tag:theconversation.com,2011:/us/topics/cyanobacteria-14126/articlesCyanobacteria – The Conversation2024-01-11T17:23:58Ztag:theconversation.com,2011:article/2157652024-01-11T17:23:58Z2024-01-11T17:23:58ZHow much life has ever existed on Earth?<figure><img src="https://images.theconversation.com/files/567152/original/file-20231221-25-fybvl8.jpg?ixlib=rb-1.1.0&rect=0%2C5%2C3619%2C2197&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In primary production, inorganic carbon is used to build the organic molecules life needs. </span> <span class="attribution"><span class="source">(Shutterstock)</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/how-much-life-has-ever-existed-on-earth" width="100%" height="400"></iframe>
<p>All organisms are made of living cells. While it is difficult to pinpoint exactly when the first cells came to exist, geologists’ best estimates suggest at least as early as <a href="https://doi.org/10.1016/S0301-9268(00)00128-5">3.8 billion years ago</a>. But how much life has inhabited this planet since the first cell on Earth? And how much life will ever exist on Earth? </p>
<p>In our new study, published in <a href="https://doi.org/10.1016/j.cub.2023.09.040"><em>Current Biology</em></a>, my colleagues from the <a href="https://www.weizmann.ac.il/">Weizmann Institute of Science</a> and <a href="https://www.smith.edu/academics/geosciences">Smith College</a> and I took aim at these big questions.</p>
<h2>Carbon on Earth</h2>
<p>Every year, about 200 billion tons of carbon is taken up through what is known as primary production. During primary production, inorganic carbon — such as carbon dioxide in the atmosphere and bicarbonate in the ocean — is used for energy and to build the organic molecules life needs. </p>
<p>Today, the most notable contributor to this effort is <a href="https://doi.org/10.1038/nrm1525">oxygenic photosynthesis</a>, where sunlight and water are key ingredients. However, deciphering past rates of primary production has been a challenging task. In lieu of a time machine, scientists like myself rely on clues left in ancient sedimentary rocks to reconstruct past environments. </p>
<p>In the case of primary production, the isotopic composition of <a href="https://doi.org/10.1038/s41586-018-0349-y">oxygen</a> in the form of sulfate in ancient salt deposits allows for such estimates to be made. </p>
<p>In <a href="https://doi.org/10.1016/j.cub.2023.09.040">our study</a>, we compiled all previous estimates of ancient primary production derived through the method above, as well as many others. The outcome of this productivity census was that we were able to estimate that 100 quintillion (or 100 billion billion) tons of carbon has been through primary production since the origin of life. </p>
<p>Big numbers like this are difficult to picture; 100 quintillion tons of carbon is about 100 times the amount of carbon contained within the Earth, a pretty impressive feat for Earth’s primary producers. </p>
<h2>Primary production</h2>
<p>Today, primary production is mainly achieved by plants on land and marine micro-organisms such as algae and cyanobacteria. In the past, the proportion of these major contributors was very different; in the case of Earth’s earliest history, primary production was mainly conducted by an entirely different group of organisms that don’t rely on oxygenic photosynthesis to stay alive.</p>
<p>A combination of different techniques has been able to give a sense of when different primary producers were most active in Earth’s past. Examples of such techniques include identifying the <a href="https://doi.org/10.1016/j.cub.2021.07.038">oldest forests</a> or using molecular fossils called <a href="https://doi.org/10.1038/nature23457">biomarkers</a>. </p>
<p>In <a href="https://doi.org/10.1016/j.cub.2023.09.040">our study</a>, we used this information to explore what organisms have contributed the most to Earth’s historical primary production. We found that despite being late on the scene, land plants have likely contributed the most. However, it is also very plausible that cyanobacteria contributed the most.</p>
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<a href="https://images.theconversation.com/files/567163/original/file-20231221-21-1tcat1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="green hair-like strands of bacteria" src="https://images.theconversation.com/files/567163/original/file-20231221-21-1tcat1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567163/original/file-20231221-21-1tcat1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567163/original/file-20231221-21-1tcat1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567163/original/file-20231221-21-1tcat1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567163/original/file-20231221-21-1tcat1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567163/original/file-20231221-21-1tcat1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567163/original/file-20231221-21-1tcat1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Filamentous cyanobacteria from a tidal pond at Little Sippewissett salt marsh, Falmouth, Mass.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/argonne/26719316190">(Argonne National Laboratory)</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Total life</h2>
<p>By determining how much primary production has ever occurred, and by identifying what organisms have been responsible for it, we were also able to estimate how much life has ever been on Earth. </p>
<p>Today, one may be able to approximate how many humans exist based on how much food is consumed. Similarly, we were able to calibrate a ratio of primary production to how many cells exist in the modern environment. </p>
<p>Despite the large variability in the number of cells per organism and the sizes of different cells, such complications become secondary since single-celled microbes dominate global cell populations. In the end, we were able to estimate that about 10<sup>30</sup> (10 noninillion) cells exist today, and that between 10<sup>39</sup> (a duodecillion) and 10<sup>40</sup> cells have ever existed on Earth. </p>
<h2>How much life will Earth ever have?</h2>
<p>Save for the ability to move Earth into the orbit of a younger star, the lifetime of Earth’s biosphere is limited. This morbid fact is a consequence of <a href="https://doi.org/10.1007/978-94-010-9633-1_4">our stars life cycle</a>. Since its birth, the sun has slowly been getting brighter over the past four and half billion years as hydrogen has been converted to helium in its core. </p>
<p>Far in the future, about two billion years from now, all of the biogeochemical fail-safes that keep Earth habitable will be pushed past their <a href="https://doi.org/10.1038/s41561-021-00693-5">limits</a>. First, land plants will die off, and then eventually the oceans will boil, and the Earth will return to a largely lifeless rocky planet as it was in its infancy. </p>
<p>But until then, how much life will Earth house over its entire habitable lifetime? Projecting our current levels of primary productivity forward, we estimated that about 10<sup>40</sup> cells will ever occupy the Earth. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567209/original/file-20231222-15-cdexst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a blue planet in space" src="https://images.theconversation.com/files/567209/original/file-20231222-15-cdexst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567209/original/file-20231222-15-cdexst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567209/original/file-20231222-15-cdexst.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567209/original/file-20231222-15-cdexst.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567209/original/file-20231222-15-cdexst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567209/original/file-20231222-15-cdexst.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567209/original/file-20231222-15-cdexst.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A planetary system 100 light-years away in the constellation Dorado is home to the first Earth-size habitable-zone planet, discovered by NASA’s Transiting Exoplanet Survey Satellite.</span>
<span class="attribution"><a class="source" href="https://images.nasa.gov/details/PIA23408">(NASA Goddard Space Flight Center)</a></span>
</figcaption>
</figure>
<h2>Earth as an exoplanet</h2>
<p>Only a few decades ago, exoplanets (planets orbiting other stars) were just a hypothesis. Now we are able to not only <a href="https://exoplanets.nasa.gov/">detect them</a>, but describe many aspects of thousands of far off worlds around distant stars. </p>
<p>But how does Earth compare to these bodies? In our new study, we have taken a birds eye view of life on Earth and have put forward Earth as a benchmark to compare other planets. </p>
<p>What I find truly interesting, however, is what could have happened in Earth’s past to produce a radically different trajectory and therefore a radically different amount of life that has been able to call Earth home. For example, what if oxygenic photosynthesis never took hold, or what if endosymbiosis never happened?</p>
<p>Answers to such questions are what will drive my laboratory at <a href="https://earthsci.carleton.ca/">Carleton University</a> over the coming years.</p><img src="https://counter.theconversation.com/content/215765/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Crockford receives funding from the Canadian Natural Sciences and Engineering Research Council and Carleton University</span></em></p>Over two billion years from now, Earth will no longer be able to sustain life. A new study looks at how much life has ever existed and what this means for the discovery of new life-supporting planets.Peter Crockford, Assistant Professor, Earth Sciences, Carleton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1962262024-01-03T13:19:09Z2024-01-03T13:19:09ZHow scientists are helping plants get the most out of photosynthesis<figure><img src="https://images.theconversation.com/files/563630/original/file-20231205-15-2tk9l4.jpg?ixlib=rb-1.1.0&rect=5%2C5%2C3860%2C2579&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/detail-leaf-backlit-showing-ribs-veins-96544981">italianestro/Shutterstock</a></span></figcaption></figure><p>Photosynthesis is the starting point for almost every food chain, sustaining most life on Earth. You would be forgiven, then, for thinking nature has perfected the art of turning sunlight into sugar. But that isn’t exactly true. If you struggle with life goals, it might reassure you to know even plants haven’t yet reached their full potential.</p>
<p>Every evolved trait is a trade-off between the benefit it provides and its <a href="https://www.journals.uchicago.edu/doi/full/10.1086/717897">cost in energy</a>. The plants we domesticated for food are only as good at converting sunlight to sugar as they had to be to survive and reproduce. From a given amount of sunshine, most plants convert less than 5% of that <a href="https://bigthink.com/the-future/artificial-photosynthesis-improve/">light</a> energy into biomass, and under some conditions, less than 1%. </p>
<p>We now have the knowledge and the tools to maximise photosynthesis in a range of food crops – but scientists aren’t just studying how we help plants become better at photosynthesis out of curiosity. Climate change-driven weather such as drought and flooding is destroying crops and <a href="https://www.nature.com/articles/s43017-023-00491-0">threatening crop yields</a> around the world. This research is about making sure we can grow enough food to feed ourselves.</p>
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<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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<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>
<p>Plants such as wheat sometimes mistakenly make a toxic substance called <a href="https://www.sciencedirect.com/topics/chemistry/2-phosphoglycolate">2-phosphoglycolate</a> which then has to be recycled inside the plant, costing it energy. Scientists call this <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/photorespiration">photorespiration</a>. It happens when an enzyme crucial to the photosynthesis process, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0981942808000041">rubisco</a>, mistakenly latches on to an oxygen molecule instead of carbon dioxide.</p>
<p>Rubisco makes this mistake up to 40% of the time. It happens because there is now a lot more oxygen in the atmosphere than in the past, put there by the very first photosynthesisers, <a href="https://www.britannica.com/science/blue-green-algae">cyanobacteria</a> – microscopic organisms found in water. Rising temperatures cause more photorespiration too.</p>
<p>If we could prevent this mistake, it would leave plants more energy for photosynthesis. </p>
<h2>Capturing sunlight</h2>
<p>Our research project, <a href="http://www.photoboost.org/">PhotoBoost</a>, is looking at how to create a kind of internal bypass that reduces photorespiration in rice and potato plants, two of the world’s most important crops. </p>
<p>In the same way a coronary bypass diverts blood around narrow or clogged arteries in humans, the photorespiratory bypass gives plants the genetic tools they need to minimise rubisco’s mistake. Genes from cyanobacteria make this and other photosynthetic improvements possible because they host an array of enzymes for better sunlight management.</p>
<p>Other researchers are looking to plants such as maize, which have evolved their own means of dealing with photorespiration, as a source of inspiration – and genes – for <a href="https://www.ox.ac.uk/news/2017-10-19-breakthrough-efforts-supercharge-rice-and-reduce-world-hunger">rice</a>.</p>
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<img alt="Leafy green shoots growing out of well tilled soil, sun setting in the background" src="https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">These plants may not be making the most of photosynthesis.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sapling-mung-bean-agriculture-garden-light-1616176942">Lamyai/Shutterstock</a></span>
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<p>We’re also improving the speed at which plants respond to changes in light intensity, as this <a href="https://www.science.org/doi/10.1126/science.aai8878">affects photosynthesis</a> too. Plants shut off their photosynthetic machinery if they get too much sun (when light is more intense), after which they can be slow to restart photosynthesising when it gets cooler again – for example, when clouds roll over.</p>
<p>A research group in the US recently showed that speeding up this photoprotection process in soybean can lead to a <a href="https://www.science.org/doi/10.1126/science.adc9831">33% increase</a> in seed yield.</p>
<p>On PhotoBoost, we’re talking to researchers, agronomists and farmers all around the world to understand how to match the needs of society with this new frontier in plant science. According to Elizabete Carmo-Silva and Ana Moreira Lobo, colleagues at Lancaster University: “Climate change, declining yields and water stress constitute major challenges for food production this century.”</p>
<p>Their team investigates plant responses to light and temperature, paying particular attention to the rubisco enzyme. Higher yield is perhaps the most obvious gain from improving photosynthesis, but it will also help make plants more resilient to drought and heat stress.</p>
<h2>New tools</h2>
<p>A new tool in the crop breeder’s arsenal, <a href="https://pubmed.ncbi.nlm.nih.gov/24157548/">gene editing</a>, allows scientists to turn genes on and off, testing the effect they have on plant performance. Once we know their function, these genes can be suppressed, promoted or, as has been done in commercial crops <a href="https://www.fda.gov/food/agricultural-biotechnology/science-and-history-gmos-and-other-food-modification-processes#:%7E:text=1994%3A%20The%20first%20GMO%20produce,safe%20as%20traditionally%20bred%20tomatoes.">since the 1990s</a>, introduced through genetic modification.</p>
<p>At the Universidade Nova de Lisboa in Portugal, Nelson Saibo and Isabel Abreu told us the tools that plant breeders have are more “fine tuners” these days. Their team is using gene editing to improve photosynthesis in rice.</p>
<p>The potato farmers we recently spoke to in the east of England saw greater photosynthesis efficiency as a route to freeing up land for nature – for example, planting trees on ancient forest sites or restoring peatland in the Fens – as more efficient plants mean you need less of them to give the same crop yield. Their major concern was whether major UK retailers would be <a href="https://www.dailymail.co.uk/news/article-9276737/Co-op-British-supermarket-reject-GM-crops-animals-without-strict-assessments.html">willing to champion</a> genetically engineered crops.</p>
<p>As well as Photoboost, the European Union is funding other photosynthesis programmes through the <a href="http://gain4crops.eu/">Gain4crops</a> (sunflower) and <a href="https://www.capitalise.eu/crop-improvement/">Capitalise</a> (tomato, maize and barley) projects. Improving photosynthesis isn’t a silver bullet for many of the agricultural problems we face. But combining knowledge and new tools will help us get the most out of light.</p><img src="https://counter.theconversation.com/content/196226/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan Menary receives funding from the European Union</span></em></p><p class="fine-print"><em><span>Sebastian Fuller receives funding from the European Commission and the UK National Institute for Health and Care Research </span></em></p><p class="fine-print"><em><span>Stefan Schillberg receives funding from the European Union</span></em></p>Plants aren’t always as good at photosynthesis as you might think. Our research project wants to help them.Jonathan Menary, Postdoctoral Researcher, Centre for Tropical Medicine and Global Health, University of OxfordSebastian Fuller, Researcher of Implementation Science, University of OxfordStefan Schillberg, Executive Director, Fraunhofer IMELicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2133262023-11-07T13:38:21Z2023-11-07T13:38:21ZEngineered ‘living materials’ could help clean up water pollution one day<figure><img src="https://images.theconversation.com/files/556959/original/file-20231031-27-mncpgs.jpg?ixlib=rb-1.1.0&rect=18%2C0%2C2048%2C1358&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers at the University of California, San Diego have developed a new 'living' material.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/jsoe/53172954946/in/album-72177720311058323/">David Baillot/UC San Diego Jacobs School of Engineering</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Water pollution is a growing concern globally, with <a href="https://doi.org/10.1016/j.oneear.2022.01.005">research estimating</a> that chemical industries discharge <a href="https://cleanwaterinternational.org/water-pollution-everything-we-need-to-know/amp/">300-400 megatonnes</a> (600-800 billion pounds) of industrial waste into bodies of water each year. </p>
<p>As a <a href="https://www.pokorskilab.com/">team of materials scientists</a>, we’re working on an engineered “living material” that may be able to transform chemical dye pollutants from the <a href="https://www.cnn.com/2023/04/21/middleeast/textile-wastewater-pollutant-cleaner-hnk-scn-spc-intl/index.html">textile industry</a> into harmless substances.</p>
<p><a href="https://www.safewater.org/fact-sheets-1/2017/1/23/industrial-waste">Water pollution</a> is both an environmental and humanitarian issue that can affect ecosystems and human health alike. We’re hopeful that the materials we’re developing could be one tool available to help combat this problem.</p>
<h2>Engineering a living material</h2>
<p>The “<a href="https://www.nature.com/collections/fhcabedjaa">engineered living material</a>” our team has been working on <a href="https://my.clevelandclinic.org/health/articles/24494-bacteria">contains programmed bacteria</a> embedded in a soft hydrogel material. We first published a paper showing the potential effectiveness of this material in <a href="https://doi.org/10.1038/s41467-023-40265-2">Nature Communications</a> in August 2023.</p>
<p><a href="https://www.snexplores.org/article/explainer-what-is-a-hydrogel">The hydrogel</a> that forms the base of the material has similar properties to Jell-O – it’s soft and made mostly of water. Our particular hydrogel is made from a natural and biodegradable <a href="https://dalchem.com.au/how-to/what-is-alginate/">seaweed-based polymer called alginate</a>, an ingredient common <a href="https://kitchen-theory.com/sodium-alginate-spherification/">in some foods</a>.</p>
<p>The alginate hydrogel provides a solid physical support for bacterial cells, similar to how <a href="https://theconversation.com/mapping-the-100-trillion-cells-that-make-up-your-body-103078">tissues support cells</a> in the human body. We intentionally chose this material so that the bacteria we embedded could grow and flourish. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A green polymer, arranged in a square with a 5 by 5 grid of smaller squares, sits on a clear surface." src="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The grid shape of the material helps the bacteria take in carbon dioxide.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/jsoe/53173442373/in/album-72177720311058323/">David Baillot/UC San Diego Jacobs School of Engineering</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>We picked the seaweed-based alginate as the material base because it’s porous and can retain water. It also allows the <a href="https://www.microscopemaster.com/photosynthetic-bacteria.html">bacterial cells</a> to take in nutrients from the surrounding environment.</p>
<p>After we prepared the hydrogel, we embedded photosynthetic – or sunlight-capturing – bacteria called <a href="https://www.britannica.com/science/blue-green-algae">cyanobacteria</a> into the gel.</p>
<p>The cyanobacteria embedded in the material still needed to take in light and carbon dioxide <a href="https://education.nationalgeographic.org/resource/photosynthesis/">to perform photosynthesis</a>, which keeps them alive. The hydrogel was porous enough to allow that, but to make the configuration as efficient as possible, we <a href="https://www.cellink.com/3d-bioprinting/">3D-printed</a> the gel into custom shapes – grids and honeycombs. These structures have a higher surface-to-volume ratio that allow more light, CO₂ and nutrients to come into the material. </p>
<p>The cells were happy in that geometry. We observed higher cell growth and density over time in the alginate gels in the grid or honeycomb structures when compared with the default disc shape.</p>
<h2>Cleaning up dye</h2>
<p>Like all other bacteria, cyanobacteria has different <a href="https://www.ibiology.org/bioengineering/genetic-circuits/">genetic circuits</a>, which tell the cells what outputs to produce. Our team <a href="https://www.britannica.com/science/genetic-engineering/Process-and-techniques">genetically engineered</a> the bacterial <a href="https://www.newscientist.com/definition/dna/">DNA</a> so that the cells created a specific enzyme <a href="https://en.wikipedia.org/wiki/Laccase">called laccase</a>. </p>
<p>The laccase enzyme produced by the cyanobacteria works by performing a chemical reaction with a pollutant that transforms it into a form that’s no longer functional. By breaking the chemical bonds, it can make a toxic pollutant nontoxic. The enzyme is regenerated at the end of the reaction, and it goes off to complete more reactions. </p>
<p>Once we’d embedded these laccase-creating cyanobacteria into the alginate hydrogel, we put them in a solution made up of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10532910/">industrial dye pollutant</a> to see if they could clean up the dye. In this test, we wanted to see if our material could change the structure of the dye so that it went from being colored to uncolored. But, in other cases, the material could potentially change a chemical structure to go from toxic to nontoxic. </p>
<p>The dye we used, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10532910/">indigo carmine</a>, is a common industrial wastewater pollutant usually found in the water near textile plants – it’s the main pigment in blue jeans. We found that our material took all the color out of the bulk of the dye over about 10 days.</p>
<p>This is good news, but we wanted to make sure that our material wasn’t adding waste to polluted water by leaching bacterial cells. So, we also engineered the bacteria to produce a protein that could damage the cell membrane of the bacteria – a programmable kill switch. </p>
<p>The genetic circuit was programmed to respond to a harmless chemical, called <a href="https://academic.oup.com/pcp/article/54/10/1724/1908151">theophylline</a>, commonly found in caffeine, tea and chocolate. By adding theophylline, we could destroy bacterial cells at will. </p>
<p>The field of engineered living materials is still developing, but this just means there are plenty of opportunities to develop new materials with both living and nonliving components.</p><img src="https://counter.theconversation.com/content/213326/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan K. Pokorski receives funding from the National Science Foundation and Department of Energy.</span></em></p><p class="fine-print"><em><span>Debika Datta 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>‘Living materials’ made with genetically engineered bacteria and Jell-O-like gel could make pollutants in water bodies nontoxic.Jonathan K. Pokorski, Professor of Nanoengineering, University of California, San DiegoDebika Datta, Postdoctoral Scholar in Nanoengineering, University of California, San DiegoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2109972023-10-23T12:25:38Z2023-10-23T12:25:38ZA layered lake is a little like Earth’s early oceans − and lets researchers explore how oxygen built up in our atmosphere billions of years ago<figure><img src="https://images.theconversation.com/files/542374/original/file-20230811-17-9wl0g5.jpeg?ixlib=rb-1.1.0&rect=0%2C12%2C4031%2C2692&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers sample water from various layers to analyze back in the lab.</span> <span class="attribution"><span class="source">Elizabeth Swanner</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Little Deming Lake doesn’t get much notice from visitors to <a href="https://www.dnr.state.mn.us/state_parks/park.html?id=spk00181#homepage">Itasca State Park</a> in Minnesota. There’s better boating on nearby Lake Itasca, the headwaters of the Mississippi River. My colleagues and I need to maneuver hundreds of pounds of equipment down a hidden path made narrow by late-summer poison ivy to launch our rowboats.</p>
<p>But modest Deming Lake offers more than meets the eye for <a href="https://scholar.google.com/citations?user=QopCtZ4AAAAJ&hl=en&oi=ao">me, a geochemist</a> interested in how oxygen built up in the atmosphere 2.4 billion years ago. The absence of oxygen in the deep layers of Deming Lake is something this small body of water has in common with early Earth’s oceans.</p>
<p>On each of our several expeditions here each year, we row our boats out into the deepest part of the lake – over 60 feet (18 meters), despite the lake’s surface area being only 13 acres. We drop an anchor and connect our boats in a flotilla, readying ourselves for the work ahead.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554300/original/file-20231017-27-mjcpvk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Smooth lake with boats in the distance against woodsy shoreline" src="https://images.theconversation.com/files/554300/original/file-20231017-27-mjcpvk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554300/original/file-20231017-27-mjcpvk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554300/original/file-20231017-27-mjcpvk.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554300/original/file-20231017-27-mjcpvk.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554300/original/file-20231017-27-mjcpvk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554300/original/file-20231017-27-mjcpvk.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554300/original/file-20231017-27-mjcpvk.jpeg?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">Researchers’ boats on Deming Lake.</span>
<span class="attribution"><span class="source">Elizabeth Swanner</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Deming Lake is <a href="https://www.worldatlas.com/articles/what-is-a-meromictic-lake.html">meromictic</a>, a term from Greek that means only partially mixing. In most lakes, at least once a year, the water at the top sinks while the water at the bottom rises because of wind and seasonal temperature changes that affect water’s density. But the <a href="https://eartharxiv.org/repository/view/4827/">deepest waters of Deming Lake never reach the surface</a>. This prevents oxygen in its top layer of water from ever mixing into its deep layer.</p>
<p>Less than 1% of lakes are meromictic, and most that are have dense, salty bottom waters. Deming Lake’s deep waters are not very salty, but of the salts in its bottom waters, <a href="https://doi.org/10.1016/j.earscirev.2020.103430">iron is one of the most abundant</a>. This makes Deming Lake one of the rarest <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/meromictic-lake">types of meromictic lakes</a>.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/554302/original/file-20231017-23-utrjoi.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="man seated in small boat wearing gloves injecting water into a collection tube" src="https://images.theconversation.com/files/554302/original/file-20231017-23-utrjoi.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/554302/original/file-20231017-23-utrjoi.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554302/original/file-20231017-23-utrjoi.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554302/original/file-20231017-23-utrjoi.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554302/original/file-20231017-23-utrjoi.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554302/original/file-20231017-23-utrjoi.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554302/original/file-20231017-23-utrjoi.jpeg?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">Postdoc researcher Sajjad Akam collects a water sample for chemical analysis back in the lab.</span>
<span class="attribution"><span class="source">Elizabeth Swanner</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The lake surface is calm, and the still air is glorious on this cool, cloudless August morning. We lower a 2-foot-long water pump zip-tied to a cable attached to four sensors. The sensors measure the temperature, amount of oxygen, pH and amount of chlorophyll in the water at each layer we encounter. We pump water from the most intriguing layers up to the boat and fill a myriad of bottles and tubes, each destined for a different chemical or biological analysis.</p>
<p>My colleagues and I have homed in on Deming Lake to explore questions about how microbial life adapted to and changed the environmental conditions on early Earth. Our planet was inhabited <a href="https://theconversation.com/were-viruses-around-on-earth-before-living-cells-emerged-a-microbiologist-explains-197880">only by microbes</a> for most of its history. The atmosphere and the oceans’ depths didn’t have much oxygen, but they did have a lot of iron, just like Deming Lake does. By investigating what Deming Lake’s microbes are doing, we can better understand how billions of years ago they helped to transform the Earth’s atmosphere and oceans into what they’re like now.</p>
<h2>Layer by layer, into the lake</h2>
