tag:theconversation.com,2011:/us/topics/biology-521/articlesBiology – The Conversation2024-03-20T22:41:06Ztag:theconversation.com,2011:article/2246822024-03-20T22:41:06Z2024-03-20T22:41:06ZHow do halibut migrate? Clues are in their ear bones<figure><img src="https://images.theconversation.com/files/578657/original/file-20240220-18-5yndy5.jpg?ixlib=rb-1.1.0&rect=24%2C18%2C3953%2C2999&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The habitats used throughout the halibut's life and the movements between them are difficult to characterize.</span> <span class="attribution"><span class="source">(Charlotte Gauthier)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>Rising temperatures, changes in major currents, <a href="https://theconversation.com/why-the-st-lawrence-estuary-is-running-out-of-breath-184626">oxygen depletion at great depths</a>: the Gulf of St. Lawrence has undergone major changes in its environmental conditions in recent decades. That has put many species in danger and, as a consequence, made them more sensitive to the effects of fishing.</p>
<p>However, these changes are benefiting other species such as Atlantic halibut, which is beating records for its abundance and is presently seeing the highest stock in the Gulf of St. Lawrence in <a href="https://waves-vagues.dfo-mpo.gc.ca/library-bibliotheque/41206708.pdf">the last 60 years</a>.</p>
<p>As a biology researcher, I’d like to shed some light on some of the mysteries that still surround this unusual species.</p>
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<img alt="" src="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>This article is part of our series, <a href="https://theconversation.com/ca-fr/topics/fleuve-saint-laurent-116908">The St. Lawrence River: In depth</a>.
Don’t miss new articles on this mythical river of remarkable beauty. Our experts look at its fauna, flora and history, and the issues it faces. This series is brought to you by <a href="https://theconversation.com/ca-fr">La Conversation</a>.</em></p>
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<h2>Atlantic halibut: champion of the Gulf of St. Lawrence</h2>
<p>Atlantic halibut is a flatfish that lives at the bottom of the estuary and gulf of the St. Lawrence. It is prized for its fine, firm white flesh, which is highly appreciated by consumers.</p>
<p>Halibut can grow to impressive sizes of <a href="https://www.tandfonline.com/doi/full/10.1080/23308249.2021.1948502">more than two metres</a>. Because of the quality of its flesh and its popularity on dinner plates, it is currently the most commercially valuable fish in the Gulf of St. Lawrence.</p>
<p>But this has not always been the case. In the 1950s, the adult, harvestable portion of halibut populations, known as the stock, <a href="https://academic.oup.com/icesjms/article/73/4/1104/2458915?login=false">suffered a major decline due to overfishing</a>.</p>
<p>If we want to continue to exploit this resource over the long term, we must not repeat the same mistakes we made in the past. To avoid these mistakes, it is vital to have a good understanding of the life cycle of halibut and the effects that fishing can have on the stock. So far, this has not been done to the fullest.</p>
<h2>The challenges for sustainable fishing</h2>
<p>The basic biology of Atlantic halibut is fairly well known. However, both the habitats they use throughout their lives and their movement between these places are more difficult to characterize.</p>
<p><a href="https://academic.oup.com/icesjms/article/77/7-8/2890/5923787?login=false">Recent studies</a> have placed satellite tags on halibut to record data on the depth and temperature of the water in which they are found, making it possible to accurately calculate their movement. By using this method, the researchers were able to identify the trajectories of adult halibut over a one-year period and discover that they reproduce in winter in the deep channels of the Gulf.</p>
<p>In the halibut’s different annual trajectories, the researchers observed that, in summer, some remain in the deep channels while others migrate to shallower areas.</p>
<p>Even with this new information, a number of questions remain, specifically about the youngest life stages, which are caught only anecdotally in the Gulf. Satellite tags also provide accurate information, but only over a one-year period, which doesn’t tell the whole story for a fish that can live up to 50 years.</p>
<p>With this in mind, the use of a new tool to study the entire life of fish becomes highly relevant.</p>
<h2>Ear bones to the rescue</h2>
<p>All bony fish have small calcareous structures in their inner ear called otoliths, or ear bones, which perform balance and hearing functions.</p>
<p>Otoliths develop at the very beginning of a fish’s life and grow at the same rate as the fish. Otoliths form annual growth rings that are comparable to those visible in tree trunks.</p>
<p>To grow, otoliths accumulate chemical elements that are found in the environment in which the fish swim. So, when the fish moves, the chemical elements accumulated in the otoliths will be different from one place to another. Each location is characterized by a unique combination of different concentrations of chemical elements. This is known as an elemental fingerprint. Identifying these fingerprints can provide us with crucial information about the movement of fish in different places throughout their lives.</p>
<p>I used this method of characterizing the chemical elements in otoliths to study the migratory patterns of Atlantic halibut in the Gulf of St. Lawrence.</p>
<h2>A wide range of migratory strategies</h2>
<p>To find out what concentrations of a chemical element correspond to the place where the fish was caught, we use the fingerprint of the otolith margin, i.e. the material at the end of the outermost ring of the otolith, which was accumulated last.</p>
<p>The concentrations of the elements found there are considered to be characteristic of the place where the fish was caught. By analyzing the margins of nearly 200 halibut otoliths from all over the Gulf, I was able to distinguish two basic fingerprints: one representative of surface waters (less than 100 metres deep) and one characteristic of deeper waters (more than 100 metres deep).</p>
<p>Once these fingerprints had been identified, I observed the concentration of chemical elements throughout the life of the fish so that I could associate each moment of life with either the surface water fingerprint or the deep-water fingerprint.</p>
<p>By separating the life of each individual into time spent in surface and deep waters, I was able to identify recurring patterns and group them into three different migratory strategies: residents, annual migrants and irregular migrants.</p>
<p>In this way, I was able to observe that halibut caught in the southern part of the Gulf were mainly annual migrants, and therefore undertake migrations between deep and shallow waters every year. However, in the northern part of the Gulf the majority are residents. Residents are fish that may have migrated early in their lives, but have settled permanently in deep waters before reaching maturity. Irregular migrants, on the other hand, show migrations on a more sporadic frequency, and are found in similar proportions throughout the study area.</p>
<h2>On the right track to optimal management</h2>
<p>My study is the first to offer a global view of the movements made by halibut over their entire lifetime.</p>
<p>This new information provides a better understanding of the structure of the stock and the diversity of migratory strategies that can be found within it.</p>
<p>Given that these strategies are distributed differently in different areas of the Gulf, we can ensure that we do not disproportionately target halibut using the same migratory strategy and avoid overfishing a single component of the stock.</p>
<p>In this way, it is possible to conserve this diversity, which helps the stock’s resilience in the face of the various changes that can occur.</p><img src="https://counter.theconversation.com/content/224682/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Charlotte Gauthier has received funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Fondation de l'Université du Québec à Chicoutimi.
</span></em></p>Atlantic halibut are making a strong comeback in the Gulf of St. Lawrence. But how do we know where the fish move throughout their lives?Charlotte Gauthier, Étudiante au doctorat, Université du Québec à Chicoutimi (UQAC)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2196872024-03-14T12:43:43Z2024-03-14T12:43:43ZCity mouse or country mouse? I collect mice from Philly homes to study how they got so good at urban living<figure><img src="https://images.theconversation.com/files/576250/original/file-20240216-24-90lbyl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">European colonizers brought mice to the Americas, where they squeaked out a comfortable life.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/mouse-peeking-out-of-the-hole-royalty-free-image/525023427">Dejan Kolar/iStock Collection via Getty Images Plus</a></span></figcaption></figure><p>Dusty barns, gleaming stables and damp basements. These are all places where you might find a house mouse – or a member of my research team. </p>
<p>I’m an <a href="https://scholar.google.com/citations?user=DMxMLmwAAAAJ&hl=en">evolutionary biologist</a>, and my lab at Drexel University studies wild house mice. With help from Philly residents, we are collecting mice from high-rises and row homes to learn more about the impacts of city living on house mice. In short, we want to know whether there is any scientific basis to <a href="https://sites.pitt.edu/%7Edash/type0112.html#aesop">“The Town Mouse and the Country Mouse” fable</a> in which the cousins eat differently based on where they live.</p>
<p><a href="https://www.npr.org/2023/07/26/1190071137/its-hot-out-there-a-new-analysis-shows-its-much-worse-if-youre-in-a-city">Cities are hotter</a> and they have a lot of people living in high densities, which means more trash and usually more pollution. This can affect how <a href="https://www.doi.org/10.1126/science.aam8327">species that live in cities evolve</a>. Cities are also dominated by artificial habitats such as sidewalks, high-rises and subways rather than open fields and forests. </p>
<p>We are interested in many possible changes, but especially in whether the many differences between urban and rural environments translate into genetic differences between city mice and country mice, such as which versions of genes related to metabolism are more common. </p>
<p>To find the answers, we sequence the mice’s genomes. With that data, we can answer a variety of questions, such as: Are city mice more or less genetically diverse than country mice? Are there regions of DNA, the molecule that encodes genetic information, that are consistently different between urban and rural mice? If so, what are the functions of genes in those regions? </p>
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<a href="https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An illustration of two mice from a translation of Aesop's Fables published in 1912." src="https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=516&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=516&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579697/original/file-20240304-16-fd7au7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=516&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">Just how different are city mice and country mice? Researchers are studying their guts and genes to find out.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Rackham_town_mouse_and_country_mouse.jpg">Arthur Rackham, public domain via Wikimedia Commons</a></span>
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<h2>Why study house mice?</h2>
<p>One reason we study house mice is because they are so widespread. European colonizers <a href="https://doi.org/10.1093/g3journal/jkac332">brought house mice to the Americas</a> around 500 years ago. The rodents have now spread into many different climates and habitats across North and South America in most places that humans live, including Philadelphia. </p>
<p>Though small in size, house mice have made immeasurable <a href="https://shop.elsevier.com/books/the-mouse-in-biomedical-research/fox/978-0-12-369456-0">contributions to genetics and medicine</a>. They are mammals like humans, but house mice reproduce quickly and are relatively easy to breed and maintain. In fact, part of why scientists adopted mice early on as a model system is because people were already breeding “<a href="https://doi.org/10.7554/eLife.05959">fancy mice</a>” as pets. As a result, methods for keeping and breeding them were known.</p>
<p>Mice have many visible traits for geneticists to study. My team wants to know more about the genes and traits that have contributed to their ability to thrive in a variety of environments. The work we do with wild house mice also feeds back into work with laboratory mice and biomedical research. The house mice found in attics and cabinets are the same species that are studied in labs, but they are <a href="http://doi.org/10.1038/ng.847">more genetically diverse</a> than laboratory strains. Our project will generate whole genome sequences from many wild mice, and that data can help scientists who study traits and diseases. </p>
<h2>Tips for catching mice</h2>
<p>I previously worked on a large project studying <a href="https://doi.org/10.1371/journal.pgen.1007672">how house mice have adapted to different climates</a> in the Americas. For that project, I went to many, many farms throughout the eastern United States and became very good at catching mice in barns. </p>
<p>Starting this project with a focus on cities was a new challenge. First, our team had to find Philly residents who wanted us to trap their mice. We spent a lot of time spreading the word on social media, talking to friends and posting flyers. </p>
<p>We talked to many Philadelphians who were frustrated with trying to rid their homes of mice. Some had videos of house mice avoiding the traps they had set or stealing the bait and running away. We share this frustration and feel it keenly. In some cases, it took us many days to catch a single mouse in an apartment.</p>
<p>Part of the reason is because many Philadelphia houses are old. This means they are often full of character – and holes that give mice great places to hide. Luring the mice out of their nests and into our traps is difficult. We had the most success with peanut butter bait, which has a strong and very appealing odor for mice. But mice are omnivores, eating a diverse diet that includes insects. We have heard many stories from community members who used bait such as chocolate, cereal, cookies and even bacon bits. </p>
<h2>What’s next</h2>
<p>We hope to start sharing results over the next two years. We are working in three cities – Philadelphia, New York City and Richmond, Virginia – and have completed our first collections. Now we need to generate and analyze genetic data, so we are very busy in the lab. </p>
<p>We are extracting DNA, as well as another form of genetic material called RNA, from different tissues. With the DNA we will study how much genetic variation exists within city mouse populations, and whether there are genetic differences between urban and rural mice. The RNA will help us understand how differences in DNA translate into differences in metabolism, physiology and other cellular processes. </p>
<p>We will also look to see whether there are differences in traits. For example, we will measure their skulls and skeletons. We will sequence the DNA of the microbes in their digestive system to learn about their gut microbiomes, the collection of bacteria that live in their digestive system, and use <a href="https://www.futurelearn.com/info/courses/archaeology/0/steps/15267">stable isotope analysis</a> to identify any differences in their diets. Stable isotope analysis of diet uses the ratios of naturally occurring atoms of elements such as carbon and nitrogen to determine what types of food an organism has eaten.</p>
<p>Cities are full of wildlife. Learning about how cities shape the evolution of mice may help us find better ways to manage mouse populations and other urban wildlife while also better understanding evolution.</p><img src="https://counter.theconversation.com/content/219687/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Megan Phifer-Rixey receives funding from the National Science Foundation (NSF CAREER 2332998 Division of Environmental Biology).
</span></em></p>An evolutionary biologist is studying what these resilient urban pests can teach us about adaptation and evolution.Megan Phifer-Rixey, Assistant Professor of Biology, Drexel UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2236462024-03-14T03:55:30Z2024-03-14T03:55:30ZWhy is the male body the scientific default when the female body drives the reproductive success of our species?<figure><img src="https://images.theconversation.com/files/581526/original/file-20240313-20-9ueone.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C2038%2C1536&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Eve – Lucas Cranach the Elder (c.1510)</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Cranach_Adam_and_Eve_(detail)_3.jpg">Public domain, via Wikimedia Commons</a></span></figcaption></figure><p>American essayist Cat Bohannon loves a bit of pop culture to contextualise her ideas. <a href="https://www.penguin.com.au/books/eve-9781529151244">Eve: How the Female Body Drove 200 Million Years of Human Evolution</a> – her ambitious, funny, intelligent history of female evolution – is threaded with it. </p>
<p>The book opens with a futuristic scene from <a href="https://www.imdb.com/title/tt1446714/">Prometheus</a>, the 2012 prequel to <a href="https://www.imdb.com/title/tt0078748/">Alien</a>. Archaeologist Elizabeth Shaw is in an AI surgery pod, seeking a life-saving caesarean (she has been impregnated with an alien squid) when an affectless voice gives her an error message: “This medpod is calibrated for male patients only.” </p>
<p>Crash-test dummies, heart-attack symptoms, anti-depressant dosages, air-conditioning systems in large office buildings: we are all pretty aware by now that these are “calibrated for male bodies only”. Alien Prometheus is set in 2093; one can only hope the scientific technology of the late 21st-century turns out to have, at least, a “female-registering” option.</p>
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<p><em>Eve: How the Female Body Drove 200 Million Years of Human Evolution – Cat Bohannon (Hutchinson Heinemann)</em> </p>
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<a href="https://images.theconversation.com/files/581482/original/file-20240313-30-i0czkw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/581482/original/file-20240313-30-i0czkw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/581482/original/file-20240313-30-i0czkw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=923&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581482/original/file-20240313-30-i0czkw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=923&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581482/original/file-20240313-30-i0czkw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=923&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581482/original/file-20240313-30-i0czkw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1160&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581482/original/file-20240313-30-i0czkw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1160&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581482/original/file-20240313-30-i0czkw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1160&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<p>While women’s hormonal cycles have made us messy in the arena of “clean science” – not good controls, not good at being controlled for – Bohannon reminds us that an understanding of the female body cannot be retrofitted to an understanding of the male body. Women are not just men with extra fleshy bits and confounding hormones. </p>
<p>Bohannon also reminds us those “fleshy bits” have a function beyond providing a curvaceous silhouette. </p>
<p>Female adipose tissue, 600 million years old, stored around our butts and thighs, is necessary to the development of babies’ brains. It is so necessary that girls begin storing it in childhood and when women liposuction it out of their lower bodies it returns in unexpected places: the armpits, for example. Bohannon points out that the possible repercussions of liposuction on the brain health of future offspring has not yet been studied.</p>
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Read more:
<a href="https://theconversation.com/women-have-heart-attacks-too-but-their-symptoms-are-often-dismissed-as-something-else-76083">Women have heart attacks too, but their symptoms are often dismissed as something else</a>
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<h2>Reproductive success</h2>
<p>The salient question here is: why is the male body the scientific default when it is the female body that crucially drives the evolution and reproductive success of our species? Eve is both a rectification of this immense blind spot and, in Bohannon’s own words, “a user’s manual for the female mammal”. </p>
<p>Yet how to collapse 200 million years of evolutionary history into 500 pages (let alone 1500 words)? </p>
<p>Bohannon does this by organising her book into a series of “Eves” from whom we inherited our current biological functions, creating an often diverging, often interlocking chronology. There is the Eve of milk, “the real Madonna”; placental Eve, “an HR Giger fever-dream meat factory” (Bohannon has fun with language); Donna, Eve of the uterus; and Pergi, the tree-dwelling Eve of perception. </p>
<p>This structure allows Bohannon to move from microbiology to paleoanthropology, evolutionary biology to gynaecology, anatomy to social history. I learnt much about my own body in her sprawling, illuminating discussions, but also about animal reproductive biology in general — from monotremal cloacas (platypuses and echidnas have them) to squamation hemipenises (snakes and lizards) and “notoriously foldy” anti-rape duck vaginas designed to circumvent corkscrew penises. </p>
<p>It was some small relief to learn the fairly straightforward design of the human penis is testament to a “not-particularly rapey” human evolutionary history. </p>
