tag:theconversation.com,2011:/au/topics/decomposition-31264/articlesDecomposition – The Conversation2023-09-28T12:28:11Ztag:theconversation.com,2011:article/2140482023-09-28T12:28:11Z2023-09-28T12:28:11ZYour microbes live on after you die − a microbiologist explains how your necrobiome recycles your body to nourish new life<figure><img src="https://images.theconversation.com/files/550423/original/file-20230926-27-qpnpj4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1794%2C1668&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">After you die, bacteria harvest your body for the nutrients that help push daisies.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/embroidery-skull-and-roses-grapes-humming-royalty-free-illustration/931298520">Matriyoshka/iStock via Getty Images Plus</a></span></figcaption></figure><p>Each human body contains a <a href="https://www.hmpdacc.org/overview/">complex community of trillions of microorganisms</a> that are important for your health while you’re alive. These <a href="https://open.oregonstate.education/generalmicrobiology/chapter/microbial-symbioses/">microbial symbionts</a> help you digest food, produce essential vitamins, protect you from infection and serve many other critical functions. In turn, the microbes, which are mostly concentrated in your gut, get to live in a relatively stable, warm environment with a steady supply of food.</p>
<p>But what happens to these symbiotic allies after you die? </p>
<p>As an <a href="https://scholar.google.com/citations?user=U_xOnjEAAAAJ&hl=en">environmental microbiologist</a> who studies <a href="https://doi.org/10.1093/femsec/fiad006">the necrobiome</a> – the microbes that live in, on and around a decomposing body – I’ve been curious about our postmortem microbial legacy. You might assume that your microbes die with you – once your body breaks down and your microbes are flushed into the environment, they won’t survive out in the real world. </p>
<p>In our September 2023 study, my research team and I share evidence that not only do your microbes continue to live on after you die, they actually play an important role in <a href="https://doi.org/10.1186/s13717-023-00451-y">recycling your body</a> so that new life can flourish.</p>
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<figcaption><span class="caption">Your microbes accompany you from cradle to grave.</span></figcaption>
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<h2>Microbial life after death</h2>
<p>When you die, your heart stops circulating the blood that has carried oxygen throughout your body. Cells deprived of oxygen start digesting themselves in a <a href="https://en.wikipedia.org/wiki/Autolysis_(biology)">process called autolysis</a>. Enzymes in those cells – which normally digest carbohydrates, proteins and fats for energy or growth in a controlled way – start to work on the membranes, proteins, DNA and other components that make up the cells. </p>
<p>The products of this cellular breakdown make excellent food for your symbiotic bacteria, and without your immune system to keep them in check and a steady supply of food from your digestive system, they turn to this new source of nutrition. </p>
<p><a href="https://doi.org/10.7717/peerj.3437">Gut bacteria</a>, especially a class of microbes called <a href="https://doi.org/10.3389/fmicb.2017.02096"><em>Clostridia</em></a>, <a href="https://doi.org/10.1016/j.forsciint.2016.03.019">spread through your organs</a> and digest you from the inside out in a process called <a href="https://www.ncbi.nlm.nih.gov/books/NBK539741/">putrefaction</a>. Without oxygen inside the body, your anaerobic bacteria rely on energy-producing processes that don’t require oxygen, such as fermentation. These create the distinctly odorous-gases signature to decomposition.</p>
<p>From an <a href="https://doi.org/10.1016/j.meegid.2017.09.006">evolutionary standpoint</a>, it makes sense that your microbes would have evolved ways to adapt to a dying body. Like rats on a sinking ship, your bacteria will soon have to abandon their host and survive out in the world long enough to find a new host to colonize. Taking advantage of the carbon and nutrients of your body allows them to increase their numbers. A bigger population means a higher probability that at least a few will survive out in the harsher environment and successfully find a new body.</p>
<h2>A microbial invasion</h2>
<p>If you’re buried in the ground, your microbes are flushed into the soil along with a soup of decomposition fluids as your body breaks down. They’re entering an entirely new environment and encountering a whole new microbial community in the soil.</p>
<p>The <a href="https://doi.org/10.1016/j.tree.2015.06.004">mixing or coalescence</a> of two distinct microbial communities happens frequently in nature. Coalescence happens when the roots of two plants grow together, when wastewater is emptied into a river or even when two people kiss.</p>
<p>The outcome of mixing – which community dominates and which microbes are active – depends on several factors, such as how much environmental change the microbes experience and who was there first. Your microbes are adapted to the stable, warm environment inside your body where they receive a steady supply of food. In contrast, soil is a particularly <a href="https://doi.org/10.1016/B978-0-12-820202-9.00002-2">harsh place to live</a> – it’s a highly variable environment with steep chemical and physical gradients and big swings in temperature, moisture and nutrients. Furthermore, soil already hosts an exceptionally diverse microbial community full of decomposers that are well adapted to that environment and would presumably outcompete any newcomers. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy image of Clostridium septicum" src="https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=501&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=501&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=501&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=629&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=629&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550417/original/file-20230926-19-r1tn2a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=629&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption"><em>Clostridium septicum</em> is one species of bacteria involved in putrefaction.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/2n1hVng">Joseph E. Rubin/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
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<p>It’s easy to assume that your microbes will die off once they are outside your body. However, my research team’s previous studies have shown that the DNA signatures of host-associated microbes can be detected in the soil below a decomposing body, <a href="https://doi.org/10.1371/journal.pone.0130201">on the soil surface</a> and <a href="https://doi.org/10.1371/journal.pone.0208845">in graves</a> for months or years after the soft tissues of the body have decomposed. This raised the question of whether these microbes are still alive and active or if they are merely in a dormant state waiting for the next host.</p>
<p>Our newest study suggests that your microbes are not only living in the soil but also <a href="https://doi.org/10.1186/s13717-023-00451-y">cooperating with native soil microbes</a> to help decompose your body. In the lab, we showed that mixing soil and decomposition fluids filled with host-associated microbes increased decomposition rates beyond that of the soil communities alone.</p>
<p>We also found that host-associated microbes <a href="https://doi.org/10.1186/s13717-023-00451-y">enhanced nitrogen cycling</a>. Nitrogen is an essential nutrient for life, but most of the nitrogen on Earth is tied up as atmospheric gas that organisms can’t use. Decomposers play a critical role recycling organic forms of nitrogen such as proteins <a href="https://doi.org/10.1016/j.soilbio.2018.03.005">into inorganic forms</a> such as ammonium and nitrate that microbes and plants can use. </p>
<p>Our new findings suggest that our microbes are likely <a href="https://doi.org/10.1186/s13717-023-00451-y">playing a part</a> in this recycling process by converting large nitrogen-containing molecules like proteins and nucleic acids into ammonium. Nitrifying microbes in the soil can then convert the ammonium into nitrate. </p>
<h2>Next generation of life</h2>
<p>The recycling of nutrients from detritus, or nonliving organic matter, is a <a href="https://doi.org/10.2307/1930126">core process in all ecosystems</a>. In terrestrial ecosystems, decomposition of dead animals, or carrion, <a href="https://doi.org/10.1007/s00442-012-2460-3">fuels biodiversity</a> and is an important <a href="https://doi.org/10.1002/ece3.7542">link in food webs</a>.</p>
<p>Living animals are a bottleneck for the carbon and nutrient cycles of an ecosystem. They slowly accumulate nutrients and carbon from large areas of the landscape throughout their lives then deposit it all at once in a small, localized spot when they die. One dead animal can support a whole pop-up food web of <a href="https://doi.org/10.1093/femsec/fiad006">microbes</a>, <a href="https://doi.org/10.1371/journal.pone.0241777">soil fauna</a> and <a href="https://doi.org/10.1007/978-3-642-88448-1_6">arthropods</a> that make their living off carcasses. </p>
<p><a href="https://theconversation.com/life-after-death-how-insects-rise-from-the-dead-and-transform-corpses-into-skeletons-148847">Insect</a> and <a href="https://doi.org/10.1890/09-0292.1">animal scavengers</a> help further redistribute nutrients in the ecosystem. Decomposer microbes convert the concentrated pools of nutrient-rich organic molecules from our bodies into <a href="https://doi.org/10.1371/journal.pone.0287094">smaller, more bioavailable forms</a> that other organisms can use to support new life. It’s not uncommon to see <a href="https://doi.org/10.1002/ecs2.1537">plant life flourishing near a decomposing animal</a>, visible evidence that nutrients in bodies are being recycled back into the ecosystem.</p>
<p>That our own microbes play an important role in this cycle is one microscopic way we live on after death.</p><img src="https://counter.theconversation.com/content/214048/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer DeBruyn receives funding from the United States Department of Agriculture, National Science Foundation, Department of Justice, and Defense Advanced Research Projects Agency.</span></em></p>With the help of the microbes that once played an essential role in keeping you alive, the building blocks of your body go on to become a part of other living things.Jennifer DeBruyn, Professor of Environmental Microbiology, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2074182023-07-30T20:08:31Z2023-07-30T20:08:31ZSecrets wrapped in fabric: how our study of 100 decomposing piglet bodies will help solve criminal cases<figure><img src="https://images.theconversation.com/files/539908/original/file-20230728-23-ku5ia8.jpeg?ixlib=rb-1.1.0&rect=19%2C3%2C1274%2C857&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Photo by Stevie Ziogos</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Until the <a href="https://www.sciencedirect.com/science/article/pii/B9780081018729000042">late 19th century</a>, the success of criminal investigations largely hung on witness reports and (often extorted) confessions. A lack of scientific tools meant investigators needed advanced <a href="https://www.sciencedirect.com/topics/psychology/deductive-reasoning">deductive reasoning</a> abilities – and even then they’d often hit a dead end.</p>
<p>Today, investigations demand an interdisciplinary and <a href="https://link.springer.com/article/10.1007/s00414-022-02846-6">high-tech</a> approach, involving experts from diverse scientific disciplines. Stabbing investigations are particularly important, as fatal stabbings are the leading cause of homicide in countries with restricted access to firearms, including <a href="https://www.aic.gov.au/sites/default/files/2020-05/tbp045.pdf">Australia</a>.</p>
<p>Carefully interpreting <a href="https://theconversation.com/the-camera-never-lies-our-research-found-cctv-isnt-always-dependable-when-it-comes-to-murder-investigations-199828">CCTV footage</a> can be useful, but sometimes the crime scene won’t have surveillance cameras. The victim’s body may be discovered days, weeks, or months after the event. By then it may be partially consumed by insects – or rain may have washed away the blood stains, or potentially even the murder weapon.</p>
<p>In such a case, analysing damage to a <a href="https://www.ojp.gov/ncjrs/virtual-library/abstracts/comparing-alleged-weapon-damage-clothing-value-multiple-layers-and">victim’s clothing</a> can provide crucial insight. But how does clothing on a decomposing body react to environmental and biological factors?</p>
<p>This was our question as we conducted research using the decomposing bodies of more than 100 stillborn piglets. Our findings from this <a href="https://www.mdpi.com/2075-4450/14/7/618">first-of-its-kind experiment</a> could help investigators solve future (and past) crimes in which stabs, tears or other damages to clothing are in question.</p>
<h2>Pigs wrapped in fabric</h2>
<p><a href="https://www.sciencedirect.com/science/article/pii/S1355030618301680">Textile analysis</a> has a significant role in forensic investigation. Clothes can preserve crucial information about the events leading up to someone’s death. Evidence might come in the form of fibres under a victim’s fingernails, <a href="https://www.pnas.org/doi/10.1073/pnas.1917222117">tears in the clothing</a> resulting from movement or traction, or cuts and holes caused by weapons. </p>
<p>However, the decomposition process itself will also alter the fabric and existing damages. It may even introduce new damages that complicate the analysis.</p>
<p>To understand how clothing might change throughout this process, we conducted an experiment in the summer heat of Western Australia. We used more than 100 stillborn piglets (simulating human remains) wrapped in common fabrics including cotton, stretchy synthetic material, and a fabric blend. Some piglets were left unclothed as control samples.</p>
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<a href="https://images.theconversation.com/files/539902/original/file-20230728-25-grpb0x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/539902/original/file-20230728-25-grpb0x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539902/original/file-20230728-25-grpb0x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539902/original/file-20230728-25-grpb0x.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539902/original/file-20230728-25-grpb0x.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539902/original/file-20230728-25-grpb0x.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539902/original/file-20230728-25-grpb0x.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539902/original/file-20230728-25-grpb0x.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>
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<span class="caption">The experiment was conducted at a facility in Western Australia.</span>
<span class="attribution"><a class="source" href="https://www.mdpi.com/2075-4450/14/7/618">Photo by Stevie Ziogos</a>, <span class="license">Author provided</span></span>
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<p>We intentionally inflicted cuts and tears on most of the fabrics, before leaving the carcasses to decompose naturally in a bushland environment until only bones remained. The bodies were shielded from <a href="https://pubmed.ncbi.nlm.nih.gov/20171028/">large scavengers</a>, but not from <a href="https://pubmed.ncbi.nlm.nih.gov/19836175/">carrion insects</a>. </p>
<p>While previous research has explored the impact <a href="https://pubmed.ncbi.nlm.nih.gov/21602003/">of clothing on decomposition</a>, we were focused on the other side of the coin: how do insects impact the fabric on a decomposing carcass? And in what ways could this jeopardise an investigation? </p>
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Read more:
<a href="https://theconversation.com/flies-maggots-and-methamphetamine-how-insects-can-reveal-drugs-and-poisons-at-crime-scenes-176981">Flies, maggots and methamphetamine: how insects can reveal drugs and poisons at crime scenes</a>
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<h2>Exposed to natural elements</h2>
<p>It wasn’t long before the fabrics started to transform due to exposure to bacteria, fungi, insects and other environmental factors. </p>
<p>They changed in shape and texture, and became stretched as a result of the natural bloating of the carcasses. Less than a week after the carcasses were placed, new holes appeared in the fabric – especially in cotton – as the fibres broke down.</p>
<p>There were also chemical changes due to potential exposure to body fluids and the chemical products of bacteria and fungi.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/539897/original/file-20230728-27-48r2yd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/539897/original/file-20230728-27-48r2yd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539897/original/file-20230728-27-48r2yd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539897/original/file-20230728-27-48r2yd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539897/original/file-20230728-27-48r2yd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539897/original/file-20230728-27-48r2yd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539897/original/file-20230728-27-48r2yd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539897/original/file-20230728-27-48r2yd.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">Experimental fabrics observed with a ‘scanning electron microscope’ (SEM) showed fungal colonisation.</span>
<span class="attribution"><a class="source" href="https://www.mdpi.com/2075-4450/14/7/618">Photo by Stevie Ziogos</a>, <span class="license">Author provided</span></span>
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<p>Insects were particularly active in areas where body fluids were present. Of twenty insect groups collected and identified, blowflies and carrion beetles were the most common antagonists. </p>
<p>Throughout the 47 days of the experiment, we managed to collect a range of data on fabric degradation throughout the decomposition process. It’s the first time this has been documented in such detail in a controlled experiment. </p>
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<img alt="" src="https://images.theconversation.com/files/539893/original/file-20230728-19-9x88ao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539893/original/file-20230728-19-9x88ao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539893/original/file-20230728-19-9x88ao.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539893/original/file-20230728-19-9x88ao.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539893/original/file-20230728-19-9x88ao.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539893/original/file-20230728-19-9x88ao.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539893/original/file-20230728-19-9x88ao.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&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">Insects visited the bloodstains of the fabric during the early stages of the experiment.</span>
<span class="attribution"><span class="source">Photo by Stevie Ziogos, Author provided</span></span>
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<h2>New tools to solve new (and old) mysteries</h2>
<p>Although textile damage analysis is vital for forensics, there has been limited research on how it overlaps with forensic entomology and taphonomy (the study of how organisms decompose). Our research shows fabrics can hold significant evidence, and this evidence changes as bodies decompose while being exposed to the environment.</p>
<p>There are myriad examples of crimes where evidence related to clothing has been crucial to solving the case. </p>
<p>In the 1980 <a href="https://www.injustice.law/2021/07/05/the-shameful-tale-of-what-happened-to-lindy-chamberlain/">Chamberlain case</a>, a jury wrongly found Lindy Chamberlain and her husband Michael guilty of murdering their nine-week-old daughter Azaria, who had disappeared. </p>
<p>It was only when Azaria’s clothing was recovered a week after her disappearance that investigators had evidence of a dingo having snatched her (as the clothes showed signs of having been dragged through sand). The Chamberlains were exonerated as a result.</p>
