work shows mosses influence important soil processes and function in the same way vascular plants do. Their effects may not be as strong, but their total cover means mosses are potentially as significant when summed across the whole globe. </p>
<p>But mosses are under increasing threats globally; disturbance by livestock, <a href="https://www.sciencedirect.com/science/article/pii/S0006320797000153">overharvesting</a>, land clearing and even <a href="https://www.pnas.org/doi/10.1073/pnas.1509150112">changing climates</a> are the greatest threats. </p>
<p>We need a greater acknowledgement of the services that soil mosses provide for all life on this planet. This means greater education about their positive benefits, identifying and mitigating the main threats they face, and including them in routine monitoring programs. </p>
<p>Soil mosses are everywhere, but their future is far from secure. They are likely to play increasingly important roles as vascular plants decline under predicted hotter, drier and more variable global climates. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/antarcticas-moss-forests-are-drying-and-dying-103751">Antarctica's 'moss forests' are drying and dying</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/203141/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David John Eldridge receives funding from The Hermon Slade Foundation.</span></em></p><p class="fine-print"><em><span>Manuel Delgado-Baquerizo receives funding from the British Ecological Society, the Spanish Ministry of Science and Innovation, and Junta de Andalucía. </span></em></p>Data from 123 sites across all continents, including Antarctica, show mosses affect all major soil functions critical for sustaining life on Earth.David John Eldridge, Professor of Dryland Ecology, UNSW SydneyManuel Delgado-Baquerizo, Ecosystem ecologist, Spanish National Research Council, Consejo Superior de Investigaciones Científicas (CSIC)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2009662023-04-17T16:09:39Z2023-04-17T16:09:39ZHow soils changed life on Earth<p>For the first 4 billion years of Earth’s existence, its continents were dusty, barren and rocky landscapes similar to the surface of Mars. But, around 500 million years ago, this all changed. </p>
<hr>
<iframe id="noa-web-audio-player" style="border: none" src="https://embed-player.newsoveraudio.com/v4?key=x84olp&id=https://theconversation.com/how-soils-changed-life-on-earth-200966 &bgColor=F5F5F5&color=D8352A&playColor=D8352A" width="100%" height="110px"></iframe>
<p><em>You can listen to more articles from The Conversation, narrated by Noa, <a href="https://theconversation.com/us/topics/audio-narrated-99682">here</a>.</em></p>
<hr>
<p>Land plants began to evolve from their freshwater algal ancestors and gradually covered the planet’s rocky surface. Originally just a few centimetres tall, the first land plants quickly evolved into more complex forms. By 385 million years ago, extensive forests covered the planet’s surface. </p>
<p>This new plant diversity was underpinned by a transition that occurred below the ground – the formation of roots and soils. Soils are so abundant today that we often take them for granted or assume they are a constant feature of our planet. But this is not the case. Deep soils as we know them have existed for <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12185">less than 10% of our planet’s history</a>. </p>
<p>The formation of these soils dramatically changed life on Earth. Soils altered terrestrial landscapes, water courses, nutrient and mineral cycling and even the composition of the atmosphere. The role soil played in making Earth habitable highlights the importance of protecting our soils today.</p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?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><em>Many people think of plants as nice-looking greens. Essential for clean air, yes, but simple organisms. A step change in research is shaking up the way scientists think about plants: they are far more complex and more like us than you might imagine. This blossoming field of science is too delightful to do it justice in one or two stories.</em> </p>
<p><em><a href="https://theconversation.com/topics/plant-curious-137238?utm_source=TCUK&utm_medium=linkback&utm_campaign=PlantCurious2023&utm_content=InArticleTop">This article is part of a series, Plant Curious</a>, exploring scientific studies that challenge the way you view plantlife.</em></p>
<hr>
<h2>The first soils</h2>
<p>The earliest evidence for how soils evolved comes from ancient land plant fossils. A rock formation in the northeast of Scotland, called the <a href="https://pubs.geoscienceworld.org/geolmag/article-abstract/157/1/47/581268/An-introduction-to-the-Rhynie-chertIntroduction-to">Rhynie Chert</a>, contains exceptionally well preserved 407 million-year-old plant fossils. This allows scientists to <a href="https://royalsocietypublishing.org/toc/rstb/2018/373/1739">study the diversity of life</a> that thrived here. </p>
<p>The majority of the plants preserved in the Rhynie chert lack the large complex roots typical of plants you may be familiar with today. Their rooting systems were instead composed of <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.2017.0042">thin stems that were covered by hairs called rhizoids</a>. These hairs helped anchor plants to the planet’s rocky surface and absorb water and nutrients. </p>