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<a href="https://images.theconversation.com/files/581824/original/file-20240314-18-pjj64q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/581824/original/file-20240314-18-pjj64q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581824/original/file-20240314-18-pjj64q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581824/original/file-20240314-18-pjj64q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581824/original/file-20240314-18-pjj64q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581824/original/file-20240314-18-pjj64q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581824/original/file-20240314-18-pjj64q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581824/original/file-20240314-18-pjj64q.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>
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<span class="caption">‘Notoriously foldy.’</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Detailed_white_duck.jpg">Image: Roger Heslop, via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Bohannon writes with tender care of her “Eves”. She manages to both penetrate and animate deep time for the reader, a textual equivalent perhaps of Walking with Dinosaurs. She describes the Jurassic insect-eater <a href="https://museum.wales/blog/1895/Meet-Morgie/">Morgie</a> (my favourite), one of the earliest known mammals, skittering over the feet of dinosaurs to get home to her burrow, where she sweats milk through mammary patches to feed her hidden brood. Morgie comes vividly alive in her small precarious existence: “funny, warm, heart-fluttering Eve”, Bohannon writes. </p>
<p>For a female with a uterus, who has twice given birth and twice breastfed, Bohannon’s book demystified many of the mysterious goings-on of my reproductive system. I had no idea, for instance, that lactation was such an intensive co-production between mother and baby. </p>
<p>I knew it enabled a baby’s gut to be colonised with good maternal bacteria, and I knew the basic mechanics of the let-down reflex. But I didn’t know that the composition of the milk itself is informed by a baby’s needs. These needs, codified in a baby’s saliva, are registered by the mother’s body, which then customises its milk accordingly, so it is full of the particular bacteria- or virus-fighting agents required.</p>
<p>This recriprocity is also apparent in the biological wonder that is the placenta. Built out of both endometrial and embryonic tissue, the placenta is “one of the only organs in the animal world made out of two separate organisms”. </p>
<p>Did you know this? I certainly didn’t. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581827/original/file-20240314-30-yukxv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/581827/original/file-20240314-30-yukxv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581827/original/file-20240314-30-yukxv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581827/original/file-20240314-30-yukxv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581827/original/file-20240314-30-yukxv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581827/original/file-20240314-30-yukxv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=369&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581827/original/file-20240314-30-yukxv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=369&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581827/original/file-20240314-30-yukxv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=369&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">‘Morgie’ – Morganucodon, one of the earliest known mammals.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Morganucodon.jpg">FunkMonk (Michael B.H.), via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<strong>
Read more:
<a href="https://theconversation.com/a-raunchy-new-big-history-tells-the-story-of-sex-but-raises-some-unanswered-questions-213538">A raunchy new 'Big History' tells the story of sex, but raises some unanswered questions</a>
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<h2>Life: a user’s manual</h2>
<p>In this sense, Eve really is a user’s manual. At the risk of sounding “miracle of life” about it, Bohannon’s book puts wonder into the commonplace by explaining not only how our reproductive systems work, but how they came to be.</p>
<p>Women’s bodies are not just about babies, of course. Bohannon charts new political territory, tracing her anatomical discoveries through to their social outcomes. Truisms of human and social evolution are turned on their heads and gynaecology gets its rightful place in the story. </p>
<p>Milk again: the population growth that enabled humans to become the ferocious planet-hogs we are today might be down to the humble wet-nurse of ancient civilisations. The prevalence of wet-nursing meant the natural contraceptive properties of breastfeeding were not in play for many women. This meant women had much shorter spaces between pregnancies and had more babies. Wet-nurses, those under-sung footnotes in history, might well have catalysed the growth of modern cities.</p>
<p>Bipedalism? It might just be that we stood up on two feet not so we could better carry spears, but so we had free arms to carry babies while hunting and still cart as much food home with us as possible.</p>
<p>Tool-making? The seminal moment here may not have been a Kubrick-style raising of a femur bone to crunch down on a challenger’s head, or beat an animal to death for dinner (fossil remains show we really didn’t eat a particularly intensive paleo diet). Instead, it might have been a woman, baby on back, chewing a sapling to a neat point to hunt “<a href="https://www.nationalgeographic.com/animals/mammals/facts/bushbabies">bush-babies</a>” asleep in tree hollows. </p>
<p>Bohannon makes a good argument that it was women, not men, who most needed tools to hunt. Our biologically stronger male counterparts often needed only the heft of their bodies to bring down an animal. Women were inventors, she says, because, being smaller, being weaker, they had more need.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/581555/original/file-20240313-18-z1f8bf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/581555/original/file-20240313-18-z1f8bf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581555/original/file-20240313-18-z1f8bf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581555/original/file-20240313-18-z1f8bf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581555/original/file-20240313-18-z1f8bf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581555/original/file-20240313-18-z1f8bf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581555/original/file-20240313-18-z1f8bf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581555/original/file-20240313-18-z1f8bf.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">Cave painting depicting a woman giving birth, Serra da Capivara national park, Brazil.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Serra_da_Capivara_-_Painting_8.JPG">Vitor 1234, via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<strong>
Read more:
<a href="https://theconversation.com/friday-essay-matrilineal-societies-exist-around-the-world-its-time-to-look-beyond-the-patriarchy-200825">Friday essay: matrilineal societies exist around the world – it's time to look beyond the patriarchy</a>
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<h2>Womb triumphalism</h2>
<p>Our most important invention, though – and this is the overarching thesis of Bohannan’s book – is gynaecology. “What got us here,” she writes, “is not tool triumphalism but womb triumphalism.” </p>
<p>Considering how hard it is for the human female body to get pregnant, stay pregnant, deliver a baby (without us or it dying), and then look after it through its protracted childhood, it is a miracle that humans populate – and over-populate — the planet in the way we have come to. Gynaecology, Bohannon writes, </p>
<blockquote>
<p>is absolutely essential for our species’ evolutionary fitness. Without it, it’s doubtful we would have made it this far […] The arrival of midwifery is one of those moments when we can truly say, “Here is when we become human” […] No other mammals on the planet have been observed regularly helping one another give birth.</p>
</blockquote>
<p>With gynaecology comes contraception, reproductive choice and birth-spacing. Knowledge about the properties of herbs and plants, about labour, about delivering a breech or posterior baby, or really <em>any</em> baby (they are all life and death situations) – all of these combine to enable the flourishing of humans, in spite of our large heads, narrow pelvises, complex gestation and birthing trajectories. </p>
<p>“Women had their hands on the actual machinery of evolution,” Bohannon writes. And while she notes that “[m]odern female coalitions are scattered, vulnerable, brittle”, her book celebrates the ancient collaboration between women and the spirit of cooperation over competition that got us here. </p>
<p>Bohannon repositions this as profound in its significance for the human race. A failure to fully apprehend the different workings of male and female bodies and not provide for these differences – or to provide comprehensively for one sex, and neglect the other – doesn’t just mean there will be no caesarean option in a future surgery-pod. </p>
<p>It means limiting human possibility and opportunity. It represents a failure to grasp the whole human story and its potential.</p>
<p>Bohannon ends her book with a practical feminist statement about the importance – and boon to society – of educating women, feeding them properly (not last), and putting financial means in their hands. </p>
<p>Smart humans of the future – who might want to flourish without destroying the means of their flourishing – will require women with adipose fat to feed the brains of their suckling babies, with reproductive choices to plan and space those babies, and with life choices which enable them to contribute their full potential to the world. </p>
<img src="https://counter.theconversation.com/content/223646/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edwina Preston has received funding from Creative Victoria and the Australia Council for the Arts. She works for the Australian Education Union</span></em></p>The story of human evolution is inextricable from the story of gynaecology.Edwina Preston, PhD Candidate, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2244942024-02-29T19:06:47Z2024-02-29T19:06:47ZWe discovered a ‘gentle touch’ molecule is essential for light tactile sensation in humans – and perhaps in individual cells<figure><img src="https://images.theconversation.com/files/578809/original/file-20240229-16-loeyq2.jpeg?ixlib=rb-1.1.0&rect=36%2C0%2C2692%2C2570&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/womans-hand-fern-leaf-man-nature-2190358695">Shutterstock</a></span></figcaption></figure><p>You were probably taught that we have five senses: sight, sound, smell, taste and touch. This is not quite right: “touch” is not a single sense, but rather several working together. </p>
<p>Our bodies contain a network of sensory nerve cells with endings sitting in the skin that detect an array of different physical signals from our environment. The pleasant sensation of a gentle touch feels distinct from the light pressure of our clothes or the hardness of a pencil gripped between our fingers, and all of these are quite different from the pain of a stubbed toe.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-do-you-feel-your-sense-of-touch-is-several-different-senses-rolled-into-one-169344">How do you feel? Your 'sense of touch' is several different senses rolled into one</a>
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<hr>
<p>How do these sensory neurons communicate such a wide range of different inputs? </p>
<p>In <a href="http://www.science.org/doi/10.1126/science.adl0495">new research published in Science</a>, the two co-authors of this article and our colleagues have found a force-sensing molecule in nerve cells called ELKIN1, which is specifically involved in detecting gentle touch. This molecule converts gentle touch into an electrical signal, the first step in the process of gentle touch perception.</p>
<h2>How we sense gentle touch</h2>
<p>Sensing gentle touch begins with tiny deformations of the skin due to a light brush. While they may not seem like much, these deformations generate enough force to activate sensory molecules that are found in specialised nerve endings in the skin. </p>
<p>These molecular force sensors form a pore in the surface of the cell that is closed until a force is applied. When the cell is indented, the pore opens and an electrical current flows. </p>
<p>This electrical current can generate a signal that moves along the sensory nerve to the spinal cord and up to the brain. </p>
<p>Our new research, led by Gary Lewin and Sampurna Chakrabarti from the Max Delbruck Center in Berlin, showed the force sensor ELKIN1 is necessary for us to detect very gentle touch.</p>
<p>They found mice lacking the ELKIN1 molecule did not appear to sense a cotton bud being gently drawn across their paw. The mice retained their ability to sense other environmental information, including other types of touch.</p>
<h2>Different molecules for different kinds of touch</h2>
<p>This new finding reveals one reason we can sense multiple types of “touch”: we have multiple, specialised force-sensing proteins that can help us distinguish different environmental signals. </p>
<p>ELKIN1 is the second touch-receptor molecule discovered in sensory neurons. The first (PIEZO2) was found in 2010 by Ardem Patapoutian, who was later awarded the Nobel Prize for the work. PIEZO2 is involved in sensing gentle touch, as well as a sense known as “proprioception”. Proprioception is the sense of where our limbs are in space that helps us regulate our movements.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578782/original/file-20240228-30-4t2s64.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A microscope image showing blobs of cyan, yellow and magenta." src="https://images.theconversation.com/files/578782/original/file-20240228-30-4t2s64.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578782/original/file-20240228-30-4t2s64.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578782/original/file-20240228-30-4t2s64.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578782/original/file-20240228-30-4t2s64.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578782/original/file-20240228-30-4t2s64.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578782/original/file-20240228-30-4t2s64.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578782/original/file-20240228-30-4t2s64.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mouse neurons with the new ion channel ELKIN1 (cyan), which is responsible for touch sensation, nucleus (yellow) and the already known ion channel PIEZO2 (magenta).</span>
<span class="attribution"><span class="source">Sampurna Chakrabarti / Max Delbrück Center</span></span>
</figcaption>
</figure>
<p>Identifying these force-sensing molecules is a challenge in itself. We need to be able to study nerve cells in isolation and measure electrical currents that flow into the cell while simultaneously applying controlled forces to the cells themselves. </p>
<h2>Do cells feel?</h2>
<p>While much of our research studied mouse neurons, not all scientific data obtained from mice can be directly translated to humans. </p>
<p>With team members at the University of Wollongong, one of us (Mirella Dottori) tried to determine whether ELKIN1 worked the same way in humans. They reprogrammed human stem cells to produce specialised nerve cells that respond to “touch” stimuli. In these human cells, ELKIN1 had similar functional properties of detecting touch. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578781/original/file-20240228-24-4t2s64.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a glass electrode prodding some cells in a Petri dish." src="https://images.theconversation.com/files/578781/original/file-20240228-24-4t2s64.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578781/original/file-20240228-24-4t2s64.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578781/original/file-20240228-24-4t2s64.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578781/original/file-20240228-24-4t2s64.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578781/original/file-20240228-24-4t2s64.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578781/original/file-20240228-24-4t2s64.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578781/original/file-20240228-24-4t2s64.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">Experiments on sensory neurons confirmed the role of the ELKIN1 molecule.</span>
<span class="attribution"><span class="source">Felix Petermann / Max Delbrück Center</span></span>
</figcaption>
</figure>
<p>While this research expands our understanding of how we make sense of the world around us, it also raises an additional, intriguing possibility. </p>
<p>ELKIN1 was first identified by one of us (Kate Poole) and her team at UNSW, with Gary Lewin and his team, while studying how melanoma cells break away from model tumours and “feel” their way through their surroundings. This could mean these tiny molecular force sensors give not only us, but our individual cells, a nuanced sense of touch.</p>
<p>Future research will continue to search for more molecular force sensors and endeavour to understand how they help our cells, and us, navigate our physical environment.</p><img src="https://counter.theconversation.com/content/224494/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kate Poole receives funding from the National Health and Medical Research Council, the Australian Research Council and the US Air Force Asian Office of Aerospace Research and Development
</span></em></p><p class="fine-print"><em><span>Mirella Dottori receives funding from the Australian Research Council, Medical Research Future Fund, Friedreich's Ataxia Research Alliance and Friedreich Ataxia Research Association. </span></em></p>Our bodies have a dedicated channel for sensing only the very lightest of touches.Kate Poole, Associate Professor in Physiology, UNSW SydneyMirella Dottori, Professor, University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2199502024-02-21T13:18:35Z2024-02-21T13:18:35ZPotato plant radiation sensors could one day monitor radiation in areas surrounding power plants<figure><img src="https://images.theconversation.com/files/575459/original/file-20240213-24-b1fnxo.jpg?ixlib=rb-1.1.0&rect=0%2C16%2C3642%2C2714&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fields of genetically modified potato plants could detect radiation. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/f4df32b6c6354b5389fd59adaae707aa?ext=true">AP Photo/John Miller</a></span></figcaption></figure><p>While expanding nuclear energy production would provide carbon-free power and can help countries around the world meet their <a href="https://unfccc.int/process-and-meetings/the-paris-agreement">climate goals</a>, nuclear energy could also come with some inherent risk. Radioactive pollution damages the environment, and it’s nearly impossible to detect without specialized equipment. But what if plants growing in the facility’s surrounding area could detect radiation pollution?</p>
<p>The mechanical radiation detectors currently used, <a href="https://remm.hhs.gov/civilian.htm">called dosimeters</a>, aren’t completely reliable – during previous nuclear <a href="https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident.aspx">accidents such as Chernobyl</a>, they’ve failed or been <a href="https://www.spokesmanbooks.com/acatalog/Zhores_Medvedev.html">buried under rubble</a>. </p>
<p><a href="https://utia.tennessee.edu/person/?id=11899">Our team</a> of <a href="https://plantsciences.tennessee.edu/racheff/">plant scientists</a> at the University of Tennessee wanted to figure out alternatives to these mechanical radiation sensors to help address their historic failures, so we decided to build a <a href="https://doi.org/10.1111/pbi.14072">plant-based sensor for gamma radiation</a>. The sensor, called a phytosensor, is a potato plant that glows fluorescent green when exposed to radiation.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/MaaZjoHDvMo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Dosimeters sense how large a dose of radiation something in an area exposed to radiation would absorb.</span></figcaption>
</figure>
<h2>Historic sensor problems</h2>
<p>Current nuclear energy production is <a href="https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/safety-of-nuclear-power-reactors.aspx">considered safe by the World Nuclear Association</a>. But safety failures still happen, whether <a href="https://www.spokesmanbooks.com/acatalog/Zhores_Medvedev.html">from human error</a> or <a href="https://shop.elsevier.com/books/fukushima-accident/povinec/978-0-12-408132-1">natural disasters</a> such as earthquakes bringing the mechanical sensors offline – and that’s where our plant sensors could come in.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black and white photo showing a large explosion hole in a building, from an overhead view." src="https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.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">Radiation sensors can help inform responses to nuclear accidents. Pictured is damage from the 1986 Chernobyl accident.</span>
<span class="attribution"><span class="source">AP Photo/Volodymyr Repik</span></span>
</figcaption>
</figure>
<p>Mechanical radiation detection equipment needs electrical power and regular maintenance, both of which make them less reliable during emergencies. A plant-based sensor wouldn’t require either of these.</p>
<p>The kinds of disasters that take mechanical sensors offline might damage the potato sensors but most likely wouldn’t kill an entire planted field of potatoes. As long as some plant cells are still alive, the plant could function as a radiation sensor. </p>
<p>Though potato plants are tough, some disasters, like a wildfire, would damage plant sensors more than mechanical sensors. While our sensors could supplement mechanical sensors, they wouldn’t completely replace their use. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two small potato plants in green and two in gray, shown from overhead, in a square pot filled with soil" src="https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.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">Genetically modified potato plants acting as radiation sensors.</span>
<span class="attribution"><span class="source">Stewart lab</span></span>
</figcaption>
</figure>
<h2>Plants as sensors</h2>
<p>Unlike mammals, plants can tolerate a lot of radiation before they die.