<p>More recently, a person of interest was arrested in New York as the “<a href="https://7news.com.au/news/crime/architect-charged-over-murders-after-pizza-crust-leads-to-craigslist-ripper-breakthrough-c-11284691">Craigslist ripper</a>”, a serial killer responsible for the murder of more than ten people. Investigators obtained DNA evidence from strands of hair found in <a href="https://www.smh.com.au/world/hunt-for-ripper-as-new-york-beach-body-count-mounts-20111202-1obc7.html">burlap sacks</a> used to hide and transport the bodies. </p>
<p>Although many details of this particular case remain undisclosed, such investigations will most likely use insect-related evidence and other trace evidence on textiles to help make important inferences, including about time of death.</p>
<p>More generally, our work will help investigators avoid misinterpreting evidence from clothing. For instance, if investigators aren’t aware holes in fabric can form through exposure to insects and natural elements, they might incorrectly attribute them to an animal or human attacker. </p>
<p>Similarly, by gauging which portion of clothing has the most insect damage, they might be able to understand where the most fluid was present on the body (if it’s found as skeletal remains). This could help them figure out where and how damage was inflicted.</p>
<p>This year we published <a href="https://pubmed.ncbi.nlm.nih.gov/37367352/">guidelines</a> to help other forensic professionals in the process of observing and collecting insects at a crime scene, and in considering how insect activity may be connected with a victim’s clothing. We hope our work can help future investigations, and maybe even reopen some cold cases.</p><img src="https://counter.theconversation.com/content/207418/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This research has been conducted in collaboration with Stevie Ziogos (PhD candidate, Murdoch University) and Kari Pitts (ChemCentre). Forensic entomology guidelines have been updated in collaboration with Tharindu Bambaradeniya (PhD candidate, Murdoch University).</span></em></p><p class="fine-print"><em><span>Ian Dadour 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>Fatal stabbings are the leading cause of homicide in countries with restricted access to firearms, including Australia. New research could help solve these cases.Paola A. Magni, Senior Lecturer in Forensic Science, Murdoch UniversityIan Dadour, Adjunct professor, Murdoch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1884562022-10-28T01:11:10Z2022-10-28T01:11:10ZCoffin? Casket? Cremation? How to make your death more environmentally friendly<figure><img src="https://images.theconversation.com/files/491536/original/file-20221025-156-2serq3.jpeg?ixlib=rb-1.1.0&rect=45%2C36%2C6045%2C3387&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>We can all agree humans need to reduce their impact on the environment. And while most of us think of this in terms of daily activities – such as eating less meat, or being water-wise – this responsibility actually extends beyond life and into death. </p>
<p>The global population is closing on <a href="https://www.un.org/en/un-chronicle/global-population-will-soon-reach-8-billion-then-what">eight billion</a>, and the amount of land available for human burial is <a href="https://www.sciencefocus.com/the-human-body/deal-with-the-dead/">running out</a>, especially in small and densely populated countries. </p>
<p>To minimise environmental impact, human bodies should return to nature as quickly as possible. But the rate of decay in some of the most common traditional disposal methods is very slow. It can take <a href="https://www.businessinsider.com/how-long-it-takes-human-body-decompose-grave-coffin-2019-8">several decades</a> for a body to decompose. </p>
<p>In a one-of-its-kind study, our team analysed <a href="https://irispublishers.com/gjfsm/fulltext/a-taphonomic-examination-of-inhumed-and-entombed-remains-in-parma-cemeteries-italy.ID.000518.php">408 human bodies</a> exhumed from grave pits and stone tombs in the north of Italy to find out what conditions help speed up decay.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/488716/original/file-20221007-21261-h17m5t.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/488716/original/file-20221007-21261-h17m5t.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488716/original/file-20221007-21261-h17m5t.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488716/original/file-20221007-21261-h17m5t.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488716/original/file-20221007-21261-h17m5t.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488716/original/file-20221007-21261-h17m5t.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488716/original/file-20221007-21261-h17m5t.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488716/original/file-20221007-21261-h17m5t.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">We conducted research on bodies exhumed from the La Villetta cemetery in Parma, Italy.</span>
<span class="attribution"><span class="source">Edda Guareschi</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>The environmental cost of traditional burials</h2>
<p>Funeral rituals should respect the dead, bring closure to families and promote the reaching of the afterlife in accordance with people’s beliefs. This looks different for different people. Although the Catholic church has allowed cremation <a href="https://www.nytimes.com/2016/10/26/world/europe/vatican-bans-scattering-of-human-ashes.html">since 1963</a>, it still prefers burials. Muslims are always supposed to be buried, while most Hindus are cremated.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/indians-are-forced-to-change-rituals-for-their-dead-as-covid-19-rages-through-cities-and-villages-160076">Indians are forced to change rituals for their dead as COVID-19 rages through cities and villages</a>
</strong>
</em>
</p>
<hr>
<p>In Australia, however, the latest census revealed almost 40% of the population identifies as “<a href="https://theconversation.com/no-religion-is-australias-second-largest-religious-group-and-its-having-a-profound-effect-on-our-laws-185697">not religious</a>”. This opens up more avenues for how people’s bodies may be handled after death.</p>
<p>Most traditional burial practices in industrialised countries have several long-lasting harmful <a href="https://apps.who.int/iris/bitstream/handle/10665/108132/EUR_ICP_EHNA_01_04_01%28A%29.pdf">effects</a> on the environment. Wood and metal fragments in coffins and caskets remain in the ground, leaching harmful chemicals through paint, preservatives and alloys. Chemicals used for embalming also remain in the ground and can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3315260/">contaminate</a> soil and waterways.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/488208/original/file-20221005-26-nf21yo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/488208/original/file-20221005-26-nf21yo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488208/original/file-20221005-26-nf21yo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488208/original/file-20221005-26-nf21yo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488208/original/file-20221005-26-nf21yo.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488208/original/file-20221005-26-nf21yo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488208/original/file-20221005-26-nf21yo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488208/original/file-20221005-26-nf21yo.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Caskets made out of processed materials like metal and wood are bad for the environment.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Cremation also has a large <a href="https://www.nationalgeographic.com/science/article/is-cremation-environmentally-friendly-heres-the-science">carbon footprint</a>. It requires lots of trees for fuel and produces millions of tons of carbon dioxide each year, as well as toxic volatile compounds.</p>
<p>There are several alternatives to traditional burials. These include “water cremation” or “resomation” (where the body is rapidly dissolved), human <a href="https://www.abc.net.au/news/2021-09-26/body-composting-a-green-alternative-to-burial-cremation/100486964">composting</a>, mummification, cryonics (freezing and storage), <a href="https://eirene.ca/blog/space-burial-ashes-in-orbit">space burials</a>, and even turning the body into <a href="https://edition.cnn.com/2017/05/03/world/eco-solutions-capsula-mundi/index.html">trees</a> or the ashes into <a href="https://www.nationalgeographic.com/magazine/article/ashes-to-diamonds-reefs-rockets-how-we-will-memorialize-dead">diamonds</a> or <a href="https://www.andvinyly.com/">record vinyls</a>.</p>
<p>However, many of these alternatives are either illegal, unavailable, costly or not aligned with people’s beliefs. The vast majority choose coffin burials, and all countries accept this method. So the question of sustainable burials comes down to choosing between the many types of <a href="https://australian.museum/about/history/exhibitions/death-the-last-taboo/burial-coffins-and-caskets/?gclid=CjwKCAjwx7GYBhB7EiwA0d8oe-mOKjLns2Gj5mpj-mu_kskmPPCKjhOqUrUAEjC05D4pnSXyBP3xrhoCE9oQAvD_BwE">coffins available</a>. </p>
<h2>What leads to faster decomposition?</h2>
<p>Coffins range from traditional wooden caskets, to cardboard coffins, to natural coffins made from willow, banana leaf or bamboo, which decompose faster. </p>
<p>The most environmentally sustainable choice is one that allows the body to decompose and reduce to a skeleton (or “skeletonise”) quickly – possibly in just a few years.</p>
<p>Our research has presented three key findings on conditions that promote the skeletonisation of human bodies.</p>
<p>First, it has confirmed that bodies disposed in traditionally sealed tombs (where a coffin is placed inside a stone space) can take more than 40 years to skeletonise. </p>
<p>In these sealed tombs, bacteria rapidly consume the oxygen in the stone space where the coffin is placed. This creates a micro-environment that promotes an almost indefinite preservation of the body. </p>
<p>We also found burial grounds with a high percentage of sand and gravel in the soil promote the decomposition and skeletonisation of bodies in less than ten years – even if they are in a coffin. </p>
<p>That’s because this soil composition allows more circulation of air and microfauna, and ample water drainage – all of which are helpful for degrading organic matter. </p>
<p>Finally, our research confirmed previous suspicions about the slow decomposition of entombed bodies. We discovered placing bodies inside stone tombs, or covering them with a stone slab on the ground, helps with the formation of corpse wax (or “<a href="https://pubmed.ncbi.nlm.nih.gov/33596512/">adipocere</a>”).</p>
<p>This substance is the final result of several chemical reactions through which the body’s adipose (fat) tissues turn to a “soapy” substance that’s very resistant to further degradation. Having corpse wax slows down (if not completely arrests) the decomposition process. </p>
<h2>A new, greener option</h2>
<p>In looking for innovative burial solutions, we had the opportunity to experiment with a new type of body disposal in a tomb called an “<a href="https://www.mdpi.com/2673-6756/2/3/37">aerated tomb</a>”.</p>
<p>Over the past 20 years aerated tombs have been developed in some European countries including France, Spain and Italy (where they <a href="https://www.tecnofar-solutions.com/prodotti/sistema-aerato-loculi">have</a> <a href="https://www.argema.net/loculi-aerati/">been</a> <a href="https://www.ala-strutture-cimiteriali.com/loculi-aerati">commercialised</a>). They allow plenty of ventilation, which in turn enables a more hygienic and faster decomposition of bodies compared to traditional tombs.</p>
<p>They have a few notable features:</p>
<ul>
<li><p>an activated carbon filter purifies gases</p></li>
<li><p>fluids are absorbed by two distinct biodegrading biological powders, one placed at the bottom of the coffin and the other in a collecting tray beneath it</p></li>
<li><p>once the body has decomposed, the skeletal remains can be moved to an ossuary (a site where skeletal remains are stored), while the tomb can be dismantled and most of its components potentially recycled.</p></li>
</ul>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/488204/original/file-20221005-26-o8c3fm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An ossuary is full of skeletal remains forming a pillar and lining the walls – with a large white cross in the centre of a back wall." src="https://images.theconversation.com/files/488204/original/file-20221005-26-o8c3fm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488204/original/file-20221005-26-o8c3fm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488204/original/file-20221005-26-o8c3fm.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488204/original/file-20221005-26-o8c3fm.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488204/original/file-20221005-26-o8c3fm.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488204/original/file-20221005-26-o8c3fm.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488204/original/file-20221005-26-o8c3fm.jpeg?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">Arguably one of the world’s most famous ossuaries, the Paris Catacombs is an underground labyrinth containing the remains of more than six million people.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Aerated tombs are also cheaper than ordinary tombs and can be built from existing tombs. They would be simple to use in Australia and would comply with public health and hygiene standards.</p>
<p>Most of us don’t spend much time thinking about what will happen to our bodies after we die. Perhaps we should. In the end this may be one of our most important last decisions – the implications of which extend to our precious planet.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/most-americans-today-are-choosing-cremation-heres-why-burials-are-becoming-less-common-186618">Most Americans today are choosing cremation – here's why burials are becoming less common</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/188456/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>Burial land is running low in certain parts of the world. It’s about time we started to consider the environmental cost of our final resting place.Paola A. Magni, Senior Lecturer in Forensic Science, Murdoch UniversityEdda Guareschi, Adjunct Lecturer in Forensic Sciences, Murdoch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1812262022-05-17T12:26:13Z2022-05-17T12:26:13ZBeyond flora and fauna: Why it’s time to include fungi in global conservation goals<figure><img src="https://images.theconversation.com/files/463377/original/file-20220516-13-dhfg86.jpg?ixlib=rb-1.1.0&rect=9%2C18%2C6246%2C4154&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Decomposers at work: Shelf fungi feeding on a rotting log.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/turkey-tail-trametes-versicolor-shelf-fungus-on-a-rotting-news-photo/1288022948">Craig Joiner/Loop Images/Universal Images Group via Getty Images</a></span></figcaption></figure><p>It’s no secret that Earth’s biodiversity is at risk. According to the <a href="https://www.iucn.org/about#how">International Union for the Conservation of Nature</a>, 26% of all mammals, 14% of birds and 41% of amphibians are <a href="https://doi.org/10.1038/d41586-021-02088-3">currently threatened worldwide</a>, mainly due to human impacts such as climate change and development. </p>
<p>Other forms of life are also under pressure, but they are harder to count and assess. Some scientists have warned of <a href="https://doi.org/10.1016/j.biocon.2019.01.020">mass insect die-offs</a>, although others say <a href="https://theconversation.com/insect-apocalypse-not-so-fast-at-least-in-north-america-141107">the case hasn’t been proved</a>. And then there are fungi – microbes that often go unnoticed, with an estimated <a href="https://www.iucn.org/news/species-survival-commission/202108/rewild-and-iucn-ssc-become-first-global-organizations-call-recognition-fungi-one-three-kingdoms-life-critical-protecting-and-restoring-earth">2 million to 4 million species</a>. Fewer than 150,000 fungi have received formal scientific descriptions and classifications. </p>
<p>If you enjoy <a href="https://food.onehowto.com/article/which-foods-are-made-thanks-to-fungi-4398.html">bread, wine or soy sauce</a>, or have taken <a href="https://doi.org/10.1371/journal.ppat.1003950">penicillin or immunosuppressant drugs</a>, thank fungi, which make all of these products possible. Except for baker’s yeast and button mushrooms, most fungi remain overlooked and thrive hidden in the dark and damp. But scientists agree that they are <a href="https://www.iucn.org/news/species-survival-commission/202108/rewild-and-iucn-ssc-become-first-global-organizations-call-recognition-fungi-one-three-kingdoms-life-critical-protecting-and-restoring-earth">valuable organisms worth protecting</a>. </p>
<p>As <a href="https://www.bls.gov/careeroutlook/2019/youre-a-what/mycologist.htm">mycologists</a> whose biodiversity work includes <a href="https://scholar.google.com/citations?view_op=list_works&hl=en&hl=en&user=aWT8ircAAAAJ">studying fungi</a> that interact with <a href="https://scholar.google.com/citations?hl=en&user=frEPl6IAAAAJ">millipedes, plants</a>, <a href="https://scholar.google.com/citations?user=9d60brMAAAAJ&hl=en&oi=ao">mosquitoes</a> and <a href="https://www.si.edu/spotlight/buginfo/true-bugs">true bugs</a>, we have devoted our careers to understanding the critical roles fungi play. These relationships can be beneficial, harmful or neutral for the fungus’s partner organism. But it’s not an overstatement to say that without fungi breaking down dead matter and recycling its nutrients, life on Earth would be unrecognizable.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/458924/original/file-20220420-25-acpci7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bright red ball with protruding orange spikes clings to an evergreen branch." src="https://images.theconversation.com/files/458924/original/file-20220420-25-acpci7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458924/original/file-20220420-25-acpci7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458924/original/file-20220420-25-acpci7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458924/original/file-20220420-25-acpci7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458924/original/file-20220420-25-acpci7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458924/original/file-20220420-25-acpci7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458924/original/file-20220420-25-acpci7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&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 fungus gall on eastern red cedar, produced by the rust fungus <em>Gymnosporangium juniperi-virginianae.</em></span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Healthy ecosystems need fungi</h2>
<p>The amazing biological fungal kingdom includes everything from <a href="https://www.britannica.com/science/shelf-fungus">bracket fungi</a>, <a href="https://www.britannica.com/science/mold-fungus">molds</a> and <a href="https://www.britannica.com/science/yeast-fungus">yeasts</a> to <a href="https://www.britannica.com/science/mushroom">mushrooms</a> and more. Fungi <a href="https://asm.org/Articles/2021/January/Three-Reasons-Fungi-Are-Not-Plants">are not plants</a>, although they’re usually stocked near fresh produce in grocery stores. In fact, they’re more closely related to animals.</p>
<p>But fungi have some unique features that set them apart. They grow by budding or as long, often branching, threadlike tubes. To reproduce, fungi typically form <a href="https://study.com/academy/lesson/what-are-spores-definition-types-quiz.html">spores</a>, a stage for spreading and dormancy. Rather than taking food into their bodies to eat, fungi release enzymes onto their food to break it down and then absorb sugars that are released. The fungal kingdom is very diverse, so many fungi break the mold.</p>
<p>Fungi play essential ecological roles worldwide. Some have been forming critical partnerships with plant roots for <a href="http://dx.doi.org/10.1126/science.289.5486.1920">hundreds of millions of years</a>. Others break down dead <a href="https://sciencing.com/fungi-contribute-ecosystem-21989.html">plants and animals</a> and return key nutrients to the soil so other life forms can use them. </p>
<p>Fungi are among the few organisms that can degrade lignin, a main component of wood that gives plants their rigidity. Without fungi, our forests would be littered with huge piles of woody debris. </p>