<p>Two and a half billion years ago, ocean waters had enough iron to form today’s globally distributed <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/banded-iron-formation">rusty iron deposits called</a> <a href="https://www.amnh.org/exhibitions/permanent/planet-earth/how-has-the-earth-evolved/banded-iron-formation">banded iron formations</a> that supply iron for the modern global steel industry. Nowadays, oceans have only <a href="https://youtu.be/EpzEv0H4lvg">trace amounts of iron</a> but abundant oxygen. In most waters, iron and oxygen are antithetical. Rapid <a href="https://bio.libretexts.org/Bookshelves/Microbiology/Microbiology_(Boundless)/05%3A_Microbial_Metabolism/5.10%3A_Chemolithotrophy/5.10D%3A__Iron_Oxidation">chemical and biological reactions between iron and oxygen</a> mean you can’t have much of one while the other is present.</p>
<p>The rise of oxygen in the early atmosphere and ocean was due to <a href="https://ucmp.berkeley.edu/bacteria/cyanointro.html">cyanobacteria</a>. These single-celled organisms <a href="https://asm.org/Articles/2022/February/The-Great-Oxidation-Event-How-Cyanobacteria-Change">emerged at least 2.5 billion years ago</a>. But it took roughly 2 billion years for the oxygen they produce via photosynthesis to build up to <a href="https://askanearthspacescientist.asu.edu/oxygen-animal-evolution">levels that allowed for the first animals</a> to appear on Earth.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/554308/original/file-20231017-27-m0c4vb.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="water concentrated on a filter looks pale green" src="https://images.theconversation.com/files/554308/original/file-20231017-27-m0c4vb.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/554308/original/file-20231017-27-m0c4vb.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=471&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554308/original/file-20231017-27-m0c4vb.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=471&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554308/original/file-20231017-27-m0c4vb.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=471&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554308/original/file-20231017-27-m0c4vb.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=592&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554308/original/file-20231017-27-m0c4vb.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=592&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554308/original/file-20231017-27-m0c4vb.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=592&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chlorophyll colors water from the lake slightly green.</span>
<span class="attribution"><span class="source">Elizabeth Swanner</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>At Deming Lake, my colleagues and I pay special attention to the water layer where the chlorophyll readings jump. <a href="https://www.britannica.com/science/chlorophyll">Chlorophyll is the pigment</a> that makes plants green. It harnesses sunlight energy to turn water and carbon dioxide into oxygen and sugars. Nearly 20 feet (6 meters) below Deming’s surface, the chlorophyll is in cyanobacteria and photosynthetic algae, not plants. </p>
<p>But the curious thing about this layer is that we don’t detect oxygen, despite the abundance of these oxygen-producing organisms. This is the depth where iron concentrations start to climb to the high levels present at the lake’s bottom.</p>
<p>This high-chlorophyll, high-iron and low-oxygen layer is of special interest to us because it might help us understand where cyanobacteria lived in the ancient ocean, how well they were growing and how much oxygen they produced. </p>
<p>We suspect the reason cyanobacteria gather at this depth in Deming Lake is that there is more iron there than at the top of the lake. Just like <a href="https://theconversation.com/blood-in-your-veins-is-not-blue-heres-why-its-always-red-97064">humans need iron for red blood cells</a>, cyanobacteria need lots of iron to help catalyze the reactions of photosynthesis.</p>
<p>A likely reason we can’t measure any oxygen in this layer is that in addition to cyanobacteria, there are a lot of other bacteria here. After a good long life of a few days, the cyanobacteria die, and the other bacteria feed on their remains. These bacteria rapidly use up any oxygen produced by still photosynthesizing cyanobacteria the way a fire does as it burns through wood.</p>
<p>We know there are lots of bacteria here based on how cloudy the water is, and we see them when we inspect a drop of this water under a microscope. But we need another way to measure photosynthesis besides measuring oxygen levels. </p>
<h2>Long-running lakeside laboratory</h2>
<p>The other important function of photosynthesis is converting carbon dioxide into sugars, which eventually are used to make more cells. We need a way to track whether new sugars are being made, and if they are, whether it’s by photosynthetic cyanobacteria. So we fill glass bottles with samples of water from this lake layer and seal them tight with rubber stoppers.</p>
<p>We drive the 3 miles back to the <a href="https://cbs.umn.edu/itasca">Itasca Biological Station and Laboratories</a> where we will set up our experiments. The station opened in 1909 and is home base for us this week, providing comfy cabins, warm meals and this laboratory space.</p>
<p>In the lab, we inject our glass bottle with carbon dioxide that carries an <a href="https://www.britannica.com/science/isotopic-tracer">isotopic tracer</a>. If cyanobacteria grow, their cells will incorporate this isotopic marker. </p>
<p>We had a little help to formulate our questions and experiments. University of Minnesota students attending summer field courses collected decades worth of data in Itasca State Park. A diligent university librarian digitized <a href="https://cbs.umn.edu/itasca/research/student-research-papers">thousands of those students’ final papers</a>.</p>
<p>My students and I pored over the papers concerning Deming Lake, many of which tried to determine whether the cyanobacteria in the chlorophyll-rich layer are doing photosynthesis. While most indicated yes, those students were measuring only oxygen and got ambiguous results. Our use of the isotopic tracer is trickier to implement but will give clearer results.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554313/original/file-20231017-17-p7jytu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woman holds a clear plastic bag aloft, she and man are seated in boat" src="https://images.theconversation.com/files/554313/original/file-20231017-17-p7jytu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554313/original/file-20231017-17-p7jytu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554313/original/file-20231017-17-p7jytu.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554313/original/file-20231017-17-p7jytu.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554313/original/file-20231017-17-p7jytu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554313/original/file-20231017-17-p7jytu.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554313/original/file-20231017-17-p7jytu.jpeg?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">Graduate students Michelle Chamberlain and Zackry Stevenson about to sink the bottles for incubation in Deming Lake.</span>
<span class="attribution"><span class="source">Elizabeth Swanner</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>That afternoon, we’re back on the lake. We toss an anchor; attached to its rope is a clear plastic bag holding the sealed bottles of lake water now amended with the isotopic tracer. They’ll spend the night in the chlorophyll-rich layer, and we’ll retrieve them after 24 hours. Any longer than that and the isotopic label might end up in the bacteria that eat the dying cyanobacteria instead of the cyanobacteria themselves. We tie off the rope to a floating buoy and head back to the station’s dining hall for our evening meal.</p>
<h2>Iron, chlorophyll, oxygen</h2>
<p>The next morning, as we wait for the bottles to finish their incubation, we collect water from the different layers of the lake and add some chemicals that kill the cells but preserve their bodies. We’ll look at these samples under the microscope to figure out how many cyanobacteria are in the water, and we’ll measure how much iron is inside the cyanobacteria. </p>
<p>That’s easier said than done, because we have to first separate all the “needles” (cyanobacteria) from the “hay” (other cells) and then clean any iron off the outside of the cyanobacteria. Back at Iowa State University, we’ll shoot the individual cells one by one into a flame that incinerates them, which liberates all the iron they contain so we can measure it.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/554323/original/file-20231017-27-p7jytu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="rowboat with one woman in it on a lake with woodsy shoreline" src="https://images.theconversation.com/files/554323/original/file-20231017-27-p7jytu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/554323/original/file-20231017-27-p7jytu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554323/original/file-20231017-27-p7jytu.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554323/original/file-20231017-27-p7jytu.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554323/original/file-20231017-27-p7jytu.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554323/original/file-20231017-27-p7jytu.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554323/original/file-20231017-27-p7jytu.jpeg?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">Biogeochemist Katy Sparrow rows a research vessel to shore.</span>
<span class="attribution"><span class="source">Elizabeth Swanner</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Our scientific hunch, or <a href="https://www.britannica.com/science/scientific-hypothesis">hypothesis</a>, is that the cyanobacteria that live in the chlorophyll- and iron-rich layer will contain more iron than cyanobacteria that live in the top lake layer. If they do, it will help us establish that greater access to iron is a motive for living in that deeper and dimmer layer.</p>
<p>These experiments won’t tell the whole story of why it took so long for Earth to build up oxygen, but they will help us to understand a piece of it – where oxygen might have been produced and why, and what happened to oxygen in that environment.</p>
<p>Deming Lake is quickly becoming its own attraction for those with a curiosity about what goes on beneath its tranquil surface – and what that might be able to tell us about how new forms of life took hold long ago on Earth.</p><img src="https://counter.theconversation.com/content/210997/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elizabeth Swanner receives funding from the U.S. National Science Foundation and the National Aeronautics and Space Administration. </span></em></p>An unusual lake with distinct layers of low-oxygen and high-iron water lets researchers investigate conditions like those in the early Earth’s oceans.Elizabeth Swanner, Associate Professor of Geology, Iowa State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2077852023-06-23T15:51:06Z2023-06-23T15:51:06ZThe melting Arctic is a crime scene. The microbes I study have long warned us of this catastrophe – but they are also driving it<p>The Arctic’s climate is warming at least four times faster than the global average, causing irrevocable changes to this vast <a href="https://news.sky.com/story/dramatic-changes-to-polar-ice-caps-revealed-on-new-map-of-arctic-and-antarctica-12898550">landscape</a> and precarious <a href="https://www.nwf.org/Educational-Resources/Wildlife-Guide/Wild-Places/Arctic#:%7E:text=The%20Arctic%20is%20a%20unique,in%20the%20summer%20to%20breed.">ecosystem</a> – from the anticipated <a href="https://earth.org/polar-bears-to-become-extinct-by-2100/">extinction of polar bears</a> to the <a href="https://www.scientificamerican.com/article/as-arctic-sea-ice-melts-killer-whales-are-moving-in/#:%7E:text=Killer%20whales%20often%20feed%20on,navigate%20through%20the%20icy%20waters.">appearance of killer whales</a> in ever-greater numbers. A new <a href="https://www.nature.com/articles/s41467-023-38511-8">study</a> suggests the Arctic Ocean could be ice-free in summer <a href="https://theconversation.com/arctic-ocean-could-be-ice-free-in-summer-by-2030s-say-scientists-this-would-have-global-damaging-and-dangerous-consequences-206974">as soon as the 2030s</a> – around a decade earlier than previously predicted.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/532508/original/file-20230618-17-lemk5e.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of Arctic sea ice changes" src="https://images.theconversation.com/files/532508/original/file-20230618-17-lemk5e.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/532508/original/file-20230618-17-lemk5e.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=700&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532508/original/file-20230618-17-lemk5e.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=700&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532508/original/file-20230618-17-lemk5e.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=700&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532508/original/file-20230618-17-lemk5e.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=879&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532508/original/file-20230618-17-lemk5e.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=879&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532508/original/file-20230618-17-lemk5e.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=879&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 new Arctic sea ice map compares the 30-year average with recent ten-year averages.</span>
<span class="attribution"><a class="source" href="https://www.bas.ac.uk/media-post/new-map-of-polar-regions-updated-to-reflect-ice-loss-name-changes-and-new-data/">British Antarctic Survey</a></span>
</figcaption>
</figure>
<p>But to properly understand the pace and force of what’s to come, we should instead focus on organisms too small to be seen with the naked eye. These single-celled microbes are both the watchkeepers and arch-agitators of the Arctic’s demise.</p>
<p>Scientists like me who study them have become forensic pathologists, processing crime scenes in our Arctic field sites. We don the same white anti-contamination suits, photograph each sampling site, and bag our samples for DNA analysis. In some areas, red-coloured microbes even create an effect known as “blood snow”.</p>
<p>In this complex criminal investigation, however, the invisible witnesses are also responsible for the damage being done. Microbes testify to the vulnerability of their Arctic habitats to the changes that humans have caused. But they also create powerful climate feedback loops that are doing ever-more damage both to the Arctic, and the planet as a whole.</p>
<h2>Zipping headlong into icy oblivion</h2>
<p>My first visit to the Arctic was also nearly my last. As a PhD student in my early 20s in 2006, I had set out with colleagues to sample microbes growing on a glacier in the Norwegian archipelago of <a href="https://www.theguardian.com/environment/2023/may/13/svalbard-the-arctic-islands-where-we-can-see-the-future-of-global-heating">Svalbard</a> – the planet’s northernmost year-round settlement, about 760 miles from the North Pole.</p>
<p>Our treacherous commute took us high above the glacier, traversing an icy scree slope to approach its flank before crossing a river at the ice’s margin. It was a route we had navigated recently – yet this day I mis-stepped. Time slowed as I slid towards the stream swollen with ice melt, my axe bouncing uselessly off the glassy ice. I was zipping headlong into icy oblivion.</p>
<p>In that near-death calm, two things bothered me. The water would carry me deep into the glacier, so it would be decades before my remains were returned to my family. And the ear-worm of that field season meant I would die to the theme tune to Indiana Jones.</p>
<hr>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/288776/original/file-20190820-170910-8bv1s7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>This article is part of Conversation Insights</em></strong>
<br><em>The Insights team generates <a href="https://theconversation.com/uk/topics/insights-series-71218">long-form journalism</a> derived from interdisciplinary research. The team is working with academics from different backgrounds who have been engaged in projects aimed at tackling societal and scientific challenges.</em></p>
<hr>
<p>Thankfully, the scree slowed my slide – I lived and learned, quickly, that dead scientists don’t get to write up their papers. And I’m still learning about the tiny organisms that populate every habitat there: from seawater in the Arctic Ocean to ice crystals buried deep in the <a href="https://en.wikipedia.org/wiki/Greenland_ice_sheet">Greenland ice sheet</a>.</p>
<p>These micro-managers of all manner of planetary processes are acutely sensitive to the temperatures of their habitats. The slightest change above freezing can transform an Arctic landscape from a frozen waste devoid of liquid water to one where microbes get busy reproducing in nutrient-rich water, transforming themselves in ways that <a href="https://www.nature.com/articles/ismej2010108">further amplify</a> the effects of climate warming.</p>
<p>The Svalbard region is now warming seven times faster than the global average. While much of the world continues its efforts to limit global warming to 1.5°C above pre-industrial levels, in the Arctic, that battle was lost long ago.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0VOGGdeB8eI?wmode=transparent&start=17" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Joseph Cook’s film on the microbes that inhabit the Greenland ice sheet.</span></figcaption>
</figure>
<h2>Decades ahead of us all</h2>
<p>It’s 2011, and <a href="http://www.earth.s.chiba-u.ac.jp/english/education/education02/staff16.html">Nozomu Takeuchi</a> is visiting Svalbard from Japan. It has been a difficult year back home, following the earthquake, tsunami and Fukushima nuclear incident, but Nozomu – a glacier ecologist and professor at Chiba University – is unrelenting in his quest to measure the effects of climate change. </p>
<p>Just hours after he stepped off a plane in the August midnight sun at Longyearbyen airport, we are marching up the nearest glacier. Above us, snow-capped mountain sides loom out of the swirling mist.</p>
<p>Since the 1990s, Nozomu has been collecting samples and measurements from glaciers all over the world. When we reach our goal near the snowline, he opens his rucksack to reveal a bento box full of sampling kit – stainless steel scoops, test tubes, sample bags, all arranged for efficiency. As he scurries around with practised efficiency, I think of offering help but fear I would only slow him down.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532612/original/file-20230619-27-w8e0xr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scientist takes a reading in snowy Arctic landscape" src="https://images.theconversation.com/files/532612/original/file-20230619-27-w8e0xr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532612/original/file-20230619-27-w8e0xr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532612/original/file-20230619-27-w8e0xr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532612/original/file-20230619-27-w8e0xr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532612/original/file-20230619-27-w8e0xr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532612/original/file-20230619-27-w8e0xr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532612/original/file-20230619-27-w8e0xr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Nozomu Takeuchi measuring the biological darkening of a Svalbard glacier in 2011.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In truth, Nozomu is decades ahead of us all. Years ago, he made the link between the future of life and the death of ice, and these melting Svalbard glaciers are adding yet more points to his graphs.</p>
<p>Just as we apply oodles of factor 50 to protect ourselves from the Sun, so the billions of microbes sandwiched between the sky and surface of the glacier protect themselves by accumulating sunscreen-like pigments. And if enough of these pigments rest in one place under the Sun, this area of “biological darkening” absorbs the heat of the Sun much more effectively than reflective white snow and ice – so it melts faster.</p>
<p>Nozomu scoops up some of the so-called blood snow, heavily laden with algae. Under the microscope, their cells are indeed reminiscent of red blood cells. But rather than haemoglobin, these cells are laden with carotenoids – pigments also found in vegetables that <a href="https://academic.oup.com/femsec/article/94/3/fiy007/4810544?login=false">protect the algae from overheating</a>. Other patches of the glacier are verdant green, rich in algae that are busy photosynthesising light into chemical energy in this 24-hour daylight world.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/532611/original/file-20230619-29-l44kho.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Man in icy landscape holding scientific sample" src="https://images.theconversation.com/files/532611/original/file-20230619-29-l44kho.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/532611/original/file-20230619-29-l44kho.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532611/original/file-20230619-29-l44kho.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532611/original/file-20230619-29-l44kho.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532611/original/file-20230619-29-l44kho.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532611/original/file-20230619-29-l44kho.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532611/original/file-20230619-29-l44kho.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The author with a sample of ‘blood snow’, collected from a glacier surface.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Further down the glacier, the professor crushes some “dirty” ice into a bag. A different kind of algae lives here that, depending on your point-of-view, is either black, brown or purple (perhaps it depends on the tint of your sunglasses). The <a href="https://www.researchgate.net/figure/Chemical-structure-of-compound-3-purpurogallin-carboxylic-acid-6-O-b-d-glucopyranoside_fig2_51806131#:%7E:text=A%20gallotannin%20derivative%20(galloylglucopyranose%2C%20i.e.,et%20al.%2C%202012b)%20.">pigment</a> created is like the compounds that colour tea, and the algae keep it in layers like parasols above the photosynthetic factories within their cells – ensuring they have just enough sunlight to photosynthesise, but not enough to burn.</p>
<p>Open Google Earth and as you zoom in on the Arctic, you may spot the large dark stripe that scars the western margin of the <a href="https://en.wikipedia.org/wiki/Greenland_ice_sheet">Greenland ice sheet</a>. This is the “dark zone”, but it’s not caused by dark <a href="https://www.nature.com/articles/s41467-020-20627-w">dust</a> or soot. It’s alive, <a href="https://www.nature.com/articles/ismej2012107">laden with algae</a> – and it has been darkening, and growing, as Greenland warms.</p>
<p>Between 2000 and 2014, the <a href="https://www.frontiersin.org/articles/10.3389/feart.2016.00043/full">dark zone’s area grew by 14%</a>. At 279,075 km² in 2012, it was already more than twice the <a href="https://www.britannica.com/summary/England#:%7E:text=Area%3A%2050%2C301%20sq%20mi%20(130%2C278,even%20with%20the%20entire%20kingdom.).%20This%20had%20a%20powerful%20impact%20on%20the%20rate%20of%20ice%20melt%20--%20areas%20blooming%20with%20algae%20%5Bmelt%20nearly%202cm%20more%20each%20day%5D(https://www.pnas.org/doi/abs/10.1073/pnas.1918412117">size of England</a> than bare ice.</p>
<p>Next morning, I am woken by the smell of chemicals, having slept beneath a coffee table. Nozomu is busy processing his samples: bags of melting ice pinned to a clothesline by bulldog clips. They resemble bunting around the crowded room, but this is no time for celebration. The tint of each bag adds a measurement which quantifies the link between these algae, their pigments, and the death of their icy home.</p>
<h2>The case becomes urgent</h2>
<p>By the summer of 2014, glaciologists all over the world have started to listen to the warnings of pioneering ecologists such as Nozomu. The glaciers are dying even as life blossoms on their darkening surfaces. The case has become urgent.</p>
<p>I am in a helicopter, flying with colleagues to a camp in the dark zone on the Greenland ice sheet – the largest mass of glacial ice in the northern hemisphere. Covering 1.7 million km², its ice holds the equivalent of the water required to raise global sea levels by 7.7 metres.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532620/original/file-20230619-23-shc4a3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A landscape of dark ice intertwined with blue rivers of meltwater." src="https://images.theconversation.com/files/532620/original/file-20230619-23-shc4a3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532620/original/file-20230619-23-shc4a3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532620/original/file-20230619-23-shc4a3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532620/original/file-20230619-23-shc4a3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532620/original/file-20230619-23-shc4a3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532620/original/file-20230619-23-shc4a3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532620/original/file-20230619-23-shc4a3.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">A highly darkened surface of the Greenland ice sheet, rich in algae and incised with rivers of meltwater.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>As we warm our climate, the rate of water flowing from this reservoir increases, with each degree Celsius added to global temperatures opening the drainage valve even wider. Feedback processes such as biological darkening have the potential to multiply the number of drainage valves that are open, hastening dramatically the rate at which sea levels rise.</p>
<p>To monitor this effect, every day <a href="https://www.gla.ac.uk/schools/ges/staff/karencameron/">Karen Cameron</a>, the leader of our camp this summer, walks to undisturbed patches of ice carrying a £100,000 backpack which contains a spectrometer to measure the darkness of the ice, capturing how it absorbs the solar energy that causes melting. The glaciologists are desperate for ground truth, and their models need data.</p>
<p>Up to this point, none of their predictions of how the Greenland ice sheet would respond to our warming climate have included biological darkening. Even if the effect were modest, it could still topple the ice sheet from a predictable, straightline response to climate warming.</p>
<p>All the time we are in Greenland, the only lifeforms we encounter are the flies that hatch from the fresh fruit and peppers in our food rations. These and the few types of glacier algae and several hundred kinds of bacteria that are biologically darkening the ice: a living scum scarring the surface of the ice sheet.</p>
<p>My work focuses on how these tiny organisms adapt to their icy habitat, but the implications of their behaviour are now of global concern. A <a href="https://screenworks.org.uk/archive/baftss-practice-research-award-2017/timeline">filmmaker</a> at the camp is weaving a thread between the ice melt in Greenland and its consequences for people living in coastal communities all over the world – from villages near my home on the <a href="https://www.theguardian.com/environment/2019/may/18/this-is-a-wake-up-call-the-villagers-who-could-be-britains-first-climate-refugees">west coast of Wales</a>, to huge metropolises like Manhattan, Amsterdam and Mumbai, and even entire low-lying island nations in the Pacific.</p>
<p>As smaller glaciers fade, and the larger ice sheets of Greenland and Antarctica start to respond with full force to our warming climate, it is these communities, capitals and countries that will bear the brunt of the flooding, inundation and erosion that comes with rising sea levels.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532622/original/file-20230619-28-oh4l8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two scientists inspecting an ice corer device dripping with meltwater." src="https://images.theconversation.com/files/532622/original/file-20230619-28-oh4l8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532622/original/file-20230619-28-oh4l8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532622/original/file-20230619-28-oh4l8z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532622/original/file-20230619-28-oh4l8z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532622/original/file-20230619-28-oh4l8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532622/original/file-20230619-28-oh4l8z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532622/original/file-20230619-28-oh4l8z.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">The author (left) and Joseph Cook high on the Greenland ice sheet, meltwater dripping from their ice corer.</span>
<span class="attribution"><span class="source">Sara Penrhyn Jones</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Before heading home, our helicopter takes us on a detour, high over the ice sheet. We fly over the brown-black-purple algae to brighter, higher elevations where the palette shrinks to the blue and white of water and ice, then snow and sky. Greenland makes its own weather and, in these higher elevations, we expect the ice to be frozen all year round. When we land and begin to collect snow samples and a small ice core, however, we find we are digging into slush. The ice has started to melt up here, too. </p>
<p>We heave up our ice corer, and meltwater dribbles out from its bottom. In periods of extreme warming, much of the surface of the ice sheet can experience melting episodes, <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2015.00225/full">disturbing the slumbering microbes</a> stored within the otherwise permanently frozen surface. It’s a sobering moment for us all.</p>
<p>Flying back to camp, I watch the streams become rivers and lakes as we head back over the dark zone, where melt and microbes dominate the icescape. I contemplate how much water, once locked in the ice, will become free to flow into the sea and into millions of homes by the end of the century.</p>
<h2>Popping a pingo</h2>
<p>The frozen lands of eight nations encircle the Arctic. Their soils store vast quantities of carbon: a third of the planet’s entire quantity of soil carbon resides in this frozen ground.</p>
<p>The carbon is a legacy of soils formed in past climates and preserved for millennia. However, human-induced climate change is reheating this leftover carbon, providing a luxuriant food source for microbes resident within the <a href="https://earthobservatory.nasa.gov/biome/biotundra.php">tundra</a>, which then emit it as greenhouse gases.</p>
<p>This is known as the <a href="https://en.wikipedia.org/wiki/Permafrost_carbon_cycle#:%7E:text=Carbon%20emissions%20from%20permafrost%20thaw,which%20increases%20permafrost%20thaw%20depths.">permafrost carbon</a> feedback loop. When even modest quantities of this vast carbon store reach the atmosphere, warming accelerates – resulting in faster thawing of the tundra and the release of yet more greenhouse gases.</p>