<figure class="align-center ">
<img alt="Artists reconstruction of rhizoid-based rooting systems from the Rhynie chert." src="https://images.theconversation.com/files/516630/original/file-20230321-24-8ozpwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516630/original/file-20230321-24-8ozpwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=478&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516630/original/file-20230321-24-8ozpwe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=478&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516630/original/file-20230321-24-8ozpwe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=478&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516630/original/file-20230321-24-8ozpwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=600&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516630/original/file-20230321-24-8ozpwe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=600&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516630/original/file-20230321-24-8ozpwe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=600&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Artists reconstruction of rhizoid-based rooting systems from the Rhynie chert, Aberdeenshire.</span>
<span class="attribution"><a class="source" href="https://royalsocietypublishing.org/doi/10.1098/rstb.2017.0042">Rosemary Wise/Royal Society Publishing</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>New hairy stems grew and intertwined with the mass of decaying older stems to gradually build up a thin peaty soil just a few centimetres thick. Despite its thinness, this soil could resist being blown or washed away, so provided a foothold for more plants to grow. </p>
<p>Early soils, like those preserved in the Rhynie chert, supported a diverse range of fungi. Some formed beneficial relationships with plants, helping them mine for nutrients in exchange for carbon provided by the plants – others fed on decaying plant tissue. </p>
<p>These soils also formed a hunting ground for <a href="https://www.britannica.com/animal/mite">mites</a>, <a href="https://www.britannica.com/animal/nematode">nematodes (roundworms)</a> and early arachnids. The plants, animals and fungi together formed a complex food web. </p>
<p>This thin soil was already teaming with life.</p>
<h2>Diversity of plants</h2>
<p>Skip forward 20 million years and Earth’s continents are covered by forests with <a href="https://www.sciencedirect.com/science/article/pii/S0960982219315696">soils over a metre deep</a>. This remarkable increase in soil depth, in what is considered a short space of geological time, was fuelled by the evolution of plant roots. Roots increase soil depth by growing downwards and adding organic matter deeper into the sediment.</p>
<p>Roots are specialised organs that enable plants to anchor and mine for water and nutrients. They are specially adapted for life below the ground and for pushing their way down into the rocky substrate below Earth’s surface.</p>
<p>The move from hairy stems clinging to the top of the rocky substrate to roots that drilled down over a metre in depth, transformed soils and allowed plants to access deep reserves of water and nutrients. This below-ground revolution provided an entirely new ecosystem for life to diversify into. </p>
<figure class="align-center ">
<img alt="Exposed modern tree roots." src="https://images.theconversation.com/files/516636/original/file-20230321-1234-v5a9sw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516636/original/file-20230321-1234-v5a9sw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516636/original/file-20230321-1234-v5a9sw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516636/original/file-20230321-1234-v5a9sw.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516636/original/file-20230321-1234-v5a9sw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516636/original/file-20230321-1234-v5a9sw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516636/original/file-20230321-1234-v5a9sw.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">
<figcaption>
<span class="caption">Exposed modern tree roots, Sutherland, Scotland.</span>
<span class="attribution"><span class="source">Sandy Hetherington</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Soils changed more than what’s under our feet</h2>
<p>Soils are the key interface between geology, the atmosphere and the water and nutrient cycles. The advent of deep soils transformed the interaction between these parts of the Earth and brought about a number of surprising changes.</p>
<p>One change was to the water cycle. What was once a landscape covered in a large number of small crisscrossing streams was transformed into floodplains with large <a href="https://www.nature.com/articles/ngeo1376">meandering river channels</a>. At the same time, soils were storing water that could sustain more plant life and be cycled quickly back into the atmosphere.</p>
<p>The period in which soils were expanding in depth and extent was also accompanied by an <a href="https://www.sciencedirect.com/science/article/pii/S0012825217304117">enormous drop in atmospheric CO₂ levels</a> and cooling global temperatures. This change to the composition of the atmosphere was partly due to two features of roots and soils. </p>
<p>Plant roots helped to increase the weathering of rocks by physically and chemically breaking down bedrock – a process that results in a <a href="https://www.pnas.org/doi/full/10.1073/pnas.0408724102">net drawdown of CO₂ from the atmosphere</a>. </p>