<p>Still other fungi form unique mutualistic partnerships with insects. <em>Flavodon ambrosius</em>, a white rot decay fungus, not only serves as the primary source of nutrition for certain <a href="https://entomologytoday.org/2016/08/02/beetle-farmers-2-0-a-super-symbiont-fungus-supports-a-complex-beetle-society/?msclkid=32065077d13111ecb1e73a7a80c541c6">fungus-farming ambrosia beetles</a>, but it also quickly out-competes other wood-colonizing fungi, which allows these beetles to build large, multigenerational communities. Similarly, <a href="https://www.sciencefocus.com/nature/leaf-cutter-ants-fungi/">leaf-cutter ants</a> raise <em>Leucoagaricus gongylophorus</em> as food by gathering dead plant matter in their nests to feed their fungus partner. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/-XuPtW8lBCM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Leaf-cutter ants and fungi have a complex symbiotic relationship that has existed for millions of years.</span></figcaption>
</figure>
<h2>A mostly unknown kingdom</h2>
<p>We can only partially appreciate the benefits fungi provide, since scientists have a narrow and very incomplete view of the fungal kingdom. Imagine trying to assemble a 4-million-piece jigsaw puzzle with only 3% to 5% of the pieces. Mycologists struggle to formally describe Earth’s fungal biodiversity while simultaneously assessing various species’ conservation status and tracking losses. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/458890/original/file-20220420-19-x7363r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A green shelf-like fungus extends from the base of a fir tree." src="https://images.theconversation.com/files/458890/original/file-20220420-19-x7363r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/458890/original/file-20220420-19-x7363r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458890/original/file-20220420-19-x7363r.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458890/original/file-20220420-19-x7363r.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458890/original/file-20220420-19-x7363r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458890/original/file-20220420-19-x7363r.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458890/original/file-20220420-19-x7363r.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The <em>Bridgeoporus nobilissimus</em> fungus, commonly known as noble polypore, is native to the Pacific Northwest, where it can reach sizes of up to 290 pounds (130 kilograms). It is listed as critically endangered on the International Union for Conservation of Nature Red List.</span>
<span class="attribution"><span class="source">Chael Thomas</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The International Union for Conservation of Nature’s <a href="https://www.iucnredlist.org/">Red List of Threatened Species</a> currently includes 551 fungi, compared to 58,343 plants and 12,100 insects. About 60% of these listed fungal species are gilled mushrooms or lichenized fungi, which represent a very narrow sampling of the fungal kingdom. </p>
<p>Asked what a fungus looks like, the average person will probably imagine a mushroom, which is partly correct. Mushrooms are <a href="https://theconversation.com/stinkhorns-truffles-smuts-the-amazing-diversity-and-possible-decline-of-mushrooms-and-other-fungi-85158">“fruiting bodies,” or reproductive structures</a>, that only certain fungi produce. But a majority of fungi don’t produce fruiting bodies that are visible to the eye, or any at all, so these “microfungi” go largely overlooked. </p>
<p>Many people see fungi as <a href="https://tcpermaculture.com/site/2013/07/01/fighting-fungophobia-or-mycophobia-the-fear-of-mushrooms/">frightening or disgusting</a>. Today, although positive interest in fungi is growing, species that cause diseases – such as chytrid fungus in <a href="https://www.nytimes.com/2019/03/28/science/frogs-fungus-bd.html">amphibians</a> and white-nose syndrome in <a href="https://www.washingtonpost.com/climate-environment/2022/03/22/disease-more-lethal-than-covid-19-has-nearly-wiped-out-northern-long-eared-bats/">bats</a> – still receive more attention than fungi playing <a href="https://www.nytimes.com/2021/11/28/science/fungus-wildfire-charcoal.html">essential, beneficial roles</a> in the environment. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1425491790476550152"}"></div></p>
<h2>Protecting our fungal future</h2>
<p>Even with limited knowledge about the status of fungi, there is increasing evidence that <a href="https://microbiologysociety.org/publication/past-issues/life-on-a-changing-planet/article/impact-of-climate-change-on-fungi.html">climate change</a> threatens them as much as it threatens plants, animals and other microbes. Pollution, drought, fire and other disturbances all are contributing to losses of precious fungi. </p>
<p>This isn’t just true on land. Recent studies of <a href="https://freshwaterblog.net/2022/05/11/forgotten-conservation-targets-the-hidden-world-of-aquatic-fungi/">aquatic fungi</a>, which play all kinds of important roles in <a href="https://doi.org/10.3389/fenvs.2018.00105">rivers, lakes</a> and <a href="https://doi.org/10.1016/j.cub.2019.02.009">oceans</a>, have raised concerns that little is being done to conserve them. </p>
<p>It is hard to motivate people to care about something they do not know about or understand. And it’s difficult to establish effective conservation programs for organisms that are mysterious even to scientists. But people who care about fungi are trying. In addition to the <a href="https://www.iucn.org/commissions/species-survival-commission/about/ssc-committees/fungal-conservation-committee">IUCN Fungal Conservation Committee</a>, which coordinates global fungal conservation initiatives, various <a href="https://ffungi.org/eng/">nongovernment organizations</a> and nonprofits advocate for fungi.</p>
<p>Over the past two years, we have seen a surge of public interest in all things fungal, from <a href="https://www.theguardian.com/lifeandstyle/2022/feb/27/fungi-farming-how-to-grow-your-own-mushrooms">home grow kits and cultivation courses</a> to <a href="https://www.wvmushroomclub.net/join-us">increased enrollment in local mycological societies</a>. We hope this newfound acceptance can benefit fungi, their habitats and people who study and steward them. One measure of success would be for people to ask not just whether a mushroom is poisonous or edible, but also whether it needs protection. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/8tGXFZmndCY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Australian naturalist Steve Axford photographs fungi in Australia’s rainforests, helping scientists document previously unknown species.</span></figcaption>
</figure>
<p>Delegations from most of the world’s countries will meet in China this fall for a <a href="https://www.cbd.int/meetings/COP-15">major conference on protecting biodiversity</a>. Their goal is to set international benchmarks for conserving life on Earth for years to come. Mycologists want the plan to include <a href="https://www.science.org/doi/10.1126/science.abj5479.">mushrooms</a>, <a href="https://www.science.org/doi/10.1126/science.abk1312">yeasts and molds</a>.</p>
<p>Anyone who takes their curiosity outdoors can use community science platforms, such as <a href="https://www.inaturalist.org/observations?place_id=any&subview=map&taxon_id=47170">iNaturalist</a>, to report their observations of fungi and learn more. Joining a <a href="https://wpamushroomclub.org/">mycology club</a> is a great way to learn how to <a href="https://www.modern-forager.com/sustainable-mushroom-picking">find and harvest fungi responsibly</a>, without overpicking or damaging their habitats. </p>
<p>Fungi are forming important networks and partnerships all around us in the environment, moving resources and information in all directions between soil, water and other living things. To us, they exemplify the power of connection and cooperation – valuable traits in this precarious phase of life on Earth.</p><img src="https://counter.theconversation.com/content/181226/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matt Kasson receives funding from the National Science Foundation, The National Geographic Society and the U.S. Department of Agriculture. </span></em></p><p class="fine-print"><em><span>Brian Lovett and Patricia Kaishian do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Fungi underpin life on Earth, but are far less well catalogued and understood than animals and plants. Three scientists call for including fungi in conservation strategies and environmental laws.Matt Kasson, Associate Professor of Mycology and Plant Pathology, West Virginia UniversityBrian Lovett, Postdoctoral Researcher in Mycology, West Virginia UniversityPatricia Kaishian, Visiting Assistant Professor of Biology, Bard CollegeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1566102021-03-10T14:13:56Z2021-03-10T14:13:56ZThe secret life of fungi: how they use ingenious strategies to forage underground<figure><img src="https://images.theconversation.com/files/388614/original/file-20210309-23-6ai9mt.png?ixlib=rb-1.1.0&rect=0%2C154%2C1051%2C928&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Three examples of the obstacle courses we tested our fungi within.</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>When you think of fungi, you’ll probably picture a huddle of chubby brown mushrooms, or the large, red-capped toadstools you stumble across in the woods. In doing so, you’re reducing fungi to their reproductive organs – tasty or striking as they may often be.</p>
<p>The main body of a fungus is actually a large interwoven network called the <a href="https://www.asmscience.org/content/journal/microbiolspec/10.1128/microbiolspec.FUNK-0033-2017">mycelium</a>, which consists of incredibly thin fungal tubes called hyphae. These hyphae are a bit like plant roots: they grow into soil, unseen by us humans, on the hunt for nutrients. </p>
<p><a href="https://www.nature.com/articles/s41396-020-00886-7">Our recent research</a> used an artificial fungal obstacle course to spy on hyphal growth and behaviour. We found a remarkable variety of growth strategies employed by fungal hyphae – so many that we had to give them names.</p>
<p>From the brute force of the “zombie”, which breaks through physical barriers, to the intrepid “marathon runner”, who sets off way ahead of the pack to explore, fungal hyphae appear to be ingenious subterranean foragers. And our findings aren’t merely fascinating: they may have important implications for our fight against climate change, too.</p>
<h2>Foraging fungi</h2>
<p>Fungi are fascinating organisms. Neither plants nor animals, they belong to their own distinct kingdom, estimated to be composed of <a href="https://link.springer.com/article/10.1007/s13225-021-00472-y">between 2 and 6 million species</a>. And though they may look very different from us, fungi still – like us – have to find ways to locate food and solve problems in their environment.</p>
<p>Fungi are also crucial for all nutrient cycles. They decompose and recycle dead biomass in the environment, and help feed water and nutrients to the roots of about <a href="https://www.nature.com/articles/ncomms1046">90% of all land plants</a>. They can be a pain, too: they can cause diseases in humans, animals and plants, and <a href="https://www.nature.com/articles/nature10947">destroy huge amounts of</a> agricultural produce.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/complex-life-may-only-exist-because-of-millions-of-years-of-groundwork-by-ancient-fungi-117526">Complex life may only exist because of millions of years of groundwork by ancient fungi</a>
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<p>Integral to fungi are the hyphae: tubes so thin that sometimes they’re not even visible to the naked eye. For reference, a human hair is about 50 micrometres wide, while fungal hyphae often are as thin as 2 or 3 micrometres. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/388601/original/file-20210309-15-pj5tpv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="One thick cylinder overlaid by one thinner one" src="https://images.theconversation.com/files/388601/original/file-20210309-15-pj5tpv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/388601/original/file-20210309-15-pj5tpv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=341&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388601/original/file-20210309-15-pj5tpv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=341&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388601/original/file-20210309-15-pj5tpv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=341&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388601/original/file-20210309-15-pj5tpv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=429&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388601/original/file-20210309-15-pj5tpv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=429&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388601/original/file-20210309-15-pj5tpv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=429&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 50 micrometre human hair intersected by a 6 micrometre filament. Hyphae are just 2 to 3 micrometres wide.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/w/index.php?curid=350295">Saperaud/wikicommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Going underground</h2>
<p>Many fungi live most of their lives underground, out of sight. As such, we know very little about how these organisms experience their underground environment: if they have the ability to feel that there is food nearby, or what strategies they use to find it.</p>
<p>This was a challenge that we wanted to tackle. Together with biomedical engineers, we manufactured a transparent system of microscopic tunnels that allowed us to simulate the structures found in soil. These “soil chips” are effectively obstacle courses designed to put fungal hyphae through their paces on their search for food.</p>
<figure class="align-center ">
<img alt="A silver surface traversed by a line that is a fungal hyphae" src="https://images.theconversation.com/files/388606/original/file-20210309-13-1psjhj9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/388606/original/file-20210309-13-1psjhj9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388606/original/file-20210309-13-1psjhj9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388606/original/file-20210309-13-1psjhj9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388606/original/file-20210309-13-1psjhj9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388606/original/file-20210309-13-1psjhj9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388606/original/file-20210309-13-1psjhj9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">One of our simplest ‘soil chip’ tests. The fungal hyphae, exploring from left to right, easily clears the obstacle.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>In plant ecology, clonal plant roots are said to grow either like a phalanx unit (short and very densely) or a guerrilla army (far but sparsely). We were surprised to find this dichotomy unusable for our fungi: we needed many more categories. </p>
<p>So, we gave the fungi nicknames to reflect their different growth strategies. Some species had hyphae that grew dense but very far and very straight, without exploring their surroundings (“the marathon runner”). </p>
<p>Others progressed slowly but constantly for months, meandering past complicated turns and corners (“the snake”). Others still branched heavily, filled up almost all free spaces, and with incredible force broke themselves through solid parts of the chips (“the zombie”). </p>
<figure class="align-center ">
<img alt="A mess of lines on a silver background" src="https://images.theconversation.com/files/388613/original/file-20210309-17-1xk7e67.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/388613/original/file-20210309-17-1xk7e67.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388613/original/file-20210309-17-1xk7e67.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388613/original/file-20210309-17-1xk7e67.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388613/original/file-20210309-17-1xk7e67.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=497&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388613/original/file-20210309-17-1xk7e67.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=497&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388613/original/file-20210309-17-1xk7e67.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=497&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In this example, ‘the zombie’ has brute-forced its way through our obstacle course.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Foraging strategies</h2>
<p>These distinct fungal strategies are probably evolutionary traits, given the diversity of environments that the different fungi might encounter. Dense growth strategies allow fungi to break down complex food sources that require large concentrated amounts of enzymes, while far-reaching exploration strategies help fungi to more quickly locate more ephemeral food sources that are spread out or far away.</p>
<p>We also found certain situations that gave fungi a hard time. For example, repeated sharp turns led some to get stuck in corners. Others lost their sense of direction after growing around a circular obstacle. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/388610/original/file-20210309-23-xfllkv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A silver surface upon which a line is meandering into a corner" src="https://images.theconversation.com/files/388610/original/file-20210309-23-xfllkv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/388610/original/file-20210309-23-xfllkv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/388610/original/file-20210309-23-xfllkv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/388610/original/file-20210309-23-xfllkv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/388610/original/file-20210309-23-xfllkv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/388610/original/file-20210309-23-xfllkv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/388610/original/file-20210309-23-xfllkv.png?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">This hyphae, an example of ‘the snake’, has become trapped in a corner of our soil chip.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We were especially interested in those obstacles that hindered fungal growth. That’s because soils are the Earth’s largest terrestrial <a href="https://www.jswconline.org/content/73/6/145A">carbon reservoir</a>, and small changes in their carbon cycling could generate huge differences for <a href="https://ourworldindata.org/emissions-by-sector">atmospheric CO₂ levels</a>. Understanding how soil structures impact fungal growth may lead us to understand how to optimise soils for carbon sequestration – helping us store more CO₂ in the ground. </p>
<p>For now, we hope that our soil chips can continue to be used to spy on the secret life of fungi. Our study only looked at seven different litter-decomposing species of fungi, so there’s plenty of scope for new findings that could reveal how the foraging of fungi underground might affect ecosystems above it.</p><img src="https://counter.theconversation.com/content/156610/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span><a href="mailto:edith.hammer@biol.lu.se">edith.hammer@biol.lu.se</a> receives funding from the Swedish Research Council and the Swedish Foundation for Strategic Research. </span></em></p><p class="fine-print"><em><span><a href="mailto:kristin.aleklett.kadish@slu.se">kristin.aleklett.kadish@slu.se</a> has received funding from the Crafoord foundation during her postdoc at Lund University. </span></em></p>Using tiny ‘soil chips’, researchers have observed the forgaging strategies of fungi at a microscopic scale for the first time.Edith Hammer, Associate Lecturer, Department of Biology, Lund UniversityKristin Aleklett, Postdoctoral research fellow, Swedish University of Agricultural SciencesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1488472020-10-28T18:52:33Z2020-10-28T18:52:33ZLife after death: How insects rise from the dead and transform corpses into skeletons<figure><img src="https://images.theconversation.com/files/366218/original/file-20201028-15-1w2f8fi.jpg?ixlib=rb-1.1.0&rect=461%2C197%2C10423%2C4841&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The process of turning a newly dead animal into a bony skeleton relies on an explosion of life that ushers in decomposition.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>It’s that time of the year when skeletons, skulls and bones have found their way onto cookies, porches and storefront windows. </p>