Potato plants, for example, can survive <a href="https://doi.org/10.1111/pbi.14072">10 times the amount of radiation</a> that would kill a human. </p>
<p>We chose potato as our sensor organism because potato plants can tolerate high levels of radiation, they’re easy to grow using tubers and they can survive in a <a href="https://www.fao.org/faostat/en/#data/QCL/visualize">variety of environments across the globe</a>. </p>
<p>Radiation exposure <a href="https://pubs.acs.org/doi/10.1021/tx000020e">damages DNA inside an organism’s cells</a>. When this happens in plants, they enter a “red alert” scenario and activate many DNA repair genes to fix the problem. </p>
<p>My colleagues and I co-opted the <a href="https://doi.org/10.3389/fpls.2015.00885">DNA damage response pathway</a> in potato plants so that when exposed to radiation, the potato leaves made a green fluorescent protein. This fluorescent protein causes the sensor plants to emit a unique green fluorescent glow when exposed to gamma radiation. </p>
<p>While the human eye can’t see the green signature, drones used for <a href="https://doi.org/10.1016/j.compag.2023.107737">agricultural and environmental monitoring</a> can. The more green fluorescence produced by the plant, the higher the radiation intensity. So the sensors can tell you “yes, there’s radiation,” as well as roughly how much radiation there is. </p>
<p><a href="https://doi.org/10.1111/pbi.14072">In our tests</a>, the plants reported radiation eight hours after exposure, but that was also the earliest our team was able to check them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small drone flying over a crop field, with a house in the background." src="https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.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">Drones, like the kinds used for agricultural monitoring, would be able to see whether the plants are lighting up, keeping humans out of the irradiated area.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/DronesAgriculture/ab91c96f7c134734a9f0fc41c003e93b/photo?Query=agricultural%20drone&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=130&digitizationType=Digitized&currentItemNo=17&vs=true&vs=true">AP Photo/Alex Brandon</a></span>
</figcaption>
</figure>
<p>Based on our testing, the current radiation phytosensor can report a minimum total dose of <a href="https://remm.hhs.gov/gray_definition.htm">10 gray of radiation</a> – a very lethal dose for a human. The sensors reported radiation eight hours after exposure to it, and they continued to do so for 10 or more days, depending on dose. </p>
<p>Mechanical sensors can detect far lower radiation levels in real time, rather than as a cumulative dose like the phytosensors detect. This makes mechanical sensors ideal for everyday monitoring of dangerous radiation within a power plant, while phytosensors are better suited to monitor the larger areas of land around a power plant.</p>
<p>The current sensor could monitor radiation levels for the general public in an emergency scenario where radioactive material could be anywhere within a large disaster area. Chernobyl contaminated an area <a href="https://www.iaea.org/newscenter/focus/chernobyl/faqs">about the size of Nebraska</a>, while Fukushima contaminated an <a href="https://www.mdpi.com/2227-9067/2/1/39">area about the size of New Jersey</a>. Most of this area had low-level contamination, with some hot spots.</p>
<p>Compared with mechanical sensors, phytosensors are slower and less sensitive, so they wouldn’t save anyone working inside the power plant, even if they were grown indoors. The current sensor could tell first responders where the hottest areas are during a large-scale disaster. After a disaster, it could inform regulators where it is safe for workers, and eventually the public, to return to. </p>
<p>We tested the sensor using an in-lab laser and camera, which are low-power and low-resolution devices. Actual drones with specialized detection systems would likely be able to detect lower radiation thresholds.</p>
<p>In addition to functioning similarly to mechanical radiation sensors, the potato-based radiation phytosensor is a living and growing organism that gets its energy from sunlight. This means that <a href="https://doi.org/10.1111/pbi.14072">the phytosensor is</a> self-repairing, self-propagating and self-powering, unlike mechanical sensors. Since potatoes grow from tubers, they don’t need to be replanted every year.</p>
<p>One obvious downside of the current sensor is that potato plants die in the winter, so during that season you’d lose the sensor. Our sensor gene potentially could be put into an evergreen species like a pine tree, but this sensor would need to be retested to understand its detection minimums and performance over time.</p>
<h2>Potential applications</h2>
<p>When used in combination with more sensitive mechanical sensors, the current radiation phytosensor could act as a fail-safe if a disaster <a href="https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/fukushima-daiichi-accident.aspx">similar to Fukushima Daiichi</a> were to occur. </p>
<p>While there are many possibilities for incorporating phytosensors into our current monitoring systems, our team still has hurdles to cross before the plants can be deployed in the field. </p>
<p>First, nuclear regulators would have to determine whether this technology is safe and useful, given their expectations for radiation monitoring equipment. Then, the plant sensor would undergo rigorous evaluation by the USDA to determine whether the phytosensors would negatively affect ecosystems if released. </p>
<p>Overcoming these hurdles will require more research, which could take months given the growth time for plants. Despite the work ahead, radiation phytosensors could help protect people and the environment in the future as countries continue producing nuclear energy.</p><img src="https://counter.theconversation.com/content/219950/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neal Stewart receives funding from federal organizations. This work was funded by the Defense Advanced Research Projects Agency. Neal Stewart is an inventor in plant biotechnology, though none of the technologies described in the Conversation article are patented. </span></em></p><p class="fine-print"><em><span>Robert Sears 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>What if plants in the area surrounding a nuclear reactor could act as radiation detectors, with the help of a drone?Robert Sears, Graduate Research Assistant in Plant Science, University of TennesseeNeal Stewart, Professor of Plant Sciences, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2208282024-02-14T13:24:42Z2024-02-14T13:24:42ZWe designed wormlike, limbless robots that navigate obstacle courses − they could be used for search and rescue one day<figure><img src="https://images.theconversation.com/files/571646/original/file-20240126-17-1c52dw.JPG?ixlib=rb-1.1.0&rect=55%2C0%2C4024%2C1578&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Limbless robots may not need lots of complex algorithms when they have mechanical intelligence. </span> <span class="attribution"><span class="source">Tianyu Wang</span></span></figcaption></figure><p>Scientists have been trying to build <a href="https://en.wikipedia.org/wiki/Snakebot">snakelike, limbless robots</a> for decades. These robots could come in handy in <a href="https://www.science.org/content/article/searching-survivors-mexico-earthquake-snake-robots">search-and-rescue</a> situations, where they could navigate collapsed buildings to find and assist survivors. </p>
<p>With slender, flexible bodies, limbless robots could readily move through confined and cluttered spaces such as debris fields, where walking or wheeled robots and human rescuers tend to fail.</p>
<p>However, even the most advanced limbless robots have not come close to moving with the agility and versatility of worms and snakes in difficult terrain. Even the tiny nematode worm <em><a href="http://www.wormbook.org/">Caenorhabditis elegans</a></em>, which has a relatively simple nervous systems, can navigate through difficult physical environments. </p>
<p>As part of a team of <a href="https://www.lulab.gatech.edu/">engineers</a>, <a href="https://crablab.gatech.edu/">roboticists and physicists</a>, we wanted to explore this discrepancy in performance. But instead of looking to neuroscience for an answer, <a href="https://en.wikipedia.org/wiki/Biomechanics">we turned to biomechanics</a>. </p>
<p>We set out to build a robot model that drove its body using a mechanism similar to how worms and snakes power their movement. </p>
<h2>Undulators and mechanical intelligence</h2>
<p>Over thousands of years, organisms have evolved <a href="https://www.britannica.com/science/nervous-system">intricate nervous systems</a> that allow them to sense their physical surroundings, process this information and execute precise body movements to navigate around obstacles. </p>
<p>In robotics, engineers design algorithms that take in information from sensors on the robot’s body – a type of robotic nervous system – and use that information to decide how to move. These algorithms and systems are usually complex. </p>
<p>Our team wanted to figure out a way to simplify these systems by highlighting mechanically controlled approaches to dealing with obstacles that don’t require sensors or computation. To do that, we turned to examples from biology.</p>
<p>Animals don’t rely solely on their neurons – brain cells and <a href="https://my.clevelandclinic.org/health/body/23123-peripheral-nervous-system-pns">peripheral nerves</a> – to control movement. They also use the physical properties of their body – for example, the elasticity of their muscles – to help them react to their environment spontaneously, before their neurons even have a chance to respond.</p>
<p>While computational systems are governed by <a href="https://en.wikipedia.org/wiki/Computational_logic">the laws of mathematics</a>, mechanical systems are governed by physics. To achieve the same task, scientists can either design an algorithm or carefully design a physical system. </p>
<p>For example, limbless robots and animals move through the world by bending sections of their body left and right, <a href="https://en.wikipedia.org/wiki/Undulatory_locomotion">a type of movement called undulation</a>. If they collide with an obstacle, they have to turn away and go around it by bending more to one side than the other.</p>
<p>Scientists could achieve this with a robot by attaching sensors to its head or body. They could then design an algorithm that tells the robot to turn away or wind around the obstacle when it “feels” a large enough force on its head or body. </p>
<p>Alternatively, scientists could carefully select the robot’s materials and the arrangement and strength of its motors so that collisions would spontaneously produce a body shape that led to a turn. This robot would have what scientists call “mechanical intelligence.”</p>
<p>If scientists like us can understand how organisms’ bodies respond mechanically to contact with objects in their environment, we can design better robots that can deal with obstacles without having to program complex algorithms. </p>
<p>If you compare a diverse set of undulating organisms with the increasingly large zoo of <a href="https://en.wikipedia.org/wiki/Snakebot">robotic “snakes</a>,” one difference between the robots and biological undulators stands out. Nearly all undulatory robots bend their bodies using a series of connected segments with motors at each joint. But that’s not how living organisms bend.</p>
<p>In contrast, all limbless organisms, from large snakes to the lowly, microscopic nematode, achieve bends not from a single rotational joint-motor system but instead through <a href="http://www.wormbook.org/chapters/www_bodywallmuscle/bodywallmuscle.html">two bands of muscles</a> on either side of the body. To an engineer, this design seems counterintuitive. Why control something with two muscles or motors when one could do the job? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/575078/original/file-20240212-26-it6ean.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing a gray worm with a window showing the inside of the worm's body, which has two bands of muscle on the left and right side, cuticle on the top and nerve cord on the bottom, top and sides." src="https://images.theconversation.com/files/575078/original/file-20240212-26-it6ean.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575078/original/file-20240212-26-it6ean.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=283&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575078/original/file-20240212-26-it6ean.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=283&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575078/original/file-20240212-26-it6ean.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=283&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575078/original/file-20240212-26-it6ean.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=355&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575078/original/file-20240212-26-it6ean.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=355&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575078/original/file-20240212-26-it6ean.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=355&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Nematodes have two bands of muscle on the sides of their bodies that control motion.</span>
<span class="attribution"><span class="source">Ralf J. Sommer and WormAtlas</span></span>
</figcaption>
</figure>
<p>To get to the bottom of this question, our team built a new robot called MILLR, for mechanically intelligent limbless robot, inspired by the two bands of muscle on snakes and worms. MILLR has two independently controlled cables that pull each joint left and right, bilaterally.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/575079/original/file-20240212-20-gtf8t7.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing the design of MILLR, with servo motors on each body segment, and cables and pulleys connecting them." src="https://images.theconversation.com/files/575079/original/file-20240212-20-gtf8t7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575079/original/file-20240212-20-gtf8t7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=275&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575079/original/file-20240212-20-gtf8t7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=275&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575079/original/file-20240212-20-gtf8t7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=275&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575079/original/file-20240212-20-gtf8t7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=345&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575079/original/file-20240212-20-gtf8t7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=345&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575079/original/file-20240212-20-gtf8t7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=345&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">MILLR’s design, inspired by nematode <em>C. elegans</em>.</span>
<span class="attribution"><span class="source">Tianyu Wang</span></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.1126/scirobotics.adi2243">We found</a> this method allows the robot to spontaneously move around obstacles without having to sense its surroundings and actively change its body posture to comply to the environment.</p>
<h2>Building a mechanically intelligent robot</h2>
<p>Rather than mimicking the detailed muscular anatomy of a particular organism, MILLR applies forces to either side of the body by spooling and unspooling a cable. </p>
<p>This way, it mirrors the muscle activation methods that snakes and nematodes use, where the left and right sides take turns activating. This activation mode pulls the body toward one side or another by tightening on one side, while the other side relaxes and is pulled along passively. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/575081/original/file-20240212-26-bro51v.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="On the left, a photo showing a worm weaving between pegs. On the right, a photo showing a worm-like robot weaving between pegs." src="https://images.theconversation.com/files/575081/original/file-20240212-26-bro51v.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575081/original/file-20240212-26-bro51v.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=122&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575081/original/file-20240212-26-bro51v.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=122&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575081/original/file-20240212-26-bro51v.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=122&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575081/original/file-20240212-26-bro51v.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=153&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575081/original/file-20240212-26-bro51v.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=153&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575081/original/file-20240212-26-bro51v.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=153&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">MILLR’s design allows it to move through obstacles the same way worms do.</span>
<span class="attribution"><span class="source">Tianyu Wang and Christopher Pierce</span></span>
</figcaption>
</figure>
<p>By changing the amount of slack in the cables, <a href="https://doi.org/10.1126/scirobotics.adi2243">we can achieve</a> varying degrees of body stiffness. When the robot collides with an obstacle, depending on the cable tension, it selectively maintains its shape or bends under the force of the obstacle. </p>
<p><a href="https://doi.org/10.1126/scirobotics.adi2243">We found that</a> if the robot was actively bending to one side and it experienced a force in the same direction, the body complied to the force and bent further. If, alternatively, the robot experienced a force that opposed the bend, it would remain rigid and push itself off the obstacle. </p>
<p>Because of the pattern of the tension along the body, head-on collisions that would normally cause the robot to stop moving or jam itself instead naturally led to a redirection around the obstacle. The robot could push itself forward consistently. </p>
<h2>Testing MILLR</h2>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/21F7IOF9BMs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>To investigate the benefits of mechanical intelligence, we built tiny obstacle courses and sent nematode worms through them to see how well they performed. We sent MILLR through a similar course and compared the results.</p>
<p>MILLR moved through its course <a href="https://doi.org/10.1126/scirobotics.adi2243">about as effectively as the real worms</a>. We noticed that the worms made the same type of body movements when they collided with obstacles as MILLR did.</p>
<p>The principles of mechanical intelligence could extend beyond the realm of nematodes. Future research could look at designing robots based on a host of other types of organisms for applications ranging from search and rescue to <a href="https://youtu.be/e0D9IVo-E9M?si=d8jGaC5GDLaMbEeS">exploring other planets</a>.</p><img src="https://counter.theconversation.com/content/220828/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work was supported by the National Science Foundation Physics of Living Systems Student Research Network, NSF-Simons Southeast Center for Mathematics and Biology, Army Research Office Grant, and the Dunn Family Professorship.</span></em></p>Robots often have a hard time navigating through debris, but robots designed based on worms and snakes could move around obstacles faster, thanks to an idea called mechanical intelligence.Tianyu Wang, Ph.D. Student in Robotics, Georgia Institute of TechnologyChristopher Pierce, Postdoctoral Scholar in Physics, Georgia Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2202782024-02-08T13:40:17Z2024-02-08T13:40:17ZSugary handshakes are how cells talk to each other − understanding these name tags can clarify how the immune system works<figure><img src="https://images.theconversation.com/files/570832/original/file-20240123-29-c6ob1s.png?ixlib=rb-1.1.0&rect=0%2C0%2C2880%2C1664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Handshakes between glycans are one way cells recognize each other.</span> <span class="attribution"><span class="source">Kelvin Anggara</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Like the people they make up, cells communicate by bumping into one another and exchanging handshakes. Unlike people, cells perform these handshakes using the diverse range of sugar molecules coating their surface like trees covering a landscape. Handshakes between these <a href="https://doi.org/10.1093/glycob/cww086">sugar molecules, or glycans</a>, trigger cells to react in specific ways toward each other, such as escape, ignore or destroy.</p>
<p>Figuring out the “body language” of glycans during these handshakes can provide clues to how cancers, infections and immune systems work, as well as solutions to health and sustainability challenges society faces today.</p>
<h2>What are glycans?</h2>
<p>Each glycan molecule is made up of a network of individual sugar molecules bonded together. The vast number of possible glycan structures that can be built from connecting these sugar molecules together allows glycans to <a href="https://doi.org/10.1093/glycob/cww086">store rich information</a>.</p>
<p>Because all living cells are covered with sugars, glycans act like ID cards for cells. They display the cell’s identity, such as whether it’s a bacteria or human cell, and its state, such as whether it’s healthy or cancer, to the rest of the body and allow <a href="https://www.ncbi.nlm.nih.gov/books/NBK579984/">other cells to recognize</a> and respond to it. For example, these identifying signs allow our immune cells to recognize and clear out harmful bacteria and cancerous cells while leaving healthy cells in peace.</p>
<p>An example of how glycan-stored information is important to daily life is <a href="https://theconversation.com/what-are-blood-types-126002">your blood type</a>. Glycans are chemically bonded to proteins and lipids on the surface of red blood cells. Notably, the surface of type A red blood cells have glycans that differ from the glycans on the surface of type B and type O red blood cells. Knowing what blood type you have is important to avoid an unwanted immune response during blood transfusions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570449/original/file-20240120-22-n2v4b4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram showing the glycan structures of types A, B and O red blood cells" src="https://images.theconversation.com/files/570449/original/file-20240120-22-n2v4b4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570449/original/file-20240120-22-n2v4b4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=505&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570449/original/file-20240120-22-n2v4b4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=505&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570449/original/file-20240120-22-n2v4b4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=505&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570449/original/file-20240120-22-n2v4b4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=635&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570449/original/file-20240120-22-n2v4b4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=635&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570449/original/file-20240120-22-n2v4b4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=635&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Your blood type is determined by the types of glycans, depicted here in circles and triangles, on your red blood cells.</span>
<span class="attribution"><span class="source">Kelvin Anggara/Created with BioRender.com</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Proteins decorated with glycans, or glycoproteins, and lipids decorated with glycans, or glycolipids, are ubiquitous in nature. </p>
<p>For example, distinctive glycoproteins cover the surface of the viruses that cause <a href="https://doi.org/10.1021/acscentsci.0c01056">COVID-19</a>, <a href="https://doi.org/10.1016/j.cell.2016.04.010">HIV</a> and <a href="https://doi.org/10.1021/acscentsci.2c00981">H1N1 influenza</a> and help them <a href="https://theconversation.com/how-do-viruses-get-into-cells-their-infection-tactics-determine-whether-they-can-jump-species-or-set-off-a-pandemic-216139">infect cells</a>. Glycolipids also coat <a href="https://doi.org/10.1016%2Fj.cell.2019.12.006">many bacteria</a>, allowing them to stick to their hosts and protect them from viruses and immune cells.</p>
<p>More recently, researchers discovered pieces of <a href="https://doi.org/10.1016/j.cell.2021.04.023">genetic material decorated with glycans</a> on the surfaces of mammalian cells, challenging the long-standing notion that genetic material could be found only in the nucleus of cells and launching research to determine the functions of these glycans. One recent study showed that these molecules are vital in <a href="https://doi.org/10.1016/j.cell.2023.12.033">attracting immune cells</a> toward infected or injured tissues.</p>
<h2>How do cells read glycans?</h2>
<p>In addition to the rich biological information contained in glycans, their easily accessible locations on cell surfaces make them highly attractive targets in scientific research and drug development.</p>
<p>Cells sense glycans on the surfaces of other cells by using <a href="https://www.ncbi.nlm.nih.gov/books/NBK579947/">proteins called lectins</a>, among others. Each lectin has a unique area that allows it to bind to glycans with a specific matching sequence, triggering complex signals that lead to a biological action.</p>