<p>Furthermore, not all greenhouse gases are equal in their impact. While carbon dioxide is relatively abundant and stable for centuries in the atmosphere, methane is less abundant and shorter-lived, but remarkably powerful as a greenhouse gas – nearly 30 times more damaging to the climate than carbon dioxide, for the same volume.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532615/original/file-20230619-1823-ekek0j.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scientist crouched on ice taking water samples." src="https://images.theconversation.com/files/532615/original/file-20230619-1823-ekek0j.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532615/original/file-20230619-1823-ekek0j.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=307&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532615/original/file-20230619-1823-ekek0j.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=307&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532615/original/file-20230619-1823-ekek0j.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=307&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532615/original/file-20230619-1823-ekek0j.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=386&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532615/original/file-20230619-1823-ekek0j.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=386&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532615/original/file-20230619-1823-ekek0j.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=386&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Andy Hodson sampling methane from a freshly ‘popped’ pingo.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>For more than three decades, <a href="https://www.unis.no/staff/andy-hodson/">Andy Hodson</a> has worked at the frontier where microbes, carbon and the Arctic landscape meet. In 2018, we join him on a brisk spring day in Svalbard. It’s -26°C but the snowmobile commute is thankfully brief – then we work quickly against the cold.</p>
<p>Hodson’s plan is to “pop” one of the many <a href="https://en.wikipedia.org/wiki/Pingo">pingos</a> that populate the floor of this wide open valley. Think of pingos as the acne of the Arctic: they form as permafrost compresses unfrozen wet sediments, erupting as small hills blistering the skin of the tundra.</p>
<p>The story of these microbes’ lives is complicated. They only live beyond the reach of oxygen – where oxygen is more prevalent, methane-consuming microbes thrive instead, quenching the belches of methane from below. Similarly, should mineral sources of iron or sulphide be nearby, then microbes that use them outcompete the methanogens.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/532614/original/file-20230619-15-6i78fv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small fountain of water in an opening in the ice, amid a snowy landscape." src="https://images.theconversation.com/files/532614/original/file-20230619-15-6i78fv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/532614/original/file-20230619-15-6i78fv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532614/original/file-20230619-15-6i78fv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532614/original/file-20230619-15-6i78fv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532614/original/file-20230619-15-6i78fv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532614/original/file-20230619-15-6i78fv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532614/original/file-20230619-15-6i78fv.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">A popped pingo discharging supercooled water rich in methane.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>It all adds up to one of the greatest uncertainties for our civilisation: the extent and composition of greenhouse gases escaping from Arctic lands. <a href="https://www.cam.ac.uk/research/news/emissions-from-melting-permafrost-could-cost-43-trillion#:%7E:text=Increased%20greenhouse%20gas%20emissions%20from,and%20the%20University%20of%20Colorado.">Estimates of the economic impacts</a> from this permafrost carbon feedback tally in the tens of trillions of dollars to the global economy. We know it is bad news, but exactly how bad depends on the microbes in their microscopic mosaic.</p>
<p>Hodson’s field work shows that, during the Arctic winter, this pingo is probably the only source of methane in the immediate area, its chimney enabling the gas to escape from the depths of the ice before methane-consuming microbes can catch it. Annually, tens of kilograms of methane and more than a ton of carbon dioxide will escape from this pingo alone - one of <a href="https://doi.org/10.1016/j.geomorph.2023.108694">more than 10,000</a> scattered across the Arctic, in addition to its other methane-producing hotspots.</p>
<h2>A near-perfect ecosystem</h2>
<p>Arctic lands are a patchwork of permafrost carbon feedbacks, and our future depends on the uncertain fate of the microbes within. </p>
<p>While the ice melt enhances the growth of microbes in the short term, if it continues to the point of erasing habitats then the microbes will be lost with them. We recognise this danger for polar bears and walruses, but not the invisible biodiversity of the Arctic. Small does not mean insignificant though.</p>
<p>To appreciate this, we can head back to the dark zone on Greenland’s ice sheet and join <a href="https://www.rolex.org/rolex-awards/exploration/joseph-cook">Joseph Cook</a> during our summer 2014 field season. He’s lying on a mat improvised from a bath towel and a binbag wrapped in duct tape, peering into a dark, pothole-like depression in the ice. It’s a cryoconite hole, and millions of them are dotted over the edges of the ice sheet. Where pingos contribute to climate warming by emitting methane, cryoconite is a good sink of greenhouse gases, but this creates its own problems. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532618/original/file-20230619-27-4a5amn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Crouching scientist takes samples in the Arctic snow." src="https://images.theconversation.com/files/532618/original/file-20230619-27-4a5amn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532618/original/file-20230619-27-4a5amn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532618/original/file-20230619-27-4a5amn.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532618/original/file-20230619-27-4a5amn.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532618/original/file-20230619-27-4a5amn.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532618/original/file-20230619-27-4a5amn.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532618/original/file-20230619-27-4a5amn.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">Joseph Cook measuring the carbon cycling activities of Greenland’s cryoconite holes.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2486.2008.01758.x">earliest estimate</a> of its ability to store carbon dioxide from the air on the ice surface of the world’s glaciers exceeded Finland’s total carbon emissions in the same year. Every cryoconite hole is a near-perfect ecosystem – with a singular flaw. Its inhabitants must melt ice to live. But the very act of melting the ice hastens the demise of their glacier habitat. </p>
<p>Despite being found in some of the harshest locations on Earth, cryoconite is home for thousands of different types of bacteria (including the all-important photosynthetic cyanobacteria), fungi, and <a href="https://microbiologysociety.org/why-microbiology-matters/what-is-microbiology/protozoa.html">protozoa</a>. Even <a href="https://www.theguardian.com/environment/2020/oct/17/tardigrade-ice-hole-arctic-greenland">tardigrades</a> thrive in cryoconite.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/532623/original/file-20230619-21-7v4otj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscope image of a single cryoconite granule." src="https://images.theconversation.com/files/532623/original/file-20230619-21-7v4otj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/532623/original/file-20230619-21-7v4otj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532623/original/file-20230619-21-7v4otj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532623/original/file-20230619-21-7v4otj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532623/original/file-20230619-21-7v4otj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532623/original/file-20230619-21-7v4otj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532623/original/file-20230619-21-7v4otj.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">Microscope image of a cryoconite granule, showing biological darkening and cyanobacteria growing through it.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Cook is professionally besotted with the perfection of this near-frozen “microscopic rainforest”. Its inhabitants are shielded and nourished at just the right depth and in the right shape for a busy ecosystem to be engineered by the interaction of sunlight with cyanobacteria, dust and ice to the benefit of all its inhabitants. The cyanobacteria use sunshine to capture carbon dioxide from the air and convert it into the slimy cement that builds each granule of cryoconite</p>
<p>However, with vast numbers of cryoconite holes dotted across the ice surface, “swarms” of these holes help <a href="https://www.frontiersin.org/articles/10.3389/feart.2015.00078/full">shape and darken the ice surface</a>. This in turn influences the melting rate, as the surface is sculpted under the sun of 24-hour daylight.</p>
<p>Writing in the scientific journal <a href="https://www.nature.com/articles/029039a0">Nature in 1883</a>, Swedish polar explorer Adolf Erik Nordenskjöld, who discovered cryoconite, thanked the organisms within cryoconite for melting away the ancient ice that once covered Norway and Sweden:</p>
<blockquote>
<p>In spite of their insignificance, [they] play a very important part in nature’s economy, from the fact that their dark colour far more readily absorbs the Sun’s heat than the bluish-white ice, and thereby they contribute to the destruction of the ice sheet, and prevent its extension. Undoubtedly we have, in no small degree, to thank these organisms for the melting away of the layer of ice which once covered the Scandinavian peninsula.</p>
</blockquote>
<h2>Taking DNA analysis to strange new places</h2>
<p>We return to Greenland in winter 2018 to explore cryoconite’s singular flaw. Cook and I are joined by Melanie Hay, then a PhD student in Arctic bioinformatics.</p>
<p>Hay and I are taking DNA analysis to strange new places to learn more about the evolution and biology of cryoconite. Powerful advances in genomics are changing our view of the microbial world, but large DNA-sequencing instruments fare best in sophisticated labs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532619/original/file-20230619-17-uv14gu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scientist sitting outside her tent with backpack, looking out at icy landscape." src="https://images.theconversation.com/files/532619/original/file-20230619-17-uv14gu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532619/original/file-20230619-17-uv14gu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=442&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532619/original/file-20230619-17-uv14gu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=442&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532619/original/file-20230619-17-uv14gu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=442&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532619/original/file-20230619-17-uv14gu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=555&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532619/original/file-20230619-17-uv14gu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=555&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532619/original/file-20230619-17-uv14gu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=555&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Melanie Hay camping and sampling on the Greenland ice sheet.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Instead, we are using a stapler-sized nanopore sequencer hooked up to the USB port of a winterised laptop. Outside the tent, it is –20°C – but the DNA sequencer must run at body temperature. The only sustainable source of warmth is body heat, so I have snuggled up with the sequencer in my sleeping bag every night and in my clothes all day.</p>
<p>That evening, we are caught in a storm of hurricane force. Becoming disorientated while moving between tents would be lethal, so we crawl in a human chain through the whiteout to our sleeping tents. Hay reaches her tent but Cook’s is lost, so we squeeze into my one-person tent. Somehow I sleep soundly, while Cook is exposed to the full force of the night’s terror.</p>
<p>In the morning, we excavate Hay, whose snow-laden tent had collapsed in the night. The sequencing is complete, but storm damage to our generator means the camp is losing power, so she must work quickly. She identifies the cyanobacteria building the cryoconite – it’s a short list dominated by one species: <em>Phormidesmis priestleyi</em>.</p>
<p>This species, found in cryoconite throughout the Arctic, seems to be the ecosystem engineer of cryoconite – a microscopic beaver building a dam of dust. But the flaw is the darkness of the near-perfect cryoconite ecosystems it creates. Like the neighbouring glacier algae we met earlier, <em>Phormidesmis priestleyi</em> is biologically darkening Arctic ice, and eventually hastening the demise of the thousands of different types of organism contained in cryoconite holes.</p>
<p>And so, this work shows us ever more clearly that the <a href="https://www.nature.com/articles/s41559-020-1163-0">loss of the planet’s glaciers</a> is as much a component of the global biodiversity crisis as it is a headline impact of climate change.</p>
<h2>Last line of defence against antibiotic resistance</h2>
<p>The loss of the Arctic’s microbial biodiversity matters in other ways too. Hay and Aliyah Debbonaire are both reformed biomedical scientists seeking cures from the Arctic in the form of new antibiotics. In the summer of 2018, we are in Svalbard looking for clues.</p>
<p>The world is running out of effective antibiotics, and the Arctic’s frontiers may be our last line of defence in this antibiotic resistance crisis. Countless species of microbes have evolved to live within its harsh habitats using all the tricks in the book, including making antibiotics as chemical weapons to kill off competitors. This means they may be sources of new antibiotics.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/532631/original/file-20230619-1900-kr9gwx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scientists (one kneeling) taking samples in the snowy Arctic landscape." src="https://images.theconversation.com/files/532631/original/file-20230619-1900-kr9gwx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/532631/original/file-20230619-1900-kr9gwx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/532631/original/file-20230619-1900-kr9gwx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/532631/original/file-20230619-1900-kr9gwx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/532631/original/file-20230619-1900-kr9gwx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/532631/original/file-20230619-1900-kr9gwx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/532631/original/file-20230619-1900-kr9gwx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aliyah Debbonaire (left) and Melanie Hay sampling a cryoconite hole.</span>
<span class="attribution"><span class="source">Arwyn Edwards</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>And this is not their only application. From cheeses to eco-friendly biological washing powders, entire shopping aisles of products have been derived from cold-adapted microbes. As climate warming threatens to disrupt entire Arctic habitats, our opportunity to use, learn from, and protect this biodiversity may be lost forever.</p>
<p>As our tiny plane returns to the nearest town, Longyearbyen, we fly low over the <a href="https://theconversation.com/after-svalbard-why-safety-of-world-seed-vaults-is-crucial-to-future-food-security-79586">Svalbard Global Seed Vault</a>, which contains the fruits of more than 12,000 years of agriculture in the form of seeds from a million different varieties of crop. Nearby, a similar facility inside a disused coal mine stores essential computer programmes on microfilm – the ultimate backup for our data-addicted world.</p>
<p>Within a snowy kilometre, you can walk between the the alpha and omega of human innovation in civilisation. Both facilities have chosen the fastest-warming town on the planet as the safest place to store these treasures of humanity. Yet no such facility is dedicated to the microbial biodiversity of the Arctic, despite its critical importance to the future of the world’s biotech and medical sectors.</p>
<p>Instead, it falls to microbiologists such as Debbonaire, racing against time to identify, nurture and screen the microbes of the melting Arctic. Her painstaking work accumulates towers of Petri dishes, each a temporary refuge for a different Arctic microbe.</p>
<p>Eventually, they will be stored in <a href="https://www.dellamarca.it/en/how-does-an-ultra-low-freezer-work/">ultra-freezers</a> in laboratories scattered across the world. Such work is unglamorous to funders, so it is done piecemeal on the edges of other projects. Yet it represents our only attempt to save the microbes of the Arctic.</p>
<h2>The battle is lost</h2>
<p>Most of all, the Arctic matters because it is the fastest-warming part of the planet, and its microbes are responding first. What happens there carries implications for everyone. It is the harbinger of change for everywhere.</p>
<p>Another Arctic microbiologist could strike plangent notes regarding permafrost or sea ice, but as an ecologist of glaciers I am drawn to glacial ice.</p>
<p>Over the first fifth of this century, Earth’s glaciers have discharged some ten quadrillion (ten to the power 25) tablespoons of melt a year – and within each tablespoon, the <a href="https://www.nature.com/articles/s43247-022-00609-0">tens of thousands of bacteria and viruses</a> that were once stored within that ice.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meltwater-is-infiltrating-greenlands-ice-sheet-through-millions-of-hairline-cracks-destabilizing-its-structure-207468">Meltwater is infiltrating Greenland’s ice sheet through millions of hairline cracks – destabilizing its structure</a>
</strong>
</em>
</p>
<hr>
<p>What’s to come is sadly predictable. Even the most modest warming scenario of 1.5°C above the pre-industrial era will lead to the extinction of at least <a href="https://www.science.org/doi/10.1126/science.abo1324">half the Earth’s 200,000 glaciers</a> by the end of the century.</p>
<p>Depending on the urgency and effectiveness of our actions as a civilisation, this century could also represent the “peak melt” in our history. Yet the battle to save many of these precious icy habitats is already lost. Instead, for scientists like me, our field work is now largely a question of documenting these “crime scenes” – so at least the knowledge of life within ice can be preserved, before it melts away forever.</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=112&fit=crop&dpr=1 600w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=112&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=112&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=140&fit=crop&dpr=1 754w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=140&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/313478/original/file-20200204-41481-1n8vco4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=140&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>For you: more from our <a href="https://theconversation.com/uk/topics/insights-series-71218?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Insights series</a>:</em></p>
<ul>
<li><p><em><a href="https://theconversation.com/prehistoric-communities-off-the-coast-of-britain-embraced-rising-seas-what-this-means-for-todays-island-nations-147879?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Prehistoric communities off the coast of Britain embraced rising seas – what this means for today’s island nations
</a></em></p></li>
<li><p><em><a href="https://theconversation.com/too-afraid-to-have-kids-how-birthstrike-for-climate-lost-control-of-its-political-message-181198?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">‘Too afraid to have kids’ – how BirthStrike for Climate lost control of its political message
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<li><p><em><a href="https://theconversation.com/climate-scientists-concept-of-net-zero-is-a-dangerous-trap-157368?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Climate scientists: concept of net zero is a dangerous trap
</a></em></p></li>
<li><p><em><a href="https://theconversation.com/noise-in-the-brain-enables-us-to-make-extraordinary-leaps-of-imagination-it-could-transform-the-power-of-computers-too-192367?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Noise in the brain enables us to make extraordinary leaps of imagination. It could transform the power of computers too
</a></em></p></li>
<li><p><em><a href="https://theconversation.com/beyond-gdp-changing-how-we-measure-progress-is-key-to-tackling-a-world-in-crisis-three-leading-experts-186488?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK">Beyond GDP: changing how we measure progress is key to tackling a world in crisis – three leading experts
</a></em></p></li>
</ul>
<p><em>To hear about new Insights articles, join the hundreds of thousands of people who value The Conversation’s evidence-based news. <a href="https://theconversation.com/uk/newsletters/the-daily-newsletter-2?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=InsightsUK"><strong>Subscribe to our newsletter</strong></a>.</em></p><img src="https://counter.theconversation.com/content/207785/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arwyn Edwards receives funding from UK Research & Innovation - Natural Environment Research Council, as well as the Research Council of Norway, the Leverhulme Trust, and the Royal Geographical Society. </span></em></p>To fully understand the extent of climate-related dangers the Arctic – and our planet – is facing, we must focus on organisms too small to be seen with the naked eye.Arwyn Edwards, Reader in Biology, Department of Life Sciences, Aberystwyth UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2030212023-04-17T12:43:33Z2023-04-17T12:43:33ZWill the Earth last forever?<figure><img src="https://images.theconversation.com/files/519862/original/file-20230406-26-bwayd8.jpg?ixlib=rb-1.1.0&rect=7%2C0%2C2329%2C1670&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">'Earthrise,' a photo of the Earth taken by Apollo 8 astronaut Bill Anders, Dec. 4, 1968.</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Overview_effect#/media/File:NASA-Apollo8-Dec24-Earthrise-b.jpg">NASA/Bill Anders via Wikipedia</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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<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>Will the Earth last forever? – Solomon, age 5, California</strong></p>
</blockquote>
<hr>
<p>Everything that has a beginning has an end. But the Earth will last for a very long time, and its end will come billions of years after anyone who is alive here now is gone. </p>
<p>Before we talk about the future of our planet, let’s review its history and when life appeared on it. The history of human beings is very, very short compared with that of Earth.</p>
<h2>4 billion years old</h2>
<p>Our planet formed from a giant cloud of gas and dust in space, which is called a nebula, <a href="https://theconversation.com/curious-kids-how-do-scientists-work-out-how-old-the-earth-is-90391">about 4.6 billion years ago</a>. The first continent might have formed on its surface as early as <a href="https://www.nationalgeographic.com/science/article/140224-oldest-crust-australia-zircon-science">4.4 billion years ago</a>. </p>
<p>The atmosphere of the early Earth <a href="https://beta.nsf.gov/news/without-oxygen-earths-early-microbes-relied">did not contain oxygen</a>, so it would have been toxic to human beings if they had been present then. It was very different from Earth’s atmosphere today, which is about 21% oxygen. Many life forms, including humans, need oxygen to live. </p>
<p>Where did that oxygen come from? Scientists believe that atmospheric oxygen started to rise <a href="https://theconversation.com/billions-of-years-ago-the-rise-of-oxygen-in-earths-atmosphere-caused-a-worldwide-deep-freeze-139722">about 2.4 billion years ago</a> in a shift they call the Great Oxidation Event. </p>
<p>Tiny microorganisms had already existed on Earth’s surface for a while. Some of them developed the ability to <a href="https://asm.org/Articles/2022/February/The-Great-Oxidation-Event-How-Cyanobacteria-Change">produce energy from sunlight</a>, the way plants do today. As they did it, they released oxygen. It built up in the atmosphere and made it possible for more complex life forms to evolve. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ZRgeh7cN9PQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Cyanobacteria, also known as blue-green algae, were the first organisms that produced oxygen on Earth. Today you can find them all around – even in a pond in New York City’s Central Park.</span></figcaption>
</figure>
<p>This took a long time. The first animals, which may have been sea sponges, probably appeared <a href="https://www.science.org/content/article/earth-s-first-animals-may-have-been-sea-sponges">about 660 million years ago</a>. Depending how we define humans,
humans emerged in Africa about 200,000 years to 2 million years ago, and <a href="https://www.history.com/news/humans-evolution-neanderthals-denisovans">spread out everywhere from there</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Ve969_F71KI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Humans have only been present on Earth for a tiny fraction of our planet’s history.</span></figcaption>
</figure>
<h2>Billions more to go</h2>
<p>Now, as we think about the future of the Earth, we know there are two essential factors that humans need to live here. </p>
<p>First, the Sun provides <a href="https://education.nationalgeographic.org/resource/power-sun/">most of the energy</a> that living things on Earth need to survive. Plants use sunlight to grow and to produce oxygen. Animals, including humans, rely directly or indirectly on plants for food and oxygen. </p>
<p>The other thing that makes the Earth habitable for life is that our planet’s surface keeps moving and shifting. This ever-changing surface environment produces weather patterns and chemical changes in the oceans and on the continents that have <a href="https://www.quantamagazine.org/why-earths-cracked-crust-may-be-essential-for-life-20180607/">enabled life to evolve on Earth</a>. </p>
<p>The movement of the <a href="https://oceanservice.noaa.gov/facts/tectonics.html">giant pieces of Earth’s outer layer</a>, which are called plates, is driven by heat in the interior of the Earth. This source will keep the Earth’s interior hot <a href="https://theconversation.com/how-has-the-inside-of-the-earth-stayed-as-hot-as-the-suns-surface-for-billions-of-years-193277">for billions of years</a>. </p>
<p>So, what will change? Scientists estimate that the Sun will keep shining for another <a href="https://theconversation.com/the-sun-wont-die-for-5-billion-years-so-why-do-humans-have-only-1-billion-years-left-on-earth-37379">5 billion years</a>. But it will gradually get brighter and brighter, and warm the Earth more and more. </p>
<p>This warming is so slow that we wouldn’t even notice it. In about 1 billion years, our planet will be too hot to maintain oceans on its surface to support life. That’s a really long time away: an average human lifetime is <a href="https://worldpopulationreview.com/country-rankings/life-expectancy-by-country">about 73 years</a>, so a billion is more than 13 million human lifetimes. </p>
<p>Long after that – about 5 billion years from now – our Sun will expand into an even bigger star that astronomers call a “red giant,” which eventually will engulf the Earth. Just as our planet existed for over 4 billion years before humans appeared, it will last for another 4 billion to 5 billion years, long after it becomes uninhabitable for humans.</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>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/203021/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shichun Huang does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The Earth isn’t permanent, but it was here for four billion years before humans arrived and should be here for several billion more.Shichun Huang, Associate Professor of Earth and Planetary Sciences, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1978802023-02-20T13:19:21Z2023-02-20T13:19:21ZWere viruses around on Earth before living cells emerged? A microbiologist explains<figure><img src="https://images.theconversation.com/files/507461/original/file-20230131-26-ml6jvg.jpg?ixlib=rb-1.1.0&rect=0%2C3%2C2305%2C1292&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Maybe the first life on Earth was part of an 'RNA world.'</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/molecule-illustration-royalty-free-illustration/1359392488">Artur Plawgo/Science Photo Library 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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<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>Were there already viruses on Earth when the first living cells appeared billions of years ago? – Aayush A., age 16, India</strong></p>
</blockquote>
<p>How life on Earth started has puzzled scientists for a long time. And it still does.</p>
<p>Fossils provide very important evidence about the evolution of plants and animals. Unfortunately, there are <a href="https://ucmp.berkeley.edu/bacteria/bacteriafr.html">very few fossils of ancient microbes available</a>, so scientists rely on modern microbes to devise theories about how life started. I studied bacteria and another type of microbe called archaea from hot environments <a href="https://scholar.google.com/citations?user=pN5i54IAAAAJ&hl=en">for many years</a> to learn how they might have evolved on early Earth, but I still have so many unanswered questions.</p>
<p>Based on the fossil evidence we have, single-celled microbes appeared on Earth before larger cellular life like plants and animals. But which kinds of microbes were the very first kind of life?</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/de1hiS_XjWg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Some scientists think hydrothermal vents are the cradle of early life on Earth.</span></figcaption>
</figure>
<h2>Which microbes are considered alive?</h2>
<p>Microbes are living, single-celled creatures surrounded by a membrane. They consume and convert nutrients into biological molecules or energy and are too small to be seen without a microscope.</p>
<p>By this definition, bacteria, archaea and single-celled eukaryotes are microbes. <a href="https://bio.libretexts.org/Courses/University_of_California_Davis/BIS_2A%3A_Introductory_Biology_(Easlon)/Readings/02.2%3A_Bacterial_and_Archaeal_Diversity">Bacteria and archaea</a> are single-celled creatures that lack internal membrane-enclosed structures, like a nucleus to hold their genetic material. Single-celled eukaryotes have a nucleus and may have other membrane-enclosed structures.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/507680/original/file-20230201-8834-kxai71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram comparing a eukaryotic and prokaryotic cell" src="https://images.theconversation.com/files/507680/original/file-20230201-8834-kxai71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/507680/original/file-20230201-8834-kxai71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507680/original/file-20230201-8834-kxai71.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507680/original/file-20230201-8834-kxai71.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507680/original/file-20230201-8834-kxai71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507680/original/file-20230201-8834-kxai71.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507680/original/file-20230201-8834-kxai71.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Unlike prokaryotic cells, eukaryotic cells have membrane-enclosed structures like a nucleus and mitochondria.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/eukaryotic-vs-prokaryotic-cells-educational-royalty-free-illustration/1201105509">VectorMine/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Some scientists <a href="https://www.genome.gov/genetics-glossary/Virus">consider viruses</a> to be microbes made of genetic material enclosed in a protein coat. They are unable to replicate on their own and hijack the machinery of other cells to make copies of themselves. Because they don’t have many <a href="https://www.khanacademy.org/test-prep/mcat/cells/viruses/a/are-viruses-dead-or-alive">features of living cells</a>, they are <a href="https://microbiologysociety.org/publication/past-issues/what-is-life/article/are-viruses-alive-what-is-life.html">not technically alive</a>.</p>