<p>While skeletons are universally considered symbols of death, the process of turning a newly dead animal into a bony skeleton relies on an explosion of life that ushers in the process of decomposition. Much of this transformative process is performed by wriggling, scuttling, scurrying insects.</p>
<p>Through decades of careful observation and experimentation, entomologists have described a five-stage model of decomposition. This model explains how insects, in close collaboration with microorganisms, transform a warm body into a pile of bones while simultaneously recycling carbon, nitrogen, phosphorous and numerous other nutrients <a href="https://link.springer.com/content/pdf/10.1007/s00442-012-2460-3.pdf">so that other living things may grow and thrive</a>.</p>
<h2>It begins with a corpse</h2>
<p>The first stage of decomposition (termed “the fresh stage”) occurs between the moment of death and the first signs of bloat. Within this period there are no outward signs of physical change, but bacteria already living within the carcass begin to digest tissues within the body. </p>
<p>Insects start arriving in the minutes to hours after the animal has died. Most insects colonizing during this initial period are flies from the <em>Calliphoridae</em> (blowflies), <em>Muscidae</em> (house flies) and <em>Sarcophagidae</em> (flesh flies) families. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/365825/original/file-20201027-23-24ihq2.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/365825/original/file-20201027-23-24ihq2.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=171&fit=crop&dpr=1 600w, https://images.theconversation.com/files/365825/original/file-20201027-23-24ihq2.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=171&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/365825/original/file-20201027-23-24ihq2.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=171&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/365825/original/file-20201027-23-24ihq2.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=214&fit=crop&dpr=1 754w, https://images.theconversation.com/files/365825/original/file-20201027-23-24ihq2.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=214&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/365825/original/file-20201027-23-24ihq2.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=214&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A selection of carrion-feeding flies that appear during the fresh stage of decomposition. A blowfly (left), a house fly (centre), a flesh fly (right).</span>
<span class="attribution"><span class="source">(Kallerna/Wikimedia Commons; USDAgov/Flickr; Muhammad_Mahdi_Karim/Wikimedia Commons)</span></span>
</figcaption>
</figure>
<p>These early flies seek out prime real estate to deposit their eggs. This is generally limited to the animal’s natural cavities (e.g. nostrils or mouth), or within any external injuries (e.g. abrasions). The moisture levels and soft tissue within these areas makes an ideal nursery habitat for young maggots to develop.</p>
<h2>Bloat, maggots and methane</h2>
<p>Bloat comes next. In this second stage of decomposition, the lack of oxygen within the body begins to favour anaerobic microbes. These bacteria thrive in the absence of oxygen within the body. </p>
<p>As the bacteria begin expelling gases like hydrogen sulphide and methane, the abdomen begins to swell. The carcass begins to darken and smells foul. Because carcasses are an uncommon and short-lived source of nutrients, numerous insects may detect and travel to a carcass <a href="https://doi.org/10.1016/S0006-3207(98)00035-4">from kilometres away</a>. </p>
<p>During the bloating stage, fly eggs hatch and large quantities of maggots begin to feed on the flesh. At this point, beetles join in on the feeding frenzy. Some beetles, such as carrion beetles, will feed on the nutrient-rich flesh of the carcass. Predaceous beetles, such as rove beetles and clown beetles, arrive to feed on the maggots.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/365846/original/file-20201027-17-1qjn6sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/365846/original/file-20201027-17-1qjn6sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/365846/original/file-20201027-17-1qjn6sn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/365846/original/file-20201027-17-1qjn6sn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/365846/original/file-20201027-17-1qjn6sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/365846/original/file-20201027-17-1qjn6sn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/365846/original/file-20201027-17-1qjn6sn.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">A carrion beetle always sports Halloween-appropriate colours.</span>
<span class="attribution"><span class="source">(ricosz/flickr)</span></span>
</figcaption>
</figure>
<h2>Maggots work their magic</h2>
<p>The third stage is known as “active decay.” This stage begins when the carcass starts to slowly deflate, a process akin to a tire pierced by a nail. Larval insects gnaw small holes into the body cavities, allowing gases to escape. </p>
<p>Tissues begin to liquefy, giving the carcass a wet appearance, followed by the release of a putrid odour. By the end of the active decay stage, maggots concentrate their feeding within the chest cavity of the animal. Soon beetles dominate, with huge huge numbers of rove beetles and clown beetles arriving to chow down on the maggots. </p>
<p>Once most of the flesh has been eaten away, the carcass enters the stage of advanced decay. The putrid odour of the carcass begins to subside and most maggots leave the carcass to pupate in the underlying soil. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/366112/original/file-20201028-19-wmruoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/366112/original/file-20201028-19-wmruoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=315&fit=crop&dpr=1 600w, https://images.theconversation.com/files/366112/original/file-20201028-19-wmruoe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=315&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/366112/original/file-20201028-19-wmruoe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=315&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/366112/original/file-20201028-19-wmruoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=396&fit=crop&dpr=1 754w, https://images.theconversation.com/files/366112/original/file-20201028-19-wmruoe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=396&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/366112/original/file-20201028-19-wmruoe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=396&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A rove beetle (Creophilus maxillosus) consuming a large maggot atop deer carcass.</span>
<span class="attribution"><span class="source">(Allan Sander/Bugguide.net)</span></span>
</figcaption>
</figure>
<p>Next, adult dermestid beetles arrive at the carcass and begin laying eggs. Dermestid beetles — small round beetles covered in tiny scales — are scavengers that feed on a variety of dry materials: fur, feathers, dead plants, even carpets! If they’re not familiar to you, perhaps you haven’t looked closely enough — a 2016 survey of arthropods in homes <a href="https://doi.org/10.7717/peerj.1582">detected dermestid beetles in 100 per cent of households</a>. </p>
<h2>Dermestid beetles finish the job</h2>
<p>The final stage of decomposition is known as dry decay. Very few adult flies are attracted to the carcass at this stage. During dry decay, the carcass is reduced to bones, cartilage, dried skin and hair. By this stage there is little odour at all.</p>
<p>Larval dermestid beetles continue to clean the skeleton, leaving behind remains that look very similar to a disassembled skeleton. Dermestid beetles are so effective in cleaning bones, in fact, that they are regularly used by museums when preparing skeletons <a href="https://www.youtube.com/watch?v=lYHXgHTEKvU">for collection and display</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/365953/original/file-20201027-13-1qxxe9e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/365953/original/file-20201027-13-1qxxe9e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=298&fit=crop&dpr=1 600w, https://images.theconversation.com/files/365953/original/file-20201027-13-1qxxe9e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=298&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/365953/original/file-20201027-13-1qxxe9e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=298&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/365953/original/file-20201027-13-1qxxe9e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=374&fit=crop&dpr=1 754w, https://images.theconversation.com/files/365953/original/file-20201027-13-1qxxe9e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=374&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/365953/original/file-20201027-13-1qxxe9e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=374&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dermestid beetles cleaning an animal skull at the Minnesota Zoo.</span>
<span class="attribution"><span class="source">(guppiecat/flickr)</span></span>
</figcaption>
</figure>
<h2>The little things that run the world</h2>
<p>While witnessing this beastly undertaking is not for those with squeamish stomachs, decomposition of animal remains is a fundamental process that cycles nutrients within ecosystems. </p>
<p>Nutrients like carbon (the basis of all life on Earth), phosphorous and nitrogen, which all living things need to grow, are in limited supply in ecosystems. They must be constantly reused and recycled to ensure the continuation of life. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/365843/original/file-20201027-17-17x8l41.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/365843/original/file-20201027-17-17x8l41.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/365843/original/file-20201027-17-17x8l41.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/365843/original/file-20201027-17-17x8l41.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/365843/original/file-20201027-17-17x8l41.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/365843/original/file-20201027-17-17x8l41.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/365843/original/file-20201027-17-17x8l41.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">The remains of a deer carcass poking through a carpet of fallen leaves.</span>
<span class="attribution"><span class="source">(lydz/flickr)</span></span>
</figcaption>
</figure>
<p>Following decomposition, the soil beneath the cadaver will contain a high concentration of nutrients <a href="https://doi.org/10.1007/s10021-009-9274-0">relative to the surrounding ecosystem</a>.</p>
<p>However, the nutrients released into the environment don’t all stay in soil and plants. Nutrients and energy contained within the dead animal (whether a mouse, raccoon or crow) are repurposed and repackaged into living, breathing insects. </p>
<p>When these insects complete feeding on a carcass, they disperse into the wider environment where they continue to be productive members of ecosystems. These very same insects help <a href="https://doi.org/10.1098/rspb.2014.2934">pollinate our crops</a> (including pumpkins), fill the bellies of insect-eating animals (<a href="https://doi.org/10.1111/j.1365-294X.2011.05040.x">such as bats</a>) and are crucial to the decomposition of other dead organisms (like rats, toadstools and snakes). </p>
<p>If you happen to stumble across animal bones this Halloween season, or any other time of the year — take a moment to consider the beastly drama that made this discovery possible.</p><img src="https://counter.theconversation.com/content/148847/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Manning receives funding from the Natural Sciences and Engineering Research Council of Canada.</span></em></p>Nutrients and energy contained within dead animals are repurposed and repackaged into living, breathing insects.Paul Manning, Postdoctoral Researcher, Faculty of Agriculture, Dalhousie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1454202020-09-03T15:26:47Z2020-09-03T15:26:47ZPlants might be able to tell us about the location of dead bodies, helping families find missing people<figure><img src="https://images.theconversation.com/files/356121/original/file-20200902-18-tgz0gl.jpg?ixlib=rb-1.1.0&rect=32%2C24%2C5431%2C3612&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Can plants signal to us when they are sick or detect radiation?</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/full-frame-shot-of-glowing-leaf-royalty-free-image/928710424?adppopup=true">Sebastian Kopp/EyeEm via Getty Images</a></span></figcaption></figure><p>The notion of plants talking to us about dead people sounds like a bad horror movie. But that’s the theme of <a href="https://www.cell.com/trends/plant-science/fulltext/S1360-1385(20)30243-0">a recent scientific paper</a> I co-authored. </p>
<p><a href="https://www.un.org/en/development/desa/population/publications/pdf/mortality/WMR2019/WorldMortality2019DataBooklet.pdf">Each day, over 160,000 people die in the world</a>. Most people die with family members present or nearby; their family and friends mourn their loss, which includes having the loved-one’s body present. Sometimes people die in the wilderness, in war and under questionable circumstances. In so many of these cases the body is never recovered and loved ones don’t get closure. In cases of murder or genocide, perpetrators go unpunished without a recovered body. </p>
<p>I didn’t usually think about this topic, until recently. <a href="https://scholar.google.com/citations?user=PLeQmrcAAAAJ&hl=en">I am a plant biologist</a> who uses biotechnology and synthetic biology approaches in research. Nearly 20 years ago, <a href="http://doi.org/10.1016/S0168-9452(03)00161-4">I coined the word “phytosensor”</a> in a paper referring to plants that had been genetically engineered for sensing and reporting.</p>
<p>Imagine a crop plant that could tell you it was getting sick before it started to die - <a href="http://doi.org/10.1016/S0168-9452(03)00161-4">that was my phytosensor idea</a>. Recently I started to wonder if native plants - those that are not engineered - could also sense and report. I found out that other people on my campus had many of the same thoughts before. </p>
<h2>Trees have a lot to tell us</h2>
<p>Maybe the notion of talking trees is not so far-fetched. After all plants are used to responding to changes in their environment. Given that they’re rooted in place, plants really have no choice but to change their chemistry and biology when attacked by pests or face other challenges such as drought or benefit from fertilizer - by way of animal feces. It would seem that long-lived plants like trees must respond quite well at sensing and responding to stresses, allowing them to grow tall and produce shade over decades and even centuries.</p>
<p>When people go missing and die — whether by natural causes or by foul play — their bodies start to decompose if the weather is warm. And if they decompose in the forest under the shade, finding and recovering their bodies can be difficult if not impossible. </p>
<p>One solution is to learn how plants respond to decomposing humans and then “listen” to what they are telling us about the people who’ve died under their canopies. </p>
<h2>The ‘Body Farm’ speaks</h2>
<p><a href="https://ag.tennessee.edu/plantsciences/Pages/FacultyPages/StewartN.aspx">My colleagues and I</a> at the University of Tennessee started such a conversation last year with anthropologists, soil scientists and people who study plants. </p>
<p>One thing that the University of Tennessee is famous for is their <a href="https://fac.utk.edu/mission-statement/">Forensic Anthropology Center</a>, which is more commonly known as the “Body Farm.” In the 1980s Bill Bass, an anthropology professor, founded the The Body Farm, the first research facility of its sort in the world. </p>
<p>Bass used donated woodland near the campus to understand the phases of human decomposition after donated human bodies are left on the surface or are buried. This outdoor facility has been a boon for vastly improving our understanding of how various organisms, such as insects, interact with dead people during various phases of decomposition. But the proverbial elephant in the room — the forest itself — has been overlooked as a responder.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/356112/original/file-20200902-14-1lubbge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scientists are researching whether plants can indicate where bodies lie buried." src="https://images.theconversation.com/files/356112/original/file-20200902-14-1lubbge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/356112/original/file-20200902-14-1lubbge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=795&fit=crop&dpr=1 600w, https://images.theconversation.com/files/356112/original/file-20200902-14-1lubbge.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=795&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/356112/original/file-20200902-14-1lubbge.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=795&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/356112/original/file-20200902-14-1lubbge.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=998&fit=crop&dpr=1 754w, https://images.theconversation.com/files/356112/original/file-20200902-14-1lubbge.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=998&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/356112/original/file-20200902-14-1lubbge.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=998&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 drone surveys plants near the Body Farm in a test flight.</span>
<span class="attribution"><span class="source">Neal Stewart</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Learning to listen</h2>
<p><a href="https://www.cell.com/trends/plant-science/fulltext/S1360-1385(20)30243-0">The paper I co-authored,</a> which is published in Trends in Plant Science, a journal, discusses how we might understand how the forest may speak to us about where people have died. We discussed large inputs that would come from cadavers, such as nitrogen, that would fertilize the plants near a body. </p>
<p>The ways that plant respond to nitrogen influxes are well understood. Nitrogen causes plant leaves to become greener as plants make more chlorophyll. In addition, there may be more nuanced signals - such as drugs or metals - that would leach from dead bodies into the soil. </p>
<p>Certainly, these soil inputs would change microbes near roots, which in turn alters the nutrients plants absorb via their roots.</p>
<p>My colleagues and I quickly came to the conclusion that we didn’t really understand the full picture of how trees and shrubs may change their chemistry, biology and physical appearance in response to cadavers. </p>
<p>But one thing our multidisciplinary team did know is that we had the perfect place to find the answers to these questions: the Body Farm. We had also been flying small drones with sensors to study how an agricultural plant — switchgrass — responded to nitrogen inputs (a paper on that work is under review). So we had some ideas about how drones might be used to detect cadavers. </p>
<p>You might wonder how my colleagues and I can distinguish between a plant’s response to a dead animal versus a human cadaver. Because most wild mammals are much smaller than humans, the plant response to a dead animal versus a dead human should create signals that blend in as background noise. Deer might be an issue since they can weigh as much as a human. </p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p>
<p>Beyond dead bodies, my lab has genetically engineered plants to sense and report problems, such as plant diseases, including those that are caused by bacterial pathogens and <a href="https://doi.org/10.1111/pbi.12247">ionizing radiation</a>. Our engineered plants produced fluorescent proteins upon sensing a particular signal, such as a pathogen or radiation exposure. And we recently custom-made a “fluorescence inducing laser projector” to <a href="https://www.biorxiv.org/content/10.1101/865428v1">take images of plant fluorescence signatures</a> in the lab.</p>
<p>So, while we don’t exactly know how plants may tell us where dead people are, we started learning in June of this year by using the multidisciplinary resources available to us. At some time in the next two years we hope to have a much better understanding of what trees and shrubs have to tell us about missing people, and learn how to “hear” them from the air.</p>