<p>For example, a subfamily of lectins called <a href="https://doi.org/10.1038/nri2569">C-type lectins</a> are able to recognize the specific glycans on the outer walls of harmful viruses, fungi and bacteria. Found on surfaces of certain immune cells, these lectins deliver the glycans to proteins on other immune cells that can now selectively destroy any viruses or cells that carry that glycan. This process allows the immune system to clear the body of harmful pathogens. For example, these lectins recognize glycans on the <a href="https://doi.org/10.1093/glycob/cwy023">surfaces of cancer cells</a> and direct other immune cells to eliminate these cancer cells.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/572940/original/file-20240201-25-cjkqvl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration of a spherical influenza virus, with red and blue spikes studding its surface" src="https://images.theconversation.com/files/572940/original/file-20240201-25-cjkqvl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/572940/original/file-20240201-25-cjkqvl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572940/original/file-20240201-25-cjkqvl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572940/original/file-20240201-25-cjkqvl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572940/original/file-20240201-25-cjkqvl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572940/original/file-20240201-25-cjkqvl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572940/original/file-20240201-25-cjkqvl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The spikes on the surface of the influenza virus are composed of glycoproteins.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/flu-virus-close-up-view-3d-illustration-royalty-free-image/1389473291">Dr_Microbe/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Another type of <a href="https://doi.org/10.1146/annurev-immunol-102419-035900">lectin called siglecs</a> are found on surfaces of immune cells and help them distinguish self from nonself, that is, between the cells that make up the body and the cells that are foreign to the body. Because siglecs are involved in <a href="https://doi.org/10.1146/annurev-immunol-102419-035900">controlling how the immune system responds</a> to many cancers, allergies, autoimmune diseases and neurodegeneration, they offer an opportunity to treat these conditions.</p>
<p>The early success of glycan-based drugs is exemplified by <a href="https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5911a1.htm">Pfizer’s Prevnar vaccine</a> to prevent bacterial pneumonia, which was approved by the Food and Drug Administration in 2010. Prevnar contains glycans from various strains of <a href="https://doi.org/10.5863%2F1551-6776-21.1.27"><em>Streptococcus pneumoniae</em></a>, the leading cause of bacterial pneumonia in children and adults. The bacterial glycans in the vaccine trigger an immune response when immune cells recognize the glycans as foreign threats. Once immune cells learn how to neutralize the threat, the body becomes immune to future invasion by bacteria with the same glycans. </p>
<h2>Examining every sugar molecule</h2>
<p>Because scientists are still <a href="https://doi.org/10.1021/jacs.9b06406">unable to extract all the biological information</a> in glycans, their full potential as treatments has remained untapped. Comprehensively extracting all the information stored in glycans is very difficult because there isn’t currently technology able to analyze the complex and diverse structures of glycans. Researchers still don’t know what these “sugar codes” look like and how they function.</p>
<p>Individual glycans are composed of sugar molecules in unique arrangements, but current analytical tools can only <a href="https://doi.org/10.17226/13446">simultaneously analyze many glycans</a>. To see why this is a problem for analysis, imagine all the glycans in a cell as candies in a jar. Some of them are the same colors and some are not. It would be difficult to identify and quantify the color of every candy in the jar if you’re unable to pour them out to individually sort through each one of them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570447/original/file-20240120-27-59622g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Jar of colorful candy on a table" src="https://images.theconversation.com/files/570447/original/file-20240120-27-59622g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570447/original/file-20240120-27-59622g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=404&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570447/original/file-20240120-27-59622g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=404&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570447/original/file-20240120-27-59622g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=404&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570447/original/file-20240120-27-59622g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=508&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570447/original/file-20240120-27-59622g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=508&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570447/original/file-20240120-27-59622g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=508&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Can you identify the color of every candy and count how many there are of each color without opening the jar?</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/round-candies-in-clear-glass-jar-with-clamp-lid-lW25Zxpkln8">Clem Onojeghuo/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p><a href="https://anggara.science">My lab</a> <a href="https://scholar.google.ca/citations?user=1SkTHegAAAAJ&hl=en">is confronting</a> this challenge by developing imaging technology that can analyze the structure of glycans by <a href="https://doi.org/10.1126/science.adh3856">imaging each individual molecule</a>. Essentially, we’re developing a technique to open the jar and study every single candy one at a time.</p>
<p>In the long run, my team aspires to unveil how these glycans present themselves to the proteins that recognize them and, finally, reveal the very language that cells use to express themselves.</p><img src="https://counter.theconversation.com/content/220278/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kelvin Anggara works for the Max Planck Institute for Solid State Research and receives funding from the European Research Council under Project GlycoX (101075996).</span></em></p>Sugar molecules called glycans cover the surface of all cells, acting as ID cards that broadcast what they are to the rest of the body.Kelvin Anggara, Group leader in Single molecule imaging, Max Planck Institute for Solid State ResearchLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2213522024-02-05T13:34:48Z2024-02-05T13:34:48ZHow bats ‘leapfrog’ their way home at night – new research<figure><img src="https://images.theconversation.com/files/572171/original/file-20240130-27-o1vlrb.jpg?ixlib=rb-1.1.0&rect=0%2C10%2C3413%2C2539&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The greater horseshoe bat is one of the UK's 18 bat species. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/flying-bat-hunting-forest-greater-horseshoe-1494098204">Rudmer Zwerver/Shutterstock</a></span></figcaption></figure><p>A silent ballet takes place above our heads at night as Britain’s bat populations leave their roosts to forage for food. Although their initial movement away from roosts is fairly well understood, until recently little was known about how they returned home. </p>
<p>But our <a href="https://link.springer.com/article/10.1007/s11538-023-01233-5">new research</a> shows how bats may use a “leap-frogging” motion to make their way home, something which could help conservationists in future.</p>
<p>As they flit through the darkness, bats play a crucial role in the health of our ecosystems. From keeping insect populations in check to dispersing seeds and pollinating plants, they provide a multitude of benefits. </p>
<p>In the UK alone, the 18 bat species devour agricultural pests such as cockchafers with impressive efficiency. So, it is imperative that we not only understand and appreciate bats, but also actively support and safeguard their populations for the wellbeing of our planet.</p>
<p>But bat populations are vulnerable to pollution, climate change and loss of roosting locations. Habitat fragmentation and light pollution can also interrupt how bats feed. This is particularly important during the maternity season <strong>in early summer</strong>, when bats gather together to have and raise their young.</p>
<p>An integral aspect of effective bat conservation lies in unravelling the mysteries of how bats move. This not only helps us understand how bats navigate and use their environment, but also helps in identifying and protecting their roosts. </p>
<h2>Radio-tracking</h2>
<p>Conventional methods for pinpointing bat roosts primarily hinge on radio-tracking surveys. This arduous process involves capturing bats, attaching small radio transmitters to them before releasing them and following the signals throughout the night. </p>
<p>Our team conducted a radio-tracking survey in Devon which monitored 12 greater horseshoe bats over 24 nights. The trajectories of seven of those bats over 14 nights were extracted from the data for analysis, ensuring that in each case, a bat’s beginning and ending roost were the same.</p>
<p>Using this data, we measured the population’s average distance from the roost. We found two distinctive patterns in the data we analysed: an initial spread of bats within the first one to two hours after sunset and a gradual return to the roost afterwards.</p>
<p>The initial spread reflects the expected random dispersal of bats leaving their roosts to forage after sunset. The return to the roost, occurring two to eight hours after sunset, is more complicated. </p>
<p>This prompted us to explore two potential mechanisms influencing the bats’ return. First, a “pull mechanism”, where the roost attracts the bats home, and second, a mechanism pushing the bats who range furthest away back to the roost.</p>
<p>We modelled the pushing mechanism as a leapfrog process. Imagine this as a cascade effect, where the outermost bats begin their return. Once the “outer” bats have passed or “leapt over” bats that are closer to the roost, the “inner” bats become the furthest out causing them to return too.</p>
<p>This motion unfolds systematically, like a synchronised dance, as each bat from the periphery of the foraging range follows suit in returning to the roost after being “leapfrogged”.</p>
<p>But what causes the bats to return in this manner? One plausible explanation underscores how bats rely on each other for effective navigation, like tiny radar signals. If a bat experiences prolonged silence or predominantly hears calls from one direction, it might decide to move closer to the roost, anticipating the presence of other colony members. </p>
<p>But a bat might return more slowly, prolonging foraging, if it perceives the presence of bats beyond its current location. So, it is the outer bats that would drive the return as they would not be surrounded by calls.</p>
<h2>How does this research help bats?</h2>
<p>The significance of these findings extends beyond just describing the movements of bats. They have laid the foundation for work that promises easier discovery of new bat roosts, potentially reducing the need for labour-intensive bat tracking surveys in the future. </p>
<p>One of the immediate effects of our research includes informing a measurement of the “core sustenance zone” for greater horseshoe bats. This is where most of their foraging occurs, so it’s important in bat ecology, conservation and construction planning.</p>
<p>The leapfrogging mechanism also allows us to ascribe intention to bat movements. Namely, through using surrounding bat calls they can identify where the population is relative to their position, suggesting whether or not they are on the periphery of the group, which is an indicator of their vulnerability. Should they be furthest from the roost they move back towards the bulk of the population and closer to the roost.</p>
<p>While these interpretations hold promise, further rigorous testing is essential. And we need to think about the safety and wellbeing of the bat population.</p>
<p>Our observations are also specific to greater horseshoe bats during the summer months. Different bat species have distinct flight patterns and habitat preferences, with the same species displaying diverse behaviours at different times of the year. </p>
<p>So, while we have taken some crucial first steps, we still have a lot of work to do in unravelling the characteristics of bat motions in general.</p><img src="https://counter.theconversation.com/content/221352/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Fiona Mathews receives funding from Devon Area of Outstanding Natural Beauty, Devon County Council and the Natural Environment Research Council. She is affiliated with the UK Mammal Society, Mammal Conservation Europe, Ecotype Genetics and Ecology Search Services Ltd. </span></em></p><p class="fine-print"><em><span>Thomas Woolley 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>Maths plays a crucial role in new research which finds that bats “leapfrog” their way home at night.Thomas Woolley, Senior Lecturer in Applied Mathematics, Cardiff UniversityFiona Mathews, Professor of Environmental Biology, University of SussexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2168532024-02-05T13:30:30Z2024-02-05T13:30:30ZStudying lake deposits in Idaho could give scientists insight into ancient traces of life on Mars<figure><img src="https://images.theconversation.com/files/568753/original/file-20240110-30-i5trcc.JPG?ixlib=rb-1.1.0&rect=23%2C398%2C3128%2C1343&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists have been studying the Clarkia site for nearly five decades.</span> <span class="attribution"><span class="source">Robert Patalano</span></span></figcaption></figure><p>Does life exist elsewhere in the universe? If so, how do scientists search for and identify it? Finding life beyond Earth is extremely difficult, partly because other planets are so far away and partly because we are not sure what to look for.</p>
<p>Yet, astrobiologists have learned a lot about <a href="https://science.nasa.gov/astrobiology/">how to find life</a> in extraterrestrial environments, mainly by studying how and when the early Earth became livable.</p>
<p>While research teams at NASA are <a href="https://mars.nasa.gov/mars2020/mission/overview/">directly combing</a> the surface of Mars for signs of life, our <a href="https://news.bryant.edu/there-life-red-planet-faculty-earns-funding-explore-theory-earth">interdisciplinary research group</a> is <a href="https://news.bryant.edu/mars-mind-bryant-students-earn-funding-nasa-ri-space-grant-consortium">using a site here on Earth</a> to approximate ancient environmental conditions on Mars. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/568752/original/file-20240110-18-1v7yda.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A rock face with several blocky layers of rock, in different stripes of color. The top layers are a darker clay, while the bottom layers are a lighter volcanic ash." src="https://images.theconversation.com/files/568752/original/file-20240110-18-1v7yda.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568752/original/file-20240110-18-1v7yda.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568752/original/file-20240110-18-1v7yda.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568752/original/file-20240110-18-1v7yda.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568752/original/file-20240110-18-1v7yda.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568752/original/file-20240110-18-1v7yda.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568752/original/file-20240110-18-1v7yda.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 close-up view of the Clarkia site where you can see lacustrine clay and volcanic ash layers. This site represents Mars in our work.</span>
<span class="attribution"><span class="source">Taylor Vahey</span></span>
</figcaption>
</figure>
<p>Contained within northern Idaho’s <a href="https://doi.org/10.1130/G48901.1">Clarkia Middle Miocene Fossil Site</a> are sediments that preserve some of Earth’s most diverse biological marker molecules, or <a href="https://doi.org/10.1016/j.epsl.2008.07.012">biomarkers</a>. These are remains of past life that offer glimpses into Earth’s history.</p>
<h2>An ancient lake</h2>
<p>About 16 million years ago, a lava flow in what would one day become Clarkia, Idaho, dammed a local drainage system and created a deep lake in a <a href="https://archive.org/details/latecenozoichist0000unse/page/424/mode/2up">narrow, steep-sided valley</a>. Although the lake has since dried up, weathering, erosion and <a href="https://www.facebook.com/p/Fossil-Bowl-100063724775941/">human activity</a> have exposed sediments of the former lake bed.</p>
<p>For nearly five decades, research teams like ours – being led by <a href="https://www.radcliffe.harvard.edu/people/hong-yang">Dr. Hong Yang</a> and <a href="https://www.bryant.edu/academics/faculty/leng-qin">Dr. Qin Leng</a> – have used <a href="https://doi.org/10.7717/peerj.4880">fossil remains</a> and <a href="https://doi.org/10.1016/0146-6380(95)80001-8">biogeochemistry</a> to reconstruct past environments of the Clarkia Miocene Lake region. </p>
<p>The lake’s depth created the <a href="https://www.jstor.org/stable/1303276">perfect conditions</a> for protecting microbial, plant and animal remains that fell to the lake’s bottom. In fact, the sediments are so well preserved that some of the fossilized leaves still show their autumn colors from when they sank into the water millions of years ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/568751/original/file-20240110-15-2y3q3p.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A reddish brown long, thin leaf shown embedded on a piece of smooth sediment." src="https://images.theconversation.com/files/568751/original/file-20240110-15-2y3q3p.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568751/original/file-20240110-15-2y3q3p.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568751/original/file-20240110-15-2y3q3p.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568751/original/file-20240110-15-2y3q3p.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568751/original/file-20240110-15-2y3q3p.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568751/original/file-20240110-15-2y3q3p.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568751/original/file-20240110-15-2y3q3p.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 fossil magnolia leaf showing fall (reddish) colors. This leaf likely fell off a tree in the fall once the trees paused photosynthesis for the winter and sank to the bottom of the lake, where it was buried. The leaf retained its fall coloring for 16 million years, though once being dug up and exposed to air, it quickly oxidized and lost its color.</span>
<span class="attribution"><span class="source">Robert Patalano</span></span>
</figcaption>
</figure>
<p>Today, ancient lake beds on Earth are becoming <a href="https://doi.org/10.1146/annurev-earth-053018-060332">important settings</a> for learning about habitable environments on other planets. </p>
<h2>Biological marker molecules</h2>
<p>Clarkia’s lake sediments <a href="https://doi.org/10.1016/0146-6380(94)90045-0">contain a suite</a> of ancient biomarkers. These compounds, or classes of compounds, can reveal how organisms and their <a href="https://doi.org/10.1016/j.quascirev.2011.07.009">environments functioned</a> in the past.</p>
<p>Since the discovery of the <a href="https://www.idahogeology.org/pub/Information_Circulars/IC-33.pdf">Clarkia fossil site in 1972</a>, multiple research teams have used various <a href="https://doi.org/10.1016/S0146-6380(02)00212-7">cutting-edge technologies to analyze</a> different biomarkers. </p>
<p>Some of those found at Clarkia <a href="https://doi.org/10.1073/pnas.90.6.2246">include lignin</a>, which is the structural support tissue of plants, <a href="https://doi.org/10.1016/S0146-6380(00)00107-8">lipids like fats and waxes</a>, and possibly <a href="https://doi.org/10.1038/344656a0">DNA and amino acids</a>.</p>
<p>Understanding the origins, history and environmental factors that have allowed these biosignatures to stay so well preserved at Clarkia may also allow our team to predict the potential of organic matter preservation in ancient lake deposits on Mars.</p>
<h2>Studying life signatures on Mars</h2>
<p>In 2021, the <a href="https://mars.nasa.gov/mars2020/">Mars Perseverance Rover</a> landed on top of lake deposits in Mars’ <a href="https://doi.org/10.1126/science.abl4051">Jezero Crater</a>. Jezero is a meteorite impact crater believed to have once been flooded with water and home to an ancient river delta. Microbial life may have lived in Jezero’s crater lake, and their biomarkers might be found in lake bed sediments today. Perseverance has been drilling into the crater’s surface to collect samples that could contain ancient signs of life, with the intent of <a href="https://mars.nasa.gov/msr/#Facts">returning the samples to Earth in 2033</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/547616/original/file-20230911-26-nc2bk5.jpg?ixlib=rb-1.1.0&rect=14%2C7%2C4977%2C2799&q=45&auto=format&w=1000&fit=clip"><img alt="An artist's rendition of the Perseverence rover, made of metal with six small wheels, a camera and a robotic arm." src="https://images.theconversation.com/files/547616/original/file-20230911-26-nc2bk5.jpg?ixlib=rb-1.1.0&rect=14%2C7%2C4977%2C2799&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547616/original/file-20230911-26-nc2bk5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547616/original/file-20230911-26-nc2bk5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547616/original/file-20230911-26-nc2bk5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547616/original/file-20230911-26-nc2bk5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547616/original/file-20230911-26-nc2bk5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547616/original/file-20230911-26-nc2bk5.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 Perseverance Rover is collecting samples to learn more about Mars’ environment.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/MarsLanding/c835b14b3e6645d7a0cd46558745752b/photo?Query=mars%20rover&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=530&currentItemNo=11&vs=true">NASA/JPL-Caltech via AP</a></span>
</figcaption>
</figure>
<p>Clarkia has many similarities to the Jezero Crater. Both Clarkia and Jezero Crater have ancient <a href="https://doi.org/10.1006/icar.2000.6530">lake deposits</a> derived from silica-rich, <a href="https://doi.org/10.1029/2017JE005478">basaltic rock</a> that formed under <a href="https://doi.org/10.1016/j.gloplacha.2022.103737">a climate with</a> higher temperatures, high humidity and a carbon dioxide-rich atmosphere. </p>
<p>At Clarkia, these conditions preserved microbial biomarkers in the ancient lake. Similar settings could have <a href="https://doi.org/10.1029/2012JE004115">formed lakes</a> on the surface of Mars. </p>
<p>The samples <a href="https://mars.nasa.gov/mars-rock-samples/#23">Perseverance is collecting</a> contain the geologic and climate history of the Jezero Crater landing site and may even contain preserved biomarkers of ancient life.</p>
<p>While Perseverance continues its mission, our group is <a href="https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1367388">establishing criteria</a> for biomolecular authentication. That means we are developing ways to figure out whether ancient biomarkers from Earth, and hopefully Mars, are true echoes of life – rather than recent contamination or molecules from nonliving sources.</p>
<p>To do so, we are studying biomarkers from Clarkia’s fossil leaves and sediments and developing laboratory experiments using <a href="https://spaceresourcetech.com/collections/regolith-simulants">Martian simulants</a>. This material simulates the chemical and physical properties of Jezero Crater’s lake sediments.</p>
<p>By deciphering the sources, history and preservation of biomarkers connected with Clarkia’s ancient lake deposits, we hope to develop new strategies for studying the Perseverance Rover samples once they are back on Earth.</p><img src="https://counter.theconversation.com/content/216853/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Patalano receives funding from the NASA Rhode Island Space Grant Program. </span></em></p>While NASA rovers on the surface of Mars look for hints of life, researchers back on Earth are studying ‘echoes of life’ from ancient basins – hoping that the two sites might be similar.Robert Patalano, Lecturer of Biological and Biomedical Sciences, Bryant UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2213872024-01-30T16:01:27Z2024-01-30T16:01:27ZThe surprising reason why insects circle lights at night: They lose track of the sky<figure><img src="https://images.theconversation.com/files/571170/original/file-20240124-21-ynct7x.png?ixlib=rb-1.1.0&rect=30%2C20%2C6679%2C4446&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A multiple-exposure photograph of insects circling a light at night.</span> <span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>It’s an observation as old as humans gathering around campfires: Light at night can draw an erratically circling crowd of insects. In art, music and literature, this spectacle is an enduring metaphor for <a href="https://roundglasssustain.com/wildvaults/moths">dangerous but irresistible attractions</a>. And watching their frenetic movements really gives the sense that something is wrong – that instead of finding food and evading predators, these nocturnal pilots are trapped by a light.</p>
<p>Sadly, centuries of witnessing what happens have produced little certainty about why it happens. How does a simple light change fast, precise navigators into helpless, flittering captives? We are researchers examining <a href="https://scholar.google.co.uk/citations?user=wG5HGs8AAAAJ&hl=en">flight</a>, <a href="https://scholar.google.com/citations?user=4i4wRGgAAAAJ&hl=en">vision</a> and <a href="https://scholar.google.co.in/citations?user=X-j5RnwAAAAJ&hl=en">evolution</a>, and we have used high-speed tracking techniques in <a href="https://www.nature.com/articles/s41467-024-44785-3">newly published research</a> to provide an answer.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FxNRDxlVyxk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The reason insects fly around light will surprise you.</span></figcaption>
</figure>
<h2>Moths to a flame?</h2>
<p>Many old explanations for this hypnotic behavior have not fully panned out. An early notion was that the insects might be attracted to the heat of a flame. This was interesting, as some insects really <a href="https://doi.org/10.1016/j.foreco.2022.120629">are pyrophilic</a>: They are attracted to fire and have evolved to take advantage of conditions in recently burned areas. But most insects around a light are not in this category, and cool lights attract them quite well. </p>
<p>Another thought was that insects were just directly attracted to light, a <a href="https://doi.org/10.1007/s13355-013-0219-x">response called phototaxis</a>. Many insects move toward light, perhaps as a way to escape dark or entrapping surroundings. But if this were the explanation for the clusters around a light, you might expect them to bump straight into the source. This theory does little to explain the wild circling behavior.</p>