<p>Soils, especially organic rich peat soils, are also huge carbon reservoirs. Plants require CO₂ to grow and when plants decay, CO₂ is released back to the atmosphere. But this plant material does not fully decay in many soils and much of it is gradually buried. </p>
<p>This locks carbon in peaty soils, which if buried, can form coal. The origin of deep soils and forests <a href="https://www.pnas.org/doi/10.1073/pnas.1517943113#:%7E:text=Rather%20than%20a%20consequence%20of,during%20the%20assembly%20of%20Pangea.">greatly increased carbon burial rates</a> on Earth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516640/original/file-20230321-28-n6814o.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An example of modern peaty soil." src="https://images.theconversation.com/files/516640/original/file-20230321-28-n6814o.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516640/original/file-20230321-28-n6814o.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516640/original/file-20230321-28-n6814o.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516640/original/file-20230321-28-n6814o.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516640/original/file-20230321-28-n6814o.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516640/original/file-20230321-28-n6814o.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516640/original/file-20230321-28-n6814o.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">Modern peaty soil, Isle of Skye, Scotland.</span>
<span class="attribution"><span class="source">Sandy Hetherington</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Soil underpins a huge amount of life on Earth. Its role in the water cycle, nutrient cycle and critically as a reserve of carbon remain key today and in the future. The fossil record serves as a reminder that we must <a href="https://theconversation.com/soil-is-our-best-ally-in-the-fight-against-climate-change-but-were-fast-running-out-of-it-128166">protect our soils</a>.</p><img src="https://counter.theconversation.com/content/200966/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sandy Hetherington works for The University of Edinburgh, and his research is currently funded by a UKRI Future Leaders Fellowship.</span></em></p>What fossil records tell us about when the Earth was first covered by plants.Sandy Hetherington, Plant Evolutionary Biologist, The University of EdinburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2007912023-04-10T12:04:23Z2023-04-10T12:04:23ZHow do trees die?<figure><img src="https://images.theconversation.com/files/517217/original/file-20230323-26-hsn4ob.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6001%2C4232&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Eventually weather, pests and disease will take their toll, but the story doesn't end there. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/dried-dead-tree-with-moss-trees-in-forest-royalty-free-image/1392619431">Emanuel David / 500px via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&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><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>How and why do trees die? – Anish K., age 11, Boston, Massachusetts</strong></p>
</blockquote>
<hr>
<p>Trees can die suddenly or quite slowly. </p>
<p>Fire, flood or wind can cause a quick death by severely damaging a tree’s ability to <a href="https://www.treehugger.com/process-of-using-water-by-trees-1343505">transport water and nutrients</a> up and down its trunk. </p>
<p>Sometimes a <a href="https://www.youtube.com/watch?v=vR30qlK0-Cw">serious insect attack</a> or disease can kill a tree. This kind of death usually takes from a few months to a couple of years. Again, a tree loses its ability to move water and nutrients, but does so in stages, more slowly. </p>
<p>A tree can also die of what you might call old age.</p>
<p>I am a <a href="https://scholar.google.com/citations?hl=en&user=g2KEhV4AAAAJ">scientist who studies trees</a> and the web of living things that surround them. The death of a tree is not exactly what it seems, because it directly leads to new life.</p>
<h2>Different trees, different life spans</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of an enormous old living tree." src="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=896&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=896&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=896&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1126&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1126&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517059/original/file-20230322-3114-n72ec5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1126&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An ancient bristlecone pine (<em>Pinus longaeva</em>) in Patriarch Grove in California’s White Mountains.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nturland/5817568646/in/photostream/">Nicholas Turland/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Trees can live an <a href="https://www.scientificamerican.com/article/trees-have-the-potential-to-live-indefinitely">incredibly long time</a>, <a href="https://onetreeplanted.org/blogs/stories/oldest-tallest-biggest-trees">depending on what kind they are</a>. Some <a href="https://www.nps.gov/grba/planyourvisit/identifying-bristlecone-pines.htm">bristlecone pines</a>, for instance, are among the oldest known trees and are more than 4,000 years old. Others, like lodgepoles or poplars, will have much shorter life spans, from 20 to 200 years. The biggest trees in your neighborhood or town are probably somewhere in that range. </p>