<p><em>This article has been updated with a new caption for the drone image.</em></p><img src="https://counter.theconversation.com/content/145420/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neal Stewart receives funding from DARPA. </span></em></p>Researchers are figuring out how plants respond to the presence of human cadavers. The findings could prove important for discovering the locations of murder victims or mass graves.Neal Stewart, Professor of Plant Sciences, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1242512020-01-10T13:29:26Z2020-01-10T13:29:26ZRotting feral pig carcasses teach scientists what happens when tons of animals die all at once, as in Australia’s bushfires<figure><img src="https://images.theconversation.com/files/309354/original/file-20200109-80122-1mps1j3.jpg?ixlib=rb-1.1.0&rect=404%2C0%2C1640%2C931&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">To understand the effects of a big die-off, researchers set up experiments with wild boar carcasses.</span> <span class="attribution"><span class="source">Brandon Barton, Mississippi State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>The unprecedented wildfire raging across Australia is not only destroying human lives, but has <a href="https://sydney.edu.au/news-opinion/news/2020/01/03/a-statement-about-the-480-million-animals-killed-in-nsw-bushfire.html">killed hundreds of millions of animals</a> – perhaps <a href="https://www.fox10phoenix.com/news/nearly-half-a-billion-animals-feared-dead-in-australia-wildfires-ecologists-say">billions</a> before it is all over. </p>
<p>Burning is not the only cause of death in this catastrophe. Many animals have outrun the flames only to die in <a href="https://www.thesun.co.uk/news/10673494/australia-fires-billion-animals-feared-dead/">fences and roads by the thousands</a>. Others may live, for now, but, without their homes, food and water, are likely to <a href="https://theconversation.com/a-season-in-hell-bushfires-push-at-least-20-threatened-species-closer-to-extinction-129533">succumb to the elements soon</a>.</p>
<p>Unfortunately, animal die-offs of massive proportions are becoming more frequent. Global change – which includes human-caused changes in climate, land use, fire regimes and other things – may largely be to blame for the <a href="https://www.dailymail.co.uk/sciencetech/article-2908325/Why-animals-dying-mass-death-events-occurring-study-claims.html">increased frequency and intensity of mass mortality events</a> across all kinds of animals. </p>
<p>This was the case in 2015 when unseasonably warm and humid weather allowed a normally benign bacteria to <a href="https://doi.org/10.3201/eid2506.180990">wipe out 200,000 saiga antelope in Kazakhstan</a> in just a few weeks. Similarly, <a href="https://www.nytimes.com/2016/08/31/science/lightning-strike-dead-reindeer.html">a single lightning strike killed 323 reindeer</a> in 2016, and another <a href="https://www.nytimes.com/2019/07/31/world/europe/norway-reindeer-climate-change.html">200 starved last year</a> at once after unseasonable rain left an impenetrable layer of ice covering their food. And, for five years in a row, <a href="https://www.dailyherald.com/news/20191214/thousands-of-dead-alaska-seabirds-are-washing-ashore-for-a-fifth-year-experts-call-that-a-climate-red-flag">tens of thousands of starved sea birds have washed up in Alaska</a>. These are just a few recent examples.</p>
<p>So, what happens when everything dies all at once?</p>
<h2>An experimental approach to die-off events</h2>
<p>Our research group studies the ecological consequences of mass mortality events – MMEs for short. </p>
<p>Studying MMEs is difficult because they are unpredictable and can occur anywhere around the world, making it logistically challenging to study the actual events. Even if we could hop on a plane and travel to a distant mass mortality event quickly, we wouldn’t have data on what the ecosystem was like before, so drawing conclusions would be nearly impossible.</p>
<p>To overcome this hurdle, we have worked with wildlife biologist <a href="https://scholar.google.com/citations?user=G84D9fQAAAAJ&hl=en&oi=ao">Marcus Lashley</a> and David Mason at the <a href="https://wec.ifas.ufl.edu">University of Florida</a> to take on the dirty task of simulating mass mortality events in large experiments with thousands of pounds of carrion.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308889/original/file-20200107-123407-10dt821.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308889/original/file-20200107-123407-10dt821.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308889/original/file-20200107-123407-10dt821.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=278&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308889/original/file-20200107-123407-10dt821.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=278&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308889/original/file-20200107-123407-10dt821.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=278&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308889/original/file-20200107-123407-10dt821.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=350&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308889/original/file-20200107-123407-10dt821.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=350&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308889/original/file-20200107-123407-10dt821.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=350&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Trappers donated nearly 15,000 pounds of feral swine carcasses to simulate mass mortality events in Oklahoma in 2019.</span>
<span class="attribution"><span class="source">Brandon Barton, Mississippi State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In spring 2019 we began our largest experiment to date, deploying nearly 15 tons of carcasses in Oklahoma. Our first challenge was finding a large – and ethical – source of carcasses. We partnered with professional trappers who were removing feral pigs, an invasive species that has potential to <a href="https://theconversation.com/feral-pigs-harm-wildlife-and-biodiversity-as-well-as-crops-120066">damage crops, spread disease and negatively affect wildlife</a>. These wild boar were trapped for conservation purposes. Rather than having their carcasses go to waste, we were able to put them to good use.</p>
<p>We wanted to see how increasing amounts of carrion affect decomposition in ways that may alter ecosystems or promote the spread of pathogens. Before the carcasses arrived, we identified plots and sampled the initial soil, microbes, plants, insects and wildlife. This provided important baseline information that wouldn’t be available during a real-world mass mortality event.</p>
<p>The real work began after the carcasses arrived. Pigs have a stinky reputation for a reason, and feral swine – especially several tons of dead ones – are not a pleasant sight or smell. We carefully placed each carcass, which averaged about 70 pounds, in the predetermined plots. Some plots received a single pig to represent a “normal” death event; others received 10 carcasses to represent an MME.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/xrQT6a8Zxaw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Decomposing carcasses become a paradise for flies and other insects.</span></figcaption>
</figure>
<p>Quickly, the plots were buzzing with flies, and vultures circled above. We monitored the decomposition during the first few days, which are by far the most gruesome. Scavengers shredded some carcasses, dragging their remains deep into nearby forests. Unscavenged carcasses bloated with gas before bursting open and revealing millions of writhing maggots inside. </p>
<p>During this time we documented decomposition rate, monitored insect and scavenger visitors, and collected microbial samples to detect disease-causing bacteria. Over the next several weeks, the microbes, insects and scavengers did their job, and soon nothing remained but bones and fur. We will monitor this experiment for several years to identify the long-term ecosystem consequences of mass mortality.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308894/original/file-20200107-123364-90x1yt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308894/original/file-20200107-123364-90x1yt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308894/original/file-20200107-123364-90x1yt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=246&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308894/original/file-20200107-123364-90x1yt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=246&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308894/original/file-20200107-123364-90x1yt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=246&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308894/original/file-20200107-123364-90x1yt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=309&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308894/original/file-20200107-123364-90x1yt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=309&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308894/original/file-20200107-123364-90x1yt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=309&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 researchers monitored carcasses in a simulated mass mortality event.</span>
<span class="attribution"><span class="source">Brandon Barton, Mississippi State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>What happens after many die at once</h2>
<p>Our group’s <a href="https://doi.org/10.1002/ecy.2027">field</a>, <a href="https://search.proquest.com/docview/2234230708">lab</a> and <a href="https://doi.org/10.1016/j.cois.2017.06.006">theoretical</a> investigations reveal that mass mortality events affect ecosystems in two general ways.</p>
<p>First, the sheer magnitude – hundreds or thousands – of individuals removed from the ecosystem means that their roles in the environment are lost too. </p>
<p>In Australia, <a href="https://www.theguardian.com/australia-news/2020/jan/07/kangaroo-island-bushfires-grave-fears-for-unique-wildlife-after-estimated-25000-koalas-killed">as much as half of the koala population</a> in some areas have been killed by fire. Besides being a national symbol and source of ecotourism, koalas are important to the ecosystem as one of the few animals that can consume and recycle nutrients from eucalyptus plants. The widespread death of koalas means a significant break in the food chain – nothing is left to eat eucalyptus.</p>
<p>Similarly, the mass mortality of small mammals, rabbits and kangaroos means that few prey will remain for <a href="https://doi.org/10.1071/RJ10052">predators like dingoes</a>, who may struggle to avoid starvation in the now barren landscape. Fires also kill less charismatic species such as insects and <a href="https://www.theguardian.com/environment/2020/jan/04/ecologists-warn-silent-death-australia-bushfires-endangered-species-extinction">bats, both of which are important for pollination</a>, and their loss may represent a challenge for post-fire plant communities. Without these and other animals present to perform their ecological jobs, Australia’s ecosystems will undoubtedly change.</p>
<p>Secondly, the large number of rotting carcasses caused by a mass mortality event will have their own environmental impacts. </p>
<p>While some of the animals in Australia will be consumed by fire and their bodies quickly transformed into ash, those that meet their fate outside of the flames will begin to decompose. Under normal circumstances, carrion triggers scavengers to flock to the carcasses, <a href="https://www.nationalgeographic.org/encyclopedia/scavenger/">consuming the flesh and recycling the nutrients</a> into the ecosystem.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308886/original/file-20200107-123368-1vzwe5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308886/original/file-20200107-123368-1vzwe5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308886/original/file-20200107-123368-1vzwe5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308886/original/file-20200107-123368-1vzwe5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308886/original/file-20200107-123368-1vzwe5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308886/original/file-20200107-123368-1vzwe5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308886/original/file-20200107-123368-1vzwe5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308886/original/file-20200107-123368-1vzwe5k.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 river of maggots emerges from a simulated mass mortality event in 2016.</span>
<span class="attribution"><span class="source">Brandon Barton, Mississippi State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>However, the ongoing mass mortality of kangaroo, koala and other large animals will produce more carcasses than scavengers – eagles, dingoes and a species of reptiles known as goannas – can keep up with. Instead of disappearing quickly, carcasses will likely become breeding grounds for bacteria and insects. This is worrisome, because many of these may be <a href="https://www.sciencealert.com/houseflies-blowflies-carry-more-diseases-than-thought-bacteria-pathogens">pathogens that affect people, wildlife and livestock</a>, and the flies can transport pathogens great distances. In fact, in previous experiments, our simulated MMEs produced enough flies to cover the ground in a <a href="https://www.nationalgeographic.com/news/2017/09/dead-feral-pig-science-ecology/">river of maggots</a>.</p>
<p>Our work has also revealed that mass mortality events can have long-lasting effects by <a href="https://esa.confex.com/esa/2019/meetingapp.cgi/Paper/145895">poisoning soil</a> and restructuring plant communities. As carcasses decompose, they release gases and spill cocktails of liquefied remains, acidic body fluids and microbes that the soil absorbs. When this happens en masse, the <a href="https://eco.confex.com/eco/2017/meetingapp.cgi/Paper/67964">toxicity can kill plants, including trees</a>. Our unpublished data repeatedly show that MMEs alter the soil microbiome and soil nutrients. How long these effects can last is unknown.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308918/original/file-20200107-107219-ufnl8f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308918/original/file-20200107-107219-ufnl8f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308918/original/file-20200107-107219-ufnl8f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308918/original/file-20200107-107219-ufnl8f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308918/original/file-20200107-107219-ufnl8f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308918/original/file-20200107-107219-ufnl8f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308918/original/file-20200107-107219-ufnl8f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308918/original/file-20200107-107219-ufnl8f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Only bones and fur remained a few weeks after a simulated MME (left). Chemicals leached into the soil during decomposition create a ‘cadaver island,’ killing plants and trees (right).</span>
<span class="attribution"><span class="source">Abby Jones and Brandon Barton, Mississippi State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>What can help get ecosystems back to normal</h2>
<p>The effects of MMEs on ecosystems are complex, but one thing has been consistent across our multiple studies: Healthy scavenger populations reduce the effects of mass mortality events.</p>
<p>Scavengers like <a href="https://doi.org/10.1046/j.1523-1739.2003.01740.x">vultures</a>, <a href="https://www.thedailystar.com/opinion/editorials/in-our-opinion-outrage-over-coyote-hunt-is-ridiculous/article_9ce1d2ae-abcb-5a58-99f3-2903fc3307d9.html">coyotes</a> and <a href="https://theconversation.com/dingoes-found-in-new-south-wales-but-were-killing-them-as-wild-dogs-126184">dingoes</a> are among the most persecuted groups of animals worldwide, yet they provide <a href="https://doi.org/10.1016/j.tree.2010.12.011">critical ecosystem services</a>. When scavengers were present in our experiments, the carcasses were consumed or dragged away quickly, producing fewer maggots and flies, leaching fewer chemicals into the soil, and having a lower impact on the plants and ecosystem.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308893/original/file-20200107-123389-1r1jsln.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308893/original/file-20200107-123389-1r1jsln.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308893/original/file-20200107-123389-1r1jsln.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308893/original/file-20200107-123389-1r1jsln.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308893/original/file-20200107-123389-1r1jsln.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308893/original/file-20200107-123389-1r1jsln.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308893/original/file-20200107-123389-1r1jsln.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308893/original/file-20200107-123389-1r1jsln.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">Researchers used fencing and bird netting to keep vultures and coyotes out, to better understand the role of scavengers – and the consequences of losing them.</span>
<span class="attribution"><span class="source">Brandon Barton, Mississippi State University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>While Earth’s ecosystems may not be able to avoid future mass mortality events, an obvious priority is to maintain the biodiversity we have – including the scavengers that clean up the mess.</p>
<p>In Australia, dingo, eagle, and goanna populations are likely to benefit from the ample carrion provided by these fires. Unfortunately, inflated scavenger numbers may cause more problems. When the carrion eventually disappears, these overabundant scavengers may be forced to seek food in populated areas, resulting in conflict and attacks on <a href="https://www.brisbanetimes.com.au/national/queensland/dingo-put-down-after-fraser-island-attack-showed-concerning-behaviour-20191212-p53jc0.html">people</a> and <a href="https://www.bbc.com/news/world-australia-49368886">domestic animals</a>. Such indirect consequences of these fires are difficult to anticipate.</p>
<p>What is certain, however, is that the ecosystem that emerges after the smoke clears will be dramatically different.</p>
<p>[ <em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklysmart">You can get our highlights each weekend</a>. ]</p><img src="https://counter.theconversation.com/content/124251/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brandon Barton received funding and assistance from Noble Research Institute to conduct this research.</span></em></p><p class="fine-print"><em><span>Abby Jones 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>Death is a natural part of ecosystems. But it’s unusual for a large number of animals to all die at once. Researchers are investigating how a mass mortality event affects what’s left afterwards.Brandon Barton, Assistant Professor of Biological Sciences, Mississippi State UniversityAbby Jones, Graduate Student in Biological Sciences, Mississippi State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1271942019-11-19T08:11:21Z2019-11-19T08:11:21ZFreshwater lakes already emit a quarter of global carbon – and climate change could double that<figure><img src="https://images.theconversation.com/files/302214/original/file-20191118-66979-1ca3kkd.jpg?ixlib=rb-1.1.0&rect=2545%2C0%2C12481%2C7232&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A lake in Banff National Park, Alberta, Canada.</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/Yk6DfYbMDIA">Sergey Pesterev/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Lakes and ponds are the final resting place for many of the Earth’s plants. Rivers collect much of the planet’s dead organic matter, transporting it to rest in calmer waters.</p>
<p>But on a microscopic scale, lakes are anything but calm. An invisible metropolis of microbes feeds on these logs and leaves, producing greenhouse gases as a byproduct.</p>
<p>As a result, lakes may be responsible for as much as a quarter of the carbon in the atmosphere – and rising. <a href="https://doi.org/10.1073/pnas.1904896116">New research</a> conducted with my colleagues in Cambridge, Germany and Canada suggests that emissions from freshwater lakes could double in the coming decades because of climate change.</p>