<h2>Evidence for early life on Earth</h2>
<p>Fossils can provide scientists with clues as to when life started, but they best record hard things like bones and teeth. Microbes are made of soft materials that do not fossilize well. However, some live together in very large groups of cells that can accumulate minerals and leave behind quite large fossils. </p>
<p>For example, cyanobacteria formed large structures called <a href="https://theconversation.com/ancient-microbial-life-used-arsenic-to-thrive-in-a-world-without-oxygen-146533">stromatolites</a> in the oceans of early Earth. Scientists have found fossil stromatolites that date back to <a href="https://www.sciencedaily.com/releases/2022/11/221107135817.htm">3.48 billion years ago</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/510650/original/file-20230216-759-docyl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Stromatolites near a river" src="https://images.theconversation.com/files/510650/original/file-20230216-759-docyl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510650/original/file-20230216-759-docyl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510650/original/file-20230216-759-docyl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510650/original/file-20230216-759-docyl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510650/original/file-20230216-759-docyl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510650/original/file-20230216-759-docyl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510650/original/file-20230216-759-docyl.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">Stromatolites can provide information about life on early Earth.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/stromatolites-found-by-the-ottawa-river-rock-royalty-free-image/1176691303">Jana Kriz/Moment via Getty Images</a></span>
</figcaption>
</figure>
<p>Other scientists found what they believe are <a href="https://www.the-scientist.com/news-opinion/microbial-fossils-found-in-3-4-billion-year-old-subseafloor-rock-68975">fossilized archaea</a> in rocks from a 3.4 billion-year-old hot seafloor. The Earth became habitable about 4 billion years ago, so bacteria and archaea must have appeared between 3.5 billion and 4 billion years ago.</p>
<p>Looking at the chemical reactions that cells carry out can also provide clues. The reactions that make biological molecules and generate energy make up what’s called the cell’s metabolism. Scientists have found evidence that some metabolic reactions were occurring at least <a href="https://newsroom.ucla.edu/releases/life-on-earth-likely-started-at-least-4-1-billion-years-ago-much-earlier-than-scientists-had-thought">4.1 billion years ago</a>. These reactions may have been occurring on their own <a href="https://news.ncbs.res.in/research/unravelling-origin-life">before cells had evolved</a>, perhaps on the surfaces of <a href="https://doi.org/10.3390/life11080795">clays or minerals</a>.</p>
<h2>Theories about how life started on Earth</h2>
<p>Cells copy their genetic material, made of DNA and RNA, to pass it on to new generations. Although DNA is the form of genetic material most living organisms use today, some scientists believe that RNA was the <a href="https://news.ncbs.res.in/research/unravelling-origin-life">first information storage molecule</a> on early Earth because it can make copies of itself. </p>
<p>Because some modern viruses use RNA to store genetic information, some scientists believe that viruses could have <a href="https://doi.org/10.1016/j.biochi.2005.03.015">evolved from self-replicating RNAs</a>. This possibility would mean that viruses may have appeared before bacteria. But because viruses don’t leave fossils behind, there isn’t available evidence to support this idea.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VYQQD0KNOis?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The RNA-world hypothesis proposes that self-replicating RNA evolved before DNA or proteins.</span></figcaption>
</figure>
<p>At some point, metabolic reactions and replication processes had to come together inside a membrane to make an early form of a cell: a pre-cell. Perhaps this happened when a viruslike structure infected a collection of metabolic reactions enclosed within a membrane. The pre-cell could then duplicate itself, leading to the <a href="https://doi.org/10.1098/rstb.2002.1183">evolution of the first living cell</a>. This cell would have been like today’s bacteria and archaea.</p>
<p>Maybe viruslike structures did form before cells. However, those simple viruslike structures might have been just pieces of DNA or RNA, so could they really be considered “viruses”? </p>
<p>Another popular theory states that viruses evolved from degenerated bacteria or archaea that lost most of the genetic instructions for carrying out metabolism and forming cells. There are <a href="http://www.biologyaspoetry.com/textbooks/microbes_and_evolution/symbioses_serial_endosymbiosis.html">many examples</a> of similar smaller degenerations that have occurred in the bacterial world today.</p>
<h2>Uncovering early life</h2>
<p>The surface of the Earth today is very different from <a href="https://eos.org/science-updates/rethinking-the-search-for-the-origins-of-life">what it was 4 billion years ago</a>. Some have speculated that deep under the Earth’s surface, where it is too hot for modern life, these early conditions <a href="https://www.chemistryworld.com/features/hydrothermal-vents-and-the-origins-of-life/3007088.article">might still be present</a>, allowing some protolife forms to continue to exist where they are protected from being consumed by other microbes. </p>
<p>When people can explore other planets or moons, perhaps we will find processes similar to those that were at work on early Earth. This kind of discovery could help us solve the puzzle of life’s origin here.</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>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/197880/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kenneth Noll previously received funding from NSF, NASA, DOE and the Office of Naval Research. </span></em></p>Fossil evidence of how the earliest life on Earth came to be is hard to come by. But scientists have come up with a few theories based on the microbes, viruses and prions existing today.Kenneth Noll, Professor Emeritus of Microbiology, University of ConnecticutLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1988652023-02-01T19:11:19Z2023-02-01T19:11:19ZThe world’s oldest fossils or oily gunk? New research suggests these 3.5 billion-year-old rocks don’t contain signs of life<figure><img src="https://images.theconversation.com/files/507466/original/file-20230131-2321-pn02rf.jpg?ixlib=rb-1.1.0&rect=9%2C4%2C3310%2C2195&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Saul Shepstein</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The Pilbara region of Western Australia is home to one of the most ancient surviving pieces of Earth’s crust, which has been geologically unchanged since its creation some 3.5 billion years ago.</p>
<p>Some of the oldest signs of life have been found here, in the North Pole area west of the town of Marble Bar, in black rocks composed of fine-grained quartz called chert.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/507493/original/file-20230201-26-f6ge10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A piece of black rock with veins of other colours, next to an Australian two dollar coin for size comparison." src="https://images.theconversation.com/files/507493/original/file-20230201-26-f6ge10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/507493/original/file-20230201-26-f6ge10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=829&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507493/original/file-20230201-26-f6ge10.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=829&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507493/original/file-20230201-26-f6ge10.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=829&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507493/original/file-20230201-26-f6ge10.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1041&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507493/original/file-20230201-26-f6ge10.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1041&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507493/original/file-20230201-26-f6ge10.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1041&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Veins of black chert found in the Pilbara open a window onto Earth as it was 3.5 billion years ago.</span>
<span class="attribution"><span class="source">Birger Rasmussen</span></span>
</figcaption>
</figure>
<p>Some features in the so-called “Apex chert” have been identified as the fossilised remains of microbes much like the bacteria that still survive today. However, scientists have debated the true origin of these features ever since they were discovered 30 years ago.</p>
<p>In <a href="https://doi.org/10.1126/sciadv.add7925">new research published in Science Advances</a>, we show the carbon-rich compounds also found in the chert may have been produced by non-biological processes. This suggests the supposed “fossils” are not remnants of early lifeforms but rather artefacts of chemical and geological processes.</p>
<h2>Controversial Pilbara fossils</h2>
<p>In 1993, American palaeobiologist William Schopf spotted carbon-rich filaments in outcrops of the 3.45 billion year old Apex chert. He <a href="https://www.science.org/doi/10.1126/science.260.5108.640">interpreted</a> them as the charred remains of fossilised microbes similar to cyanobacteria, which were Earth’s first oxygen-producing organisms and are still abundant today.</p>
<p>The existence of fossilised cyanobacteria in such old rocks would imply that life was already pumping oxygen into the air more than a billion years before Earth’s atmosphere became rich in oxygen.</p>
<p>A key piece of evidence in favour of life was the association of organic compounds with the ancient fossils. This is because living cells are made up of large organic molecules, which comprise mainly carbon as well as hydrogen, nitrogen, oxygen and other elements.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/507482/original/file-20230201-19-qbpzqq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscope images showing biological-looking structures in rock." src="https://images.theconversation.com/files/507482/original/file-20230201-19-qbpzqq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/507482/original/file-20230201-19-qbpzqq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=890&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507482/original/file-20230201-19-qbpzqq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=890&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507482/original/file-20230201-19-qbpzqq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=890&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507482/original/file-20230201-19-qbpzqq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1118&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507482/original/file-20230201-19-qbpzqq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1118&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507482/original/file-20230201-19-qbpzqq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1118&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tiny structures like these, found in ancient black chert, have been interpreted as fossilised bacteria.</span>
<span class="attribution"><a class="source" href="https://www.pnas.org/doi/abs/10.1073/pnas.1405338111">Brasier et al.</a></span>
</figcaption>
</figure>
<p>In 2002, <a href="https://www.nature.com/articles/416076a">Schopf’s interpretation was challenged</a> by English palaeobiologist Martin Brasier and his team. They showed the “fossils” displayed a variety of shapes and sizes uncharacteristic of cyanobacteria, and indeed, inconsistent with microbial life. What’s more, they also showed the fossil-bearing black cherts were not horizontal beds deposited on the seafloor, but angled veins cutting across the underlying layers of rock.</p>
<p>The fossil-bearing cherts appeared to have formed at high temperatures during volcanic activity. Brasier argued this environment was hostile to life and the “fossils” were, in fact, formed from graphite impurities in the rock. They also speculated that the carbon associated with the “fossils” may not even be biological in origin.</p>
<p>A lively debate ensued, and it has continued ever since.</p>
<h2>Microbes or hot fluids?</h2>
<p>To try to determine where the carbon-rich deposits in the black chert veins came from, we took a very close look at them with a high-magnification electron microscope. </p>
<p>We found it did not come from fossilised bacteria. The oil-like substance occurs as residues in fractures and as petrified droplets, which have previously been mistaken for ancient fossils.</p>
<p>The textures in the black chert veins indicate they were formed when hot fluids rich in silica and carbon moved through cracks in lava flows below vents in the seafloor similar to modern “<a href="https://en.wikipedia.org/wiki/Hydrothermal_vent">black smoker</a>” vents. Upon approaching the seafloor, the hot fluids infiltrated layers of volcanic sediment, replacing it with black chert. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/507479/original/file-20230201-17-p846uv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An underwater photo showing smoke above glowing lava on the seafloor." src="https://images.theconversation.com/files/507479/original/file-20230201-17-p846uv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/507479/original/file-20230201-17-p846uv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=336&fit=crop&dpr=1 600w, https://images.theconversation.com/files/507479/original/file-20230201-17-p846uv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=336&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/507479/original/file-20230201-17-p846uv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=336&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/507479/original/file-20230201-17-p846uv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/507479/original/file-20230201-17-p846uv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/507479/original/file-20230201-17-p846uv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Black chert veins may have formed when water came into contact with lava at seafloor vents.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/noaaphotolib/5277255059/in/album-72157635360690997/">NOAA</a></span>
</figcaption>
</figure>
<p>If the carbon came from such a hot fluid, this supports findings that the carbon-rich filaments in the Apex chert are not fossils. However, it also raises a new question. </p>
<p>Typically, organic compounds such as oil and gas, which are referred to as “fossil fuels” because they form from the dead remains of algae, bacteria and plants, are generated when these remains are buried and heated to temperatures above 65°C. Chemical reactions release organic compounds, which may accumulate to form oil and gas fields. </p>
<p>However, the sediments from the North Pole area are very thin (less than 50m thick), poor in organic molecules, and sandwiched between kilometres of lava flows. So, how did the organic compounds form in such surroundings?</p>
<h2>Seafloor vents on early Earth</h2>
<p>A possible alternative pathway is suggested from experimental evidence and <a href="https://www.science.org/doi/10.1126/science.abg7905">research on Martian meteorites</a>. In the absence of traditional biological sources, some of the organic molecules in the chert veins could have formed by non-biological processes. </p>
<p>For instance, when hot water circulates through lava or other igneous rock, water and carbon dioxide can react with mineral surfaces to form organic compounds. Similar reactions have been proposed to explain the presence of organic molecules in Martian meteorites and in some igneous rocks on Earth.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-3-5-billion-year-old-pilbara-find-is-not-the-oldest-fossil-so-what-is-it-40482">A 3.5-billion year old Pilbara find is not the oldest fossil: so what is it?</a>
</strong>
</em>
</p>
<hr>
<p>The carbon in black cherts from the Pilbara outback may therefore represent relics of organic compounds that were produced by reactions between water and rock. Indeed, on the early Earth seafloor vents may have created more organic compounds than biological processes did, making it difficult to distinguish between authentic carbon-bearing fossils and oily artefacts.</p>
<p>While more work is underway, early results suggest life was only just surviving 3.5 billion years ago, struggling to gain a foothold in an inhospitable environment. The world then was wracked by regular volcanic eruptions that covered Earth’s surface in lava, and bathed in harsh solar radiation streaming through an atmosphere with no protective ozone layer.</p>
<p>Looking further back in time, the black cherts offer a glimpse of a lifeless planet. Reactions between water and rock at seafloor vents produced a cocktail of organic compounds, perhaps supplying the raw materials for the assembly of the first living cells.</p><img src="https://counter.theconversation.com/content/198865/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Birger Rasmussen receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Janet Muhling receives funding from the Australian Research Council. </span></em></p>Ancient rocks from Western Australia may not contain the world’s oldest fossils – but they do preserve organic compounds that may have formed the raw materials for the first living cells.Birger Rasmussen, Adjunct Professor, The University of Western AustraliaJanet Muhling, Adjunct Research Fellow, Earth Sciences, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1924922023-01-23T19:10:29Z2023-01-23T19:10:29ZThe food systems that will feed Mars are set to transform food on Earth<figure><img src="https://images.theconversation.com/files/504939/original/file-20230117-14-bdarwc.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2000%2C1425&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Growing food in space will rely on innovative agricultural technologies.</span> <span class="attribution"><a class="source" href="https://www.nasa.gov/feature/students-help-solve-space-farming-challenges">(NASA)</a></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/the-food-systems-that-will-feed-mars-are-set-to-transform-food-on-earth" width="100%" height="400"></iframe>
<p>Could we feed a city on Mars? This question is central to the future of space exploration and has serious repercussions on Earth too. To date, a lot of thought has gone into <a href="https://www.atlasobscura.com/articles/what-do-astronauts-eat">how astronauts eat</a>; <a href="https://www.nasa.gov/mission_pages/station/research/benefits/so-you-want-to-be-a-space-farmer">however, we are only beginning to produce food in space</a>.</p>
<p>Space launches <a href="https://www.nbcnews.com/science/space/space-launch-costs-growing-business-industry-rcna23488">are quite expensive</a>. And with the growing desire to establish a human presence in space, we are going to have to consider food production in space. But the challenges are vast, requiring research into how plants respond to a variety of changes including to <a href="https://modernfarmer.com/2022/02/cotton-in-space/">gravity</a> and <a href="https://agrilifetoday.tamu.edu/2022/12/20/exploring-the-impact-of-space-radiation-on-plants/">radiation</a>.</p>
<p>As food and agriculture researchers, we explored this question in our latest book, <a href="https://ecwpress.com/products/dinner-on-mars"><em>Dinner on Mars</em></a>. We believe that a sustainable Martian food system is possible — and that in building it, we’ll change food systems on Earth. However, this will take some out-of-the-box thinking.</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>Martian agriculture</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/502316/original/file-20221221-13-qemw5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Book cover image showing an astronaut holding a fork and the title DINNER ON MARS" src="https://images.theconversation.com/files/502316/original/file-20221221-13-qemw5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/502316/original/file-20221221-13-qemw5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=927&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502316/original/file-20221221-13-qemw5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=927&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502316/original/file-20221221-13-qemw5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=927&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502316/original/file-20221221-13-qemw5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1165&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502316/original/file-20221221-13-qemw5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1165&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502316/original/file-20221221-13-qemw5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1165&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">To explore Mars, we’ll need a sustainable Martian food system.</span>
<span class="attribution"><a class="source" href="https://ecwpress.com/products/dinner-on-mars">(ECW Press)</a></span>
</figcaption>
</figure>
<p>The basis of food systems on Mars would involve water harvested from the soil (<a href="https://news.asu.edu/20221219-nasas-curiosity-rover-discovers-waterrich-fracture-halos-gale-crater">rovers have shown that there are small but significant amounts of frozen water in the crust</a>) and <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/cyanobacteria">cyanobacteria, often referred to as blue-green algae</a>. </p>
<p>On earth, cyanobacteria can be a big problem as it grows in polluted waterways causing <a href="https://oceanservice.noaa.gov/facts/eutrophication.html">eutrophication — a nutrient-induced increase in phytoplankton productivity in the water body</a>. </p>
<p>On Mars, however, cyanobacteria can use the carbon dioxide in the atmosphere and grow on the sandy inorganic and toxic regolith — <a href="https://mars.nasa.gov/mars2020/mission/status/424/the-robotics-of-sampling-regolith/">the layer of loose rocks and dust covering bedrock</a> — to produce the basic organic molecules on which the rest of the food system will rest. </p>
<p>Cyanobacteria is capable of <a href="https://doi.org/10.3389/fmicb.2021.611798">growing in Martian conditions</a>, which has the very real added benefit of <a href="https://doi.org/10.1017/S1473550420000300">neutralizing extremely toxic chemicals called perchlorates</a>. Perchlorates are laced throughout <a href="https://www.space.com/21554-mars-toxic-perchlorate-chemicals.html">the Martian regolith and are toxic to humans in minute quantities</a>, so having cyanobacteria provide a double duty of neutralizing the toxins while producing organic material will be a huge boon to any Martian community.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/504788/original/file-20230116-16-u1cjp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="an illustration showing a toxic, arid, reddish landscape including a toxic waste symbol on the left, and a lush, fertile, green landscape on the right with a cross-section of healthy, bacteria-filled soil" src="https://images.theconversation.com/files/504788/original/file-20230116-16-u1cjp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504788/original/file-20230116-16-u1cjp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504788/original/file-20230116-16-u1cjp7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504788/original/file-20230116-16-u1cjp7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504788/original/file-20230116-16-u1cjp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=379&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504788/original/file-20230116-16-u1cjp7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=379&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504788/original/file-20230116-16-u1cjp7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=379&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cyanobacteria can help detoxify the environment on Mars.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/directorates/spacetech/niac/2017_Phase_I_Phase_II/Mars_Soil_Agriculture/">(NASA/Adam Arkin)</a></span>
</figcaption>
</figure>
<h2>Greenhouse technologies</h2>
<p>Once bacteria are happily growing away under a Martian sky, they will provide nutrients needed to support luxurious crops of plants. A Martian city could be imagined as a lush green place, with hydroponics and soil-bound crops filling tunnels, carpeting domed craters and growing away in every unused corner. </p>
<p>Advanced greenhouse technologies — <a href="https://www.sciencefocus.com/science/what-is-vertical-farming/">like vertical agriculture</a> — that create a <a href="https://www.forbes.com/sites/jordanstrickler/2020/08/28/high-tech-greenhouses-could-be-the-future-of-agriculture/">suitable controlled environment</a> will provide abundant leafy greens, vegetables, fruits and specialty crops such as herbs, coffee and chocolate.</p>
<p><a href="https://modernfarmer.com/2023/01/grain-farming-goes-indoors/">Carbohydrates might be in short supply, however, as they take up large amounts of space</a>. Our grain consumption is likely to be lower on Mars, though legumes and grains will still appear in Martian diets in smaller quantities reflecting what can economically be produced on site. </p>
<p><a href="https://www.digitaltrends.com/web/agriculture-on-mars/">All plants on Mars will also play key roles in oxygen generation, water recycling and the provision of raw organic material for manufacturing</a></p>
<p>These technologies are also valuable on Earth as we attempt to shorten supply chains and improve the availability of healthy fruit and vegetables in the winter months.</p>
<h2>Meat on Mars?</h2>
<p>Animal agriculture is <a href="https://doi.org/10.1126/science.aaq0216">notoriously inefficient</a>. On Earth, <a href="https://www.theguardian.com/environment/2018/may/31/avoiding-meat-and-dairy-is-single-biggest-way-to-reduce-your-impact-on-earth">billions of domestic animals</a> threaten natural biodiversity, contribute to climate change and suffer from needless animal cruelty.</p>
<p>Animal-based systems will not be viable on Mars, but protein could be abundantly produced through cellular agriculture and precision fermentation. <a href="https://www.forbes.com/sites/forbestechcouncil/2023/01/18/understanding-the-cellular-agriculture-industrys-impact-and-growth/?sh=6cc70d02696f">Precision fermentation</a> involves creating proteins by utilizing modified yeasts, fungus and bacteria that consume starches and sugars — on Mars, this will largely come from <a href="https://www.foodnavigator-usa.com/Article/2022/11/28/watch-next-gen-biomanufacturing-from-lower-cost-feedstocks-for-precision-fermentation-to-cell-free-approaches">food waste</a> — and turn them into desired proteins. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/kTu3X6yy3fQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Start-up companies are already making real dairy products without using cows.</span></figcaption>
</figure>
<p>Cellular agriculture <a href="https://www.bbc.com/future/article/20211116-how-the-food-industry-might-cut-its-carbon-emissions">involves taking stem cell samples and growing them in the lab to create cuts of meat identical to those from animal agriculture</a>.</p>
<h2>Reducing inefficiencies</h2>
<p>Imagining what agriculture could be like on Mars is a fascinating project, but it’s when we think about how these technologies may affect life on Earth that this topic becomes extremely serious. This is because on Mars — where each gram of organic matter, millilitre of water and photon of solar energy is scarce — there can be no inefficiencies.</p>
<p>The “waste” products of one part of the system need to be deliberately used as inputs into another part, such as using the dead cyanobacteria as a growth medium for later parts of the food system. But more than the technologies themselves, it may be the mindset of building a Martian food system that will change how things are done here on Earth, <a href="https://doi.org/10.1146/annurev-environ-101718-033228">where one-third of all food is thrown away</a>.</p>
<p>Our excitement about food technologies comes through in <em>Dinner on Mars</em>, but we are not techno-optimists. Technology isn’t a panacea. For example, if technologies like vertical farming reduce the need for farmland, then policies are required to ensure that the land will not just be paved over. </p>
<p>We also need to be mindful of the negative impacts of technologies, and be sensitive to how people’s livelihoods may need to change and adapt. Helping manage this transition and minimize disruption is another important area for policy. </p>
<p>The technologies unlocked by Mars, together with equitable policies, could place us on a much more sustainable trajectory on Earth.</p><img src="https://counter.theconversation.com/content/192492/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lenore Newman consults with a range of agritech companies and receives funding from Genome BC and SSHRC.</span></em></p><p class="fine-print"><em><span>Evan Fraser consults with a range of vertical farming companies and initiatives including the Weston Family Foundation's Home Grown Innovation Challenge and Cubic Farms. He receives funding from a range of governmental and philanthropic sources including the Canada First Research Excellence Fund, the Social Sciences and Humanities Research Council and the Arrell Family Foundation. He is affiliated with the Canadian Food Policy Advisory Council, Protein Industries Canada, Genome Quebec, and the Maple Leaf Centre for Action on Food Security.</span></em></p>Agricultural technologies to grow food on Mars can help address climate change, sustainability and food scarcity challenges.Lenore Newman, Director, Food and Agriculture Institute, University of The Fraser ValleyEvan Fraser, Director of the Arrell Food Institute and Professor in the Dept. of Geography, Environment and Geomatics, University of GuelphLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1734712021-12-20T16:48:54Z2021-12-20T16:48:54ZOur lakes are losing their ice cover faster than ever — here’s what that means for us<figure><img src="https://images.theconversation.com/files/438131/original/file-20211216-23-1c590ch.jpg?ixlib=rb-1.1.0&rect=0%2C14%2C2484%2C1632&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The decreasing ice cover in northern lakes will severely impact the lake ecology as well as winter recreation activities in the northern region.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 175px; border: none; position: relative; z-index: 1;" allowtransparency="" src="https://narrations.ad-auris.com/widget/the-conversation-canada/our-lakes-are-losing-their-ice-cover-faster-than-ever--—-here-s-what-that-means-for-us" width="100%" height="400"></iframe>
<p>Every winter when Lake Suwa in Japan freezes, locals believe that the Shinto male god Takeminakata crosses the frozen lake with his dragon to visit the female god Yasakatome. He leaves only his footsteps on the ice in the form of a <a href="https://www.nationalgeographic.com/science/article/ice-lake-suwa-japan-torne-river-climate-change-monk-shinto">sinusoidal ice ridge called the <em>omiwatari</em></a>.</p>
<p>In 1397, Shinto priests began celebrating and recording the appearance of the <em>omiwatari</em>. <a href="https://www.japantimes.co.jp/news/2019/12/16/national/nagano-lake-suwa-climate-change/">They used the direction of the cracks left by the <em>omiwatari</em></a> to forecast the agricultural harvest for the upcoming summer. In the first 250 years of the ice record, <a href="https://doi.org/10.1038/srep25061">Lake Suwa froze every year, except for three years</a> during which time the region saw widespread famine. Since the turn of the millennium, however, the lake has only frozen seven times.</p>