<p>You’ve probably noticed that different living things have different life spans – a hamster is generally not going to live as long as a cat, which isn’t going to live as long as a person. Trees are no different. Their life spans are determined by their DNA, which you can think of as the <a href="https://kids.britannica.com/kids/article/DNA/390730">operating system embedded in their genes</a>. Trees that are programmed to grow very quickly will be less strong – and shorter lived – <a href="https://extension.psu.edu/why-do-some-trees-live-longer-than-others">than ones that grow very slowly</a>. </p>
<p>But even a tough old tree will eventually die. The years and years of damage done by insects and microscopic critters, combined with abuse from the weather, will slowly end its life. The death process may start with a single branch but will eventually spread to the entire tree. It may take a while for an observer to realize a tree has finally died. </p>
<p>You might think of death as a passive process. But, in the case of trees, it’s surprisingly active. </p>
<h2>The underground network</h2>
<p>Roots do more than anchor a tree to the ground. They are the place where microscopic fungi attach and <a href="https://www.nytimes.com/interactive/2020/12/02/magazine/tree-communication-mycorrhiza.html">act like a second root system for a tree</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo of thin spiderweb-looking filaments attached to roots." src="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517062/original/file-20230322-1527-aqtnic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&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 fungi look like fragile spiderwebs, but these tiny tubes act like superhighways underground.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Mycorhizes-01.jpg">André-Ph. D. Picard</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Fungi form long, superfine threads called hyphae. Fungal hyphae can <a href="https://www.scientificamerican.com/article/do-trees-support-each-other-through-a-network-of-fungi">reach much farther than a tree’s roots can</a>. They gather nutrients from the soil that a tree needs. In exchange, the tree repays fungi with <a href="https://www.youtube.com/watch?v=D1Ymc311XS8">sugars it makes out of sunlight</a> in a process known as <a href="https://www.britannica.com/science/photosynthesis">photosynthesis</a>. </p>
<p>You might have heard that fungi can also pass nutrients from one tree to another. This is a topic that scientists are still working out. Some trees are likely connected to other trees by a complex underground network of fungi, sometimes called the “<a href="https://www.newyorker.com/tech/annals-of-technology/the-secrets-of-the-wood-wide-web">wood wide web</a>.”</p>
<p>How the wood wide web functions in a forest is still not well understood, but scientists do know that the fungi forming these networks are important for keeping trees healthy.</p>
<h2>Afterlife of a tree</h2>
<p>Before it topples over, a dead tree can stand for many years, providing a safe home for bees, squirrels, owls and <a href="https://www.nwf.org/Garden-for-Wildlife/Cover/Trees-and-Snags">many more animals</a>. Once it falls and becomes a log, it can host other living things, like badgers, moles and reptiles. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A mossy trunk from a dead tree lies in the forest." src="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517065/original/file-20230322-3058-nf6b9f.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">One day the remains of this tree will be completely gone.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/october-2021-lower-saxony-uslar-a-mossy-trunk-from-a-dead-news-photo/1236121962">Swen Pförtner/picture alliance via Getty Images</a></span>
</figcaption>
</figure>
<p>Logs also host a different kind of fungi and bacteria, called decomposers. These <a href="https://vinsweb.org/the-fallen-log/">tiny organisms help break down big dead trees</a> to the point where you would never know they had existed. Depending on the conditions, this process can take from a <a href="https://vinsweb.org/the-fallen-log/">few years to a century or more</a>. As wood breaks down, its nutrients return to the soil and become available for other living things, including nearby trees and fungal networks.</p>
<p>A tree leaves a legacy. While alive, it provides shade, home for many animals and a lifeline to fungi and other trees. When it dies, it continues to play an important role. It gives a boost to new trees ready to take its place, shelter to a different set of animals and, eventually, nourishment for the next generation of living things.</p>
<p>It’s almost as if a tree never truly dies but just passes its life on to others.</p>
<hr>
<p><em>Editor’s note: This story has been updated to emphasize that much remains unknown about the relationship between trees and fungi.</em></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 <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