<p>All known life on Earth is made of carbon. When plants and animals reach the end of their lives, microorganisms such as bacteria and fungi come to feast. They feed on the carbon-based remains of other organisms and their waste products — collectively known as organic matter.</p>
<p>As a byproduct of this never-ending feast, microbes release gases such as carbon dioxide and methane into the environment. While each individual microbe releases a minuscule amount of gas, they are the most abundant organisms on Earth, so it adds up. Energy from sunlight can also break the chemical bonds between molecules of organic matter, releasing smaller molecules, such as carbon dioxide, into the environment.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/302220/original/file-20191118-66932-18tyzwc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/302220/original/file-20191118-66932-18tyzwc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/302220/original/file-20191118-66932-18tyzwc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/302220/original/file-20191118-66932-18tyzwc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/302220/original/file-20191118-66932-18tyzwc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/302220/original/file-20191118-66932-18tyzwc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/302220/original/file-20191118-66932-18tyzwc.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">
<figcaption>
<span class="caption">Lakes and land are not isolated systems.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/4_5HELfe-Zo">Aaron Burden/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Some of this degradation happens on the forest floor. But much of the organic matter that falls to the ground ends up in the water. Winds, rain and snow transport it into lakes, or more often into the rivers that feed them.</p>
<p>The amount of greenhouse gases released from lakes by microbes and sunlight is huge. Initial estimates were <a href="https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter06_FINAL.pdf">about 9%</a> of the net carbon released from the Earth’s surface to the atmosphere – that is, the amount released over and above the Earth’s carbon-storing processes.</p>
<p>But, thanks to improved measurements, recent research has revised the figure to <a href="https://doi.org/10.1002/lol2.10055">as high as 25%</a>. These numbers are substantial given that that lakes only comprise about <a href="https://doi.org/10.1002/2014GL060641">4% of the global land surface</a>.</p>
<p>In the coming years, lakes will receive more and more organic matter for microbes to digest. A warming climate will bring <a href="https://doi.org/10.1038/nclimate3004">more forest cover</a> around lakes and a <a href="https://doi.org/10.1890/ES14-00111.1">greater proportion</a> of broad-leaved trees, such as maples and oaks, as compared to needle-leaved trees, such as pines.</p>
<h2>Carbon in a thousand forms</h2>
<p>To understand how changes to forests will alter the role that lakes play in the carbon cycle, we performed an experiment in two Canadian lakes.</p>
<p>We filled plastic containers with rocks, sand, clay and different amounts and types of organic matter from nearby forests. This was intended to mimic the change in forest cover and composition expected from climate change.</p>
<p>We then submerged the containers in shallow lake waters where organic matter is most likely to accumulate and monitored them for three years.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/NqOVUz76ERo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Using new techniques to analyse the carbon chemistry of water, <a href="https://doi.org/10.1073/pnas.1904896116">we found</a> that those containers simulating a level of forest growth expected in the next few decades led to between 1.5 and 2.7 times more greenhouse gases in the water than conditions simulating today’s forest conditions.</p>
<p>The invisible diversity of organic compounds in the water was the most important factor causing this rise – even more important than the diversity of microbes and the overall amount of organic matter.</p>
<p>The likely explanation for this result is that the same microbes can feed on many different types of molecule. So as the number of carbon-based compounds in the water increases, there are more ways for microbes to feed and release greenhouse gases.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/302219/original/file-20191118-66973-1dp22lq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/302219/original/file-20191118-66973-1dp22lq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/302219/original/file-20191118-66973-1dp22lq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/302219/original/file-20191118-66973-1dp22lq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/302219/original/file-20191118-66973-1dp22lq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/302219/original/file-20191118-66973-1dp22lq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/302219/original/file-20191118-66973-1dp22lq.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">
<figcaption>
<span class="caption">They’ll find their way to a lake sooner or later.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/4_5HELfe-Zo">Aaron Burden/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The increase in diversity of organic matter alone was enough to raise greenhouse gas concentrations by about 50%. But the size of this effect nearly doubled in containers with darker overlying waters – <a href="https://link.springer.com/article/10.1007/s10584-015-1514-z">a scenario expected in most lakes</a> as climate change brings increased tree cover.</p>
<p>Accurately tracing how carbon makes its journey from land to atmosphere is vital to predict the pace of climate change and mitigate its effects. By better understanding how the vegetation around lakes controls greenhouse gas concentrations in waters, our research can inform whether changing the way we manage land near lakes could help reduce carbon emissions.</p>
<p>For example, we might want to plant fewer aquatic plants such as cattails in lakeside areas, because they produce <a href="https://doi.org/10.1038/s41467-018-04236-2">much higher</a> concentrations of greenhouse gases than organic matter from forests.</p>
<p>Work also remains to understand fully the role lakes play in the carbon cycle. Not all organic matter that reaches lakes is digested by microbes. Some sinks to the lake floor to form muddy sediment, locking away carbon. The amount of sediment formed will also increase with climate change, but we don’t yet know by how much – and so to what degree this increase in stored carbon will offset the increased greenhouse gas emissions from lakes.</p>
<p>Answering this question will be crucial in improving the accuracy of carbon accounts – and assessing how much time humanity has to balance them.</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=140&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=140&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=140&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=176&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=176&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263883/original/file-20190314-28475-1mzxjur.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=176&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption"></span>
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<p><em><a href="https://theconversation.com/imagine-newsletter-researchers-think-of-a-world-with-climate-action-113443?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=Imagineheader1127194">Click here to subscribe to our climate action newsletter. Climate change is inevitable. Our response to it isn’t.</a></em></p><img src="https://counter.theconversation.com/content/127194/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew J Tanentzap receives funding for climate change research from the Natural Environment Research Council, European Research Council, and Royal Society.</span></em></p>Lakes are the final resting place for many of the Earth’s plants – and these organic graveyards are about to get a whole lot busier.Andrew J Tanentzap, Reader in Global Change Ecology, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1224682019-09-03T20:04:36Z2019-09-03T20:04:36ZFraming the fearful symmetry of nature: the year’s best photos of landscapes and living things<figure><img src="https://images.theconversation.com/files/290443/original/file-20190902-165989-182rpby.JPG?ixlib=rb-1.1.0&rect=3%2C5%2C955%2C788&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Detail from Reed Plummer's photograph Surge, in which a breaking wave drops tons of water even as it pulls tons of sand from the sea bed.</span> <span class="attribution"><span class="source">South Australian Museum</span></span></figcaption></figure><p>Nature. Some see it as beautiful and some as red “<a href="https://interestingliterature.com/2016/01/01/a-short-analysis-of-tennysons-nature-red-in-tooth-and-claw-poem/">in tooth and claw</a>”. Of course nature is dynamic, it changes between both the beautiful and the dangerous as in <a href="https://www.poetryfoundation.org/poems/43687/the-tyger">Blake’s famous words</a>:</p>
<blockquote>
<p>Tyger Tyger, burning bright, <br>
In the forests of the night; <br>
What immortal hand or eye, <br>
Could frame thy fearful symmetry?</p>
</blockquote>
<p>With the support of the <a href="http://www.samuseum.sa.gov.au/">South Australian Museum</a>, this year’s <a href="https://naturephotographeroftheyear.com.au">Australian Geographic Nature Photographer of the Year</a> competition attracted hundreds of photographers who have attempted to frame the symmetry of nature’s danger and the beauty - both in landscape and living things.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/290484/original/file-20190902-175710-110lkn4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290484/original/file-20190902-175710-110lkn4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/290484/original/file-20190902-175710-110lkn4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=899&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290484/original/file-20190902-175710-110lkn4.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=899&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290484/original/file-20190902-175710-110lkn4.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=899&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290484/original/file-20190902-175710-110lkn4.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290484/original/file-20190902-175710-110lkn4.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290484/original/file-20190902-175710-110lkn4.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Richard Smith’s Small But Mighty captures a crustacean inside a sea squirt.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>The <a href="https://naturephotographeroftheyear.com.au/gallery/">finalists</a> no doubt have mastered the photographers’ tools of trade - metering and focus; composition and colour; balance and visual weight. Experts have critiqued the work, <a href="https://naturephotographeroftheyear.com.au/gallery/?year=2019&category=0&iswinneronly=true">announced winners</a>, and awarded their <a href="https://naturephotographeroftheyear.com.au/gallery/?year=2019&category=Overall%20Winner&iswinneronly=true">grand prize</a>. But does this exhibition capture the multiple dimensions of nature? Well, yes.</p>
<p>Nature is based on <a href="http://environment-ecology.com/what-is-ecology/205-what-is-ecology.html">ecology</a> and ecology is about dynamics and flows. Energy and material cycle through a balanced natural system where everything is used and nothing is lost. Sometimes, though, the balance is disrupted and cycles may be broken or forced to reform in novel ways. </p>
<p>The physical dimensions (length, breadth, depth) and the dangerous beauty inherent in a creature like an echidna leap out in a photograph titled “Under the Spikes” by Isaac Wilson. It captures both the fearsome spikes of an echidna and the beauty of shape and form within. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290427/original/file-20190902-166014-1c6pppf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290427/original/file-20190902-166014-1c6pppf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290427/original/file-20190902-166014-1c6pppf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290427/original/file-20190902-166014-1c6pppf.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290427/original/file-20190902-166014-1c6pppf.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290427/original/file-20190902-166014-1c6pppf.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290427/original/file-20190902-166014-1c6pppf.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290427/original/file-20190902-166014-1c6pppf.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">Under the Spikes by Isaac Wilson.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>Likewise, in the “Clash of the Crabs”, the photographer Samuel Horton has captured the spiky drama of the daily dance of solder crabs as they fight for their future. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/290438/original/file-20190902-166001-1jhg6wv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290438/original/file-20190902-166001-1jhg6wv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290438/original/file-20190902-166001-1jhg6wv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290438/original/file-20190902-166001-1jhg6wv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290438/original/file-20190902-166001-1jhg6wv.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=538&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290438/original/file-20190902-166001-1jhg6wv.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=538&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290438/original/file-20190902-166001-1jhg6wv.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=538&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Clash of the Crabs, by Samuel Horton.</span>
</figcaption>
</figure>
<p>Others see the ecology at wildly different scales, which look alien yet beautiful to our eyes. “New Life in a Far-off World” by Wade Hughes shows what appears, at first, to be destruction by an other-worldly volcano. It turns out to be a sponge’s way of spreading its desire for life as spores across the seas. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290439/original/file-20190902-165985-fulbf9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290439/original/file-20190902-165985-fulbf9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290439/original/file-20190902-165985-fulbf9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=314&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290439/original/file-20190902-165985-fulbf9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=314&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290439/original/file-20190902-165985-fulbf9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=314&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290439/original/file-20190902-165985-fulbf9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=395&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290439/original/file-20190902-165985-fulbf9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=395&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290439/original/file-20190902-165985-fulbf9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=395&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">New Life in a Far-off World by Wade Hughes.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>And in “Small but Mighty”, Richard Smith captures a steadfast soldier defending his crustacean family despite being small enough to live inside a sea squirt. </p>
<p>The image “Surge” by Reed Plummer returns to human scale, but shows us the awesome, daily power of nature. A breaking wave drops tons of water even as it pulls tons of sand from the sea bed.</p>
<p>“Barron Falls” by Neil Pritchard almost lets you hear the tumultuous violence of flood waters heading to the coast. Yet within this drama, the picture draws your eye to a single, small island of green that has found its space within the natural cycle of flooding noise and peace.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290444/original/file-20190902-175700-y618t6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290444/original/file-20190902-175700-y618t6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290444/original/file-20190902-175700-y618t6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290444/original/file-20190902-175700-y618t6.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290444/original/file-20190902-175700-y618t6.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290444/original/file-20190902-175700-y618t6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290444/original/file-20190902-175700-y618t6.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290444/original/file-20190902-175700-y618t6.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">Barron Falls by Neil Pritchard.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>Tim Wrate’s “Above” at first looks like an Aboriginal painting. But, as you draw nearer, the image resolves into a complex maze of mangroves and salt in emerald waterways. You can feel the dynamics of the system and the interplay between life and water. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290434/original/file-20190902-165985-wk7zne.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290434/original/file-20190902-165985-wk7zne.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290434/original/file-20190902-165985-wk7zne.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=480&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290434/original/file-20190902-165985-wk7zne.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=480&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290434/original/file-20190902-165985-wk7zne.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=480&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290434/original/file-20190902-165985-wk7zne.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=603&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290434/original/file-20190902-165985-wk7zne.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=603&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290434/original/file-20190902-165985-wk7zne.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"></a>
<figcaption>
<span class="caption">Above by Tim Wrate.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>The jigsaw of cracked clay in “The Watering Hole” by Melissa Williams-Brown again draws the viewer into pattern. But as you follow the cracks out, a single kangaroo carcass reminds us of the cycles of water, with extreme droughts and floods. We disrupt or misinterpret this cycle at everyone’s peril. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290423/original/file-20190902-166014-1gk8q6q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290423/original/file-20190902-166014-1gk8q6q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290423/original/file-20190902-166014-1gk8q6q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290423/original/file-20190902-166014-1gk8q6q.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290423/original/file-20190902-166014-1gk8q6q.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290423/original/file-20190902-166014-1gk8q6q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290423/original/file-20190902-166014-1gk8q6q.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290423/original/file-20190902-166014-1gk8q6q.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Watering Hole by Melissa Williams-Brown.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>In nature, death can be beautiful. In “The Ghost of the Forest” (Marcia Riederer) an elusive mushroom, feeding on dead material, illuminates the green with its bioluminescence. Without such decomposers feeding on dead things, the cycling of essential materials would cease - no beauty, no death and no life. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290432/original/file-20190902-166001-n46g6l.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290432/original/file-20190902-166001-n46g6l.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290432/original/file-20190902-166001-n46g6l.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=949&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290432/original/file-20190902-166001-n46g6l.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=949&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290432/original/file-20190902-166001-n46g6l.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=949&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290432/original/file-20190902-166001-n46g6l.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1192&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290432/original/file-20190902-166001-n46g6l.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1192&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290432/original/file-20190902-166001-n46g6l.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1192&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 Ghost of the Forest by Marcia Riederer.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>Some people hike for days to experience the beauty of these natural bio-lights, others avoid them for fear that the lights are the souls of the departed. In ecological terms, the luminescence attracts insects, which help disperse the mushroom spore and thus the future of this life form. </p>