<p>Lake Suwa is one of many lakes in the Northern Hemisphere that is rapidly losing its ice cover. In our research, we found that <a href="https://doi.org/10.1029/2021JG006348">ice is forming later and melting earlier across these lakes, leaving a shorter period of seasonal ice cover</a>. In recent decades, many lakes are experiencing the shortest seasons of ice cover ever recorded. </p>
<p>If the ice cover in northern lakes continues to decline at the same pace, it will have severe ecological and cultural consequences.</p>
<figure class="align-center ">
<img alt="Melting ice chunks floating on Lake Sunapee, New Hampshire" src="https://images.theconversation.com/files/437596/original/file-20211214-13-8ci4fo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437596/original/file-20211214-13-8ci4fo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437596/original/file-20211214-13-8ci4fo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437596/original/file-20211214-13-8ci4fo.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437596/original/file-20211214-13-8ci4fo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437596/original/file-20211214-13-8ci4fo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437596/original/file-20211214-13-8ci4fo.jpeg?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">Lakes in the Northern Hemisphere are losing their ice cover faster than ever.</span>
<span class="attribution"><span class="source">(Midge Eliassen)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Lakes losing ice at rapid rates</h2>
<p>Ice duration was more than two weeks shorter per century, on average, since the Industrial Revolution, with lakes losing up to 34 per cent of their total ice cover. In the past 25 years, the <a href="https://www.washingtonpost.com/weather/2021/11/04/great-lakes-fastest-warming-study/">loss of ice escalated with lakes losing ice six times faster</a> than any other period in the past 100 years. </p>
<p>Around 15,000 lakes, including Lake Suwa and the North American Great Lakes — Lake Michigan and Lake Superior — are beginning to <a href="https://www.bbc.com/news/science-environment-47029482">remain ice-free in some winters</a>. Lakes situated at lower latitudes and in some coastal regions, where winter air temperatures hover around 0 C (the freshwater freezing point) in addition to large, deep lakes in colder regions, are most sensitive to experiencing ice-free winters. </p>
<p><a href="https://doi.org/10.1038/s41558-018-0393-5">Large, deep lakes</a>, such as the North American Great Lakes, require sustained cold temperatures to sufficiently cool their waters to allow ice to form, as deeper lakes take longer to cool in autumn due to their immense thermal mass. </p>
<p>Larger lakes with a longer fetch — the area over which the wind blows — also tend to freeze later because they are more sensitive to increased wind action breaking up the initial skim of ice on the lake surface.</p>
<h2>Why does ice loss matter?</h2>
<p>Lake Superior is one of the <a href="https://www.theweathernetwork.com/en/news/climate/impacts/lake-superior-is-one-of-the-fastest-warming-lakes-on-the-planet">fastest warming lakes</a> in the world. Since 1867, it has lost over two months of ice cover. By removing the “lid” of ice, evaporation rates can increase in Lake Superior, as well many other <a href="https://doi.org/10.1038/s41561-018-0114-8">lakes across the Northern Hemisphere</a>, further affecting water availability. As lakes transition to becoming ice-free and the physical barrier between the lake surface and the atmosphere is removed, the <a href="https://theconversation.com/extreme-heat-waves-are-putting-lakes-and-rivers-in-hot-water-this-summer-164227">potential for evaporation</a> to occur year-round increases. </p>
<p>Ice loss can also lead to year-round impacts on lake ecology. For example, an earlier ice break-up in the spring leads to a <a href="https://www.carbonbrief.org/climate-change-could-cause-irreversible-impacts-to-lake-ecosystems?">longer open-water season</a> and <a href="https://theconversation.com/extreme-heat-waves-are-putting-lakes-and-rivers-in-hot-water-this-summer-164227">warmer summer water temperatures</a>. </p>
<figure class="align-center ">
<img alt="A lake covered with a layer of green algae ." src="https://images.theconversation.com/files/438282/original/file-20211217-19-onqnhr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/438282/original/file-20211217-19-onqnhr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/438282/original/file-20211217-19-onqnhr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/438282/original/file-20211217-19-onqnhr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/438282/original/file-20211217-19-onqnhr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/438282/original/file-20211217-19-onqnhr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/438282/original/file-20211217-19-onqnhr.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">Reduced ice cover on northern lakes can contribute to summer blue-green algal blooms which cause the depletion of dissolved oxygen within the lake waters.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Less ice cover, warmer temperatures, and increased storm events deliver more nutrients to the lakes, leading to widespread summer <a href="https://www.greatlakesnow.org/2021/08/lake-superior-summer-algae-bloom/">blue-green algal blooms</a>, also known as cyanobacterial blooms, which were once thought to be implausible in the cold, deep and pristine waters of Lake Superior.</p>
<p>In some lakes, algal blooms are becoming particularly thick, decreasing the amount of sunlight that reaches deeper waters. With less sunlight, photosynthesis is reduced, ultimately leading to a decrease in the concentration of <a href="https://doi.org/10.1038/s41586-021-03550-y">dissolved oxygen</a> available to support aquatic life.</p>
<p>Some fish communities rely on long winters. For example, following short winters, <a href="https://doi.org/10.1038/ncomms8724">Lake Erie yellow perch</a> produced smaller eggs and weaker young fish that were less likely to survive to adulthood. Fish life stages most sensitive to temperature changes in the earlier part of the open-water season include <a href="https://doi.org/10.1007/s10584-020-02887-z">embryos and spawning adults</a>. Furthermore, an earlier start to summer (i.e., due to earlier ice loss) can cause mismatches in the timing of critical activities, such as spawning and foraging, often with widespread ramifications across the food web. </p>
<figure class="align-center ">
<img alt="A frozen lake in Finland" src="https://images.theconversation.com/files/437597/original/file-20211214-21-sjsdch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437597/original/file-20211214-21-sjsdch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437597/original/file-20211214-21-sjsdch.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437597/original/file-20211214-21-sjsdch.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437597/original/file-20211214-21-sjsdch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437597/original/file-20211214-21-sjsdch.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437597/original/file-20211214-21-sjsdch.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">Reducing greenhouse gases and slowing down climate change is the only way to save lake ice cover, and protect the local ecology and culture that depends on it.</span>
<span class="attribution"><span class="source">(Johanna Korhonen)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A future without lake ice</h2>
<p>As temperatures continue to warm globally due to anthropogenic climate change, <a href="https://doi.org/10.1038/s41558-018-0393-5">215,000 lakes may no longer freeze every winter</a> and almost 5,700 lakes may permanently lose ice cover by the end of the century. <a href="https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2020GL091108">Large and deep lakes, including Lakes Michigan and Superior, are most likely to permanently lose ice cover</a> as early as the 2060s if global air temperatures continue to rise. </p>
<p><a href="https://www.esa.int/Applications/Observing_the_Earth/Space_for_our_climate/Humans_to_blame_for_warming_lakes">Our research</a> has shown that the global decline of lake ice cover in recent decades can <a href="https://doi.org/10.1038/s41561-021-00833-x">only be explained</a> by increased greenhouse gas emissions since the Industrial Revolution. There is <a href="https://www.bbc.com/future/article/20211115-how-cities-are-going-carbon-neutral">no magic solution</a> beyond limiting greenhouse gas emissions to slow climate change and ultimately preserve lake ice cover. </p>
<p>For northern communities, ice cover provides a way of life in the winter. Countless Canadian kids have learned how to skate and play hockey at nearby lakes, local ponds, and backyard ice rinks, just as <a href="https://www.si.com/nhl/2019/04/22/climate-change-canada-winter-sports-hockey-backyard-rinks">hockey legend, Wayne Gretzky, did in Brantford, Ont</a>. Warmer winters are contributing to shorter outdoor <a href="https://www.nytimes.com/2018/03/20/climate/canada-outdoor-rinks.html">ice hockey</a> and <a href="https://www.nature.com/articles/nclimate2465">skating seasons</a>. </p>
<p>Ice fishing tournaments are increasingly cancelled, with widespread consequences for local economies. For example, the winter ice fishing season in Lake Winnipeg alone generates over <a href="https://mwf.mb.ca/archives/674">$200 million</a> each year. </p>
<p>The increasingly unpredictable and unstable ice cover is a safety hazard and is contributing to <a href="https://theconversation.com/winter-drownings-may-increase-in-northern-countries-as-ice-thins-with-climate-change-150029">increased fatal winter drownings</a> through ice in northern countries, with <a href="https://www.nytimes.com/2020/11/20/climate/thin-ice-winter-drowning.html">northern Indigenous communities at most risk</a>. </p>
<figure class="align-center ">
<img alt="The view of the ice cover and ice ridges on Lake Suwa, Japan, with the mountains in the background." src="https://images.theconversation.com/files/437594/original/file-20211214-19-xx6j1w.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/437594/original/file-20211214-19-xx6j1w.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/437594/original/file-20211214-19-xx6j1w.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/437594/original/file-20211214-19-xx6j1w.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/437594/original/file-20211214-19-xx6j1w.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/437594/original/file-20211214-19-xx6j1w.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/437594/original/file-20211214-19-xx6j1w.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 ice ridges on Lake Suwa form an integral part of the community’s spiritual traditions and culture.</span>
<span class="attribution"><span class="source">(Satoe Kasahara)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Finally, for the Shintos living in Suwa, protecting ice cover is essential to preserving the spiritual traditions maintained by generations of Shinto priests. At current rates of greenhouse gas emissions, climate projections predict that the lake will <a href="https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2020GL091108">rarely freeze in the very near future, and following 2040 will never freeze again</a>. </p>
<p>However, slowing climate change and limiting temperature increases below 1.5 C will allow Takeminakata to periodically cross the frozen lake to visit Yasakatome as he has done for centuries.</p><img src="https://counter.theconversation.com/content/173471/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sapna Sharma receives funding from NSERC, Ontario Ministry of Economic Development and Innovation, Ontario Ministry of Environment, Conservation and Parks, Genome Canada, and the York University Research Chair Program. She is affiliated with the Royal Canadian Institute for Science. </span></em></p><p class="fine-print"><em><span>David Richardson has received funding from National Science Foundation and New York State Water Resources Institute. </span></em></p><p class="fine-print"><em><span>Iestyn Woolway receives funding from the Natural Environment Research Council. </span></em></p>Lakes in the northern hemisphere are rapidly losing their ice cover due to rising greenhouse gas emissions. The only way to preserve lake ice is to limit GHG emissions and slow down climate change.Sapna Sharma, Associate Professor and York University Research Chair in Global Change Biology, York University, CanadaDavid Richardson, Professor, Department of Biology, State University of New York at New PaltzIestyn Woolway, Research Fellow in Climate Science, University of ReadingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1658662021-11-12T13:36:08Z2021-11-12T13:36:08ZNeurotoxins in the environment are damaging human brain health – and more frequent fires and floods may make the problem worse<figure><img src="https://images.theconversation.com/files/428985/original/file-20211028-23-ey0fbd.jpg?ixlib=rb-1.1.0&rect=242%2C177%2C3352%2C2204&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wildfire smoke contains a mixture of toxic pollutants that can be harmful to both the lungs and the brain. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/california-wildfires-royalty-free-image/1281624333?adppopup=true">Bloomberg Creative/ Bloomberg Creative Photos via Getty Images</a></span></figcaption></figure><p>In the summer of 2021, a toxic, smoky haze stemming from <a href="https://www.nbcnews.com/western-wildfires">Western wildfires</a> wafted across large parts of the United States, while hurricanes wrought extensive flooding in the southern and eastern U.S. Air quality websites such as <a href="https://www.airnow.gov">AirNow</a> warned of <a href="https://www.npr.org/2021/07/21/1018865569/the-western-wildfires-are-affecting-people-3-000-miles-away">hazardous conditions</a> on the U.S. East Coast from Western forest fires 3,000 miles away, with recommendations to stay indoors. </p>
<p>Journalists reported the immediate impact of lives lost and homes and property destroyed, but more insidious dangers escaped notice. Few people realize that these <a href="https://www.npr.org/2021/09/11/1035241392/climate-change-disasters-mental-health-anxiety-eco-grief">climate change-fueled</a> <a href="https://www.washingtonpost.com/world/interactive/2021/cop26-extreme-weather-climate-change-action/">disasters</a> – both fires and <a href="https://doi.org/10.1080/10807030903051309">floods</a> – could <a href="https://doi.org/10.1080/10962247.2017.1401017">adversely affect human health</a> in longer-term ways. </p>
<p>I’m a <a href="https://scholar.google.com/scholar?as_ylo=2017&q=Arnold+Eiser&hl=en&as_sdt=0,39">scientist-author</a> who studies the links between environmental factors and the development of neurological disorders, which is the <a href="https://rowman.com/ISBN/9781538158074/Preserving-Brain-Health-in-a-Toxic-Age-New-Insights-from-Neuroscience-Integrative-Medicine-and-Public-Health">subject of my recent book</a>. My <a href="https://doi.org/10.1016/j.brainres.2017.06.032">research on this topic</a> adds to a growing body of evidence that <a href="https://www.nytimes.com/2019/07/15/climate/flooding-chemicals-health-research.html">more frequent environmental disasters</a> may be raising <a href="https://doi.org/10.1007/s11356-015-4913-9">human exposure to neurotoxins</a>.</p>
<h2>Neurotoxic smoke</h2>
<p>Many scientists have identified links between <a href="https://doi.org/10.1016/j.bj.2018.06.001">air pollution</a> in various forms, including from <a href="https://theconversation.com/breathing-wildfire-smoke-can-affect-the-brain-and-sperm-as-well-as-the-lungs-166548">forest fire smoke</a>, and an increased risk and prevalence of adverse health effects, including brain disorders. </p>
<p>Wildfire smoke is a mixture of <a href="https://health.ny.gov/environmental/outdoors/air/smoke_from_fire">countless noxious chemical compounds</a>. Fires burning <a href="https://www.theguardian.com/world/2021/aug/09/fires-rage-around-the-world-where-are-the-worst-blazes%20and%20Australia">across the warming planet</a> – from California to Greece and Australia – are adding dangerous particulate matter to the atmosphere that includes <a href="https://doi.org/10.5772/intechopen.97204">neurotoxic heavy metals</a> such as mercury, lead, cadmium and manganese nanoparticles. <a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">These toxins</a> are an added environmental burden on top of the pollutants emitted by factories, power plants, trucks, automobiles and other sources. </p>
<p>The greatest potential for health problems comes from minuscule particles, smaller than 2.5 microns – or PM 2.5 (for context, the width of a human hair is typically 50 to 70 microns). This is, in part, because <a href="https://doi.org/10.1164/rccm.201903-0635LE">tiny particles are easily inhaled</a>; from the lungs, they enter the bloodstream and circulate widely throughout the body. <a href="https://doi.org/10.3389/fphys.2020.00155">In the brain</a> they may inflame the microglial cells, the brain’s defensive cells, causing harm to neurons instead of protecting them. Studies show that these extremely tiny particles may damage neurons or brain cells by <a href="https://doi.org/10.1016/j.tins.2009.05.009">promoting inflammation</a>. Brain inflammation can lead to conditions <a href="https://doi.org/10.3233/JAD-180631">like dementia</a> and <a href="https://doi.org/10.1097/JOM.0000000000000451">Parkinson’s disease</a>, a movement disorder in adults.</p>
<p>In addition, <a href="https://doi.org/10.1001/jamapediatrics.2018.3101">prenatal</a> and <a href="https://doi.org/10.1097/EDE.0000000000001109">early-life exposure</a> to air pollution has been linked to an increased risk of autism spectrum disorder in children. Research suggests that <a href="https://doi.org/10.1001/jamanetworkopen.2021.7508">air pollution exposure</a> during these critical periods, particularly in the third trimester of pregnancy and the first few months of life, <a href="https://doi.org/10.1515/tnsci-2016-0005">may impair normal neural development</a>. </p>
<h2>Waterborne neurotoxins</h2>
<p>As part of my book research, I investigated potential links between environmental neurotoxins and related health effects in Finland. Seeking unique environmental factors that might underlie the disproportionately high rates of fatal dementia that occurred in Finland in the past decade, I found that <a href="https://doi.org/10.1016/j.brainres.2017.06.032">water pollution</a> – exacerbated by flooding, use of fertilizer and higher water temperatures – may be affecting brain health. </p>
<p>As I reviewed the environmental concerns in Finland, the widespread presence of <a href="https://www.usgs.gov/centers/kswsc/science/cyanobacterial-blue-green-algal-blooms-tastes-odors-and-toxins-0?qt-science_center_objects=0#qt-science_center_objects">blue-green algae in waterways</a> stood out to me. Though it’s commonly called algae, blue-green algae is actually a type of bacteria called cyanobacteria. These toxic microorganisms thrive and proliferate in warm waterways when excessive nutrients, particularly phosphorus from fertilizer runoff, pour into fresh and brackish water. It produces <a href="https://www.epa.gov/cyanohabs/health-effects-cyanotoxins">cyanotoxins</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Blue-green algae bloom on surface of lake with trees in the distance." src="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=468&fit=crop&dpr=1 754w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=468&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/428983/original/file-20211028-23-lejb0a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=468&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Harmful blooms of blue-green algae on lakes and ponds can be toxic to humans and dogs alike.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sefton-park-lake-in-liverpool-which-has-been-closed-off-news-photo/1228294229?adppopup=true">Peter Byrne/PA Images via Getty Images</a></span>
</figcaption>
</figure>
<p>One of these cyanotoxins, β-methylamino-L-alanine, or BMAA, is linked to <a href="https://doi.org/10.3389/fnagi.2020.00026">neurodegenerative disorders</a> including amyotrophic lateral sclerosis, or ALS, Parkinson’s disease and Alzheimer’s disease.
In particular I was struck by scientists’ finding high levels of BMAA in <a href="https://doi.org/10.1073/pnas.0914417107">mollusks and fish found in the Baltic Sea</a>, which could potentially play a role in Finland’s high incidence of dementia, as fish is heavily consumed there.</p>
<p>Blue-green algae is found in <a href="https://www.cdc.gov/habs/index.html">rivers, lakes and seas</a>. Its presence is a widespread problem for humans, dogs and wildlife in the U.S. and Canada, as well as around the globe. In 2020, <a href="https://www.bbc.com/news/world-africa-54234396">more than 300 elephants in Botswana died</a> after drinking from water sources contaminated by the cyanobacteria that cause these algal blooms. Blue-green algae is so widely present in Finland that scientists there have developed <a href="https://www.utu.fi/en/news/news/novel-testing-device-will-reveal-whether-water-contains-toxic-blue-green-algae">a quick test to determine whether it is present or not.</a></p>
<h2>Mold neurotoxins</h2>
<p>In Finland, warm, humid air creates the perfect conditions for mold to grow, and water-damaged buildings are particularly susceptible. Some species emit mycotoxins, or mold toxins. Long-term exposure to mycotoxins, even at low levels, can present <a href="https://doi.org/10.1080/00039896.2003.11879142">serious health hazards</a> for both people and animals. </p>
<p>Mold spores are tiny, making them easy to inhale or ingest. Inside the body they can trigger an immune response, leading to chronic inflammation. Ultimately, exposure to these spores may cause <a href="https://doi.org/10.1016/j.shaw.2020.01.003">cognitive impairment</a>, including memory loss, irritability, numbness, tremors and other symptoms. Such a situation is likely to develop after a region has experienced the flooding of residences or workplaces in the weeks after they have been damaged.</p>
<p>Mold toxins, particularly <a href="https://doi.org/10.1002/mnfr.200600137">ochratoxin A</a>, can trigger inflammation that may harm neurons and brain function. It has been <a href="https://doi.org/10.1016/j.jns.2006.06.006">specifically implicated</a> in Parkinson’s disease. </p>
<h2>Reducing risk and a way forward</h2>
<p>Education, greater awareness of environmental health concerns and public action are the best ways to minimize risks from environmental neurotoxins.</p>
<p>By learning to recognize blue-green algae, people may avoid swimming or boating near it and avoid letting their pets near it too. Consumers can advocate for greater environmental monitoring of food and water sources. Exercise that involves sweating can <a href="https://doi.org/10.1155/2017/3676089">help eliminate neurotoxic substances</a>. But before you exercise outdoors, it is prudent to check air quality on an app or website like <a href="https://www.airnow.gov/">AirNow</a>, a partnership of federal, state, local and tribal agencies.</p>
<p>If environmental policies aren’t put into place to mitigate the health risks posed by environmental neurotoxins, <a href="https://doi.org/10.4172/2161-0460.1000249">research suggests</a> that we may continue to experience increases in a variety of neurodegenerative disorders as the toxins rise. Many of these conditions are labeled idiopathic, or lacking a known cause. The neurotoxic connection is rarely considered, and environmental health hazards are <a href="https://doi.org/10.1186/s12909-020-02458-x">often overlooked in American health care</a>. This is in large part because environmental health is rarely taught in medical education, which can lead to a lack of awareness about potential diagnoses related to an environmental illness.</p>
<p>The U.S. Environmental Protection Agency is currently <a href="https://www.epa.gov/system/files/documents/2021-10/draft-policy-assessment-for-the-reconsideration-of-the-pm-naaqs_october-2021_0.pdf">reevaluating</a> air quality standards for particulate matter. A new EPA <a href="https://www.epa.gov/system/files/documents/2021-09/_epaoig_20210929-21-e-0264.pdf">inspector general report</a> calls for a strategic plan to control harmful algal blooms. Ohio, a leading state for public policy initiatives aimed at neurotoxic algal blooms, <a href="https://grist.org/politics/toxic-algae-blooms-are-multiplying-the-government-has-no-plan-to-help">now regulates</a> cyanotoxins in drinking water and advises farmers against adding fertilizer when the ground is saturated or when rain is in the forecast. </p>
<p>Since <a href="https://doi.org/10.1038/s41586-019-1468-9">climate change may be a driver for rising neurotoxins</a>, cutting greenhouse gas emissions and ensuring better environmental stewardship are essential to human health. Achieving this will require strong international and domestic efforts and a wide range of interventions by governments around the world. But all of these efforts must begin with a deeper and more widespread understanding of the profound nature of this problem – which should be a universal, nonpartisan concern. </p>
<p>[<em>Over 115,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-newsletter-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p><img src="https://counter.theconversation.com/content/165866/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Arnold R. Eiser 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>Pollution from more frequent floods and wildfires – exacerbated by the warming climate – is threatening human health and poses particular risks to the brain.Arnold R. Eiser, Emeritus Professor of Medicine, Drexel UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1312992020-05-28T16:56:29Z2020-05-28T16:56:29ZSmart cars, smart cities, why not smart Great Lakes?<figure><img src="https://images.theconversation.com/files/338065/original/file-20200527-20237-1oog01l.jpg?ixlib=rb-1.1.0&rect=13%2C8%2C1479%2C1111&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Buoys and underwater probes can measure water quality, like this one outside of Cleveland, Ohio. </span> <span class="attribution"><span class="source">(Ed Verhamme, LimnoTech)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Smart home controllers, like Google’s Nest Hub, are changing how we manage our home environments. Self-driving cars promise to revolutionize the transportation sector. Smart, connected communities are popping up around the globe, integrating intelligent technologies between the natural and built environments. </p>
<p>Efforts to monitor our natural environment have followed suit. Increasingly, we rely on autonomous monitoring of air to inform us of allergens and pollutants that affect our health. Why not do the same for our waterways?</p>
<p>Human activities exacerbated by climate change have had huge impacts on Lake Erie and its watershed. Warm water temperatures, increased rainfall and fertilizer and manure run-off from agricultural fields fuel summer algal blooms that pose a danger to fish, wildlife and people while <a href="https://www.sciencedirect.com/science/article/pii/S1568988319300915">harming the economies of coastal communities</a>.</p>
<p>With autonomous sensors transmitting data in real time about the conditions of the shallowest of the Great Lakes, the <a href="https://doi.org/10.3389/fmars.2019.00731">Smart Lake Erie pilot project</a> will provide drinking water utilities with an early warning system for harmful algal blooms that can lead to public health crises. Eventually, this ambitious cross-border venture could lead to a <a href="https://www.glos.us/smartgreatlakes/">Smart Great Lakes initiative</a>. </p>
<h2>Innovation spurred by crisis</h2>
<p>As recently as 15 years ago, only a handful of sensors were deployed in Lake Erie. These measured weather and water quality data such as temperature, pH and dissolved oxygen. But the data were stored on the device itself and downloaded periodically between May and October, meaning that there was no way for the public, utilities or governments to react to potentially dangerous changes in the lake’s environmental conditions. </p>
<p>Scientists at the <a href="https://www.glerl.noaa.gov/">Great Lakes Environmental Research Laboratory</a>, part of the U.S. National Oceanographic and Atmospheric Administration (NOAA), advanced autonomous sensing with the rollout of the <a href="https://doi.org/10.1029/2007EO280001">Real-Time Coastal Observation Network (ReCON)</a> in 2005. ReCON-networked buoys deployed throughout the Great Lakes system provide real-time data about episodic events such as <a href="https://doi.org/10.4031/002533208786842471">incursions of low-oxygen water into municipal water intakes</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/337735/original/file-20200526-106828-nh5bjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/337735/original/file-20200526-106828-nh5bjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/337735/original/file-20200526-106828-nh5bjw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/337735/original/file-20200526-106828-nh5bjw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/337735/original/file-20200526-106828-nh5bjw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/337735/original/file-20200526-106828-nh5bjw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/337735/original/file-20200526-106828-nh5bjw.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">An algal bloom covers Lake Erie near the water intake crib for Toledo, Ohio, in August 2014.</span>
<span class="attribution"><span class="source">(AP Photo/Haraz N. Ghanbari)</span></span>
</figcaption>
</figure>
<p>A 2014 water crisis in Toledo, Ohio, spurred the next wave of innovation. In early August 2014, residents were warned not to drink or use their tap water due to a harmful algal bloom in Lake Erie, which left more than 400,000 residents without access to safe drinking water. </p>
<p>In response, a flotilla of more than 20 water quality sondes were deployed through Ohio waters. The instruments included sensors for phycocyanin, the pigment diagnostic of the toxin-producing cyanobacteria that was responsible for the water crisis. Many of the instruments are <a href="https://doi.org/10.1016/j.hal.2016.01.003">deployed near municipal water intakes</a>, providing water utilities with an early warning system for cyanobacterial harmful algal blooms. </p>
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<a href="https://theconversation.com/great-lakes-waters-at-risk-from-buried-contaminants-and-new-threats-128992">Great Lakes waters at risk from buried contaminants and new threats</a>
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<p>The <a href="http://habs.glos.us/map/">Great Lakes Observing System (GLOS)</a> has made moves to broaden the impact of these efforts by integrating instruments so that they provide real-time data to scientists, water utilities and the public. Some sensors now measure changes in nitrogen and phosphorus, which can stimulate harmful algal blooms, and water flows, which help scientists understand where these blooms may move. With its partners, GLOS is developing an early warning system that will even send a text message about water quality to your smartphone.</p>
<p>Events like <a href="https://eriehack.io/">Erie Hack</a> and the Internet of H2O have produced smart lake technologies, including an <a href="https://doi.org/10.1002/opfl.1050">automated nutrient monitor</a> that transmits data to <a href="https://www.h2ometrics.com/">H2Ometrics, a cloud-based data analytics platform</a>, and is currently being piloted in Sandusky Bay. </p>
<h2>Dead zones</h2>