<p>Still another idea was that insects might mistake a nearby light for the Moon, as they attempted to use <a href="https://doi.org/10.1146/annurev.en.29.010184.001425">celestial navigation</a>. Many insects reference the Moon to keep their course at night.</p>
<p>This strategy relies on how objects at great distance seem to hover in place as you move along a straight path. A steady Moon indicates that you have not made any unintentional turns, as you might if you were buffeted by a gust of wind. Nearer objects, however, don’t appear to follow you in the sky but drift behind as you move past.</p>
<p>The celestial navigation theory held that insects worked to keep this light source steady, turning sharply in a failed attempt to fly straight. An elegant idea, but this model predicts that many flights will spiral inward to a collision, which doesn’t usually match the orbits we see. So what’s really going on?</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Several cameras face a bright light on a stand in a forest setting at night." src="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571761/original/file-20240128-21-f7q5vs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scientists used high-speed stereo motion capture to document how the presence of artificial light at night affects insects’ flight behavior.</span>
<span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Turning their backs to the light</h2>
<p>To examine this question in detail, we and our colleagues captured high-speed videos of insects around different light sources to precisely determine flight paths and body postures, both in the lab at <a href="https://www.imperial.ac.uk">Imperial College London</a> and at two field sites in Costa Rica, <a href="https://www.ciee.org/go-abroad/college-study-abroad/locations/costa-rica/monteverde">CIEE</a> and the <a href="https://www.estacionbiologica.com/">Estación Biológica</a>. We found that their flight patterns weren’t a close match for any existing model. </p>
<p>Rather, a broad swath of insects consistently pointed their backs toward the lights. This is a known behavior called the <a href="https://doi.org/10.1146/annurev.en.29.010184.001425">dorsal light response</a>. In nature, assuming that more light comes down from the sky than up from the ground, this response helps keep insects in the proper orientation to fly.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/qECYfEN70qs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Artificial light at night interrupts the normal flight patterns of insects. This compilation video shows an orbiting behavioral motif in which insects circle the light.</span></figcaption>
</figure>
<p>But pointing their backs toward nearby artificial lights alters their flight paths. Just as airplanes bank to turn, sometimes rolling until the ground seems nearly straight out your window, banking insects turn as well. When their backs orient to a nearby light, the resulting bank loops them around the light, circling but rarely colliding. </p>
<p>These orbiting paths were only one of the behaviors we observed. When insects flew directly under a light, they often arched upward as it passed behind them, keeping their backs to the bulb until, eventually flying straight up, they stalled and fell out of the air. And even more compelling, when flying directly over a light, insects tended to flip upside down, again turning their backs to the light but then abruptly crashing.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagrams show insects rolling vertically or horizontally or inverting in the presence of artificial light." src="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=410&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=410&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=410&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=515&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=515&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571763/original/file-20240128-21-1bjvpv.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=515&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Three different observed turning behaviors in which flying insects turn their backs to artificial light.</span>
<span class="attribution"><span class="source">Jamie Theobald</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Why have a dorsal light response?</h2>
<p>Although light at night can harm <a href="https://www.jstor.org/stable/43597777">other animals</a> – for example, by <a href="https://doi.org/10.1073/pnas.1708574114">diverting migrating birds into urban areas</a> – larger animals don’t seem to lose their vertical orientation. So why do insects, the oldest and most species-rich group of flyers, rely on a response that leaves them so vulnerable?</p>
<p>It may have to do with their small size. Larger animals can sense gravity directly with sensory organs pulled by its acceleration, or any acceleration. Humans, for example, use the <a href="https://www.ncbi.nlm.nih.gov/books/NBK279394/">vestibular system of our inner ear</a>, which regulates our sense of balance and usually gives us a good sense of which way is down.</p>
<p>But insects have only small sensory structures. And especially as they perform rapid flight maneuvers, acceleration offers only a poor indication of which way is down. Instead, they seem to bet on the brightness of the sky. </p>
<p>Before modern lighting, the sky was usually brighter than the ground, day or night, so it provided a fairly reliable cue for a small active flyer hoping to keep a steady orientation. The artificial lights that sabotage this ability, by cueing insects to fly in circles, are relatively recent. </p>
<h2>The growing problem of nighttime lighting</h2>
<p>As new technology spreads, lights that pervade the night are <a href="https://doi.org/10.3390/rs13163311">proliferating faster then ever</a>. With the introduction of cheap, bright, <a href="https://www.energy.gov/eere/ssl/led-basics">broad-spectrum LEDs</a>, many areas, such as large cities, never see a dark night.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A view upward through treetops to a starry dark sky, with a bright light at the top of the screen from a light bulb near the ground." src="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571762/original/file-20240128-31-eh9yyj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This upward view at the authors’ field research site in Monteverde, Costa Rica, shows how artificial light competes with the night sky.</span>
<span class="attribution"><span class="source">Samuel Fabian</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Insects aren’t the only creatures affected. Light pollution disrupts circadian rhythms and physiological processes in other <a href="https://darksky.org/resources/what-is-light-pollution/effects/wildlife-ecosystems/">animals, plants</a> and <a href="https://darksky.org/resources/what-is-light-pollution/effects/human-health/">humans</a>, often with <a href="https://theconversation.com/new-atlas-shows-extent-of-light-pollution-what-does-it-mean-for-our-health-60836">serious health consequences</a></p>
<p>But insects trapped around a light seem to get the worst of it. Unable to secure food, easily spotted by predators and prone to exhaustion, many die before the morning comes.</p>
<p>In principle, light pollution is one of the easiest things to fix, often by just <a href="https://www.youtube.com/watch?v=EfhuU5Ceo_w">flipping a switch</a>. <a href="https://darksky.org/what-we-do/advancing-responsible-outdoor-lighting/">Restricting outdoor lighting</a> to useful, targeted warm light, no brighter than necessary, and for no longer than necessary, can greatly improve the health of nocturnal ecosystems. And the same practices that are good for insects help restore views of the night sky: Over one-third of the world population lives in areas where the <a href="http://dx.doi.org/10.1126/sciadv.1600377">Milky Way is never visible</a>. </p>
<p>Although insects circling around a light are a fascinating spectacle, it is certainly better for the insects and the <a href="https://www.si.edu/spotlight/buginfo/benefits">benefits they provide to humans</a> when we leave the night unlit and let them go about the activities they so masterfully perform under the night sky.</p><img src="https://counter.theconversation.com/content/221387/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samuel Fabian receives funding from the European Research Council and a National Geographic Explorer Grant.</span></em></p><p class="fine-print"><em><span>Jamie Theobald receives funding from the National Science Foundation and the U.S. Air Force Office of Scientific Research.</span></em></p><p class="fine-print"><em><span>Yash Sondhi receives funding from the Florida International University Graduate School, the Susan Levine Foundation, a National Geographic Explorer Grant, the American Philosophical Society, and the Kimberly-Green Latin-American and Caribbean Center.</span></em></p>A new study shows how artificial light at night scrambles insects’ normal flight patterns, pulling them off course into orbit around the light.Samuel Fabian, Postdoctoral Research Associate in Bioengineering, Imperial College LondonJamie Theobald, Associate Professor of Biological Sciences, Florida International UniversityYash Sondhi, Postdoctoral Research Associate in Entomology, Mcguire Center for Lepidoptera & Biodiversity, Florida Museum of Natural History, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2164102024-01-10T14:16:10Z2024-01-10T14:16:10ZMating anchovies stir up the sea as much as a major storm – and it’s good for the environment too<figure><img src="https://images.theconversation.com/files/568398/original/file-20240109-21-v0brit.jpg?ixlib=rb-1.1.0&rect=1556%2C8%2C3891%2C3620&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/school-anchovies-swimming-deep-blue-sea-2292958167">ennar0/Shutterstock</a></span></figcaption></figure><p>Why would oceanographers ever care about anchovies having sex? We do because these small fish can help mix different layers of the ocean when they mate. This circulates nutrients, oxygen and greenhouse gases around different layers of the ocean, thereby sustaining the ecosystem.</p>
<p>Mixing layers of the ocean vertically requires energy. Most of this energy is provided by winds and tides. However, <a href="https://www.sciencedirect.com/science/article/pii/0011747166906024">research</a> that was conducted in 1966 found a mismatch between the energy required for mixing and the energy provided by available sources. </p>
<p>This prompted an intriguing question: can swimming animals such as fish and crustaceans fill the energy gap and contribute to ocean mixing?</p>
<p>After decades of mixed and extremely scarce evidence, the oceanographic community came close to reaching a verdict on the topic in 2019. A <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev-marine-010318-095047">study</a> conducted by an American researcher called Eric Kunze concluded that biological mixing is extremely unlikely to happen. </p>
<p>The rationale for this conclusion is simple. Marine swimmers do create some turbulent eddies as they move around, but these eddies are too small to cause any substantial vertical mixing. Whirls shed by marine swimmers are so small that they are instead dissipated as heat due to friction between water molecules. </p>
<p>But in a <a href="https://www.nature.com/articles/s41561-022-00916-3">study</a> published in 2022, my colleagues and I challenged this conclusion. Our findings show that biological mixing can happen under certain circumstances.</p>
<figure class="align-center ">
<img alt="A boat sailing through a bay." src="https://images.theconversation.com/files/568401/original/file-20240109-27-n09bw7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568401/original/file-20240109-27-n09bw7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568401/original/file-20240109-27-n09bw7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568401/original/file-20240109-27-n09bw7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568401/original/file-20240109-27-n09bw7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568401/original/file-20240109-27-n09bw7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568401/original/file-20240109-27-n09bw7.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">Spanish research vessel Ramon de Margalef leaving the coast of Galicia in 2018.</span>
<span class="attribution"><span class="source">Bieito Fernández Castro</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>A surprising observation</h2>
<p>In July 2018, our team left the coast of Galicia in north-west Spain on a mission to understand if variations in ocean mixing conditions were to blame for the frequent occurrence of harmful algal blooms that threaten the region’s thriving mussel aquaculture industry. We measured water turbulence along with various ecological indicators every 30 minutes for 15 consecutive days. </p>
<p>We monitored turbulence by measuring fluctuations in the velocity and temperature of water at very small scales. These fluctuations are an indication of the intensity of turbulent motions and mixing respectively. To our surprise, we detected extremely high levels of turbulence every night, at a level similar to that caused by a major storm. </p>
<p>But, at the time of our study, the weather was calm and tides were weak. So what was happening? The key to unravelling this mystery came from the casual observation of screens in the lab onboard our research vessel. These screens show signals from the ship’s echo-sounder, an instrument designed to detect the presence of fish. </p>
<p>No one was paying much attention initially, since we were – in principle – not interested in fish. But the acoustic measurements revealed very strong echo signals that coincided with our strong nighttime turbulence measurements. This suggested that the strong nighttime turbulence was related to the presence of fish. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/568400/original/file-20240109-27-ydgca9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bongo-shaped nets being lowered into the sea." src="https://images.theconversation.com/files/568400/original/file-20240109-27-ydgca9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/568400/original/file-20240109-27-ydgca9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568400/original/file-20240109-27-ydgca9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568400/original/file-20240109-27-ydgca9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568400/original/file-20240109-27-ydgca9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568400/original/file-20240109-27-ydgca9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568400/original/file-20240109-27-ydgca9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The bongo-shaped nets used to capture tiny fish eggs.</span>
<span class="attribution"><span class="source">Bieito Fernández Castro</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>The obvious solution was to capture the fish. We used some of the small bongo-shaped nets designed to capture microscopic algae. </p>
<p>What we found in the nets caught us by surprise. They were full of thousands and thousands of tiny fish eggs, probably belonging to European <a href="https://www.britannica.com/animal/anchovy">anchovies</a>. </p>
<p>The circle was closed, the mystery solved. Hundreds of anchovies aggregated around our sampling station every night to mate and fertilise their eggs. In their nightly frenzy, they created the strong turbulence that we measured. </p>
<h2>Reviving the ‘biomixing’ controversy</h2>
<p>However, an important question was still unanswered. Were the small but energetic water motions created by the libidinous fish capable of mixing the different ocean layers together? </p>
<p>To answer this question we examined the millimetre-scale temperature signals from our turbulence profiler. We found that the small-scale temperature fluctuations were more than ten times larger during the night, when lively anchovies were around, than during the day. Biological mixing was indeed happening beneath our feet. </p>
<p>We believe that the explanation for our unique finding is related to a fundamental aspect of the physics of turbulence rather than to the sexual preferences of anchovies. </p>
<p>The water column in our study region shows very sharp vertical variations of water properties, referred to as “vertical stratification”. Water layers displaying different properties are thus relatively “thin”, meaning that the small-scale motions created by the fish can mix them together. This contrasts with <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2014JC010659">previous studies</a> that have been conducted in more open ocean regions where stratification is usually weaker.</p>
<p>Our fortuitous observation proved the longstanding conjecture of biologically driven mixing of the ocean. However, our finding remains an isolated observation. </p>
<p>There is much work to do to assess the significance of biological mixing for the local ecosystem. But one thing is for sure: the biological mixing controversy will stick around for much longer than we would have expected a few years ago.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<hr><img src="https://counter.theconversation.com/content/216410/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bieito Fernandez Castro receives funding from the Natural Environment Research Council, UK. </span></em></p>Anchovies cause a stir as they mate – getting the oceans moving.Bieito Fernandez Castro, Lecturer in Physical Oceanography, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2207562024-01-09T20:18:23Z2024-01-09T20:18:23ZWhy don’t fruit bats get diabetes? New understanding of how they’ve adapted to a high-sugar diet could lead to treatments for people<figure><img src="https://images.theconversation.com/files/568452/original/file-20240109-23-jjo6l0.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2376%2C1442&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fruit bats have honed their sweet tooth through adaptive evolution.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/fruit-bat-feeding-in-a-tree-royalty-free-image/1293525000">Keith Rose/iStock via Getty Images Plus</a></span></figcaption></figure><p>People around the world eat too much sugar. When the body is unable to process sugar effectively, leading to excess glucose in the blood, this can result in diabetes. According to the World Health Organization, diabetes became the <a href="https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death">ninth leading cause of death</a> in 2019.</p>
<p>Humans are not the only mammals that love sugar. Fruit bats do, too, eating up to <a href="https://dem.ri.gov/sites/g/files/xkgbur861/files/programs/bnatres/fishwild/outreach/critter-kits/bat-ex-benefits.pdf">twice their body weight</a> in sugary fruit a day. However, unlike humans, fruit bats thrive on a sugar-rich diet. They can <a href="https://doi.org/10.1007/s00360-019-01242-8">lower their blood sugar faster</a> than bats that rely on insects as their main food source.</p>
<p>We are a team of <a href="https://www.menlo.edu/about/find-an-expert/wei-gordon/">biologists</a> and <a href="https://scholar.google.com/citations?user=kkrPGvcAAAAJ&hl=en">bioengineers</a>. Determining how fruit bats evolved to specialize on a high-sugar diet sent us on a quest to approach diabetes therapy from an unusual angle – one that sent us all the way to Lamanai, Belize, for the <a href="https://www.batcon.org/belize-bat-a-thon/">Belize Bat-a-thon</a>, an annual gathering where researchers collect and study bats.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two people wearing face masks, one with a headlamp and one holding a small bat up to the camera" src="https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568470/original/file-20240109-29-2hgb6j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Authors Nadav Ahituv, left, and Wei Gordon.</span>
<span class="attribution"><span class="source">Wei Gordon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In our <a href="https://doi.org/10.1038/s41467-023-44186-y">newly published research</a> in Nature Communications, we and colleagues <a href="https://netbiolab.org/w/People:SB_Baek">Seungbyn Baek</a> and <a href="https://scholar.google.com/citations?user=H4jO_DQAAAAJ&hl=en">Martin Hemberg</a> used a technology that analyzes the DNA of individual cells to compare the unique metabolic instructions encoded in the genome of the Jamaican fruit bat, <em>Artibeus jamaicensis</em>, with those in the genome of the insect-eating big brown bat, <em>Eptesicus fuscus</em>. </p>
<p><a href="https://doi.org/10.1038/nature11247">Approximately 2% of DNA</a> is composed of genes, which are segments of DNA that contain the instructions cells use to create certain traits, such as a <a href="https://doi.org/10.1016/j.acthis.2020.151503">longer tongue in fruit bats</a>. The other 98% are segments of DNA that regulate genes and determine the presence and absence of the traits they encode.</p>
<p>To understand how fruit bats evolved to consume so much sugar, we wanted to identify the genetic and cellular differences between bats that eat fruit and bats that eat insects. Specifically, we looked at the genes, regulatory DNA and cell types in two significant organs involved in metabolic disease: the pancreas and the kidney. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four male *Artibeus jamaicensis* and four male *Eptesicus fuscus* bats were put in a fast then fed fruit or worms, respectively, or no meal before analyzing the cells and genes of their kidney and pancreas." src="https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=244&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=244&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=244&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=306&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=306&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568363/original/file-20240109-25-d0snov.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=306&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 flowchart outlines the authors’ study methodology.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s41467-023-44186-y">Wei Gordon, created with BioRender.com/Nature Communications</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.1038/s41580-020-00317-7">The pancreas</a> regulates blood sugar and appetite by secreting hormones like insulin, which lowers your blood sugar, and glucagon, which raises your blood sugar. We found Jamaican fruit bats have <a href="https://doi.org/10.1038/s41467-023-44186-y">more insulin-producing and glucagon-producing cells</a> than big brown bats, along with regulatory DNA that primes fruit bat pancreatic cells to initiate production of insulin and glucagon. Together these two hormones work to keep blood sugar levels balanced even when the fruit bats are eating large amounts of sugar.</p>
<p><a href="https://doi.org/10.1093%2Fndt%2Fgfx027">The kidney</a> filters metabolic waste from the blood, maintains water and salt balance and regulates blood pressure. Fruit bat kidneys need to be equipped to remove from their bloodstreams the large amounts of water that come from fruit while retaining the low amounts of salt in fruit. We found Jamaican fruit bats have adjusted the compositions of their kidney cells in accordance with their diet, <a href="https://doi.org/10.1038/s41467-023-44186-y">reducing the number of urine-concentrating cells</a> so their urine is more diluted with water compared with big brown bats.</p>
<h2>Why it matters</h2>
<p>Diabetes is one of the most expensive chronic conditions in the world. The <a href="https://doi.org/10.2337/dci23-0085">U.S. spent US$412.9 billion</a> in 2022 on direct medical costs and indirect costs related to diabetes.</p>
<p>Most approaches to developing new treatments for diabetes are based on traditional laboratory animals such as mice because they are easy to reproduce and study in a lab. But outside the lab, there exist mammals like fruit bats that have actually evolved to withstand high sugar loads. Figuring out how these mammals deal with high sugar loads can help researchers identify new approaches to treat diabetes.</p>
<p>By applying new cell characterization technologies on these <a href="https://theconversation.com/e-coli-is-one-of-the-most-widely-studied-organisms-and-that-may-be-a-problem-for-both-science-and-medicine-206045">nonmodel organisms</a>, or organisms researchers don’t usually use for research in the lab, we and a growing body of researchers show that nature could be leveraged to develop novel treatment approaches for disease. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/QIBMyj8ebRU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The authors disentangle a fruit bat from a net during the Belize Bat-a-thon.</span></figcaption>
</figure>
<h2>What still isn’t known</h2>
<p>While our study revealed many potential therapeutic targets for diabetes, more research needs to be done to demonstrate whether our fruit bat DNA sequences can help understand, manage or cure diabetes in humans.</p>
<p>Some of our fruit bat findings may be unrelated to metabolism or are specific only to Jamaican fruit bats. There are <a href="https://www.britannica.com/animal/Old-World-fruit-bat">close to 200 species</a> of fruit bats. Studying more bats will help researchers clarify which fruit bat DNA sequences are relevant for diabetes treatment. </p>
<p>Our study also focused only on bat pancreases and kidneys. Analyzing other organs involved in metabolism, such as the liver and small intestine, will help researchers more comprehensively understand fruit bat metabolism and design appropriate treatments.</p>
<h2>What’s next</h2>
<p>Our team is now testing the regulatory DNA sequences that allow fruit bats to eat so much sugar and checking whether we can use them to better regulate how people respond to glucose.</p>
<p>We are doing this by <a href="https://www.youtube.com/watch?v=Cv59sjupd1Y&t=77s">swapping the regulatory DNA sequences</a> in mice with those of fruit bats and testing their effects on how well these mice manage their glucose levels.</p>
<p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p><img src="https://counter.theconversation.com/content/220756/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wei Gordon receives funding from NSF. </span></em></p><p class="fine-print"><em><span>Nadav Ahituv is a cofounder and on the scientific advisory board of Regel Therapeutics and also received funding from BioMarin Pharmaceutical Incorporate.