<p>Other photographers have focused their lenses on points where the ecological cycles are disrupted. The disruption might be relatively small, like the Flying Fox new parent who almost drowns her own child while getting a drink in “Just Hanging On” (Neil Edwards). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290445/original/file-20190902-175668-ox6j8f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290445/original/file-20190902-175668-ox6j8f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290445/original/file-20190902-175668-ox6j8f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=440&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290445/original/file-20190902-175668-ox6j8f.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=440&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290445/original/file-20190902-175668-ox6j8f.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=440&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290445/original/file-20190902-175668-ox6j8f.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=553&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290445/original/file-20190902-175668-ox6j8f.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=553&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290445/original/file-20190902-175668-ox6j8f.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=553&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Just Hanging On by Neil Edwards.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>Did you know Flying Foxes drink by dipping into water and then licking their wet fur? “Foxes on the Wing” by Paul Huntley catches them doing it just right. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290485/original/file-20190902-175663-1k79w7z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290485/original/file-20190902-175663-1k79w7z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290485/original/file-20190902-175663-1k79w7z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=373&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290485/original/file-20190902-175663-1k79w7z.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=373&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290485/original/file-20190902-175663-1k79w7z.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=373&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290485/original/file-20190902-175663-1k79w7z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=469&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290485/original/file-20190902-175663-1k79w7z.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=469&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290485/original/file-20190902-175663-1k79w7z.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=469&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Paul Huntley’s Foxes on the Wing.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<h2>Larger disruptions</h2>
<p>In Richard Smith’s “In the Can”, tiny fish, peering out of discarded packaging hint at much larger disruptions caused by human efficiency in taking raw materials. Is there a deliberate irony here that humans efficiently take raw resources but neglect to recycle those that now litter the otherwise barren ocean floor?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290431/original/file-20190902-165989-1hcku9j.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290431/original/file-20190902-165989-1hcku9j.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290431/original/file-20190902-165989-1hcku9j.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=446&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290431/original/file-20190902-165989-1hcku9j.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=446&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290431/original/file-20190902-165989-1hcku9j.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=446&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290431/original/file-20190902-165989-1hcku9j.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=560&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290431/original/file-20190902-165989-1hcku9j.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=560&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290431/original/file-20190902-165989-1hcku9j.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=560&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In the Can by Richard Smith.</span>
<span class="attribution"><span class="source">South Australian Musem</span></span>
</figcaption>
</figure>
<p>Other tiny eyes peer from within a roof cavity in “A Possum’s Lookout” (Gary Meredith). These small mammals may be taking advantage of a new preferred habitat created by humans, or they may have been forced out of their usual habitats by other animals or disruptions. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290441/original/file-20190902-165989-1di6h5e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290441/original/file-20190902-165989-1di6h5e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290441/original/file-20190902-165989-1di6h5e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290441/original/file-20190902-165989-1di6h5e.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290441/original/file-20190902-165989-1di6h5e.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290441/original/file-20190902-165989-1di6h5e.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290441/original/file-20190902-165989-1di6h5e.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290441/original/file-20190902-165989-1di6h5e.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 Possum’s Lookout by Gary Meredith.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>Meanwhile, a Satin Bowerbird proudly surrounded by beautiful blue bottle tops adds a new symmetry in “Trash or Treasure” by Matt Wright.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/290426/original/file-20190902-166009-w2b1hq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/290426/original/file-20190902-166009-w2b1hq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/290426/original/file-20190902-166009-w2b1hq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/290426/original/file-20190902-166009-w2b1hq.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/290426/original/file-20190902-166009-w2b1hq.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/290426/original/file-20190902-166009-w2b1hq.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/290426/original/file-20190902-166009-w2b1hq.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/290426/original/file-20190902-166009-w2b1hq.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">Trash or Treasure by Matt Wright.</span>
<span class="attribution"><span class="source">South Australian Museum</span></span>
</figcaption>
</figure>
<p>In this show, each photographer has brought a different perspective on nature. Each of these can enhance your <a href="http://cogprints.org/6094/2/Vidal_2008-what-is-a-worldview.pdf">worldview</a> - allowing you to see the dynamics and resilience; the power and quiet; the destruction and rebirth inherent in it.</p>
<p>Next time you step out of your front door and see a tree in the street, really look at it.</p>
<p>See in it the young seedling of the past, its efforts to survive to the present, and the old senescent trunk full of decomposers of the future.</p>
<p>See in it the life of other organisms and how they <a href="https://theconversation.com/trees-are-made-of-human-breath-99368">use even the dead</a> and ugly. See in it the beauty and power of nature “burning bright”.</p>
<p><em>The Australian Geographic Nature Photographer of the Year competition is produced by the South Australian Museum. It can be seen at the <a href="https://maas.museum/powerhouse-museum/">Powerhouse Museum in Sydney</a> in
partnership with the Australian Museum until 20 October and at the South Australian Museum until 10 November.</em></p><img src="https://counter.theconversation.com/content/122468/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cris Brack is a Senior Fellow of the Higher Education Academy and Member of the Institute of Foresters, Australia.
</span></em></p>The cycles of life, in their fierce glory, are reflected in a stunning exhibition of nature photography.Cris Brack, Associate professor, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1066482018-11-14T13:57:11Z2018-11-14T13:57:11ZHow scavengers can help forensic scientists identify human corpses<figure><img src="https://images.theconversation.com/files/245022/original/file-20181112-83573-jo8xm1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Yellow mongoose probably don't come to mind when thinking of scavengers - but they have been found to scavenge and scatter body parts.</span> <span class="attribution"><span class="source">Jonathan Pledger/Shutterstock</span></span></figcaption></figure><p>When the police recover skeletonised, burnt or heavily decomposed bodies, they need forensic experts to make sense of what they’ve found. One important question in such cases is: when did the person die?</p>
<p>Forensic taphonomists study what happens to human remains after death. They try to provide answers by analysing the state of decomposition and the context in which the remains were found. By doing this, they can establish an approximate <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/post-mortem-interval">post-mortem interval</a> – the time that’s passed since someone died. </p>
<p>This is important for several reasons. First, it reduces the potential pool of individuals the remains could belong to, which increases the chances of identification. Post-mortem interval can also be used to exclude possible perpetrators or to corroborate evidence in investigations.</p>
<p>Sometimes, there’s another reason that bodies are difficult to identify or aren’t found in one piece: they’ve been scavenged. The usual suspects that come to mind when talking about scavengers are hyenas, vultures, or jackals. But there are other animals you’d probably be surprised to find on the list: baboons, porcupines, badgers, racoons, opossums, and even deer.</p>
<p>For a long time we haven’t understood what effect this sort of scavenging and scattering has on the rate of decomposition. For instance, does it change the rate or pattern of decay?</p>
<p>We’ve been trying <a href="http://www.anatomybioanth.uct.ac.za/">to fill this research gap</a> at the University of Cape Town. We’ve researched decomposition since 2014, conducting a number of studies that focus on scavenging and scattering in a large swathe of vegetation in the heart of Cape Town.</p>
<p>The results have helped us to understand the role that scavenging plays in calculating post-mortem intervals. They’ve also already been applied to active forensic cases. This sort of cooperation between science and law enforcement can help to get accurate as well as just results.</p>
<h2>Why scavenging matters</h2>
<p>Our projects are conducted at the South African Medical Research Council’s secure research facility in Delft, Cape Town, within an area called the Cape Flats.</p>
<p>Human remains are often recovered from the particular kind of vegetation that grows in and around the facility, and which is common across the Cape Flats. That’s because the surrounding areas are so densely populated; the area’s <a href="https://www.economist.com/middle-east-and-africa/2018/10/04/why-cape-towns-murder-rate-is-rising">struggle with crime</a> and poverty is also well documented.</p>
<p>Existing methods of studying and measuring post-mortem interval in this vegetation have traditionally relied exclusively on the relationship between temperature and decomposition progression. The effect of scavenging is ignored. But, as our work has shown, it shouldn’t be.</p>
<p>For example, we have gained some invaluable insights from tracking the scavenging habits of the Cape grey mongoose. The knowledge we gained from a research project by an honours student was recently applied to a live police case – to astonishing effect.</p>
<p>Max Spies, an honours student, <a href="https://www.sciencedirect.com/science/article/pii/S037907381830344X?via%3Dihub">found</a> that the Cape grey mongoose (<em>Galerella pulverulenta</em>) was the major and possibly only wild vertebrate scavenger of decomposing carcasses remaining in the environment. (Spies was supervised by myself and PhD candidate <a href="http://uct.academia.edu/DevinFinaughty">Devin Finaughty</a>).</p>
<p>To test their scavenging habits, we set up an experiment using three small pig carcasses. One of these was completely caged to prevent scavenging; the other two were placed out in the open. We set up motion-activated infrared camera traps to catch scavengers in the act and to see how they behaved around the carcasses.</p>
<p>Spies visited the site every second day to track the direction and distance that bony elements were moved away from each original deposition site by the scavengers.</p>
<p>We found that the Cape grey mongoose’s daily scavenging activity had a significant effect. Carcasses the scavengers could access decomposed to skeletonisation within 14 days. But the carcass in the cage took more than 93 days.</p>
<p>We <a href="https://www.sciencedirect.com/science/article/pii/S0379073818303359?via%3Dihub">also discovered</a> that mongoose target smaller, more manageable elements from larger carcasses and move them under cover to eat them. </p>
<p>The insight from this research opened the door for us to take part in an active police case which resulted in the recovery of a complete body in the area. We were called in to assist after a body was found.</p>
<h2>Practical use</h2>
<p>One of the first things we noticed was that the corpse’s hands were missing. Spoor and scat were found around the remains and along the undergrowth paths. These were positively identified by a South African National Parks tracker as belonging to a yellow mongoose (<em>Cynictis penicillata</em>) –- a species similar to the Cape grey mongoose.</p>
<p>The scat was analysed microscopically for its contents and clothing fibres matching those of the deceased were found. </p>
<p>A small tunnel under the bush was seen heading away from the body. After following the tunnel and removing the bushes to five metres from the body, most of the bones of each hand – along with the individual’s watch – were recovered at the entrance to an underground burrow.</p>
<p>Armed with these details, as well as our estimates of how long the corpse had been there, it was possible for the police to identify the person. </p>
<p>Based on the time the deceased went missing, the rapidity of skeletonisation was surprising. But it could be explained because of our knowledge about the way in which the local scavenger operated. </p>
<p>This knowledge, and our accumulated insights, could be crucial in evidence being gathered for other cases, including criminal investigations.</p><img src="https://counter.theconversation.com/content/106648/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Victoria Gibbon 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>Scavengers play an important but often poorly understood role in how fast bodies decompose.Victoria Gibbon, Senior Lecturer in Biological Anthropology, Division of Clinical Anatomy and Biological Anthropology, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/760292017-05-23T06:36:22Z2017-05-23T06:36:22ZWood beetles are nature’s recyclers – with a little help from fungi<figure><img src="https://images.theconversation.com/files/165334/original/image-20170413-25894-vg034a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Larvae of longhorn beetle feeding on pine stump.</span> <span class="attribution"><span class="source">Michał Filipiak</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Dead wood-eating beetles can cause damage to residential properties, just like termites may do. But they repay humans by performing a priceless service: helping us recycle decomposing dead trees. </p>
<p>Decomposition may have an unpleasant ring to it but it is a fundamental process in a functioning ecosystem, ensuring that we are not buried under the huge mass of dead organic matter that is produced every year right on our own doorsteps. </p>
<p>Dead wood-eating beetles are among the insect world’s best decomposers – organisms that digest dead matter and make their own living cells and tissues <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0115104">out of the acquired atoms</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/165339/original/image-20170413-25894-1ulepbq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/165339/original/image-20170413-25894-1ulepbq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165339/original/image-20170413-25894-1ulepbq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165339/original/image-20170413-25894-1ulepbq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165339/original/image-20170413-25894-1ulepbq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165339/original/image-20170413-25894-1ulepbq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165339/original/image-20170413-25894-1ulepbq.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">Huhu beetle (<em>Prionoplus reticularis</em>) larvae contribute to the decomposition of dead pine wood.</span>
<span class="attribution"><span class="source">Charlotte Simmonds/Wikimedia</span></span>
</figcaption>
</figure>
<p>The vast majority of organic matter produced worldwide every year is stored in wood, which is tough, and hard to digest and decompose. Worse yet, <a href="http://www.mdpi.com/2075-4450/7/2/13">wood is nutritionally stingy</a>. Dead wood is rich in sugars (cellulose, hemicelluloses and <a href="https://www.merriam-webster.com/dictionary/lignin">lignin</a>), but try surviving on sugar alone! </p>
<p>Digested wood may be source of energy, but it is insufficiently nutritious so that all the organisms developing in dead wood – beetles but also flies, moths, and bacteria – struggle with <a href="http://onlinelibrary.wiley.com/doi/10.1111/phen.12168/full">growth, development and maturation</a>.</p>
<p>Still, <a href="https://www.fs.usda.gov/treesearch-beta/pubs/11999">dead wood eaters</a> are able to survive and thrive on this low-quality food source. How they do it?</p>
<h2>Sugar-craving wood eaters</h2>
<p>All living organisms have their own ecosystems, with digestive tracts inhabited by symbionts, the scientific term for <a href="http://www.oxfordbibliographies.com/view/document/obo-9780199830060/obo-9780199830060-0006.xml?rskey=9xQ1Wi&result=1&q=symbiosis#firstMatch">organisms living in symbiosis</a>. </p>
<p><a href="http://what-when-how.com/insects/symbionts-aiding-digestion-insects/">Common knowledge would suggest that</a> the activity of wood-eating beetles’ symbionts provides them with nutritionally balanced diets. And we know that beetles are able to <a href="http://doi.wiley.com/10.1111/j.1365-2435.2008.01442.x">synthesise important organic compounds</a> out of nutrients furnished by their primary food, the dead wood. </p>