<p>Environment and Climate Change Canada has maintained a handful of autonomous sensors in Lake Erie for several decades. Yet momentum in Canada recently amped up through the <a href="https://raeon.org/">Real-time Aquatic Ecosystem Observation Network (RAEON)</a>, an initiative led by the University of Windsor. </p>
<p>Last summer, RAEON rolled out a series of buoys near Pelee Island, on the Canadian side of the western end of Lake Erie. The sensors provide real-time data to the GLOS network on incursions of low-oxygen water (hypoxia) from the lake’s central basin.</p>
<p>Water containing two milligrams or less of dissolved oxygen per litre of water is considered hypoxic. Zones of hypoxia are considered degraded habitat for aquatic life and can result in poor water quality to consumers. </p>
<p>The data from RAEON sensors will be used to refine <a href="https://www.glerl.noaa.gov/res/HABs_and_Hypoxia/hypoxiaWarningSystem.html">predictive models of Lake Erie hypoxia</a> used by water utilities and fisheries.</p>
<p>In the future, the system might automatically respond when predetermined thresholds are exceeded. The data the sensor networks produce can also help with the development and assessment of environmental restoration. </p>
<h2>Ontario remains vulnerable</h2>
<p>The value of having such a network in place is now more apparent than ever as we deal with the wide-ranging implications of the <a href="https://www.nejm.org/doi/full/10.1056/nejmp2003762">COVID-19 pandemic</a>. While municipalities, along with federal, state and provincial agencies, continue to ensure the safety of our drinking water, <a href="https://www.greatlakesnow.org/2020/03/great-lakes-delay-research-coronavirus-covid-19/">environmental monitoring initiatives are on hold</a>. </p>
<p>For example, scientists typically begin surveillance programs in the Great Lakes and their connecting waterways as early as April. <a href="https://www.sciencedirect.com/science/article/pii/S0380133018302302">These samples help validate the satellite data</a> on the expanse of harmful algal blooms in western Lake Erie and Lake St. Clair. An array of autonomous instruments would offer continuous monitoring during times like now. </p>
<p>But realizing this vision of intelligent water management in Lake Erie and its watershed is expensive. The initiative is supported with <a href="https://doi.org/10.3389/fmars.2019.00731">US$2 million</a> as part of the NOAA Integrated Ocean Observing System Ocean Technology Transition program in the U.S. But there is no dedicated support for Great Lakes initiatives in Canada. </p>
<p>Canadians will benefit from the U.S. investment in lake-based sensors, but it doesn’t enhance the infrastructure that is critically needed in Canadian waters. Indeed, these gaps in coverage <a href="https://doi.org/10.3390/toxins10110430">leave water utilities in Ontario vulnerable to the toxins from harmful algal blooms</a>.</p><img src="https://counter.theconversation.com/content/131299/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Michael Lee McKay receives funding from the Natural Sciences and Engineering Research Council of Canada. </span></em></p><p class="fine-print"><em><span>George S Bullerjahn receives funding from the US National Science Foundation (award OCE-1840715) and the National Institutes of Environmental Health Sciences (project PO1ES028939-01). </span></em></p>A networked array of sensors could warn drinking water utilities in real time of harmful algal blooms and prevent public health crises.Robert Michael McKay, Executive Director and Professor, Great Lakes Institute for Environmental Research, University of WindsorGeorge S Bullerjahn, Distinguished Research Professor and Director, Great Lakes Center for Fresh Waters and Human Health, Bowling Green State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1312792020-03-23T12:01:42Z2020-03-23T12:01:42ZBuildings grown by bacteria – new research is finding ways to turn cells into mini-factories for materials<figure><img src="https://images.theconversation.com/files/321652/original/file-20200319-22590-j5lr20.png?ixlib=rb-1.1.0&rect=0%2C4%2C1495%2C833&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A block of sand particles held together by living cells.</span> <span class="attribution"><span class="source">The University of Colorado Boulder College of Engineering and Applied Science</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Buildings are not unlike a human body. They have bones and skin; they breathe. Electrified, they consume energy, regulate temperature and generate waste. Buildings are organisms – albeit inanimate ones.</p>
<p>But what if buildings – walls, roofs, floors, windows – were actually alive – grown, maintained and healed by living materials? Imagine architects using genetic tools that encode the architecture of a building right into the DNA of organisms, which then grow buildings that self-repair, interact with their inhabitants and adapt to the environment. </p>
<p>Living architecture is moving from the realm of science fiction into the laboratory as interdisciplinary teams of researchers turn living cells into microscopic factories. At the University of Colorado Boulder, I lead the <a href="https://spot.colorado.edu/%7Ewisr7047/">Living Materials Laboratory</a>. Together with collaborators in biochemistry, microbiology, materials science and structural engineering, we use <a href="https://www.genome.gov/about-genomics/policy-issues/Synthetic-Biology">synthetic biology</a> toolkits to engineer bacteria to create useful minerals and polymers and form them into living building blocks that could, one day, bring buildings to life. </p>
<p>In one study published in Scientific Reports, my colleagues and I <a href="https://doi.org/10.1038/s41598-019-51133-9">genetically programmed <em>E. coli</em> to create limestone particles</a> with different shapes, sizes, stiffnesses and toughness. In another study, we showed that <a href="https://doi.org/10.1016/j.ymben.2019.09.007"><em>E. coli</em> can be genetically programmed to produce styrene</a> – the chemical used to make polystyrene foam, commonly known as Styrofoam.</p>
<h2>Green cells for green building</h2>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/321957/original/file-20200320-22622-k9ydze.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/321957/original/file-20200320-22622-k9ydze.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=724&fit=crop&dpr=1 600w, https://images.theconversation.com/files/321957/original/file-20200320-22622-k9ydze.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=724&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/321957/original/file-20200320-22622-k9ydze.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=724&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/321957/original/file-20200320-22622-k9ydze.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=910&fit=crop&dpr=1 754w, https://images.theconversation.com/files/321957/original/file-20200320-22622-k9ydze.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=910&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/321957/original/file-20200320-22622-k9ydze.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=910&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Juliana Artier, a University of Colorado Boulder postdoctoral researcher, works with a flask of cyanobacteria that’s been genetically altered to produce building materials.</span>
<span class="attribution"><span class="source">The University of Colorado Boulder College of Engineering and Applied Science</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In our most recent work, published in Matter, we used photosynthetic cyanobacteria <a href="https://doi.org/10.1016/j.matt.2019.11.016">to help us grow a structural building material</a> – and we kept it alive. Similar to algae, cyanobacteria are green microorganisms found throughout the environment but best known for growing on the walls in your fish tank. Instead of emitting CO2, cyanobacteria use CO2 and sunlight to grow and, in the right conditions, create a biocement, which we used to help us bind sand particles together to make a living brick.</p>
<p>By keeping the cyanobacteria alive, we were able to manufacture building materials exponentially. We took one living brick, split it in half and grew two full bricks from the halves. The two full bricks grew into four, and four grew into eight. Instead of creating one brick at a time, we harnessed the exponential growth of bacteria to grow many bricks at once – demonstrating a brand new method of manufacturing materials.</p>
<p>Researchers have only scratched the surface of the potential of engineered living materials. Other organisms could impart other living functions to material building blocks. For example, different bacteria could produce materials that heal themselves, sense and respond to external stimuli like pressure and temperature, or even light up. If nature can do it, living materials can be engineered to do it, too.</p>
<p>It also take less energy to produce living buildings than standard ones. Making and transporting today’s building materials uses a lot of energy and emits a lot of CO2. For example, limestone is burned to make cement for concrete. Metals and sand are mined and melted to make steel and glass. The manufacture, transport and assembly of <a href="https://architecture2030.org/buildings_problem_why/">building materials account for 11% of global CO2 emissions</a>. <a href="https://reader.chathamhouse.org/making-concrete-change-innovation-low-carbon-cement-and-concrete#">Cement production alone accounts for 8%</a>. In contrast, some living materials, like our cyanobacteria bricks, could actually sequester CO2.</p>
<h2>A growing field</h2>
<p>Teams of researchers from around the world are demonstrating the power and potential of engineered living materials at many scales, including <a href="https://doi.org/10.1557/mrc.2019.27">electrically conductive biofilms</a>, <a href="https://doi.org/10.1073/pnas.1800869115">single-cell living catalysts</a> for polymerization reactions and <a href="https://doi.org/10.1002/admt.201900931">living photovoltaics</a>. Researchers have made <a href="https://doi.org/10.1002/adfm.201907401">living masks that sense and communicate exposure to toxic chemicals</a>. Researchers are also trying to <a href="https://doi.org/10.1021/acssynbio.8b00448">grow and assemble bulk materials</a> from a genetically programmed single cell.</p>
<p>While single cells are often smaller than a micron in size – one thousandth of a millimeter – advances in biotechnology and 3D printing enable commercial production of living materials at the human scale. <a href="https://ecovativedesign.com">Ecovative</a>, for example, grows foam-like materials using fungal mycelium. <a href="http://www.biomason.com">Biomason</a> produces biocemented blocks and ceramic tiles using microorganisms. Although these products are rendered lifeless at the end of the manufacturing process, researchers from Delft University of Technology have devised a way to <a href="https://doi.org/10.1021/acssynbio.7b00424">encapsulate and 3D-print living bacteria into multilayer structures</a> that could emit light when they encounter certain chemicals. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/321958/original/file-20200320-22610-ccgc1d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/321958/original/file-20200320-22610-ccgc1d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=341&fit=crop&dpr=1 600w, https://images.theconversation.com/files/321958/original/file-20200320-22610-ccgc1d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=341&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/321958/original/file-20200320-22610-ccgc1d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=341&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/321958/original/file-20200320-22610-ccgc1d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=428&fit=crop&dpr=1 754w, https://images.theconversation.com/files/321958/original/file-20200320-22610-ccgc1d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=428&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/321958/original/file-20200320-22610-ccgc1d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=428&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">Living building materials can be formed into many shapes, like this truss.</span>
<span class="attribution"><span class="source">The University of Colorado Boulder College of Engineering and Applied Science</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>The field of engineered living materials is in its infancy, and further research and development is needed to bridge the gap between laboratory research and commercial availability. Challenges include cost, testing, certification and scaling up production. Consumer acceptance is another issue. For example, the construction industry has a negative perception of living organisms. Think mold, mildew, spiders, ants and termites. We’re hoping to shift that perception. Researchers working on living materials also need to address concerns about safety and biocontamination. </p>
<p>The National Science Foundation recently named engineered living materials <a href="https://www.nsf.gov/news/news_summ.jsp?cntn_id=299946">one of the country’s key research priorities</a>. Synthetic biology and engineered living materials will play a critical role in tackling the challenges humans will face in the 2020s and beyond: climate change, disaster resilience, aging and overburdened infrastructure, and space exploration. </p>
<p>If humanity had a blank landscape, how would people build things? Knowing what scientists know now, I’m certain that we would not burn limestone to make cement, mine ore to make steel or melt sand to make glass. Instead, I believe we would turn to biology to help us build and blur the boundaries between our built environment and the living, natural world.</p>
<p>[<em>Get facts about coronavirus and the latest research.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=upper-coronavirus-facts">Sign up for our newsletter.</a>]</p><img src="https://counter.theconversation.com/content/131279/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wil Srubar receives funding from the US National Science Foundation, the US Department of Energy, and the US Department of Defense.</span></em></p>Researchers are turning microbes into microscopic construction crews by altering their DNA to make them produce building materials. The work could lead to more sustainable buildings.Wil Srubar, Assistant Professor of Architectural Engineering and Materials Science, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1266712019-11-12T19:02:47Z2019-11-12T19:02:47ZClimate explained: how growth in population and consumption drives planetary change<figure><img src="https://images.theconversation.com/files/301157/original/file-20191111-178525-ht8l9a.jpg?ixlib=rb-1.1.0&rect=98%2C117%2C4263%2C2785&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rapid population growth and increased consumption are now seen as the main drivers of environmental changes.</span> <span class="attribution"><span class="source">from www.shutterstock.com</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?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="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p><em><strong><a href="https://theconversation.com/nz/topics/climate-explained-74664">Climate Explained</a></strong> is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.</em> </p>
<p><em>If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz</em></p>
<blockquote>
<p><strong>The growth of the human population over the last 70 years has exploded from 2 billion to nearly 8 billion, with a compounding net growth of over 30,000 per day. We all breathe out carbon dioxide with every breath. That equates to about 140 billion CO₂ breaths every minute. Isn’t it logical that atmospheric carbon will continue to increase with the birth rate regardless of what we do about fossil fuel reduction?</strong></p>
</blockquote>
<p>This question touches on the core of our impact on planetary change. It highlights the exponential growth in the human population, but also homes in on the potential direct input of carbon dioxide from humans, through respiration. </p>
<p>As I explain in more detail below, our breathing does not contribute to the net accumulation of carbon dioxide in the atmosphere. But population growth, combined with an increase in consumption, is now seen as the <a href="https://www.stockholmresilience.org/research/research-news/2015-01-15-new-planetary-dashboard-shows-increasing-human-impact.html">main driver of change in the Earth system</a>. </p>
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Read more:
<a href="https://theconversation.com/climate-explained-why-your-backyard-lawn-doesnt-help-reduce-carbon-dioxide-in-the-atmosphere-122312">Climate explained: why your backyard lawn doesn't help reduce carbon dioxide in the atmosphere</a>
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<h2>Humans: a moment in geological time</h2>
<p>Earth has been around for 4.56 billion years. The <a href="https://www.livescience.com/1804-greatest-mysteries-life-arise-earth.html">earliest evidence for life on Earth</a> comes from fossilised mats of cyanobacteria that are about 3.7 billion years old. </p>
<p>From around 700 million years ago, and certainly from 540 million years ago, life exploded into its present myriad forms, from molluscs to lung fish, reptiles, insects, plants, fishes and mammals – culminating in hominids and finally <em>Homo sapiens</em>. Genetic studies suggest <a href="https://www.nature.com/scitable/knowledge/library/overview-of-hominin-evolution-89010983/">hominids evolved from primates around 6 million years ago</a>, with the oldest hominid fossil dating from 4.4 million years ago in East Africa. </p>
<p>Our species appeared around 200,000 to 300,000 years ago, a blink of an eye in geological terms. From Africa, <em>Homo sapiens</em> migrated through Europe and Asia and spread across the world, at lightning speeds. </p>
<p>Part of the question is about a putative link between human biological functions and climate. <em>Homo sapiens</em> is <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1001127">one of more than 28 million living species today</a>, and some <a href="https://link.springer.com/chapter/10.1007/978-94-011-5874-9_7">35 billion species that have ever lived on Earth</a>. There has always been a link between life and Earth’s atmosphere, and perhaps the clearest indicator is oxygen. </p>
<h2>Life, carbon and climate</h2>
<p>Cyanobacteria were the first organisms to master photosynthesis and <a href="https://www.pnas.org/content/96/20/10955">began adding oxygen to Earth’s early atmosphere</a>, producing levels of 2% by 1 billion years ago. Today oxygen levels are at 20%. </p>
<p>While people inhale oxygen and exhale carbon dioxide (billions of tonnes each year), this does <a href="https://slate.com/news-and-politics/2009/08/are-you-heating-the-planet-when-you-breathe.html">not represent new carbon in the atmosphere</a>, but rather recycled carbon that had been taken up by the animals and plants we eat. Furthermore, the hard parts of human skeletons are potential carbon stores, if buried sufficiently deep. </p>
<p>There is a constant cycling of carbon between geological, oceanographic and biological processes. <em>Homo sapiens</em> is part of this carbon cycle that plays out at the Earth’s surface. Like all living organisms, we derive the carbon we need from our immediate environment and give it up again through breathing, living and dying. </p>
<p>Carbon is only added to the atmosphere if it is taken out of long-term geological stores such as carbon-rich sediments, oil, natural gas and coal.</p>
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<strong>
Read more:
<a href="https://theconversation.com/climate-explained-why-carbon-dioxide-has-such-outsized-influence-on-earths-climate-123064">Climate explained: why carbon dioxide has such outsized influence on Earth's climate</a>
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<h2>Planetary impact of humans</h2>
<p>But the <a href="https://ourworldindata.org/world-population-growth">remarkable growth in human population</a> is surely the critical issue. Ten thousand years ago, there were 1 million people on Earth. By 1800, there were 1 billion, 3 billion by 1960 and almost 8 billion today.</p>
<p>When these figures are plotted on a graph, the growth line looks almost vertical from the 1800s onwards. <a href="https://www.pewresearch.org/fact-tank/2019/06/17/worlds-population-is-projected-to-nearly-stop-growing-by-the-end-of-the-century/">Population growth may eventually flatten out</a>, but only at around 10-11 billion. </p>
<p>Alongside the unprecedented population growth of humans has been the <a href="https://www.ipbes.net/news/million-threatened-species-thirteen-questions-answers">loss of many non-human species</a> (10,000 extinctions per million populations per year, or <a href="https://www.theguardian.com/environment/2018/oct/30/humanity-wiped-out-animals-since-1970-major-report-finds">60% of animal populations since 1970</a>), the rapid loss of wilderness habitat and consequent growth in farmed land, over-fishing (with up to <a href="http://blogs.edf.org/edfish/2012/07/11/fao-reports-87-of-the-worlds-fisheries-are-overexploited-or-fully-exploited/">87% of fisheries fully exploited</a>), and a staggering growth in global car numbers (from zero in the 1920s to 1 billion in 2013 and a projected <a href="https://www.weforum.org/agenda/2016/04/the-number-of-cars-worldwide-is-set-to-double-by-2040">2 billion by 2040</a>).</p>
<p>The <a href="https://www.usgs.gov/centers/nmic/copper-statistics-and-information">world production of copper</a> is an instructive proxy for human global impacts. As with many commodity curves, the trend from 1900, and particularly from the 1950s, is exponential. In 1900 around half-a-million tonnes of copper was produced worldwide. Today it is 18 million tonnes per year, with no sign of lowering consumption rates. Copper is the feedstock for much of modern-day and future green technologies. </p>
<p>Most parts of the world now experience material consumption as never before. But serious inequality remains, with over <a href="https://www.worldbank.org/en/news/press-release/2018/10/17/nearly-half-the-world-lives-on-less-than-550-a-day">3 billion living on less than US$5.50 a day</a>, and a <a href="https://www.oxfam.org/en/press-releases/just-8-men-own-same-wealth-half-world">tiny percentage who own so much</a>. </p>
<p>Some argue that it is not the numbers of people on Earth that count, but rather the way we consume and share. Whatever the politics and economics, the gross consumption level of billions of humans is, surely, the main cause of planetary change, especially since 1950. Present-day atmospheric levels of carbon dioxide are one of many symptoms of human impact.</p><img src="https://counter.theconversation.com/content/126671/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Petterson has received funding for research and international development programmes during his career.</span></em></p>Discussions about climate change often skirt around the issue of population growth, but it is the main driver of rising carbon dioxide levels and many other environmental changes on a planetary scale.Michael Petterson, Professor of Geology, Auckland University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/982822018-08-16T10:34:39Z2018-08-16T10:34:39ZBio-based plastics can reduce waste, but only if we invest in both making and getting rid of them<figure><img src="https://images.theconversation.com/files/230455/original/file-20180802-136652-h12bs5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Food packaging is one of the top uses for plastic in consumer goods.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/frozen-food-refrigerator-vegetables-on-freezer-522227719?src=Fy5Wf1UhghnB1lwZq4LqiQ-1-15">BravissimoS</a></span></figcaption></figure><p>With news that companies like Starbucks, Hyatt and Marriott have agreed to <a href="http://time.com/money/5333715/starbucks-hyatt-ban-plastic-straws/">ban plastic straws</a>, it’s a fitting time to consider the role of plastic in our daily lives. Plastics are an often overlooked modern wonder – cheap and multipurpose substances that can be fashioned into myriad products. </p>
<p>Drinking straws are just the literal tip of humanity’s plastic addiction. In 2016 global plastic resin production reached nearly <a href="https://www.plasticseurope.org/application/files/5715/1717/4180/Plastics_the_facts_2017_FINAL_for_website_one_page.pdf">335 million metric tons</a>. By some estimates, it could grow to approximately 650 million metric tons by 2020, roughly 100 times the <a href="https://www.livescience.com/18589-cost-build-great-pyramid-today.html">weight of the Pyramid of Giza</a>. </p>
<p><a href="https://prl.natsci.msu.edu/">Our lab</a> is one of a number of research teams looking for potential solutions to society’s plastic problems. We study a tiny photosynthetic bacteria, which we are using as a production platform to convert light and carbon dioxide into renewable compounds, including bioplastic alternatives. Bio-based plastics are a promising option for reducing plastic waste, but scaling them up will require substantial investments, both in making them and in special facilities for disposing of them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/230487/original/file-20180802-136652-1gue5os.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/230487/original/file-20180802-136652-1gue5os.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/230487/original/file-20180802-136652-1gue5os.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=390&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230487/original/file-20180802-136652-1gue5os.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=390&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230487/original/file-20180802-136652-1gue5os.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=390&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230487/original/file-20180802-136652-1gue5os.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=490&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230487/original/file-20180802-136652-1gue5os.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=490&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230487/original/file-20180802-136652-1gue5os.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=490&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Worldwide, only 14 percent of plastic packaging is recycled.</span>
<span class="attribution"><a class="source" href="https://www.ellenmacarthurfoundation.org/assets/downloads/Foundation_New-Plastics-Economy_5.jpg">Ellen MacArthur Foundation</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Long-lived waste</h2>
<p>Much of the world’s plastic output is manufactured into single-use objects, such as drinking straws. Indeed, food packaging and food-related objects, such as cups, carryout containers, shrink wrap and plastic bags, account for a large proportion of all plastics made. </p>
<p><a href="http://advances.sciencemag.org/content/3/7/e1700782.full">Less than 10 percent</a> of all waste plastic is recycled worldwide. Most plastic food packaging cannot be easily recycled if it has any food remnants stuck to it, because these residues can interfere with various stages of processing. As a result, many recycling plants will not accept food packaging.</p>
<p>What about other plastic waste? About 12 percent is incinerated, but nearly 80 percent ends up in landfills or the environment. In the ocean, currents aggregate plastic trash in large <a href="https://oceanservice.noaa.gov/podcast/mar18/nop14-ocean-garbage-patches.html">floating “islands” of garbage</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/oUKUP2s5_VY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A NASA simulation shows how ocean currents steer plastic waste into huge floating garbage patches.</span></figcaption>
</figure>
<p>Whether they are buried or floating at sea, plastics can take hundreds of years to break down. In the process they can wash up on shore, creating <a href="https://www.theguardian.com/environment/2017/may/15/38-million-pieces-of-plastic-waste-found-on-uninhabited-south-pacific-island">litter and tourism headaches</a>. Furthermore, large plastic objects, and even the microparticles they can wear down into, are <a href="https://theconversation.com/the-oceans-are-full-of-plastic-but-why-do-seabirds-eat-it-68110">harmful to a variety of wildlife, including seabirds</a>, <a href="https://news.nationalgeographic.com/2018/06/whale-dead-plastic-bags-thailand-animals/">marine life</a> and <a href="http://www.sciencemag.org/news/2018/01/plastic-trash-making-coral-reefs-sick">corals</a>. </p>
<h2>Plastic from plants</h2>
<p>A wide variety of bio-based plastics made from renewable biological compounds have been under study for many years. Today, many can serve as drop-in replacements for the fossil-fuel based plastics that most of us are familiar with, such as polystyrene and polyethylene. </p>
<p>Most bioplastics are currently made by taking sugars derived from plants, such as corn and sugarcane, and using microorganisms to convert them into raw materials that can be eventually formed into plastic resin. But there is a trade-off between making bioplastics biodegradable on the one hand and still durable enough for their purpose on the other. A straw and cup that disintegrate halfway through your road trip are not much use at all. </p>
<p>Many of the most promising bioplastics in production and in development can be rapidly degraded under controlled conditions, such as those in a <a href="https://www.pca.state.mn.us/waste/compost-facilities">large-scale composting facility</a>. Here, bioplastics may be intermingled with other organics and mixed regularly to ensure that there is adequate aeration to promote rapid decomposition. One such facility that is particularly engaged in testing and improving the degradation of bioplastics is <a href="https://cedar-grove.com/">Cedar Grove</a>, operated out of Washington state. The end result is a rich compost that is suitable for fertilizing gardens and crops.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/230667/original/file-20180805-41366-1rfz8xz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/230667/original/file-20180805-41366-1rfz8xz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/230667/original/file-20180805-41366-1rfz8xz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/230667/original/file-20180805-41366-1rfz8xz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/230667/original/file-20180805-41366-1rfz8xz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/230667/original/file-20180805-41366-1rfz8xz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/230667/original/file-20180805-41366-1rfz8xz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/230667/original/file-20180805-41366-1rfz8xz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">At Jepsen Prairie Organics in Vacaville, California, shredded organic waste is laid out in rows and covered to conserve heat as bacteria convert the materials into compost.</span>
<span class="attribution"><a class="source" href="https://sfenvironment.org/solution/what-happens-during-composting-and-why-do-we-do-it">San Francisco Department of the Environment</a></span>
</figcaption>
</figure>
<p>However, even bio-based plastics will still languish for decades or centuries if they are thrown in the trash and buried in landfills. Below the surface layer of a landfill, the conditions are often dry, cool and lacking in oxygen. All of these factors discourage the growth of microbes that can accelerate the breakdown of bioplastics. By contrast, compostable plastics are largely degraded within three months inside industrial compost facilities, where conditions are managed to promote aeration and temperatures are often substantially higher because of all of the microbial activity. </p>
<p>Similarly, it is unlikely that any developed materials will be biodegradeable under all environmental conditions. For example, they may not break down in the Arctic or at the bottom of the ocean. Conditions in such environments, such as low temperatures and oxygen levels and high pressure, can inhibit the growth of organisms that act to break the bonds within plastic polymers, leading to much slower rates of breakdown. </p>