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<p class="fine-print"><em><span>Camille Stevens-Rumann 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>Even in death, a tree helps others live.Camille Stevens-Rumann, Assistant Professor of Forest & Rangeland Stewardship, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1998062023-02-13T16:06:34Z2023-02-13T16:06:34ZDo trees really stay in touch via a ‘wood-wide web’? Here’s what the evidence says<figure><img src="https://images.theconversation.com/files/509766/original/file-20230213-22-ajz7li.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1920%2C1279&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://pixabay.com/photos/mushroom-mushrooms-forest-nature-2087997/">Anders Floor/Pixabay </a></span></figcaption></figure><p>Trees in a forest might look solitary but they are connected underground by a complex network of thread-like strands of fungi, some of which may only be visible to us as mushrooms on the surface. Through these connections in the soil, trees are widely believed to share <a href="https://www.science.org/doi/full/10.1126/science.aad6188?casa_token=lZFqF7BuB5EAAAAA:TNX0hpsJGxjxKm9XgxgRCBlZa_mzmDCI4tU-FQOeHYrGJkOHCibUsBntOS1gxZQW4oWoYlT4vvtPa2g">food</a>, <a href="https://link.springer.com/article/10.1007/s00442-008-1136-5">water</a> and even information, such as warnings of <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.12115?casa_token=NbTImmZal1EAAAAA:MYAvQZTMw75bLCnfkgWgEtiuN8FRT2gFo7fPY7r3KeLOUicnw7W3w6kg8AaW6TzU5INfikNimitwXwQo">enemy attack</a>. The concept of an interconnected forest has evoked comparisons with the internet, hence the moniker “the wood-wide web”.</p>
<p>The idea that trees share resources and potentially communicate with each other through fungal interlocutors seemed fantastical and was a startling revelation upon its first discovery in the mid-1990s. Nearly three decades on, <a href="https://www.nature.com/articles/s41559-023-01986-1">researchers</a> have examined the evidence and found that while soil fungi are important, some of the popular claims made about the wood-wide web lack proof.</p>
<p>Nearly all plants form partnerships with fungi living in their roots, together known as mycorrhizas. Some of these fungi sprout mushrooms at the soil surface, but a mushroom is really just the tiny bit we see. Most mycorrhizal fungi live entirely underground, existing only as near-invisible thread-like strands called hyphae that grow out from the roots of plants to explore the soil. </p>
<p>By allowing these fungi to live in their roots, plants receive essential nutrients from the soil. The fungi meanwhile receive the fruits of photosynthesis (sugars and fats) from their plant hosts. These fungal threads form vast webs in the soil known as common mycorrhizal networks which can connect plants together.</p>
<figure class="align-center ">
<img alt="White threads forming webs in a clump of soil." src="https://images.theconversation.com/files/509767/original/file-20230213-15-yqohhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/509767/original/file-20230213-15-yqohhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/509767/original/file-20230213-15-yqohhv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/509767/original/file-20230213-15-yqohhv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/509767/original/file-20230213-15-yqohhv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/509767/original/file-20230213-15-yqohhv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/509767/original/file-20230213-15-yqohhv.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">Mycorrhizal fungi form the fibre optic cables in the wood-wibe web analogy.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fungal-mycelium-mycorrhizae-that-provide-symbiotic-1596740923">KYTan/Shutterstock</a></span>
</figcaption>
</figure>
<h2>A disconnect in the wood-wide web</h2>
<p>In 1997, scientists <a href="https://www.nature.com/articles/41557">demonstrated</a> that carbon, a primary energy source for all life, could be transmitted between trees across a mycorrhizal network. This finding prompted speculation that mycorrhizal fungi were helping trees communicate and share resources. Cooperation, rather than competition, was more significant in nature it seemed – a notion that challenged prevailing evolutionary dogma. The authors of this new study have some doubts.</p>
<p>Despite the widespread belief that plants share food using mycorrhizal networks, the evidence remains inconclusive. In lab and field experiments, the amount of carbon and other resources transferred between plants is typically small and stays mostly in the mycorrhizal roots. This means that while fungi are receiving carbon from one plant, much of it probably stays with the fungus rather than being transferred to another plant. This raises the question of how important these transfers might actually be to trees in a forest. </p>
<p>And is it the plants or the fungi who are in charge of transferring these sugars, fats and nutrients? What fungi are doing and why they do it is rarely considered in these studies. It is just as likely that the transfer of food between plants is driven by fungal appetite as it is fungal altruism. These considerations underline the need for more research to understand the role of mycorrhizal networks in transmitting resources and information through communities of plants.</p>