Funding for this research was supported by the National Human Genome Research Institute grant R01HG012396.
</span></em></p>Fruit bats can eat up to twice their body weight in fruit a day. But their genes and cells evolved to process all that sugar without any health consequences − a feat drug developers can learn from.Wei Gordon, Assistant Professor of Biology, Menlo CollegeNadav Ahituv, Professor, Department of Bioengineering and Therapeutic Sciences; Director, Institute for Human Genetics, University of California, San FranciscoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2201062024-01-09T13:25:50Z2024-01-09T13:25:50ZI set out to investigate where silky sharks travel − and by chance documented a shark’s amazing power to regenerate its sabotaged fin<figure><img src="https://images.theconversation.com/files/567867/original/file-20240104-19-fvz9ed.jpg?ixlib=rb-1.1.0&rect=0%2C114%2C919%2C596&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rather than a tracking tag telling scientists where this shark traveled, its violent removal let them observe an unexpected regeneration process.</span> <span class="attribution"><span class="source">Josh Schellenberg</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>I made an accidental and astonishing discovery while studying the movements of sharks off the coast of Jupiter, Florida. I set out to record the migration routes of silky sharks, named for their smooth skin. Instead, in a story filled with twists and turns, I ended up documenting the rare phenomenon of a shark <a href="https://doi.org/10.1155/2023/6639805">regenerating a dorsal fin</a>. </p>
<h2>Tagging, then trauma</h2>
<p>It all started in the summer of 2022, when my team and I tagged silky sharks (<em>Carcharhinus falciformis</em>) as part of my <a href="https://chelsealeighblack.com/research-projects/biotrack/">Ph.D. research</a>. <a href="https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/carcharhinus-falciformis/">Silky sharks</a> are commonly found in the open ocean and grow to be 10 feet long. Scientists know these sharks congregate in South Florida each summer, but where they go the rest of the year remains a mystery – one I hoped to solve. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three scientists wearing latex gloves lean over the side of a boat holding a still shark. Woman in middle attaches a hand-sized tag with an short antena to the fin on the shark's back." src="https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=493&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=493&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=493&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=620&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=620&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567682/original/file-20240103-23-h8z0ck.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=620&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chelsea Black, center, leads a satellite tagging team from the University of Miami in June 2022.</span>
<span class="attribution"><span class="source">Tanner Mansell</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Local boat captain John Moore took us to a site where sharks are known to gather. We carefully caught and gently attached GPS trackers to the dorsal, or top, fin of 10 silky sharks. </p>
<p>The tags, which are attached like large earrings, do not interfere with swimming and are designed to fall off after a few years. When the tag’s antenna breaks the surface of the water, its GPS location is picked up by overhead satellites, hopefully revealing details of the shark’s secret life.</p>
<p>I headed home to track their travels from my laptop. </p>
<p>The story took an unexpected turn a few weeks later, when I received disturbing photos from an avid diver and underwater photographer, Josh Schellenberg, who knew of my work.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Silky shark swiming in water with its dorsal fin missing a chunk of tissue shaped like a satellite tag." src="https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=333&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=333&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=333&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=419&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=419&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567714/original/file-20240103-23-9nlx4h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=419&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 first sighting of the wounded silky shark in July 2022.</span>
<span class="attribution"><span class="source">Josh Schellenberg</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The photos showed a male silky shark with a large, gaping wound in its dorsal fin, as if someone had taken a satellite-tag-shaped cookie cutter and punched it right through. Josh wondered if this individual was one of the sharks from my study. </p>
<p>When placing the GPS tags, I also place a second tag beneath each shark’s dorsal fin that displays a unique ID number, so I was able to confirm the injured shark was one from my study, #409834.</p>
<p>I felt a mixture of relief and sadness. Relief that the shark survived this ordeal; sadness for the scientific data that would now go uncollected. </p>
<p>Silky sharks are often caught by local fishermen in this area but are protected in Florida and <a href="https://myfwc.com/fishing/saltwater/commercial/sharks/">illegal to kill or retain</a>. Josh’s photos of #409834 showed several hooks in his mouth, so I knew this animal had been captured several times since my team tagged him.</p>
<p>The way the satellite tag attaches means it’s impossible for it to naturally rip out of the fin and leave a wound of this shape. Why someone cut off the shark’s satellite tag remains a mystery, but perhaps they thought they could resell it or possibly wanted to interfere with research. I never expected to see that shark again.</p>
<h2>The return of #409834</h2>
<p>Flash forward to one year later, the summer of 2023. I received several photos of silky sharks from John Moore, our boat captain, who is also an avid diver. John was on the lookout for any of our sharks making their seasonal return to Jupiter. In the many shark photos he sent, I noticed a silky shark with an oddly shaped dorsal fin. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Silky shark swimming through water with an oddly shaped dorsal fin." src="https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567740/original/file-20240103-15-s905sn.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">Shark #409834 spotted a year later, in June 2023, with a healed dorsal fin.</span>
<span class="attribution"><span class="source">Josh Schellenberg</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>I knew immediately it had to be #409834 from the previous summer. A few days later, John was able to get close enough to photograph the ID tag to confirm my hunch. Josh Schellenberg also spotted and photographed #409834. With both John’s and Josh’s photos, I was able to compare the healed dorsal fin with the freshly injured one. </p>
<p>I wasn’t expecting to make a groundbreaking discovery. Simple curiosity led me to start analyzing the photos. But the revelation was astonishing: Not only had the wound completely healed, but the 2023 dorsal fin was 10.7% larger in size than it was after the injury in 2022. New fin tissue had regenerated.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A collage of four photos – two are close ups of the dorsal fin freshly injured in 2022 and two are close ups of it healed in 2023. Much of it has grown back." src="https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567744/original/file-20240103-29-ocqay6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=451&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Changes in the dorsal fin from 2022 and 2023.</span>
<span class="attribution"><span class="source">Josh Schellenberg and John Moore</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.1155/2023/6639805">My analysis</a> determined that within 332 days, the shark regenerated enough tissue that his dorsal fin was almost back to 90% of its original size, growing back more than half of what had been cut off in 2022.</p>
<p>The <a href="https://dlnr.hawaii.gov/sharks/anatomy/fins-swimming/">dorsal fin</a>, pivotal for balance, steering and hydrodynamics, is vital for a shark to be able to hunt and survive. Seeing no infection or any signs of malnourishment in #409834 suggests an extraordinary feat of endurance.</p>
<p>Scientists know that sharks have an incredible <a href="https://doi.org/10.1093/conphys/cov062">aptitude for healing</a> – but mechanisms behind these observations are still poorly understood. While limb regeneration has been widely documented in other marine animals like <a href="https://ssec.si.edu/stemvisions-blog/all-about-starfish">starfish</a> and <a href="https://doi.org/10.1016/j.jembe.2023.151895">crabs</a>, there is only <a href="https://doi.org/10.1093/conphys/coaa120">one other documented case</a> of dorsal fin regeneration in a shark – a whale shark in the Indian Ocean that regrew its dorsal fin after a boat accident in 2006.</p>
<h2>400 million years of resilience</h2>
<p>There’s a reason sharks have been on Earth <a href="https://www.sciencedaily.com/releases/1999/04/990422060147.htm">longer than trees</a> and have survived <a href="https://doi.org/10.1101/2021.01.20.427414">multiple mass extinction events</a> that wiped out other species. They are a product of <a href="https://www.nhm.ac.uk/discover/shark-evolution-a-450-million-year-timeline.html">400 million years</a> of <a href="https://www.floridamuseum.ufl.edu/discover-fish/sharks/fossil/basics/">evolutionary adaptations</a> that demonstrate their remarkable resilience and have primed them for survival.</p>
<p>To be able to pinpoint an ability that helps make them so resilient is a major scientific advance – especially considering scientists are still questioning where silky sharks spend most of their time in the Atlantic. </p>
<p>One person’s attempt to undermine shark science and harm a shark ultimately proved futile. Instead, the shark’s toughness prevailed and led to an amazing discovery about this species. This story also shows there are countless individual people, including scientists like me and shark enthusiasts like Josh and John, who share a genuine love and respect for these animals.</p>
<p>While I’ll never know for certain where #409834 spends the rest of the year, I hope he continues to return to Jupiter each summer so we can further assess his progress. Based on the healing rate calculated in my study, we just might see his dorsal fin grow back to 100% its original size.</p><img src="https://counter.theconversation.com/content/220106/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chelsea Black 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>After scientists’ GPS tracking tag was violently removed from one shark’s dorsal fin, they were in for a surprise: The wound didn’t just heal, but the missing tissue grew back.Chelsea Black, Ph.D. Candidate in Marine Ecosystems and Society, University of MiamiLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2203182024-01-08T23:41:27Z2024-01-08T23:41:27ZWhen polar bears hunt snow geese, hunger justifies the means<figure><img src="https://images.theconversation.com/files/567181/original/file-20231220-19-d2je5g.jpg?ixlib=rb-1.1.0&rect=2%2C1%2C989%2C745&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The adaptations that polar bears will have to make to meet the challenges brought about by climate change are numerous and unpredictable.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Polar bears (<em>Ursus maritimus</em>) take advantage of the winter to build up their <a href="https://doi.org/10.1086/physzool.69.2.30164186">fat reserves</a>. Intensive hunting of seals, <a href="https://doi.org/10.1139/z75-117">a resource rich in fat</a>, allows bears to store up enough energy to get through the summer.</p>
<p>As the climate warms, hunting opportunities on the ice pack are <a href="https://doi.org/10.1111/1365-2656.12685">diminishing</a>. Experts believe that as a result, there is not sufficient food resources on the land to allow bears to build up <a href="https://doi.org/10.1890/140202">the energy reserves they require</a>.</p>
<p>Faced with these changes, some polar bears are taking advantage of colonies <a href="https://doi.org/10.1098/rspb.2013.3128">of nesting birds and their eggs</a>, one of the few resources readily available on land, to compensate for their energy deficits. The adaptations that bears will have to make to meet the challenges brought about by climate change are numerous and unpredictable.</p>
<p>As a student researcher in ecology, I was going to take advantage of a short trip north of Baffin Island, in Nunavut, to do some work on the small fauna of Bylot Island. One afternoon, a polar bear decided otherwise. Here we report on his exploits, which led to observations of unprecedented behaviour.</p>
<h2>An unusual sighting – a polar bear in fresh water</h2>
<p>It was Aug. 8, 2021. Some 80 km from the Inuit community of Mittimatalik, the Bylot Island field station was bustling with activity.</p>
<p><a href="https://doi.org/10.1139/as-2023-0029">Established 30 years ago</a>, the field station is located in the heart of the breeding grounds of the largest known colony of snow geese (<em>Anser caerulescens caerulescens</em>). Today, scientists from a variety of backgrounds scour the Quarliktuvik valley floor, which is generally flat, to study the soil, water, plants and wildlife.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566995/original/file-20231220-25-jybcic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bylot Island main research station TimMoser x" src="https://images.theconversation.com/files/566995/original/file-20231220-25-jybcic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566995/original/file-20231220-25-jybcic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=246&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566995/original/file-20231220-25-jybcic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=246&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566995/original/file-20231220-25-jybcic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=246&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566995/original/file-20231220-25-jybcic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=310&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566995/original/file-20231220-25-jybcic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=310&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566995/original/file-20231220-25-jybcic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=310&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 Bylot Island research camp.</span>
<span class="attribution"><span class="source">(Tim Moser)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>Coming out of a ravine, one of the few landforms in the area, I was scanning the valley with my binoculars when two pairs of legs in the distance caught my eye. The image was foggy, but what I initially thought were two colleagues walking side by side, turned out to be the distinctive shape of a polar bear. Everyone in our group had the necessary protective equipment — bear spray, anti-bear cartridges and sometimes even a rifle — but I alerted them by radio and immediately returned to the field station.</p>
<p>Several colleagues had gathered on a small hill to keep an eye on the newcomer. In fact, by the time I’d covered the kilometre distance to the camp, the bear had walked three kilometres and was moving around a pond where geese were gathered. At this time of year, <a href="https://doi.org/10.1111/jav.00982">the geese are moulting</a> — and therefore unable to fly — so they congregate near ponds to avoid the <a href="https://doi.org/10.14430/arctic604">Arctic fox (<em>Vulpes lagopus</em>)</a>, which is reluctant to jump into the water. With a bear in the vicinity, we ceased our field activities and took advantage of the radiant afternoon to watch the king of the ice pack.</p>
<p>True to form, the geese took refuge in the nearest pond at the first sight of danger. They waded in quickly enough to keep the bear, who was swimming on the surface, at a safe distance.</p>
<p>But the bear was about to use a new hunting technique: he dove under the water, disappeared from the eyes of the geese who had stopped fleeing, and emerged from underneath one of them.</p>
<p>My colleague Mathilde Poirier recorded the behaviour in her notebook:</p>
<blockquote>
<p>1:45 p.m. - 2:00 p.m.: the bear swims in the lake […], makes 4 dives to try to catch a goose. Succeeds in its 4th attempt (catches the goose from below, during a dive).</p>
</blockquote>
<p>During the afternoon, the bear used this technique two more times, once failing and once with success.</p>
<h2>What are the benefits of this behaviour for bears?</h2>
<p>Two months later, back at Laval University, we were still fascinated by this observation. Nowhere in the scientific literature is there any mention of such behaviour. At best, there are reports of <a href="https://doi.org/10.33265/polar.v41.8176">attacks on murres in the ocean</a> near the coasts, an environment very different from the calm, shallow ponds where we observed the bear’s attacks.</p>
<p>Being aware of the <a href="https://doi.org/10.1890/140202">energy challenges</a> bears face during the summer, our research group — led by Matthieu Weiss-Blais — wanted to answer the following question: would this hunting technique allow polar bears to benefit from eating snow geese?</p>
<p>The information recorded in the field, i.e. the time the bear spent swimming and its success in hunting, allowed us to answer this question. By combining our observations with <a href="https://doi.org/10.1007/s00300-017-2209-x">estimates of the energy cost</a> of swimming in bears and <a href="https://doi.org/10.1093/conphys/cow045">the energy contained in a snow goose</a>, we were able to model the energy efficiency of the technique.</p>
<p><a href="https://doi.org/10.1139/AS-2023-0036">These calculations reveal</a> that this hunting technique could allow bears to acquire more energy than they expend, particularly for smaller bears, and if they manage to catch a goose quickly.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/566994/original/file-20231220-25-lint0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="polar bear" src="https://images.theconversation.com/files/566994/original/file-20231220-25-lint0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/566994/original/file-20231220-25-lint0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566994/original/file-20231220-25-lint0u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566994/original/file-20231220-25-lint0u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566994/original/file-20231220-25-lint0u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566994/original/file-20231220-25-lint0u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566994/original/file-20231220-25-lint0u.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 bear was moving around near a pond occupied by geese.</span>
<span class="attribution"><span class="source">(Yannick Seyer)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<h2>An energy boost, but far from sufficient</h2>
<p>However, this energy contribution would be very limited in scope.</p>
<p>First of all, a goose provides relatively little energy — around 200 times less than a <a href="https://doi.org/10.1139/z75-117">ringed seal weighing 45 kilograms</a>.</p>
<p>What’s more, the geese are rarely available as prey: they lose the ability to fly for only three or four weeks each summer and they only have colonies in <a href="http://dx.doi.org/10.1002/jwmg.879">a few places</a> in the Arctic.</p>
<p>Hunting geese could therefore be of benefit to certain bears from time to time, but on a population-wide scale, it will not alleviate the energy deficits caused by the melting ice pack.</p>
<p>Although our observation highlights the range of behaviours bears can adopt in order to exploit terrestrial resources, this type of interaction between snow geese and polar bears should have no impact on the populations of either species.</p><img src="https://counter.theconversation.com/content/220318/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Bolduc received funding from the NSTP and the Canadian Association for Humane Trapping.</span></em></p><p class="fine-print"><em><span>Matthieu Weiss-Blais received funding from NSERC, FRQNT and NSTP.