<p>But according to the <a href="https://www.nature.com/scitable/knowledge/library/the-conservation-of-mass-17395478">law of conservation of mass</a>, which dictates that the mass of the products in a chemical reaction must equal the mass of the reactants, a complete diet based on pure wood would be impossible. The atoms composing nutrients cannot be created out of nothing. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/165342/original/image-20170413-10077-1dwx6n1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/165342/original/image-20170413-10077-1dwx6n1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/165342/original/image-20170413-10077-1dwx6n1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=502&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165342/original/image-20170413-10077-1dwx6n1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=502&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165342/original/image-20170413-10077-1dwx6n1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=502&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165342/original/image-20170413-10077-1dwx6n1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=631&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165342/original/image-20170413-10077-1dwx6n1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=631&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165342/original/image-20170413-10077-1dwx6n1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=631&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Adult female wood-borer on a pine stump.</span>
<span class="attribution"><span class="source">Gailhampshire/Wikimedia</span></span>
</figcaption>
</figure>
<p>The problem is the organic composition of wood. Even if sugars (chemical structure CxH2yOy) are split into atoms, they are a source of only three chemical elements: <a href="https://www.nature.com/scitable/knowledge/library/biological-stoichiometry-102248897">carbon, hydrogen and oxygen</a>. This is not enough to live off even when we consider that sybionts have the ability to assimilate the fourth element, nitrogen, <a href="https://link.springer.com/article/10.1007%2FBF02181997">directly from the air</a>. </p>
<p><a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0115104">It has been estimated</a> that for wood-eating beetles to consume the atomic composition of their bodies from wood alone would require approximately 40 years for males and 85 years for females, which are bigger. In fact, the beetle’s growth period spans at most three to four years in nature. </p>
<p>Beetles must therefore have a source of proper food, offering the needed atoms in the right proportions, and it cannot be the wood that seemingly comprises the whole of their diet. Where do they get the nutrients needed to grow and mature?</p>
<h2>Dead wood</h2>
<p>The answer is fungi.</p>
<p>During the first few years of decay after living wood dies, its <a href="http://www.mdpi.com/2075-4450/7/2/13">nutritional composition is changed by fungi</a>. Fungal tissues growing inside of dead wood are connected to nutritionally-rich areas of the environment outside of the wood. </p>
<p>These may consist of either <a href="http://www.asmscience.org/content/journal/microbiolspec/10.1128/microbiolspec.FUNK-0010-2016">protein-rich organic matter or of minerals and rocks</a>. Rocks may be disintegrated by fungi, and are sources of specific atoms utilised to build fungal tissues. Fungi may even “<a href="http://www.nature.com/doifinder/10.1038/35070643">predate</a>” on soil fauna. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/165331/original/image-20170413-11758-fclizj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/165331/original/image-20170413-11758-fclizj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/165331/original/image-20170413-11758-fclizj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165331/original/image-20170413-11758-fclizj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165331/original/image-20170413-11758-fclizj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165331/original/image-20170413-11758-fclizj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165331/original/image-20170413-11758-fclizj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165331/original/image-20170413-11758-fclizj.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 larvae of the dead wood-eating longhorn beetle feeding on pine stump overgrown by fungi.</span>
<span class="attribution"><span class="source">Michał Filipiak</span></span>
</figcaption>
</figure>
<p>Acquired nutrients are translocated from the outside of dead wood to the inside via the fungal <a href="https://www.anbg.gov.au/fungi/mycelium.html">mycelium</a> (that is, mushroom “body”). By consuming decomposed wood that is rich in fungal tissues, the dead wood eater is able to grow, develop and reach maturity. </p>
<p>But even then its growth is constrained. <a href="http://onlinelibrary.wiley.com/doi/10.1111/phen.12168/full">To cope with the nutritional limitations</a> of dead wood, these beetles prolong their development, slowly growing over several years. During this time, they are able to gather all the necessary building blocks (atoms) for their adult bodies. </p>
<p>Their prolonged development time is made possible by the relative safety and climatic comfort of living inside logs and tree trunks, as opposed to in the outside world, which reduces mortality.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/165344/original/image-20170413-25882-zt4j9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/165344/original/image-20170413-25882-zt4j9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/165344/original/image-20170413-25882-zt4j9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165344/original/image-20170413-25882-zt4j9a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165344/original/image-20170413-25882-zt4j9a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165344/original/image-20170413-25882-zt4j9a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165344/original/image-20170413-25882-zt4j9a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165344/original/image-20170413-25882-zt4j9a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fungi may cover large areas and connect distant patches of the ecosystem, connected by its mycelium.</span>
<span class="attribution"><span class="source">James Lindsey/Wikipedia</span></span>
</figcaption>
</figure>
<h2>Ecological interactions</h2>
<p>Growth and development of dead-wood eating beetles are <a href="http://onlinelibrary.wiley.com/doi/10.1111/phen.12168/full">co-limited</a> by the scarcity of non-sugar nutrients rich in essential bioelements, such as nitrogen, phosphporous, potassium, sodium, magnesium, zinc and copper. Atoms of these elements have the nutrients used for building and maintaining the bodies of growing dead wood-eaters. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/165343/original/image-20170413-25875-1hihfge.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/165343/original/image-20170413-25875-1hihfge.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165343/original/image-20170413-25875-1hihfge.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165343/original/image-20170413-25875-1hihfge.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165343/original/image-20170413-25875-1hihfge.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165343/original/image-20170413-25875-1hihfge.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165343/original/image-20170413-25875-1hihfge.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">
<figcaption>
<span class="caption">Borers like dark-colored (fungi-overgrown) wood.</span>
<span class="attribution"><span class="source">Svajcr/Wikimedia</span></span>
</figcaption>
</figure>
<p>Fungi utilise dead wood as a source of energy, and as they sprout all over logs during the first four or five years of decay, they nutritionally <a href="http://www.mdpi.com/2075-4450/7/2/13">enrich and rearrange</a> dead wood. In doing so, they create a nutritional niche for dead wood-eaters, allowing them to undergo <a href="http://onlinelibrary.wiley.com/doi/10.1111/phen.12168/full">growth and development to maturity</a>. </p>
<p>In turn, <a href="http://doi.wiley.com/10.1111/brv.12158">deadwood-eaters affect the wood</a>, fragmenting and shredding it and producing what’s known as <a href="http://doi.wiley.com/10.1002/ecs2.1300">frass</a> (wood pieces mixed with excrement that may be further decomposed by microorganisms). Beetles therefore contributing to further wood decomposition and nutrient cycling on the forest floor. </p>
<p>Thanks to complicated ecological interactions between dead wood, fungi and dead wood-eaters, the huge mass of the most common organic matter in land ecosystems is being continuously decomposed in forest ecosystems. It’s nature’s own recycling system.</p><img src="https://counter.theconversation.com/content/76029/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michał Filipiak received funding from the Polish Ministry of Science and Higher Education (GrantNo.DS/WBiNoZ/INoŚ/DS761) and the National Science Centre, Poland (Grant No. DEC-2013/11/N/NZ8/00929). The funders had no role in decision to publish, or preparation of this text.
</span></em></p>It’s thanks to decomposition brought about by beetles and fungi that we’re not all buried under dead organic matter.Michał Filipiak, Environmental Biologist, Institute of Environmental Sciences, Jagiellonian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/643182016-09-15T10:51:56Z2016-09-15T10:51:56ZHere’s the clever chemistry that can stop your food rotting<figure><img src="https://images.theconversation.com/files/137783/original/image-20160914-4989-jrve94.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">All things must die. But when?</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-171293201/stock-photo-green-and-rotten-isolated-object-element-of-design.html?src=ovyhEhsrvj86cyOI0fmtUQ-1-62">Shutterstock</a></span></figcaption></figure><p>A hotel in Reykjavík has on display a McDonald’s burger and fries, seemingly undecomposed after 2,512 days – and counting. It was bought on October 30, 2009, the day that the last McDonald’s in Iceland <a href="http://news.bbc.co.uk/1/hi/8327185.stm">closed</a>. But you don’t have to go to Reykjavík to see it: it has its <a href="http://bushostelreykjavik.com/last-mcdonalds-in-iceland">own webcam so you can watch it from your armchair</a>.</p>
<p>What makes this meal so long-lived? Well, I haven’t examined this particular burger myself, but chemical reactions cause food to decay – and understanding them can help us to keep food better and for longer.</p>
<p>Let’s start with uncooked rice – in many peoples’ minds it’s a foodstuff that will keep for a long while. Experts reckon that <a href="http://www.thefreedictionary.com/polished+rice">polished white rice</a> will keep for 30 years when properly sealed and stored in a cool, dry place. This means in an airtight container with oxygen absorbers that remove the gas that can oxidise molecules in the rice.</p>
<figure>
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<p>Hotter food goes off faster; as you may remember from school science lessons, chemical reactions are faster at high temperatures because hotter molecules have more energy and so are more likely to react when they collide. It’s one reason we have fridges. But there is a limit. Above a certain temperature (approximately 50-100°C), the enzymes in a bacterium get denatured – their “active site”, where its catalytic activity happens and it binds to molecules to carry out reactions on them, loses its shape and can no longer carry out reactions. </p>
<p>Back in the 19th century, <a href="http://www.bbc.co.uk/timelines/z9kj2hv">Louis Pasteur</a> invented the process that bears his name. <a href="http://www.dairycouncil.co.uk/consumers/industry/what-is-pasteurisation">Pasteurisation</a> kills the bacteria that make food go off and today this is applied mainly to milk. Milk that has been pasteurised by heating to just over 70°C will keep for two to three weeks when refrigerated, while UHT milk, made by heating to 140°C, will keep in airtight, sterile containers for up to nine months. Raw milk left in the fridge would <a href="http://www.raw-milk-facts.com/Raw_Milk_FAQ.html">last only a few days</a>. </p>
<h2>Living off the land</h2>
<p>The short life of food was the reason that medieval armies “lived off the land” by scavenging, but in 1809 a Frenchman named <a href="https://www.britannica.com/biography/Nicolas-Appert">Nicholas Appert</a> won a prize offered by his government for a process for preserving food. He showed that food sealed inside a container to exclude air and then cooked to a high enough temperature to kill microbes such as <em>Clostridium botulinum</em> kept for a long time. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/137908/original/image-20160915-30587-1idxx66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/137908/original/image-20160915-30587-1idxx66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/137908/original/image-20160915-30587-1idxx66.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/137908/original/image-20160915-30587-1idxx66.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/137908/original/image-20160915-30587-1idxx66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/137908/original/image-20160915-30587-1idxx66.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/137908/original/image-20160915-30587-1idxx66.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">
<figcaption>
<span class="caption">Clostridium botulinum bacteria.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-389771695/stock-photo-clostridium-botulinum-bacteria.html?src=XDVER4N7CUntq4gxBPRVoQ-1-0">Shutterstock</a></span>
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<p>He’d invented <a href="https://kayjayaitch.wordpress.com/2016/04/15/the-truth-about-canning/">canning</a>, which came into widespread use, and not just for feeding armies and expeditions – it was immediately taken up by the civilian sector, too. <a href="http://www.emeraldinsight.com/doi/pdfplus/10.1108/eb011318">Tinned food certainly works</a>. Sir William Edward Parry, for example, took 26 tons of canned pea soup, beef and mutton with him in 1824 on his expedition to find the Northwest Passage. One of these mutton cans was opened in <a href="http://alanskitchen.com/Food_Preservation/Canning/0001-0025/0001-Canning_History.htm">1939 and found to be edible, if not very palatable</a>. </p>
<p>Conversely, cold slows germ growth. Keeping food at around 5°C in a fridge slows microbial growth – but it doesn’t stop it. People living in very cold areas like the Arctic discovered this sooner, of course, without the need for fridges. And watching the Inuit fish under thick ice gave <a href="http://www.biography.com/people/clarence-birdseye-9213147">Clarence Birdseye</a> the idea of fast-freezing food; this creates smaller ice crystals than ordinary freezing, resulting in less damage to cell walls, so the food not only keeps for longer but also tastes better.</p>
<h2>Sugar and spice and all things nice</h2>
<p>Beginning with communities in hotter regions like the Middle East, dried food has been around for thousands of years – the earliest cases are thought to date back to 12,000BC. Drying food, whether using the sun (and wind) or modern factory processes, removes water from the cells of the microbes that break down food. This stops them reproducing and ultimately kills them.</p>
<p>An extension of this is the use of salt (or sugar) to preserve food. While salt beef and pork may conjure up thoughts of the Royal Navy in the days of <a href="https://savoringthepast.net/2013/01/08/salted-meat-for-a-journey-at-sea/">Jack Aubrey and Stephen Maturin</a> – heroes of Patrick O'Brian’s Napoleonic novels – the process goes back much further than that.</p>
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<figcaption><span class="caption">Master and Commander: Aubrey and Maturin.</span></figcaption>
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<p>In the Middle Ages, salted fish like herring and cod were widely eaten in northern Europe, and fish was of course essential during Lent. The cells of microorganisms have walls that are <a href="http://www.scienceclarified.com/everyday/Real-Life-Chemistry-Vol-2/Osmosis-Real-life-applications.html">permeable to water but not to salt</a>. When the cell is in contact with salt, osmosis takes place, so water moves out of the cell in order to try to equalise the salt concentration inside and outside the cell, and eventually so much water is removed from the cell that it dies. No more bacteria.</p>
<p><a href="http://www.scientificamerican.com/article/how-do-salt-and-sugar-pre/">Sugar</a> has a similar effect, just think of fruit preserves, jam or jellies. Smoking also dries out food. Some of the molecules formed when wood is burned, <a href="https://podfanatic.com/podcast/chemistry-in-its-element/episode/vanillin-chemistry-in-its-element-1">like vanillin</a>, will add flavour, while others, including formaldehyde and organic acids have preservative properties.</p>
<p>Freeze-drying is an up-to-date way of removing water from food, perhaps this is the kind of coffee that you use. Modern manufacturers are tapping into something that the Incas in the High Andes developed 2,000 years ago to prepare freeze-dried potatoes, <a href="http://photos.oregonlive.com/photo-essay/2013/08/method_of_freeze-drying_potato.html">known as chuño</a>. The practice continues today. Potatoes are left out overnight, when freezing temperatures are guaranteed, then they trample on them, bare-footed, to mash them up. The blistering sun then completes the job – you have a food that will keep for months, food either for the Inca armies or the peasants of Bolivia and Peru.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/137907/original/image-20160915-30605-11qjxjl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/137907/original/image-20160915-30605-11qjxjl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/137907/original/image-20160915-30605-11qjxjl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/137907/original/image-20160915-30605-11qjxjl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/137907/original/image-20160915-30605-11qjxjl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/137907/original/image-20160915-30605-11qjxjl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/137907/original/image-20160915-30605-11qjxjl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&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">Turmeric: hidden powers.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-273715592/stock-photo-fresh-turmeric-roots-on-wooden-table.html?src=dvWdaYYTPXXD8cYEMJMA7Q-1-0">Shutterstock</a></span>
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<p>How about spices? Well, <a href="http://theplate.nationalgeographic.com/2014/12/01/stinky-smelly-wonderful-onions/">both onion and garlic have antimicrobial properties</a>. There is <a href="https://blogs.cornell.edu/cibt/files/2015/05/Antimicrobial-Functions-of-Spices.pdf">evidence</a> that the use of spices in warmer climates is linked with their <a href="http://news.nationalgeographic.com/news/2005/11/1111_051111_spicy_medicine.html">antimicrobial properties</a>, so adding them to food can help preserve it.</p>
<p>The antibacterial activity of some spices, notably cinnamon and coriander, is probably due to the <a href="https://www.chemistryworld.com/podcasts/hexenal/6836.article">aldehydes</a> – reactive molecules containing a –CHO group, formed by oxidising alcohols and including hexenal, the molecule we smell when grass is freshly cut – <a href="http://www.academicjournals.org/article/article1380527716_Joe%20et%20al.pdf">they contain</a>. </p>
<p>The spice that has got most attention is turmeric, made from the roots of a plant in the ginger family, <em>Curcuma longa</em>, and particularly a molecule it contains, called <a href="http://www.ncbi.nlm.nih.gov/pubmed/26652155">curcumin</a>. Turmeric was used in food in the Indus valley over 4,000 years ago, as well as in medicine. Today, it may be a useful lead molecule against <a href="http://news.vanderbilt.edu/2015/01/curcumin%E2%80%99s-ability-to-fight-alzheimer-studied/">Alzheimer’s disease</a>, as well as possibly interfering with various signalling pathways implicated in cancers.</p>
<p>So there is sound science behind the processes used to preserve food and some of these substances <a href="http://www.ccsenet.org/journal/index.php/jfr/article/download/26027/17077">may have hidden benefits to our health</a>. That hamburger in Iceland, however, remains a mystery. There certainly have been plenty of media stories trying to get the <a href="http://www.businessinsider.com.au/myth-mcdonalds-burgers-dont-rot-2012-10?_ga=1.255710472.1434746596.1397489641">bottom of its apparent immortality</a> – but the only way to be sure would be to subject it to rigorous scientific enquiry. Perhaps I’ll book my flight.</p><img src="https://counter.theconversation.com/content/64318/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Cotton 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>Anyone for a 2,512-day-old burger?Simon Cotton, Senior Lecturer in Chemistry, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.