<p>This means that any breakthroughs in materials science need to be coupled with sustainable methods for bioplastic production and a well-oiled system to direct bioplastic goods into composting facilities. </p>
<h2>Using microbes to make bioplastics</h2>
<p>Making plastic from plant sources is certainly more sustainable than fossil fuel-based approaches, but it requires land and fresh water to grow and process the feedstock materials. Our research lab is looking for ways to train photosynthetic microbes (cyanobacteria) that can naturally <a href="https://prl.natsci.msu.edu/news-events/news/better-together-a-bacteria-community-creates-biodegradable-plastic-with-sunlight/">harness the sun to make these same bioplastic compounds</a>. </p>
<p>In this process, these microbes perform the same role as plants, using sunlight and carbon dioxide to create sugars that can be converted to bioplastics. In fact, cyanobacteria are more efficient solar converters and don’t require soil or fresh water, so this approach could reduce competition for land and resources. </p>
<p>While it’s easy to malign the lowly plastic straw, it’s hard to come up with substitutes that are as cheap, lightweight and durable and are environmentally benign. I believe progress is possible, but only if scientists can collectively come up with bioplastic alternatives and social policies support the composting infrastructure to dispose of them suitably.</p><img src="https://counter.theconversation.com/content/98282/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Danny Ducat receives funding from the National Science Foundation and the US Department of Energy. </span></em></p>Bio-based plastics made from natural sources break down more easily than conventional plastic, without producing toxic byproducts. But for this to happen they have to be composted, not buried in landfills.Danny Ducat, Assistant Professor of Biochemistry and Molecular Biology, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/998182018-07-17T10:46:56Z2018-07-17T10:46:56ZPigments from microbes provide clue to evolution in ancient oceans – but weren’t pink a billion years ago<figure><img src="https://images.theconversation.com/files/227876/original/file-20180716-44076-p499t1.jpg?ixlib=rb-1.1.0&rect=308%2C242%2C1628%2C1153&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cyanobacteria filled the ancient oceans and used chlorophyll to harvest the sun's energy.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/28594931@N03/4726914132">Specious Reasons</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Possibly the most <a href="https://doi.org/10.1126/sciadv.1603076">significant event in the evolution of life</a> on Earth occurred 2.4 billion years ago. That was when the amount of oxygen in the atmosphere and ocean surface waters rapidly increased – setting the stage for a new phase of life on our planet.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/227886/original/file-20180716-44103-139nuoz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/227886/original/file-20180716-44103-139nuoz.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/227886/original/file-20180716-44103-139nuoz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1155&fit=crop&dpr=1 600w, https://images.theconversation.com/files/227886/original/file-20180716-44103-139nuoz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1155&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/227886/original/file-20180716-44103-139nuoz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1155&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/227886/original/file-20180716-44103-139nuoz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/227886/original/file-20180716-44103-139nuoz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/227886/original/file-20180716-44103-139nuoz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1451&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Most of the forms of life we’re familiar with are relatively recent additions to the planet.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:LifeTimeline-TemplateImage-20170116.png">Drbogdan</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Oxygen is produced by photosynthesis, a process that evolved in a type of bacteria <a href="http://www.ucmp.berkeley.edu/bacteria/cyanointro.html">called cyanobacteria</a>. Also known – incorrectly – as blue-green algae, you can encounter them today as pond scum.</p>
<p>Cyanobacteria are prokaryotes: simple single-celled organisms. <a href="http://www.ucmp.berkeley.edu/greenalgae/greenalgae.html">True algae</a> are eukaryotes: more complex, larger organisms. Both perform the same photosynthetic reactions to turn energy from the sun into oxygen and food molecules. The first true algae, as well as other single-celled eukaryotes, arose at least 1.4 billion years ago, but, mysteriously, appear to have remained in the background of life for another 800 million years, at which point they <a href="https://doi.org/10.1042/ETLS20180039">rapidly expanded in number and diversity</a>.</p>
<p><a href="https://doi.org/10.1073/pnas.1803866115">New research</a> by Australian National University earth scientists <a href="https://nationalmaglab.org/about/around-the-lab/meet-the-users/nur-gueneli">Nur Gueneli</a>, <a href="https://scholar.google.com/citations?user=oqL0DAUAAAAJ&hl=en&oi=ao">Jochen Brocks</a> and colleagues confirms the early importance of cyanobacteria in the primordial oceans and provides insights into why it took so long for the true algae to become the base of the food chain.</p>
<h2>Billion-year-old biomarkers</h2>
<p>Much of our knowledge of evolutionary history comes from the fossil record. Unfortunately, soft-bodied organisms, such as algae, rarely leave fossils. But researchers can recover the biomolecules they contained that are resistant to degradation. Found within ancient sediments, scientists can use these molecular fossils, <a href="http://summons.mit.edu/biomarkers/what-is-a-biomarker/">called biomarkers</a>, to identify what types of organisms were present when the sediments formed.</p>
<p>The new study published in the Proceedings of the National Academy of Science examined extracts of 1.1 billion-year-old sediments from 140 to 200 meters below the surface of a site in Mauritania. This corner in northwest Africa was once covered by an ocean. The researchers didn’t detect any biomarkers indicative of eukaryotes, but did find biomarkers indicating that several types of prokaryotes had been present. So no true algae, but plenty of evidence of photosynthetic bacteria. Of particular interest, they found molecules, <a href="http://physicsopenlab.org/2016/07/04/porphyrins-the-colors-of-life/">called porphyrins</a>, that are the remains of <a href="https://www.worldofmolecules.com/colors/chlorophyll.htm">chlorophyll</a>, the molecular basis of photosynthesis.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/227877/original/file-20180716-44070-1h0p9yy.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/227877/original/file-20180716-44070-1h0p9yy.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/227877/original/file-20180716-44070-1h0p9yy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=602&fit=crop&dpr=1 600w, https://images.theconversation.com/files/227877/original/file-20180716-44070-1h0p9yy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=602&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/227877/original/file-20180716-44070-1h0p9yy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=602&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/227877/original/file-20180716-44070-1h0p9yy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=756&fit=crop&dpr=1 754w, https://images.theconversation.com/files/227877/original/file-20180716-44070-1h0p9yy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=756&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/227877/original/file-20180716-44070-1h0p9yy.png?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">Chemical structure of a simple porphyrin ring. The porphyrin in chlorophyll has a magnesium atom in the middle.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Porphyrin.svg">Lukáš Mižoch</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Using a clever analysis, the scientists were able to identify with near certainty what organisms were the source of the porphyrins. <a href="https://www.webelements.com/nitrogen/isotopes.html">Nitrogen has two atomic forms, called isotopes</a>, the most common of which, ¹⁴N, has an atomic weight of 14 while the rare isotope, ¹⁵N, has an atomic weight of 15. Although ¹⁴N is preferred, the various enzymes that make chlorophyll also incorporate ¹⁵N in proportions that differ among different classes of photosynthetic organisms. So the ratio of ¹⁴N to ¹⁵N in porphyrin molecules, which have four nitrogen atoms, can indicate what type of organism produced them. By measuring the N-isotope ratios in the porphyrins from the sediments, the scientists were able to trace the molecules to the cyanobacteria.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/227854/original/file-20180716-44100-1435prr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/227854/original/file-20180716-44100-1435prr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/227854/original/file-20180716-44100-1435prr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/227854/original/file-20180716-44100-1435prr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/227854/original/file-20180716-44100-1435prr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/227854/original/file-20180716-44100-1435prr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/227854/original/file-20180716-44100-1435prr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/227854/original/file-20180716-44100-1435prr.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 vial of pink-colored porphyrins recovered from sediments that are more than a billion years old.</span>
<span class="attribution"><a class="source" href="http://dx.doi.org/10.1073/pnas.1803866115">The Australian National University</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Not pink, but green</h2>
<p>A dramatic picture in the Gueneli paper showed that some of the extracts of the ancient sediments were brilliant pink. News coverage ran with headlines focused on Earth’s “oldest color” being bright pink. But that’s not quite right.</p>
<p>In order to do its chemical job, the porphyrin in chlorophyll contains a magnesium atom that’s responsible for its green color. This is what makes leaves and algae look green. But in these pink extracts, the porphyrin turned out to have a nickel atom instead. Most likely the nickel replaced the magnesium sometime over the billion-plus years the molecules <a href="https://doi.org/10.1098/rstb.1991.0083">aged in the sediments</a>.</p>
<p>So pink was not the original color of the chlorophyll. It must have been green, as it is in living plants today.</p>
<h2>Algae take over from bacteria</h2>
<p>The researchers’ major conclusion is that 1.1 billion years ago, photosynthetic bacteria, most likely dominated by cyanobacteria, were the base of the food chain in the ocean. Because the bacteria were small, they would sink slowly and be degraded by other bacteria high in the water column. Little of the precious nutrients they contained would reach the ocean bottom.</p>
<p>Nutrient distribution throughout an ocean depends upon <a href="https://oceanservice.noaa.gov/facts/upwelling.html">upwelling from the bottom</a>. So most of the ocean would be nutrient-poor, restricting the development of a community of larger organisms.</p>
<p>In addition, cyanobacteria survive better than eukaryotic algae when nutrients are low, which would further <a href="https://doi.org/10.1042/ETLS20180039">restrict the evolution of these larger-celled photosynthetic organisms</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/227906/original/file-20180716-44070-1fmw20b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/227906/original/file-20180716-44070-1fmw20b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/227906/original/file-20180716-44070-1fmw20b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/227906/original/file-20180716-44070-1fmw20b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/227906/original/file-20180716-44070-1fmw20b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/227906/original/file-20180716-44070-1fmw20b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/227906/original/file-20180716-44070-1fmw20b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/227906/original/file-20180716-44070-1fmw20b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">True algae have larger and more complex cells than the cyanobacteria they took over from.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/noaaphotolib/9787178153">NOAA MESA Project</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>What caused the shift about 650 million years ago from an ocean dominated by cyanobacteria to one dominated by true algae? One of the authors of the PNAS paper, geobiologist Jochen Brocks, points out in a recent review article that this shift occurred a mere <a href="https://doi.org/10.1042/ETLS20180039">4 million years after the end of a worldwide glaciation</a>, during which the oceans were frozen for more than 50 million years. Then the glaciers melted, probably because rising carbon dioxide levels created a greenhouse effect, heating the Earth. The temperature of the oceans rose rapidly, possibly killing many remaining cyanobacteria. In addition, as the glaciers melted, vast amounts of nutrients would have been swept into the oceans, reversing the competitive disadvantage for the algae, that then were able to evolve and expand.</p>
<p>With the arrival of these larger, rapidly-settling algae as the basis of the food chain, the stage was set for the evolution and expansion of larger eukaryotic consumers.</p><img src="https://counter.theconversation.com/content/99818/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patricia L. Foster receives funding from the US Army Research Office. She is a member of the American Association for the Advancement of Science, Union of Concerned Scientists and Concerned Scientists at IU.</span></em></p>Did you recently hear news that Earth’s oldest pigments were hot pink? That’s not quite right. When they were in living bacteria a billion years ago, they were performing photosynthesis – and green.Patricia L. Foster, Professor Emerita of Biology, Indiana UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/979982018-06-11T10:09:57Z2018-06-11T10:09:57ZThe hunt for life on Mars: new findings on rock ‘chimneys’ could hold key to success<p>The search for life on Mars has taken a step forward with the NASA Curiosity rover’s <a href="http://science.sciencemag.org/content/360/6393/1096">discovery</a> of organic matter on the bottom of what was once a lake. <a href="https://theconversation.com/rover-detects-ancient-organic-material-on-mars-and-it-could-be-trace-of-past-life-97755">It may once</a> have been part of an alien life form or it might have a non-biological origin – either way this carbon would have provided a food source for any organic living thing in the vicinity. </p>
<p>The discovery adds extra intrigue to NASA’s search for extra-terrestrial life forms themselves. When hunting remotely with one car-sized machine, the question is where best to focus your efforts. It makes sense to look for the same types of places we expect to find fossilised microorganisms on Earth. This is complicated by the fact that these fossils are measured in microns – mere millionths of a metre. </p>
<p>The Curiosity rover looks for certain sedimentary rocks deposited near water, as it did for the latest discovery. This is based on the latest geological advice about the best prospects. Yet which rocks to prioritise is still a matter of some debate – and it’s a question that is just as relevant to geologists trying to unlock the secrets of our own ancient world. The Earth’s rocks and fossils are the nearest thing we have to time machines. </p>
<p>For a century or so, geologists focused on a type of rock called a stromatolite – devoting long hours to crawling around in awkward spaces trying to find them. Stromatolites occur mainly in shallow water and are layered on a millimetre scale. Many of them are undoubtedly built by slimy microbial “biofilms”, but to cut a long story short we now appreciate there is more than one way to make a stripy rock – and they don’t all involve microbes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/221981/original/file-20180606-137306-1vsbzhq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/221981/original/file-20180606-137306-1vsbzhq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/221981/original/file-20180606-137306-1vsbzhq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/221981/original/file-20180606-137306-1vsbzhq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/221981/original/file-20180606-137306-1vsbzhq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/221981/original/file-20180606-137306-1vsbzhq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/221981/original/file-20180606-137306-1vsbzhq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/221981/original/file-20180606-137306-1vsbzhq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=527&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Stromatolite city.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/31856336@N03/6188521133">Mike Beauregard</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>More recently geologists have become more interested in other types of rocks, including the “<a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/black-smoker">black smoker</a>” tube-type deposits formed by hot hydrothermal water being squeezed out of the Earth’s crust in the deep sea. Slightly easier to examine are similar chimney-like formations found in certain alkaline lakes around the world. </p>
<h2>Mono Lake</h2>
<p>One place on Earth where these chimneys occur is Mono Lake in California, a vast and beautiful stretch of water several hundred miles north of Los Angeles on the eastern slope of the Sierra Nevada mountains. In October 2014, our team obtained permission from the California State Parks to examine and sample some of the calcium carbonate chimneys that have formed there.</p>
<p>The rocks, which are frequently between two and three metres tall, are very young in geological terms, usually only tens of thousands of years old. But since first being <a href="https://books.google.co.uk/books/about/Quaternary_History_of_Mono_Valley_Califo.html?id=AE7nAAAAMAAJ&redir_esc=y">described</a> by the famous American geologist Israel Russell in 1889 they have proven an excellent natural laboratory for groups of scientists trying to understand how these structures came about. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/221985/original/file-20180606-137295-11ddjcf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/221985/original/file-20180606-137295-11ddjcf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/221985/original/file-20180606-137295-11ddjcf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/221985/original/file-20180606-137295-11ddjcf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/221985/original/file-20180606-137295-11ddjcf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/221985/original/file-20180606-137295-11ddjcf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/221985/original/file-20180606-137295-11ddjcf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/221985/original/file-20180606-137295-11ddjcf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Exploration begins.</span>
<span class="attribution"><span class="source">Alexander Brasier</span></span>
</figcaption>
</figure>
<p>Before our visit, geologists were essentially divided about these chimneys. A group we might call “pure geochemists” <a href="https://www.sciencedirect.com/science/article/pii/001670379390339X">proposed</a> they were nothing to do with microbes, but produced by calcium-rich spring waters coming into contact with the alkaline lake, with its abundance of carbonate ions. </p>
<p>A smaller opposing camp <a href="http://archives.datapages.com/data/sepm/journals/v33-37/data/034/034002/0309.htm">agreed</a> it should be possible for these structures to emerge in the way that pure geochemists were suggesting. But they pointed out that, in the few recorded observations of carbonate rocks forming at the lake in the 19th and 20th centuries, some kind of biofilm did appear to have an influence. They also cited other studies that had shown that waterborne microbes called cyanobacteria did produce slimy substances that can accumulate calcium. </p>
<p>We went to Mono Lake to find out who was right. Our six-strong expedition divided into two factions: one looked for chimneys on the lake bottom using a research boat, while the other explored the famous “tufa towers” that rise up from the lake shore. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/221983/original/file-20180606-137309-1mr6wj3.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/221983/original/file-20180606-137309-1mr6wj3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/221983/original/file-20180606-137309-1mr6wj3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/221983/original/file-20180606-137309-1mr6wj3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/221983/original/file-20180606-137309-1mr6wj3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/221983/original/file-20180606-137309-1mr6wj3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/221983/original/file-20180606-137309-1mr6wj3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/221983/original/file-20180606-137309-1mr6wj3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&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">Tufa towers on the shoreline.</span>
<span class="attribution"><span class="source">Alexander Brasier</span></span>
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<p>The boat party toiled and cursed the astonishingly salty waters of the lake, while the shore party made steady progress with the invaluable assistance of local state park ranger, Dave Marquart. Their peace was interrupted only by a phone call from the stranded boaters requesting they urgently try to find someone with a four-wheel drive capable of pulling the boat back out of the water – luckily help was at hand. </p>
<p>One of the sites the shore party visited was in Marquart’s own back garden to the north-west of the lake. The rocks there were part of a set of ancient chimneys formed along a small tectonic fault. Their features suggested they had been built by microbes, but we needed to send them to a lab to be sure. </p>
<h2>Microbial ‘threads’</h2>
<p>Using an optical microscope, we were able to see dark thread-like structures entombed in slices of the rock. As we outline in our <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gbi.12292">new study</a> published in Geobiology, these “threads” are millions of fossilised photosynthesising cyanobacteria that once surrounded waters rising from a spring on the lake floor. </p>
<p>We sent the samples to Australia for further testing to establish whether the microbes played a key role in building the chimneys. This revealed surrounding patches of carbon and nitrogen, which we took to be fossilised cyanobacterial slime. This slime traps calcium and when it breaks down it creates calcium carbonate, entombing any living and dead cells in rock. </p>
<p>We found other ways in which this microbial slime had affected the fabric of the rock: grains of quartz and aluminosilicates that were clearly sand that had got stuck there, too. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/221982/original/file-20180606-137315-1fu6owr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/221982/original/file-20180606-137315-1fu6owr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/221982/original/file-20180606-137315-1fu6owr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/221982/original/file-20180606-137315-1fu6owr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/221982/original/file-20180606-137315-1fu6owr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/221982/original/file-20180606-137315-1fu6owr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/221982/original/file-20180606-137315-1fu6owr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/221982/original/file-20180606-137315-1fu6owr.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">Thread-like filaments in the Mono Lake rock.</span>
<span class="attribution"><span class="source">Alexander Brasier</span></span>
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<p>In short, we found evidence that cyanobacteria formed tubular mats around rising spring water in the ancient Mono Lake – probably producing the majority of the resulting chimneys there, though there may be examples of “pure geochemistry” chimneys as well. This suggests that these rock formations do indeed represent a promising and fairly large target for exploring ancient or extra-terrestrial life. </p>
<p>They have the added advantage that the calcite rocks in question are geologically quite stable. This means the fossils could potentially be preserved for a very long time – easily hundreds of millions, quite plausibly billions of years. </p>
<p>To our knowledge no chimneys have been found on Mars yet, but they are not common on Earth and there is every chance that they have a Martian equivalent. There, and on other planets and moons, we should be looking for areas with conditions as similar as possible to where these chimneys exist on Earth – volcanic rocks where spring waters might once have risen through the bedrock into an alkaline lake. Without any question, NASA’s hunt for suitable rocks on the red planet should make finding them a high priority.</p><img src="https://counter.theconversation.com/content/97998/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors 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>Following NASA’s latest discovery of organic matter on the red planet, new findings in a salt lake in California could point to where to look for alien life.Alexander Brasier, Lecturer in Geology, University of AberdeenDavid Wacey, Australian Research Council Future Fellow, The University of Western AustraliaMike Rogerson, Senior Lecturer in Earth System Science, University of HullLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/956462018-05-06T20:14:26Z2018-05-06T20:14:26ZToxin linked to motor neuron disease found in Australian algal blooms<figure><img src="https://images.theconversation.com/files/217445/original/file-20180503-153873-1srnuq3.jpg?ixlib=rb-1.1.0&rect=44%2C0%2C5000%2C3323&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cyanobacterial blooms and algae are common in water bodies around the world. However, Australia is yet to monitor the growth of neurotoxins in our algae.</span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>Algal blooms in major Australian rivers are releasing a toxic chemical that may contribute to the development of motor neuron disease (MND).</p>
<p>My colleagues and I <a href="https://www.sciencedirect.com/science/article/pii/S1568988318300313">tested</a> algae from waterways in New South Wales, and found that a neurotoxin called BMAA was present in 70% of samples, including those from crucial water sources such as the Darling and Murrumbidgee rivers. </p>
<p>This compound is well known overseas, and has been found in waterways in the United States, Europe, Asia, and the Middle East. But this is the first time it has been detected in Australia. Although its presence has been suspected, it was never specifically tested until now.</p>
<p>Two samples containing BMAA were collected from the Murrumbidgee River, which runs through the NSW Riverina, a hotspot for MND in Australia. Positive samples were also collected in Centennial Park and Botany wetlands in central Sydney, as well as Manly Dam on Sydney’s Northern Beaches. </p>
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Read more:
<a href="https://theconversation.com/what-we-know-dont-know-and-suspect-about-what-causes-motor-neuron-disease-79409">What we know, don’t know and suspect about what causes motor neuron disease</a>
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<p>In the past 30 years, Australian rivers have had the dubious honour of hosting some of the largest algal blooms in history. In 1991 a bloom stretched along more than 1,200km of the Darling River, prompting the New South Wales government to declare a <a href="http://riverstories.mdba.gov.au/heartbreak/article/blue-green-algae-outbreak-on-the-darling-river,-1991%E2%80%931992">state of emergency</a>. The army was mobilised to provide aid to towns.</p>
<p>Since then, southeast Australia has had four large blooms, <a href="https://theconversation.com/are-toxic-algal-blooms-the-new-normal-for-australias-major-rivers-59526">most recently in 2016</a>. The future isn’t promising either. Rising water temperatures mean blooms are likely to <a href="https://www.epa.gov/nutrientpollution/climate-change-and-harmful-algal-blooms">increase in frequency</a> and duration in the future. </p>
<p>Multiple state agencies monitor populations of types of bacteria in Australia, regularly testing water quality and issuing alerts when blooms are present. This testing is necessary because of the impressive number of toxins that cyanobacteria can produce, ranging from skin irritants to liver and neurological toxins. Most of these compounds are relatively fast-acting, meaning that their effects take hold rapidly after exposure. </p>
<p>The neurotoxic compound BMAA, however, is not currently part of regular testing, despite links between <a href="https://www.scientificamerican.com/article/are-algae-blooms-linked-to-lou-gehrig-s-disease/">long-term</a> exposure to algal blooms and the <a href="https://theconversation.com/exposure-to-algae-toxin-increases-the-risk-of-alzheimers-like-illnesses-52981">development of diseases such as MND</a>. BMAA is known to be produced by a type of freshwater and marine bacteria, as well as some species of algae. </p>
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Read more:
<a href="https://theconversation.com/watch-out-australia-a-red-hot-summer-means-blue-green-algae-49585">Watch out, Australia: a red-hot summer means blue-green algae</a>
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<h2>How BMAA affects our health</h2>
<p>Research in America found that regular participation in water-based recreational activity resulted in a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5383428/">threefold increase</a> in the risk of developing MND. Satellite mapping also revealed that lakes prone to algal blooms were often <a href="https://www.dartmouth-hitchcock.org/stories/article/50429">surrounded by clusters</a> of MND patients.</p>
<p>Southwestern NSW has <a href="https://www.theaustralian.com.au/news/health-science/algal-bloom-linked-to-motor-neurone-disease/news-story/2e8d55deede2d7f2cfc116556da3ad56">become a focus for MND researchers</a> since 2014, due to the presence of a hotspot for MND cases around the Riverina. The town of Griffith has reported a prevalence of this disease that is nearly seven times higher than the <a href="http://www.mndaust.asn.au/Influencing-policy/Economic-analysis-of-MND-(1)/Economic-analysis-of-MND-in-Australia.aspx">national average of 8.7 cases per 100,000 people</a>. Hotspots like these can help researchers identify environmental factors that contribute to diseases. </p>
<p>This is particularly important in MND, in which only 5-10% of patients have a family history. The other 90-95% of cases are sporadic, occurring without warning. It is possible that BMAA exposure, in association with genetic, or other environmental risk factors, contributes to the high incidence of MND in the Riverina.</p>
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Read more:
<a href="https://theconversation.com/exposure-to-algae-toxin-increases-the-risk-of-alzheimers-like-illnesses-52981">Exposure to algae toxin increases the risk of Alzheimer's-like illnesses</a>
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<p>BMAA also has a similar structure to the amino acids that make up the proteins in our body. We hypothesise that this <a href="https://theconversation.com/toxic-load-blue-green-algaes-role-in-motor-neuron-disease-16041">contributes to its toxicity</a> and ability to build up in animal tissue and in plants that are exposed to contaminated water. </p>
<p>Similar to mercury, BMAA can accumulate in the food chain, which means that people could be consuming relatively large amounts of it through their diet. A <a href="https://theconversation.com/exposure-to-algae-toxin-increases-the-risk-of-alzheimers-like-illnesses-52981">US animal study</a> found that dietary exposure to BMAA resulted in the formation of plaques and protein tangles in the brain, which are hallmark features of neurodegeneration.</p>
<p>Research now needs to focus on tracking and monitoring algal blooms to detect the presence of BMAA, and determining how long it remains in the ecosystem after these blooms occur. </p>
<p>This can potentially help to reduce human exposure to BMAA. Although the factors that cause MND are many and varied, we hope this understanding could ultimately help to reduce the number of people who develop the disease.</p><img src="https://counter.theconversation.com/content/95646/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brendan Main receives funding from The Motor Neurone Disease Research Institute of Australia and the Australian Government Research Training Program. </span></em></p>A toxic chemical produced by algae and linked to motor neuron disease has been detected in NSW rivers. Its presence - long suspected but now confirmed - could be linked to a disease hotspot in the Riverina.Brendan Main, PhD Candidate, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/638182016-08-11T07:19:53Z2016-08-11T07:19:53ZGoing for … green? Why Rio’s swimming pools are changing colour<p>On Monday, the diving pool at the Rio Olympics was fine. By Tuesday, it had <a href="http://www.smh.com.au/sport/olympics/rio-2016/diving-pool-turns-green-for-synchronised-final-at-rio-olympics-20160809-gqov5i.html">turned green</a>. Now, the water polo pool is <a href="http://www.smh.com.au/sport/olympics/rio-2016/olympics-swimming/australians-left-with-stinging-eyes-after-another-%20rio-olympics-pool-turns-green-20160810-gqpqgr.html">showing a distinctly green tone</a>. </p>
<p>Authorities were <a href="http://www.smh.com.au/sport/olympics/rio-2016/diving-pool-turns-green-for-synchronised-final-at-rio-olympics-20160809-gqov5i.html">quick to deny</a> that the green pool posed a risk to divers’ health, but that actually depends on why the water changed colour.</p>
<p>The possible culprits are: a sudden algae bloom; a change in pool alkalinity; or a chemical reaction in the water. How do these cause a change in the water colour?</p>
<h2>Blooming algae</h2>
<p>Algal blooms, caused by a sudden proliferation of microscopic algae or cyanobacteria, are found in ponds, rivers and seas the world over. But they are certainly not expected in Olympic swimming pools. </p>
<p>Phenomena such as “<a href="http://www.smh.com.au/environment/water-issues/red-beaches-glow-blue-after-dark-20121129-2ahu9.html">red tides</a>” and their beautiful night-time bioluminescence occur when conditions are perfect for rapid algae growth. </p>
<p>There’s no single triggering factor for this growth, but large amounts of rain (which cause nutrients to be flushed into the water), followed by sunny and warm weather as well as calm waters, are thought to be contributing environmental factors.</p>
<p>Olympic officials <a href="http://www.espn.com/olympics/swimming/story/_/id/17258143/2016-summer-olympics-green-pool-olympic-organizers-loss-explain-why">have suggested</a> that the remarkable change in pool colour could be a result of the sudden growth of an algal species. While small amounts of algae are present in swimming pools, they are not detectable by the human eye and the chemicals used to treat the water usually keep them at bay. </p>
<p>Warm weather conditions compounded by low winds may have contributed to an algae outbreak, but it seems more likely that a chemical imbalance or broken filter system is the underlying cause of the change in colour. </p>
<h2>A not-so-basic explanation</h2>
<p>Some news sources have reported that a “<a href="http://www.reuters.com/article/us-olympics-rio-diving-pool-idUSKCN10L1XN">decrease in alkalinity</a>” is responsible for the fluctuations in the colour of the diving and water polo pools. One of the tanks connected to the pool is said to have run out of one of the chemicals used to moderate the pH of the water.</p>
<p>An <a href="https://www.betterhealth.vic.gov.au/health/healthyliving/swimming-pools-water-quality">ideal pH for a swimming pool</a> is slightly alkaline (just over pH 7) to match the pH of our eyes and mucus membranes and hence avoid irritation. </p>
<p>The chemicals responsible for maintaining a safe pH also influence the multitude of chemical reactions occurring in the swimming pool. </p>
<p>Chlorine, for example, is the most widely known disinfectant used in swimming pools. But chlorine’s ability to kill pathogens is reduced when the pH of the pool is altered.</p>
<p>A reduction in alkalinity could have triggered the suspected algal bloom.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133779/original/image-20160811-18023-2vdau6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rio’s water polo pool also turned green.</span>
<span class="attribution"><span class="source">Reuters/Kai Pfaffenbach</span></span>
</figcaption>
</figure>
<h2>Chemical relay reaction</h2>
<p>A cocktail of chemicals is necessary to keep pools, which are basically large bodies of stagnant water, safe for swimming and, in particular, to kill harmful bacteria or parasites such as <em>E. Coli</em> and <em>Giardia lamblia</em>. </p>
<p>Chemicals such as chlorine aren’t just reactive to pathogens, though. They also react with chemicals introduced to the water by the swimmers. Olympian perspiration, <a href="http://www.telegraph.co.uk/sport/olympics/swimming/9457088/Michael-Phelps-admits-we-do-pee-in-the-pool.html">urine</a> and sun tan lotion can all react with the chemicals added to the water to produce byproducts. </p>
<p>The addition of extra chlorine to the chameleon-like water polo pool has been blamed for the <a href="http://www.smh.com.au/sport/olympics/rio-2016/olympics-swimming/australians-left-with-stinging-eyes-after-another-rio-olympics-pool-turns-green-20160810-gqpqgr.html">stinging eyes</a> of the Australian water polo players. But one of the aforementioned byproducts may actually be responsible. </p>
<p>Urine contains a lot of a nitrogen-rich molecule called urea, which reacts with chlorine to form an irritant called trichloramine. Even the characteristic smell of a swimming pool is not actually chlorine but rather a collection of similar byproducts. </p>
<h2>Gold, silver or copper?</h2>
<p>The presence of metal ions can also lead to changes of colour in aqueous environments such as swimming pools. Some have suggested that copper or other metals from water pipes could be responsible for the dramatic green of the diving pool. </p>
<p>The simplest complex that copper forms with water is a blue solution, hexaaquacopper (II), where a copper ion is completely surrounded by six molecules of water. If the water is displaced by other molecules, such as chloride, colour changes can result. </p>
<p>Different metals form different coloured solutions depending on their oxidation state and the nature of the molecules coordinated to the metal. Some combinations result in green solutions. But none of the analyses from the Rio pools have mentioned metal complexes so far. </p>
<h2>No need to adjust your sets</h2>
<p>Both Brazilian experts and <a href="http://www.fina.org/">FINA</a> have checked the water quality and determined that it poses no risk to athletes. Olympic officials will be hoping the colour of the pool changes back to blue and that the focus returns to the feats of those in the water rather than the water itself.</p><img src="https://counter.theconversation.com/content/63818/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alice Motion 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 possible culprits are: a sudden algae bloom; a change in pool alkalinity; or a chemical reaction in the water. How do these cause a change in the colour of the water?Alice Motion, Postdoctoral Research Associate and Teaching Fellow in Chemistry, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/495852015-10-22T19:07:29Z2015-10-22T19:07:29ZWatch out, Australia: a red-hot summer means blue-green algae<figure><img src="https://images.theconversation.com/files/99294/original/image-20151022-19646-167uhf4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pretty, but also pretty nasty.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File%3ACSIRO_ScienceImage_4628_Bluegreen_algae_in_irrigation_drain.jpg">Willem van Aken/CSIRO/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>As the Bureau of Meteorology has <a href="http://www.bom.gov.au/climate/enso/archive/ensowrap_20150915.pdf">already warned us</a>, Australia is in for a hot, dry summer as the <a href="https://theconversation.com/when-the-indian-ocean-and-el-nino-join-forces-things-can-get-hot-and-dry-48969">current El Niño</a> takes hold. Those conditions are ideal for blue-green algae to bloom in lakes, ponds and reservoirs.</p>
<p>Photosynthesising bacteria, also known as cyanobacteria, are found in all aquatic environments from the tropics to the poles. Most species have no adverse impact on the environment, but a few have nastier effects, and some are toxic to humans and animals. </p>
<p>Blue-green algae can form vast “blooms”, some large enough to be seen from space. In the Australian drought summers of 2009 and 2010, for example, hundreds of kilometres of the Murray River suffered <a href="http://www.ncbi.nlm.nih.gov/pubmed/22081581,%20http://www.abc.net.au/news/2009-03-28/potentially-toxic-algae-bloom-threatens-murray/1633630">major cyanobacterial blooms</a>, which hampered the use of water for drinking, agriculture and recreation.</p>
<p>These blooms occur mostly in still water bodies and can be found throughout Australia. Some blue-green algae form visible surface scums, while others remain hidden in the water column. Some live in freshwater; others float in the open ocean or even live on the sea bed.</p>
<h2>Tiny and toxic</h2>
<p>The toxins produced by some blue-green algae can affect the nervous system, the liver and kidneys, or be toxic to cells more generally. Humans can be affected by drinking contaminated water or eating affected shellfish. Direct contact with water can also cause itching and rashes. Worse still, the toxins can remain in the water even after the blue-green algae themselves have vanished - in some cases for weeks, depending on the conditions. </p>
<p>Larger blooms tend to occur where there is an excess of nutrients, often the result of fertiliser runoff from intensive agriculture or other degradation of the catchment system. This means that, throughout Australia, the <a href="http://www.ncbi.nlm.nih.gov/pubmed/20598731">potential for blooms is increasing</a>. </p>
<p>Water temperature also influences algal blooms, for two reasons. First, blue-green algae grow faster in warmer water and, second, warmer temperatures increase “thermal stratification”, in which a warmer surface layer overlies deeper, cooler water. Stratification allows cyanobacteria to flourish in the warmer sunlit surface waters because of their unique ability to make themselves float.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/99295/original/image-20151022-7999-p8yjxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/99295/original/image-20151022-7999-p8yjxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/99295/original/image-20151022-7999-p8yjxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/99295/original/image-20151022-7999-p8yjxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/99295/original/image-20151022-7999-p8yjxy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/99295/original/image-20151022-7999-p8yjxy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/99295/original/image-20151022-7999-p8yjxy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/99295/original/image-20151022-7999-p8yjxy.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">This bloom in Western Australia’s Shark Bay was big enough for NASA to spot it from space.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File%3AShark_Bay_Phytoplankton_in_Bloom.jpg">NASA</a></span>
</figcaption>
</figure>
<p>So how do you steer clear of blue-green algae? The obvious tips are to avoid drinking untreated water from still, calm water bodies, and to be mindful of children or dogs playing by the water.</p>
<p>Green surface scum is the most obvious tell-tale sign of an algal bloom, but not all species of cyanobacteria form scums. Discolouration of the water, particularly a green colour, can also indicate the presence of blue-green algae. Some species, such as <em>Microcystis</em>, give off a distinctive odour, although some other blue-green algae also create musty-smelling chemicals that are non-toxic.</p>
<p>It is comforting to know that if water quality is at risk, your local water authority is probably on top of it already, and will typically erect warning signs each summer. Many lakes and reservoirs are routinely closed for recreational use to protect the public from toxic blooms during the hotter months. </p>
<h2>Blooming hot</h2>
<p>The forecast hot, dry summer is likely to be a boon for blooms, given that blue-green algae prefer warm, still water. This means that areas that typically get algal blooms might find they are bigger and longer-lasting this summer. In Australia’s southern states, the blooms might also start earlier in the summer and last longer into autumn. </p>
<p>But the scale of blooms also depends on nutrients, so reducing the amount of nutrients that are washed off the land during rainfall events can provide a way of controlling them. This can be done by reducing land degradation, for example, reducing erosion, creating vegetation buffer zones along river banks, and avoiding excessive fertiliser use. </p>
<p>Some of these processes will take time to implement and therefore won’t help us this summer. But combating cyanobacteria in the longer term will help to protect the environment, allow continued recreational use of water and, most importantly, protect our precious drinking water.</p><img src="https://counter.theconversation.com/content/49585/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anusuya Willis works for the Australian Rivers Institute, Griffith University, and receives funding from the Australian Research Council and Seqwater. Anusuya is also a member of the Greens political party. </span></em></p><p class="fine-print"><em><span>Michele Burford receives funding from the Australian Research Council and Seqwater</span></em></p>With El Niño ramping up, Australia is in for a long, hot, dry summer - perfect conditions for blue-green algae. And that innocuous-looking pond scum can pack a toxic punch if you’re not careful.Anusuya Willis, Research Fellow, Australian Rivers Institute, Griffith UniversityMichele Burford, Professor of Aquatic Ecology, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/384092015-03-17T06:23:25Z2015-03-17T06:23:25ZEcological engineering: a breath of life for marine ecosystems<figure><img src="https://images.theconversation.com/files/74528/original/image-20150311-24194-1jwzjnc.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Swedish Byfjord: it may look healthy, but has a deep and stifling secret</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>Oxygen is essential for many life forms. But we don’t often give it the attention it deserves because we assume that it is always there. While oxygen is ubiquitous in our atmosphere, it is not necessarily the case for many bodies of water like rivers, lakes or even oceans. Here a lack of oxygen can result in significant impacts on the ecosystem like the killing of fish that subsequently float to the surface. But artificially oxygenating water can breathe new life, as <a href="http://www.nature.com/ismej/journal/v9/n3/abs/ismej2014172a.html">we found recently</a> while working with a fjord in Sweden. </p>
<p>Lack of oxygen and the death of wildlife is a phenomenon that can be observed not only in lakes but also in marine environments – which might seem surprising given the mixing of water by ocean currents. Oceans generally contain oxygen – we call them “oxic” – but we easily forget that this has not always been the case. </p>
<p>If we look back in Earth’s history the original oceans were without oxygen (anoxic) and had a significantly different water chemistry than today. With the advent of photosynthetic bacteria, the oceans became oxygenated over time. Initially the oxygen concentrations were fairly low (hypoxic) compared to present-day levels, but over time oxygen increased in the water and the atmosphere. This meant that hypoxic and anoxic areas were more and more on the retreat.</p>
<p>Nowadays, areas with hypoxic and anoxic waters are re-appearing all around the globe, from the eastern Pacific (several places on the west coast of Canada, the US, Central America, Chile, and Peru), to the Bay of Bengal (India), the Arabian Sea, the Black Sea, the Baltic and the Namibian shelf.</p>
<h2>How do oxygen-deprived waters develop?</h2>
<p>Different mechanisms drive the development of hypoxic and anoxic waters in different regions and will result in different water chemistries. In areas with upwelling of cold water to the surface (for example off the coasts of Peru and Chile), nutrient-rich deep water is transported to the surface. This causes blooms of photosynthetic bacteria and algae to form. The increased organic carbon in the water serves as a nutrient source for other microbes, and they in turn lower the oxygen concentration by respiration, creating hypoxic water.</p>
<p>In contrast, places like the Baltic have large and deep basins that have a naturally low frequency of water exchange (for example with the North Sea) and therefore receive little input of oxygen-rich water from outside. This often results in hypoxic conditions in these basins. In addition, non-treated waste-water, nutrient runoff from farmland and the dumping of organic waste increase the nutrient loading of Baltic waters. This results in blooms of photosynthetic bacteria and algae and, subsequently, the increased abundance of other bacteria which eat them. Their respiration draws down the oxygen concentration to a point where no oxygen is left. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/74637/original/image-20150312-13505-1ql5rd7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/74637/original/image-20150312-13505-1ql5rd7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/74637/original/image-20150312-13505-1ql5rd7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/74637/original/image-20150312-13505-1ql5rd7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/74637/original/image-20150312-13505-1ql5rd7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/74637/original/image-20150312-13505-1ql5rd7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/74637/original/image-20150312-13505-1ql5rd7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=603&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Harmful algal blooms can develop and lower the oxygen content of the oceans.</span>
<span class="attribution"><a class="source" href="http://en.wikipedia.org/wiki/Algal_bloom#/media/File:Cwall99_lg.jpg">Askewmind</a></span>
</figcaption>
</figure>
<p>Obviously, really low levels of oxygen (or its total absence) will be harmful to fish and many other life forms. Additionally, microbial processes that don’t require oxygen take over in waters where there isn’t any, creating further problems such as massive decreases in available nitrogen. When huge blooms of toxic cyanobacteria form, it is more likely that toxins will come into contact with humans. </p>
<p>Increasing surface temperatures in the oceans as a result of climate change will further decrease the oxygen content in surface waters, leading to the expansion of already known low to nil oxygen marine waters, and the formation of new ones. This is more than an ecological problem: the economy also suffers due to detrimental effects on fisheries, tourism and water quality.</p>
<p>Are there solutions? Yes and no. In some regions there is no obvious way to address the challenge. In others, such as the Baltic, remediation is possible and several ways to solve the problem have been suggested. Reducing the input of nutrients into the Baltic, for example, would treat the cause of the problem, and initiatives to improve waste-water treatment have been introduced. </p>
<h2>Oxygenating the water</h2>
<p>But we can also treat the symptom itself. One idea is to oxygenate the water by increasing the frequency of naturally occurring inflows of oxygen-rich water from the North Sea with the help of wind-driven pumps in an ecological engineering project. </p>
<p>Our Swedish colleagues tested this idea in a <a href="http://link.springer.com/article/10.1007%2Fs13280-014-0524-9">large-scale experiment in the Swedish Byford</a>. Electrically-driven pumps were installed and the water column was mixed by pumping surface water to outlets in the basin that lacked oxygen. While the capacity of the pump was not high enough to introduce sufficient oxygen to completely oxygenate the basin, the disturbance of the water column triggered inflows of oxygen-rich water from a neighbouring oxygen-rich fjord. This resulted in a significant increase in oxygen throughout the water column, including the anoxic basin. Throughout this process we monitored the response of the bacterial community in the fjord using molecular methods. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/74830/original/image-20150313-7039-1bv3sbq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/74830/original/image-20150313-7039-1bv3sbq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/74830/original/image-20150313-7039-1bv3sbq.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/74830/original/image-20150313-7039-1bv3sbq.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/74830/original/image-20150313-7039-1bv3sbq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/74830/original/image-20150313-7039-1bv3sbq.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/74830/original/image-20150313-7039-1bv3sbq.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">Deployment of scientific equipment to determine the water quality in the Byfjord.</span>
</figcaption>
</figure>
<h2>Testing the waters</h2>
<p>Our recent work shows that oxygen-requiring bacteria, initially only present in surface waters, could also be found in the deep basin after oxygenation. They replaced the community of anaerobic bacteria observed there previously, showing that oxygen had reached the depths of the fjord and was supporting life. Overall it became clear that the change of the bacterial community was similar to what could have been expected in a natural oxygenation event, such as the mixing of waters. </p>
<p>Could ecological engineering to oxygenate anoxic marine zones be the solution for the future? Maybe. Reducing human inputs of nutrients into these zones is important, and these programmes should be continued as they address the root of the problem. However, ecological engineering is another option to oxygenate certain marine zones. This will especially help in systems where large amounts of nutrients are stored in the sediments; these would take a long time to be restored naturally even if all further nutrient input were stopped immediately.</p>
<p>But especially for the Baltic, the question is not only whether an oxygenation project is technically feasible or ecologically meaningful, but also whether it is economically viable and whether there is the political will to commit to a long-term project such as this.</p><img src="https://counter.theconversation.com/content/38409/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Treusch 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>Low oxygen levels in the oceans can dramatically change the community of organisms that live there – but new techniques to re-introduce oxygen have given a breath of life to a Swedish fjord.Alexander Treusch, Associate Professor, University of Southern DenmarkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/354432015-01-05T06:02:08Z2015-01-05T06:02:08ZWhy bacteria could be the answer to a future without oil<figure><img src="https://images.theconversation.com/files/67369/original/image-20141216-14144-11ut9i5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fossil free.</span> <span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:Bacillus_subtilis.jpg">Allonweiner</a></span></figcaption></figure><p>Chemicals are all around us. They are crucial in all manner of industries, from agriculture to food to cosmetics. Most people give little thought to how these chemicals are made – and certainly very few would consider the chemical industry as a contributor to our society’s dependence on oil. But it is.</p>
<p>Historically petroleum has been used to develop the chemicals needed for products such as pesticides, food supplements and make-up. Although many of the building blocks required to make these chemicals occur naturally, trying to take those natural materials and use them in large-scale industrial processes has proved difficult and costly. So petroleum is used instead.</p>
<p>Until recently, oil was seen as a cheap commodity which was available in abundance, so petroleum was perfect for use in the chemical industry. However, the world has changed. We now recognise the need to reduce our reliance on oil in order to protect the environment and maintain our national security. There are also <a href="http://www.organicmakeup.ca/ca/PetroleumCosmetics.asp">health concerns</a> over the use of petroleum in products we eat and apply to our bodies.</p>
<p>This is why new advanced methods for industrial biotechnology are so important; they are enabling the use of engineered bacterial cells, rather than petroleum, in developing chemicals to be used in these products. Importantly, the bacteria can be grown on a range of cheap and renewable resources, even various kinds of farmland waste.</p>
<p>However, in order to use bacteria effectively – and in a manner which can be scaled up by industry – we need to know a lot more about bacterial cell biology. Only by investigating the machinery and processes at the heart of cells can we learn how to use them to develop organic chemicals in a manner that was previously unfeasible for industry.</p>
<h2>Friendly bacteria</h2>
<p>At Newcastle University’s <a href="http://www.ncl.ac.uk/cbcb/">Centre for Bacterial Cell Biology</a> we’ve spent years studying <em>Bacillus subtilis</em>, a bacterium that lives peacefully in soil or even <a href="https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCMQFjAA&url=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F23643574_Bacillus_subtilis_isolated_from_the_human_gastrointestinal_tract%2Flinks%2F0fcfd50b8df915d40a000000&ei=mGiQVI60H43LaIG9gsAE&usg=AFQjCNE3nQMUp_HAYZ_wtqpDLbcXNiIfIg&bvm=bv.81828268,d.d2s">in the human gut</a>. This organism and its relatives are very good at making and secreting enzymes which are catalysts for all sorts of useful processes. It means <em>Bacilli</em> are already used widely by industry, for example in producing the <a href="http://biotechlearn.org.nz/themes/biotech_at_home/enzymes_in_washing_powders">enzymes that are used in biological washing powders</a> such as proteases (which break down blood, egg and other protein stains) or amylases (which dissolve starch).</p>
<p>However, the range of enzymes they can secrete efficiently is much more limited than we would like. Studies on fundamental structures and processes of the bacterium are now beginning to give us the ability to engineer the cells to secrete a wider range of proteins from a diverse range of sources.</p>
<p>This means that before long <em>Bacillus</em> will be used to make all kinds of enzymes, including those needed in the chemical industry to replace processes presently dependent on petroleum.</p>
<p>This is a huge opportunity. The European industrial biotechnology industry has an estimated annual turnover of more than €60 billion, and the global industrial enzyme market is predicted to be <a href="http://www.bccresearch.com/pressroom/bio/global-market-industrial-enzymes-reach-nearly-$7.1-billion-2018">worth US$7.1 billion</a> by 2018. Detergent enzymes alone make up a billion dollar business.</p>
<p>However, continued reliance on oil-based solutions will hamper growth and could have significant societal and environmental consequences. Replacing petroleum with bacteria will have a real impact on people’s lives.</p>
<h2>Algae vs sunburn</h2>
<p>Suncream is a good example. One of the <a href="http://www.bbsrc.ac.uk/pa/grants/AwardDetails.aspx?FundingReference=BB/L004399/1">projects</a> we are working on at Newcastle is to develop organic UV-absorber compounds from renewable materials to be used in sunscreens.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/67491/original/image-20141217-31021-1at4g5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/67491/original/image-20141217-31021-1at4g5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/67491/original/image-20141217-31021-1at4g5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/67491/original/image-20141217-31021-1at4g5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/67491/original/image-20141217-31021-1at4g5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/67491/original/image-20141217-31021-1at4g5y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/67491/original/image-20141217-31021-1at4g5y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Next time, use bacteria?</span>
<span class="attribution"><a class="source" href="http://www.flickr.com/photos/dogwalkerbrasil/1594757774">Indexorama</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Damage from exposure to UV radiation is a major worry, and there is increasing demand for cosmetics that block UV rays. The industry relies on oil-based technology and inorganic metal oxide particles to create materials that block UV rays for use in sunscreen.</p>
<p>However, we know that photosynthetic bacteria called cyanobacteria that grow in the sea make their own <a href="http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=47595&fileId=S096702629900219X">organic sunscreen molecules</a>. By taking the relevant genes from cyanobacteria and transplanting them into a bacterium that is already widely used in chemical production, we hope to be able to change this. If we are successful, the process could easily be scaled up so the cosmetics industry will be able to develop cheap organic sunscreen.</p>
<p>This is just one example of the way in which bacteria could support a future without oil. Work is already in progress to explore the potential of using waste to grow bacteria or other micro-organisms that could make chemicals such as ethanol for use as “biofuel” for cars and aeroplanes, further reducing the use of oil. </p>
<p>There is a lot of work still to be done to make this vision a reality, but by continuing to investigate how bacterial cells work and how they could be used in chemical production we can see a future in which waste becomes energy and we can live without oil.</p><img src="https://counter.theconversation.com/content/35443/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jeff Errington receives funding from the Technology Strategy Board (now Innovate UK).</span></em></p>Chemicals are all around us. They are crucial in all manner of industries, from agriculture to food to cosmetics. Most people give little thought to how these chemicals are made – and certainly very few…Jeff Errington, Director of the Centre for Bacterial Cell Biology, Newcastle UniversityLicensed as Creative Commons – attribution, no derivatives.