</span></em></p>Researchers have made a fascinating observation: a polar bear used a diving hunting technique, never before reported, to capture large moulting snow geese.David Bolduc, Étudiant au doctorat en écologie animale, Université LavalMatthieu Weiss-Blais, Étudiant la maîtrise en biologie, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2135112023-12-27T09:11:18Z2023-12-27T09:11:18ZFascia: the most neglected part of our body is finally starting to receive attention<figure><img src="https://images.theconversation.com/files/551706/original/file-20231003-16-lps8ae.jpg?ixlib=rb-1.1.0&rect=13%2C13%2C4587%2C3049&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/human-anatomy-exhibition-by-gunther-von-1275690106">Photo Inspiration/Shutterstock</a></span></figcaption></figure><p>We are constantly reminded about how exercise benefits our <a href="https://ijbnpa.biomedcentral.com/articles/10.1186/s12966-020-01040-4">bone</a> and <a href="https://www.nia.nih.gov/news/how-can-strength-training-build-healthier-bodies-we-age#muscle">muscle</a> health or <a href="https://pubmed.ncbi.nlm.nih.gov/37497435/">reduces fat</a>. However, there is also a growing interest in one element of our anatomy that is often overlooked: our <a href="https://my.clevelandclinic.org/health/body/23251-fascia">fascia</a>. </p>
<p>Fascia is a thin casing of connective tissue, mainly made of <a href="https://www.ncbi.nlm.nih.gov/books/NBK507709/">collagen</a> – a rope-like structure that provides strength and protection to many areas of the body. It surrounds and holds every organ, blood vessel, bone, nerve fibre and muscle in place. And scientists increasingly recognise its importance in muscle and bone health.</p>
<p>It is hard to see fascia in the body, but you can get a sense of what it looks like if you look at a steak. It is the thin white streaks on the surface or between layers of the meat.</p>
<p>Fascia provides general and special functions in the body, and is arranged in several ways. The closest to the surface is the <a href="https://pubmed.ncbi.nlm.nih.gov/17061033/">superficial fascia</a>, which is underneath the skin between layers of fat. Then we have the deep fascia that covers the muscles, bones and blood vessels.</p>
<p>The link between fascia, muscle and bone health and function is reinforced by recent studies that show the important role fascia has in helping <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6455047/">the muscles work</a>, by assisting the contraction of the muscle cells to <a href="https://link.springer.com/article/10.1007/s11916-014-0441-4">generate force</a> and affecting muscle stiffness. </p>
<p>Each <a href="https://training.seer.cancer.gov/anatomy/muscular/structure.html">muscle is wrapped in fascia</a>. These layers are important as they enable muscles that sit next to, or on top of, each other to move freely without affecting each other’s functions.</p>
<p>Fascia also assists in the transition of force through the musculoskeletal system. An example of this is our ankle, where the achilles tendon <a href="https://pubmed.ncbi.nlm.nih.gov/10710257/">transfers force</a> into the plantar fascia. This sees forces moving vertically down through the achilles and then transferred horizontally into the bottom of the foot - the plantar fascia – when moving. </p>
<p>Similar force transition is seen from muscles in the chest <a href="https://onlinelibrary.wiley.com/doi/10.1002/ca.23424">running down through to</a> groups of muscles in the forearm. There are similar <a href="https://pubmed.ncbi.nlm.nih.gov/26281953/">fascia connective chains</a> through other areas of the body. </p>
<h2>When fascia gets damaged</h2>
<p>When fascia doesn’t function properly, such as after injury, the layers become less able to facilitate movement over each other or help transfer force. Injury to fascia takes a long time to <a href="https://link.springer.com/article/10.1007/s11916-014-0441-4">repair</a>, probably because it possesses similar cells to tendons (fibroblasts), and has a <a href="https://www.nature.com/articles/s41598-023-33479-3">limited</a> blood supply. </p>
<p>Recently, fascia, particularly the layers close to the surface, have been shown to have <a href="https://www.frontiersin.org/articles/10.3389/fnana.2022.981426/full">the second-highest number of nerves</a> after the skin. The fascial linings of muscles have also been linked to <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1002/jor.24665">pain</a> from surgery to musculoskeletal injuries from sports, exercise and ageing. Up to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1026905/">30% of people</a> with musculoskeletal pain may have fascial involvement or <a href="https://pubmed.ncbi.nlm.nih.gov/27475508/">fascia may be the cause</a>.</p>
<p>A type of massage called <a href="https://pubmed.ncbi.nlm.nih.gov/19118795/">fascial manipulation</a>, developed by Italian physiotherapist Luigi Stecco in the 1980s, has been shown to improve the pain from patellar tendinopathy (pain in the tendon below the kneecap), both in the short and long term. </p>
<p>Fascial manipulation has also shown positive results in treating <a href="https://www.sciencedirect.com/science/article/pii/S1360859208000752">chronic shoulder pain</a>. </p>
<p>One of the growing trends for helping with musculoskeletal injuries is Kinesio tape, which is often used in professional sports, although evidence for its effectiveness is mixed. It is also being used to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4491400/">complement the function</a> of the fascia, and is used to treat chronic lower back pain where <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0250686">fascial involvement</a> is a factor. </p>
<figure class="align-center ">
<img alt="A runner with Kinesio tape on his legs." src="https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563005/original/file-20231201-25-fkbu1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A runner with Kinesio tape on his legs.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/male-athlete-tape-on-his-knees-472723348">Real Sports Photos/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Fascia in disease</h2>
<p>Aside from getting damaged, fascia can also provide paths that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2823166/">infections can travel along</a>, <a href="https://www.sciencedirect.com/science/article/pii/S1743919112007650">within muscles</a>. </p>
<p>The spaces between fascial layers are usually closed (think of cling film being folded over), but when an infection occurs, germs can spread between these layers. This is a particular problem <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6716171/">in the neck</a>, where there are <a href="https://www.ncbi.nlm.nih.gov/books/NBK513262/">several layers of fascia</a> for infections to travel along. </p>
<p>In severe cases, surgery is often needed to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4286984/">remove the dead tissue</a> and save the healthy remaining tissue.</p>
<p>One of the primary examples of fascia functioning in health, and the challenges its dysfunction can bring, is seen in the common complaint <a href="https://www.nhs.uk/conditions/plantar-fasciitis/">plantar fasciitis</a>, which causes pain on around the heel and arch of the foot. </p>
<p>This incredibly common ailment affects <a href="https://cks.nice.org.uk/topics/plantar-fasciitis/background-information/prevalence/">5-7%</a> of people, rising to <a href="https://bjsm.bmj.com/content/52/5/322.long">22% in athletes</a>. It is recognised as an overuse injury, causing the thickening of the fascial bands on the soles of the feet that help give the arch support. </p>
<p>Fascia can also be implicated in more serious health conditions, such as <a href="https://www.cdc.gov/groupastrep/diseases-public/necrotizing-fasciitis.html">necrotising fasciitis</a>. This is a rare but serious bacterial condition that can spread through the body quickly and cause death. </p>
<p>The condition is almost always caused by bacteria, specifically group A <a href="https://pubmed.ncbi.nlm.nih.gov/23795951/">Streptococcus</a> or <a href="https://www.frontiersin.org/articles/10.3389/fgene.2022.964358/full"><em>Staphylococcus aureus</em></a>. The initial infection comes from a cut or scratch, and then the bacteria travel along the fascia to other areas away from the initial site of access and multiply in the ideal environment afforded by the warm recesses of the body.</p>
<h2>We can see it better now</h2>
<p>One reason fascia has been overlooked in health and disease is because it was difficult to see using current imaging technology. More recently, though, MRI and ultrasound imaging have been shown to be beneficial in visualising fascia, particularly in musculoskeletal conditions such as <a href="https://bmcmedimaging.biomedcentral.com/articles/10.1186/s12880-019-0361-1">plantar fasciitis</a>, and pathological changes in the fascia of the <a href="https://www.mdpi.com/2075-4418/13/15/2601">shoulder</a> and <a href="https://www.sciencedirect.com/science/article/pii/S1360859221000395">neck</a>.</p>
<p>With the growing interest in fascia and the growing understanding of its contribution to musculoskeletal health, it’s sensible to suggest that we look after it in the same way we do with the rest of the musculoskeletal system - by using it. Simple techniques like foam rollers and stretching are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4637917/">beneficial in increasing mobility</a>, but there is still much to learn about our fascia and the role it plays in our day-to-day health. </p>
<p><em>Clarification. The sentence: “One of the growing trends for helping with musculoskeletal injuries is Kinesio tape, which is often used in professional sports” has been amended to make it clear that evidence for the tape’s effectiveness is mixed.</em></p><img src="https://counter.theconversation.com/content/213511/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adam Taylor does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The much understudied fascia – our body’s own version of Spanx – is now coming under increasing scientific scrutiny.Adam Taylor, Professor and Director of the Clinical Anatomy Learning Centre, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2192672023-12-18T16:17:09Z2023-12-18T16:17:09ZHow a Victorian trip to Palestine spurred modern ornithology – and left it with imperial baggage<p>Palestine’s natural splendour offered a landscape ripe for scientific “discovery”, description and expropriation by European imperial powers in the 19th century. And in the 1860s an English vicar named <a href="https://www.sacristy.co.uk/books/history/henry-baker-tristram-ornithology#">Henry Baker Tristram</a> claimed its birds. </p>
<p>Tristram was a co-founder of <a href="https://bou.org.uk/about-the-bou/">Ibis</a>, the ornithology journal published since 1859 by the British Ornithologists’ Union. His articles on Palestinian ornithology began with the first issue, when he contributed a list of birds he’d collected during a brief visit there the previous year. The list included a species previously unknown to western science, which was named in his honour as Tristram’s grackle (now more commonly known as Tristram’s <a href="https://ebird.org/species/trista1?siteLanguage=en_GB">starling</a>). </p>
<p>Tristram made a major contribution to the study of birds. At that time ornithology reflected imperial priorities and was concerned with collecting, describing and mapping. His observations of Palestine’s birds, in particular, laid the groundwork for the modern ornithology of the area. </p>
<p>However, his exploits in Palestine, still honoured in the name “Tristram’s starling”, also show why honorific bird names like this have come under increasing <a href="https://americanornithology.org/about/english-bird-names-project/">scrutiny</a>. </p>
<p>Tristram returned to Palestine for a fuller investigation in 1864. He travelled south from Beirut with a group of fellow naturalists and a large baggage train. The account of his ten-month-long journey was published in 1865 as <a href="https://books.google.co.uk/books/about/The_Land_of_Israel.html?id=Qd8TAAAAIAAJ&redir_esc=y">The Land of Israel</a>. </p>
<p>This book, and the several <a href="https://onlinebooks.library.upenn.edu/webbin/book/lookupname?key=Tristram%2C%20H.%20B.%20%28Henry%20Baker%29%2C%201822-1906">others</a> he wrote about Palestine, formed part of a growing wave of popular tourist accounts of the Holy Land. They fed the interest and shaped the perceptions of British readers fascinated by the area’s historical and Biblical remnants, its living inhabitants, and the missionary efforts to achieve conversions to Christianity. </p>
<p>Unusually, Tristram and his companions travelled far off the well-beaten tourist and Christian pilgrimage routes throughout Palestine. The Land of Israel includes detailed descriptions of Palestine’s diverse ethnic groups, their domestic, religious, military and economic traditions and practices, and their relationships with one another. </p>
<h2>Imperialism</h2>
<p>Tristram’s descriptions of Palestine’s people in many ways reflected typical British imperial views of “natives”, not least in his use of the terms “childlike” and “savage”, and his comparison of Bedouins to “red Indians”. His racialising and religious views were also shaped by his inclinations as a natural historian – he categorised those he observed according to type, and deviation from type. </p>
<p>At best, his characterisations are paternalistic; at worst, deeply offensive. The terms “debased” and “degraded” repeat often. Of one group near Jericho he writes: “I never saw such vacant, sensual, and debased features in any group of human beings of the type and form of whites”. </p>
<p>Of some Bedouin further south, he observes that “they were all decidedly of the Semitic type, and, excepting the colour and the smell, had nothing of the negro about them. They must, however, be far inferior to the races they have supplanted.”</p>
<p>Occasionally, he acknowledges Ottoman oppression and neglect as the cause of poverty, but in most cases links it to “Moslem fanaticism” and “Oriental indolence”. Although there are exceptions, Muslim settlements and their inhabitants are almost invariably “filthy”, “squalid” and “miserable”. </p>
<p>Of religious sites, he notes many instances of churches which have been “perverted” into mosques. One of his most offensive observations is of a Bedouin sheikh, Abu Dahuk: “like all his followers, he is very dark – not so black as the commonalty, but of a deep olive brown. This may partly arise from the habit of these people, who never wash. They occasionally take off their clothes, search them, slaughter their thousands, and air themselves, but never apply water to their persons”. The odour, he remarks, “is unendurable”.</p>
<p>Conversion to Christianity appeared to redeem this degradation. In the Galilee he notes: “Christianity had here, as elsewhere, stamped the place and its substantial houses with a neatness and cleanliness to which the best of Moslem villages are strangers”. </p>
<p>Conversion also seemed to him to transform racial attributes. Of two Protestant converts he observes that “so much had religion and education elevated them, that they seemed of a different race from those around them”. Among Bethlehem’s Christians, he particularly admires “the handsome faces of the men and women, and the wondrous beauty of the children, so fair and European-like”. </p>
<figure class="align-left ">
<img alt="An old brown book cover with the words The Land of Israel." src="https://images.theconversation.com/files/566291/original/file-20231218-24-apod48.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/566291/original/file-20231218-24-apod48.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=846&fit=crop&dpr=1 600w, https://images.theconversation.com/files/566291/original/file-20231218-24-apod48.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=846&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/566291/original/file-20231218-24-apod48.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=846&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/566291/original/file-20231218-24-apod48.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1063&fit=crop&dpr=1 754w, https://images.theconversation.com/files/566291/original/file-20231218-24-apod48.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1063&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/566291/original/file-20231218-24-apod48.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1063&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The cover of Land of Israel 1872 edition.</span>
<span class="attribution"><span class="source">Jasmine Donahaye</span></span>
</figcaption>
</figure>
<p>Tristram describes Jewish ethnicity in typical missionary terms. The Jews were a “decayed and scattered people”, with “musty and crumbling learning”. At a Protestant missionary tent in Tiberias he notes that “the Polish Jews, very numerous here, were willing to listen … but the native Jews, with whom were mingled a few Moslems, were occasionally very violent in their expressions”. The Jews, he concludes, “are a stiff-necked race”. </p>
<p>During his months in Palestine in 1864, Tristram shot hundreds of birds for his collection, and shot many more during subsequent visits. His surviving collection in the Liverpool World Museum includes, among others, the original 1858 <a href="https://www.liverpoolmuseums.org.uk/stories/whats-type-guide-type-specimens">type specimens</a> of Tristram’s grackle, and 17 Palestine sunbird skins.</p>
<p>Tristram depended on many people – servants, dragomen, muleteers, cooks, collectors and guards – for their expertise, labour and protection, and sometimes even for <a href="https://newwelshreview.com/book/birdsplaining-a-natural-history-by-jasmine-donahaye">saving his life</a>. He also depended on them for help with obtaining specimens. But for that help with collecting he only names one person: “Gemil, with a little training,” he writes, “would soon have made a first-rate collector.”</p>
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Read more:
<a href="https://theconversation.com/why-dozens-of-north-american-bird-species-are-getting-new-names-every-name-tells-a-story-217886">Why dozens of North American bird species are getting new names: Every name tells a story</a>
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<p>Those British imperial values that coloured Tristram’s view of Palestine’s people enabled him to name and claim its natural resources for western science, and for personal glory. They also gave him licence to propose that the land itself should be claimed: “Either an European protectorate or union with Egypt seems requisite to save Palestine from gradual dissolution,” he remarked, “unless, which seems hopeless, the Arabs can be induced to cultivate the sod.”</p><img src="https://counter.theconversation.com/content/219267/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jasmine Donahaye 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>H.B. Tristram was a Victorian clergyman and ornithologist who categorised a list of birds he’d found in Palestine.Jasmine Donahaye, Professor in English Literature and Creative Writing, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2188742023-12-18T13:20:32Z2023-12-18T13:20:32ZStudents could get more sleep and learn better if school started a little later<figure><img src="https://images.theconversation.com/files/564471/original/file-20231208-27-k39utf.jpg?ixlib=rb-1.1.0&rect=23%2C11%2C3916%2C2280&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">About 58% of middle schoolers and 73% of high schoolers do not get enough sleep.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/girl-is-tired-and-sleeping-at-the-desk-in-classroom-royalty-free-image/1503343198?phrase=students+sleeping+in+class">JackF via iStock / Getty Images Plus</a></span></figcaption></figure><p>Nearly three-quarters of high school students do not get enough sleep on school nights, according to the <a href="https://www.cdc.gov/healthyschools/features/students-sleep.htm">Centers for Disease Control and Prevention</a>.</p>
<p>The National Sleep Foundation recommends that teens sleep for <a href="https://doi.org/10.1016/j.sleh.2014.12.010">eight to 10 hours per night</a>. But various factors hinder this, including early school start times and <a href="https://doi.org/10.1093/sleep/16.3.258">shifts in adolescents’ circadian rhythms</a> – the biological internal clock that regulates the sleep-wake cycle and repeats roughly every 24 hours. <a href="https://theconversation.com/school-start-times-and-screen-time-late-in-the-evening-exacerbate-sleep-deprivation-in-us-teenagers-179178">Healthy sleep is crucial</a> for teens’ physical, cognitive and emotional development. When teens don’t get enough sleep, it can have lifelong impacts. They range from <a href="https://doi.org/10.1111/j.1365-2869.2011.00934.x">poor mental health</a> to <a href="https://doi.org/10.5664/jcsm.10156">lower attendance and graduation rates</a>.</p>
<p>As a neurologist <a href="https://scholar.google.com/citations?user=sTqquL0AAAAJ&hl=en">specializing in sleep disorders</a>, I have studied the profound importance of sleep in optimizing the body and mind. I believe insufficient sleep among adolescents is a public health crisis. This is why I reached out to my local state representative in Pennsylvania, <a href="https://www.legis.state.pa.us/cfdocs/legis/home/member_information/house_bio.cfm?id=1951">Rep. Jill Cooper</a>, a member of the House Education Committee, in October 2023 and pushed for legislative change. The resulting <a href="https://legiscan.com/PA/bill/HB1848/2023">proposed bill</a> would mandate that middle and high schools start no earlier than 8:15 a.m. by the 2026-27 school year.</p>
<p>While parents, educators and school administrators cannot alter biology, they can change school start times to allow students to obtain sufficient sleep for academic success and physical and mental well-being. In fact, the American Academy of Pediatrics <a href="https://doi.org/10.1542/peds.2014-1697">recommends pushing back school start times</a> to 8:30 a.m. or later.</p>
<p>Around the world, <a href="https://worldpopulationreview.com/country-rankings/average-school-day-length-by-country">school start times vary considerably</a>, from 7 a.m. in Brazil to 9 a.m. in Finland. While I’m not aware of any global dataset or research on the relationship between school start times and academic performance, Finland was ranked No. 2 on the list of <a href="https://worldpopulationreview.com/country-rankings/education-rankings-by-country">best educational systems</a> in the Global Citizens for Human Rights report in 2020. Canada, where the average school day begins at 8:30 a.m., was ranked No. 4.</p>
<h2>Sleep and the teenage brain</h2>
<p>Parents may notice that their kids, who were once early birds, start to sleep later and later as they hit their teen years. This is not just due to typical teen behavior like playing video games late at night, but rather it’s a <a href="https://doi.org/10.1093/sleep/16.3.258">biological response</a>.</p>
<p>During adolescence, changes in hormone levels, along with physical and brain maturation, lead to natural shifts in the circadian rhythm. The body tends to delay the release of melatonin, the hormone responsible for bringing on drowsiness at night. </p>