<p>The way experiments are reported also affects scientific and public perceptions. Positive citation bias, where positive results are cited more often in the scientific literature than neutral or negative findings, means studies showing evidence for resource transfer between trees via fungal networks have tended to be more readily cited than those that don’t, perpetuating misconceptions among the public and scientists. </p>
<p>The authors of the new paper showed how exaggerated claims of experimental results can become subject to even more misinterpretation over time. This leads to scientific studies being cited for documenting effects that were not claimed by the original authors. For example, many papers attribute their observed effects to <em>potential</em> common mycorrhizal networks, but are then quoted as offering hard proof of their existence and function. And while the use of anthropomorphic language, such as “talk”, “share”, and “trade”, can help to simplify and communicate findings, it can also distort the complexity and prevent a full understanding of a natural phenomenon.</p>
<h2>Why the concept is still useful</h2>
<p>Despite these considerations, there is some supporting evidence for the communication and sharing of resources between plants via mycorrhizal fungi.</p>
<p>Fungi have been shown to act as conduits for communicating defensive signals, at least between some types of plants. This has been <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.12115?casa_token=T7fHzCQ1wf8AAAAA:4BrV1EJR-kT-Dqv752nO27VpHG_uXLbrEcrQdfqLp1cN2L_JJoDIYPIITL71lql1AVB3mGzjhuIYRH-V">shown to help</a> bean plants prepare for future attacks by aphids in experiments where fungal connections between plants were either severed or left intact. Although, what these signals are and how they are transmitted remains unknown.</p>
<figure class="align-center ">
<img alt="Several small, green bugs gnawing holes in a leaf." src="https://images.theconversation.com/files/509770/original/file-20230213-18-xjxa9o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/509770/original/file-20230213-18-xjxa9o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/509770/original/file-20230213-18-xjxa9o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/509770/original/file-20230213-18-xjxa9o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/509770/original/file-20230213-18-xjxa9o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/509770/original/file-20230213-18-xjxa9o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/509770/original/file-20230213-18-xjxa9o.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">When insects graze a plant it releases stress signals which warn those nearby.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/aphid-close-on-green-leaf-crop-1395581459">Vera Larina/Shutterstock</a></span>
</figcaption>
</figure>
<p>Other experiments have shown carbon and water moving between <a href="https://nph.onlinelibrary.wiley.com/doi/10.1046/j.1469-8137.2001.00010.x">Japanese red pine</a> and <a href="https://link.springer.com/article/10.1007/BF02182684">Scots pine</a> tree seedlings in controlled laboratory conditions, although these may not reflect the conditions found in nature. A field experiment showed a dye moving between <a href="https://nph.onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.2008.02377.x">ponderosa pine</a> seedlings via mycorrhizal fungi. However, there is still no definitive proof that a common mycorrhizal network was involved. There are equally plausible alternative explanations, including other soil microbes, diffusion of the dye through water in the soil and direct contact between plant roots.</p>
<p>Considering the evidence, it is clear that the function of common mycorrhizal networks between trees in forests has been overstated. But the wood-wide web concept can still help scientists highlight and communicate the significance of mycorrhizal fungi in natural and managed ecosystems.</p>
<p>The world beneath our feet is easy to overlook and, as a result, soil ecology has often been neglected in scientific research, public policy and resource management, despite its importance to the health and stability of ecosystems. The concept of a wood-wide web can alert a broad audience to the role soil fungi play, and with appropriate constraints on the idea, scientists can highlight how important a better understanding of soil ecology is. This may increase investment in research and policy aimed at preserving and protecting organisms that underpin nearly all of Earth’s terrestrial ecosystems.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.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">
<figcaption>
<span class="caption"></span>
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</figure>
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<p class="fine-print"><em><span>Katie Field receives funding from the ERC, NERC, BBSRC and the Leverhulme Trust. </span></em></p><p class="fine-print"><em><span>Emily Magkourilou 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>A new study looked at the many claims made about soil fungi and found some misconceptions.Katie Field, Professor in Plant-Soil Processes, University of SheffieldEmily Magkourilou, PhD Candidate in Soil Ecology, University of SheffieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1989032023-02-08T08:48:18Z2023-02-08T08:48:18ZPulses 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 CambridgeLicensed as Creative Commons – attribution, no derivatives.