<p>Consequently, teens often find it <a href="https://doi.org/10.1016/j.pcl.2011.03.003">challenging to fall asleep early</a>, leading to a later bedtime. This delayed circadian rhythm also results in a preference for waking up later in the morning. These changes clash with societal and cultural expectations such as early school start times, often contributing to sleep deprivation among teenagers.</p>
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<figcaption><span class="caption">Changes in hormones and the circadian rhythm make it difficult for teens to fall asleep and wake up early. Healthy Hours via Vimeo</span></figcaption>
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<p>More than 80% of public middle and high schools across the United States <a href="https://nces.ed.gov/pubs2020/2020006/index.asp">start before 8:30 a.m.</a>, with 42% starting before 8 and 10% before 7:30. Consequently, bus pickup for some children can be as early as <a href="https://www.orlandosentinel.com/2015/04/18/5-am-bus-rides-630-walks-to-school-all-too-early/">5 a.m. in some districts</a>. What follow are four negative outcomes associated with early school start times.</p>
<h2>Hindered academic success</h2>
<p>Numerous studies have linked early school start times to poorer performance on <a href="https://doi.org/10.1542/peds.2014-1697">academic tests</a>. </p>
<p>One study looked at <a href="https://doi.org/10.5664/jcsm.10156">school start times, graduation rates and attendance rates</a> for 30,000 students in 29 high schools across seven states. It found a significant improvement in attendance rates, from 90% to 93%, and graduation rates, from 80% to 90%, four years after delaying school start times to 8:30.</p>
<p>Sleep deprivation has been shown to worsen <a href="https://doi.org/10.1093/sleep/zsab051">memory, learning ability, attention span</a>, <a href="https://doi.org/10.1016/B978-0-444-53702-7.00007-5">creativity</a>, <a href="https://doi.org/10.1177/019263650208663302">school attendance</a> and <a href="https://doi.org/10.1001/archpediatrics.2010.96">first-period tardiness</a> – a perfect storm for poor academic performance. </p>
<h2>Poorer mental health</h2>
<p>A recent <a href="https://www.hhs.gov/sites/default/files/sg-youth-mental-health-social-media-advisory.pdf">advisory from the U.S. surgeon general</a> raised the alarm on the harmful impacts of social media on youth mental health. Researchers have unearthed mounds of evidence on the negative effects, including <a href="https://theconversation.com/mounting-research-documents-the-harmful-effects-of-social-media-use-on-mental-health-including-body-image-and-development-of-eating-disorders-206170">poor body image</a>. In these discussions, however, a simple yet powerful solution for improving mental well-being is often overlooked – the profound impact of sleep. </p>
<p>During REM sleep – or the dream state – our memories consolidate and we process emotions. Insufficient sleep increases the risk of <a href="https://doi.org/10.1111/j.1365-2869.2011.00934.x">depression</a>, <a href="https://doi.org/10.1542/peds.2014-1696">anxiety</a> and <a href="https://doi.org/10.1093/sleep/27.7.1351">suicide</a> among adolescents. One study showed that for every extra hour of sleep among adolescents, their <a href="https://doi.org/10.1016/j.smrv.2018.07.003">risk of suicide decreased</a> by 11%. </p>
<h2>Impaired physical health and social behavior</h2>
<p>Sleep is fundamental for physical well-being. For both children and adults, it plays a key role in essential bodily functions. During slow-wave sleep – or deep sleep – our bodies restore themselves: Our <a href="https://doi.org/10.1007/s00424-011-1044-0">immune system strengthens</a> to keep us healthy. And our waste-clearing glymphatic system <a href="https://doi.org/10.3389/fnins.2021.639140">eradicates neurotoxic proteins</a>, which are linked to diseases like Alzheimer’s. </p>
<p>Sleep deprivation is associated with higher rates of <a href="https://doi.org/10.1155/2012/476914">obesity</a>, <a href="https://doi.org/10.5664/jcsm.6288">diabetes, cardiovascular problems, chronic health conditions</a>, <a href="https://doi.org/10.1016/j.sleep.2019.03.008">physical injuries</a> and weakened immune function. Sleep-deprived students are more likely to fall asleep when sedentary, such as when driving a car. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2603528/">Motor vehicle accidents</a> related to driving while drowsy are especially prevalent among teen drivers.</p>
<p>Sleep-deprived students are also more likely to demonstrate aggression, struggle with social communication and engage in risk-taking behaviors. One study found that the amount of sleep that high school students get is directly related to their <a href="https://doi.org/10.1001/jamapediatrics.2018.2777">engagement in unsafe behaviors</a>, such as substance abuse, risky driving, aggressive behavior and tendency toward self-harm. </p>
<h2>An economic cost</h2>
<p>The economic ramifications of this crisis may not be immediately obvious, but they are undeniable. Contrary to <a href="https://lacomadre.org/2019/10/beyond-students-late-school-start-times-could-impact-parents-and-transportation-budgets/">concerns that delayed school start times might increase transportation costs</a> by changing bus schedules, a 2017 study conducted by the nonprofit RAND Corp. found that the economic benefits <a href="https://doi.org/10.7249/RR2109">far outweigh the expenses</a>. </p>
<p>The study showed that a universal shift to 8:30 a.m. school start times would result in an $8.6 billion gain in the U.S. economy over two years. Investing in delayed school start times, therefore, isn’t a drain on resources. Instead, it contributes to a healthier future for generations to come.</p><img src="https://counter.theconversation.com/content/218874/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joanna Fong-Isariyawongse 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>Most teens aren’t getting enough sleep, leading to poorer academic performance. Early school start times combined with natural changes in hormones and the circadian rhythm could be to blame.Joanna Fong-Isariyawongse, Associate Professor of Neurology, University of PittsburghLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2144042023-11-24T13:17:20Z2023-11-24T13:17:20ZThe way a sperm tail moves can be explained by mathematics worked out by Alan Turing<figure><img src="https://images.theconversation.com/files/560823/original/file-20231121-4807-l2zivo.jpg?ixlib=rb-1.1.0&rect=5%2C11%2C3988%2C2982&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sperms-on-egg-1762528">SciePro / Shutterstock</a></span></figcaption></figure><p>Alan Turing might be best known for his work helping to crack Germany’s <a href="https://www.iwm.org.uk/history/how-alan-turing-cracked-the-enigma-code">“Enigma” communications code during the second world war</a>. But he also came up with a theory where patterns can form just through chemical compounds spreading out (diffusing) and reacting with one another. This became known as <a href="https://en.wikipedia.org/wiki/Turing_pattern">reaction-diffusion theory for pattern formation</a>. </p>
<p>PhD student James Cass and I recently published a study in <a href="https://www.nature.com/articles/s41467-023-40338-2">Nature Communications</a> that revealed the tail of a sperm, known as a flagellum, generates patterns as it moves – and that these patterns can be described by Turing’s theory.</p>
<p>Patterns formed by chemical interactions create a large variety of shapes and colours such as spirals, stripes and spots. They <a href="https://www.csiro.au/en/news/all/articles/2017/february/patterns-nature-zebra-stripes">are everywhere in nature</a>, and are believed to be behind animal markings such as those on zebras and leopards, the whorl of seeds in a sunflower head and patterns formed by beach sand. </p>
<p>Turing’s theory can be applied to various fields in science, from <a href="https://people.maths.ox.ac.uk/maini/PKM%20publications/462.pdf">biology</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9916983/">robotics</a> to <a href="https://journals.aps.org/prx/abstract/10.1103/PhysRevX.7.041002">astrophysics</a>.</p>
<p>We wanted to explore whether there was a mathematical connection between these chemical patterns and how sperm tails move. If there was, it might suggest that nature uses similar templates to create patterns of motion at tiny scales.</p>
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<figcaption><span class="caption">Animated reaction-diffusion patterns.</span></figcaption>
</figure>
<h2>Tale of a tail</h2>
<p>The mathematics of how the sperm flagellum moves is very complex. The flagellum uses <a href="https://academic.oup.com/molehr/article/17/8/524/1073668?login=false">molecular scale “motors”</a> to effectively shape-shift. They use energy in one form and convert it into mechanical work, generating motion. These motors power tiny fibres that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5204319/#:%7E:text=The%20axoneme%20is%20the%20main%20part%20of%20flagella%20and%20cilia,zone%20">exist in a bundle called an axoneme</a>. These are beautiful, geometric and slender structures that can be up to 0.05 millimetres long in human sperm – about half the width of a human hair.</p>
<p>The axoneme is very flexible, meaning micrometre-scale waves can travel along it. It is the active core of the flagellum and is responsible for propelling sperm cells along. They can even <a href="https://www.annualreviews.org/doi/10.1146/annurev.physiol.69.040705.141236">sense the environment around them</a>. </p>
<p>The swimming motion is a result of complex interactions between passive components such as the axoneme and its elastic connector parts, active parts (the molecular motors) and the surrounding fluid. </p>
<figure class="align-center ">
<img alt="Axoneme" src="https://images.theconversation.com/files/560832/original/file-20231121-16-f62myv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560832/original/file-20231121-16-f62myv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=479&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560832/original/file-20231121-16-f62myv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=479&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560832/original/file-20231121-16-f62myv.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=479&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560832/original/file-20231121-16-f62myv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=602&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560832/original/file-20231121-16-f62myv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=602&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560832/original/file-20231121-16-f62myv.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=602&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cross section through an axoneme.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Axoneme#/media/File:Chlamydomonas_TEM_17.jpg">Wikipedia</a></span>
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</figure>
<p>The fluid environment in which sperm travel generates drag that resists motion by the flagellum. In order for sperm to travel, multiple, partly antagonistic, factors need to reach a balance where undulations by the flagellum propel sperm along. </p>
<p>We were partially inspired by scientific findings that suggest the surrounding fluid has little effect on sperm flagellum movements. To investigate this, we <a href="https://www.ibm.com/topics/what-is-a-digital-twin">created a digital “twin”</a> of the sperm flagellum in a computer. </p>
<p>This twin is a representation in the computer that should behave in a very similar way to the real thing. This complex task was carried out by James F. Cass at the <a href="https://www.polymaths-lab.com">Polymaths Lab</a>.</p>
<p>This allowed us to determine how much the surrounding fluid influenced the movement of the tail. We found that low viscosity (watery) fluids, the kind that aquatic species are adapted for, had very little effect on how the flagellum was shaped.</p>
<p>Using a combination of mathematical modelling, simulations and model fitting, we showed that undulations in sperm tails arise spontaneously, without the influence of their watery surroundings. This means that the flagellum has a foolproof mechanism to enable swimming in low viscosity fluids.</p>
<p>Mathematically, this spontaneous movement is equivalent to the way patterns arise under Turing’s reaction-diffusion system that was first proposed for chemical patterns. The similarity between chemical patterns and patterns of movement was striking and unexpected.</p>
<p>Typically, we would not think about chemical patterns working the same way as motion patterns (or patterns of contractions), nor would we expect the mathematics to be similar. But now we know this is the case, we think the motion pattern may only need two simple ingredients. The first is chemical reactions that drive molecular motors and the second is a bending motion by the elastic flagellum. The surrounding fluid has little to no effect in aquatic environments.</p>
<p>The molecular motors all along the sperm’s flagellum create “shearing” forces which bend the tail. If an elastic rod is bent and released, the rod will eventually unbend until it reaches a straight equilibrium. In other words, bending “diffuses” along the structure in the same way that a dye diffuses in fluid until it reaches a balanced level of dilution – known as equilibrium. It harks back to Turing’s mathematics.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/how-animals-got-their-spots-and-stripes-according-to-maths-85053">How animals got their spots and stripes – according to maths</a>
</strong>
</em>
</p>
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<p>These findings may be used in future to better understand fertility issues <a href="https://link.springer.com/article/10.1007/s10815-016-0652-1">associated with abnormal motion of the flagellum</a>. The mathematics behind this could also be explored for new robotic applications, including artificial muscles and what are known as animate materials – materials that seem “alive”, changing their response according to how they’re being used.</p>
<p>The same mathematics that describes how the sperm tail moves also applies to cilia. These are thread-like projections found on many types of biological cells that propel fluid along a surface. Researching their movement could help us better understand <a href="https://genomemedicine.biomedcentral.com/articles/10.1186/gm275#:%7E:text='Ciliopathies'%20are%20an%20emerging%20class,that%20affect%20ciliary%20structure%2Ffunction.">ciliopathies</a>, diseases caused by ineffective cilia in the human body.</p>
<p>However, we need to be cautious. Mathematics is an imperfect tool for examining nature’s perfect work. Although this takes us a step closer to mathematically decoding spontaneous movement in flagella and cilia, the proposed animated reaction-diffusion theory is far too simple to fully capture all the complexity. Different teams have investigated whether Turing’s pattern formation theory is at work in other biological systems and have found the evidence lacking.</p>
<p>Likewise, other mathematical models may fit equally well, or even better, with experiments. As the British statistician George Box once rightly said: <a href="https://en.wikipedia.org/wiki/All_models_are_wrong">“All models are wrong, but some are useful”</a>. We hope the patterns we have discovered can offer useful insights to the scientific community.</p><img src="https://counter.theconversation.com/content/214404/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hermes Bloomfield-Gadêlha receives funding from EPSRC. </span></em></p>The movement patterns in sperm could be explained by maths often used to describe the way chemicals interact.Hermes Bloomfield-Gadêlha, Mathematician, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2178562023-11-21T21:53:50Z2023-11-21T21:53:50ZOxygen in the St. Lawrence Estuary is decreasing – and having a major impact on small animals living there<figure><img src="https://images.theconversation.com/files/559651/original/file-20231025-23-oo8vam.jpeg?ixlib=rb-1.1.0&rect=24%2C0%2C4001%2C2752&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The majestic St. Lawrence River, a jewel of economic, historical and environmental importance, reminds us of the need to preserve this essential ecosystem.</span> <span class="attribution"><span class="source">(Ludovic Pascal)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>The waters of the St. Lawrence Estuary are running out of breath. The lack of oxygen in deep waters is affecting the organisms that live on the bottom of the estuary.</p>
<p>How do deep ecosystems react to this deoxygenation?</p>
<p>In a previous article, we highlighted the <a href="https://theconversation.com/why-the-st-lawrence-estuary-is-running-out-of-breath-184626">causes of the decrease in the concentration of oxygen in the bottom waters of the estuary and Gulf of St. Lawrence</a>. This phenomenon, called hypoxia, is intensifying in this environment. In this article, we look at the impacts of low oxygen levels on the organisms that live at the bottom of the estuary and the Gulf of St. Lawrence, and on the overall functioning of this ecosystem.</p>
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<img alt="" src="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/469058/original/file-20220615-9549-jj1phn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>This article is part of our series, <a href="https://theconversation.com/ca-fr/topics/fleuve-saint-laurent-116908">The St. Lawrence River: In depth</a>.
Don’t miss new articles on this mythical river of remarkable beauty. Our experts look at its fauna, flora and history, and the issues it faces. This series is brought to you by <a href="https://theconversation.com/ca-fr">La Conversation</a>.</em></p>
<hr>
<h2>The seabed, an environment teeming with life</h2>
<p>A large number of organisms live at the very bottom of the oceans. These are known as <a href="https://theconversation.com/discover-6-fascinating-animals-that-live-at-the-bottom-of-the-st-lawrence-river-215977">benthic organisms</a>. </p>
<p>This group of small animals includes starfish, worms, crustaceans and molluscs. They colonize the surface of the sediment (known as epifauna; “epi” for “on,” and “fauna” for “animal”) or burrow into the sediment (known as endofauna; “endo” for “inside”). </p>
<p>These organisms are not very mobile and cannot travel great distances.</p>
<h2>Bioturbation or the art of mixing sediment</h2>
<p>Benthic organisms don’t move around much, but they are far from being useless. On the contrary, they play a crucial role in the functioning of benthic ecosystems, through bioturbation. </p>
<p><a href="https://doi.org/10.3354/meps09506">Bioturbation</a> refers to all the activities that benthic organisms carry out, both on, and in sediments. Bioturbation can be compared to what earthworms do in our gardens: they dig burrows, mix grains of sediment and inject water containing oxygen into areas of the sediment that lack it. </p>
<p>Benthic organisms are therefore the “gardeners” of the ocean floor. And they help to maintain a healthy ecosystem. By bringing oxygen into the sediments, bioturbation allows many organisms to establish themselves there. It also increases biodiversity and promotes the decomposition of organic matter while <a href="https://doi.org/10.1007/s00227-019-3597-y">reducing the concentration of potentially toxic waste, such as hydrogen sulphide</a>.</p>
<h2>Oxygen and bioturbation: a not-so-simple relationship</h2>
<p>Twenty years ago, researchers used <a href="https://doi.org/10.4319/lo.2007.52.6.2555">models to try to predict the consequences of deoxygenation on the ecosystems of the bottom of the St. Lawrence</a>. Their work highlighted a critical element in anticipating future changes: how bioturbation responds to oxygen depletion.</p>
<p>Deoxygenation can lead to several types of responses in ecosystems. In a linear response scenario, the intensity of bioturbation decreases gradually and proportionally with the decrease in oxygen concentration. In such cases, it is relatively simple to predict the consequences, as the relationship is predictable. </p>
<p>However, there is another type of response that is non-linear and characterized by a threshold effect. This means that there is a certain critical point, a threshold, at which responses change abruptly. Before this threshold, the responses differ from those observed afterwards. These non-linear responses are associated with the development of resistance (or compensatory) mechanisms. These mechanisms operate at the level of the individual, the population (the set of individuals of the same species in a given location) and/or the community (the set of populations in a given location). They compensate for the effects of a disturbance until they are no longer sufficient. It is these compensatory mechanisms that make it difficult to predict the consequences of a disturbance.</p>
<h2>A non-linear relationship</h2>
<p>Our team has been studying the deoxygenation of the St. Lawrence for more than 20 years, but we had never before observed a clear relationship between the bioturbation of communities of benthic organisms and oxygen concentrations.</p>
<p>This raises an important question: does bioturbation respond in a linear or non-linear way to oxygen depletion? And is this a predictable relationship?</p>
<p><a href="https://doi.org/10.5194/bg-20-839-2023">The recent fall in oxygen concentrations in the bottom waters of the St. Lawrence</a> has enabled us to answer this question by observing a threshold effect for the first time. <a href="https://doi.org/10.1111/gcb.16994">We now know that the relationship between oxygen concentration and the functioning of benthic ecosystems is not linear</a>. </p>
<p>In other words, these ecosystems can resist deoxygenation up to a certain critical threshold, which is observed at an oxygen concentration of around 60 micromolar (i.e. approximately 20 per cent saturation, or 20 per cent of what the dissolved oxygen concentration should be if the water were in equilibrium with the atmosphere). This concentration is close to the value above which we speak of hypoxia. Below this threshold, communities of benthic organisms change, but surprisingly, without any significant loss of biodiversity. </p>
<p>However, the organisms that make up these communities are much less active. They are actually running out of air! They considerably reduce their movements, move towards the surface of the sediment and the intensity of bioturbation becomes practically zero. </p>
<p>In other words, in these conditions of severe hypoxia, the organisms no longer have enough energy to mix and irrigate the sediment.</p>
<h2>When bioturbation stops, what happens?</h2>
<p>These results have major implications for the role of sediments in the overall health of ecosystems in the estuary and Gulf of St. Lawrence. When bioturbation stops, the sediments are neither mixed nor irrigated efficiently, leading to the accumulation of toxic waste very close to the surface of the sediment. </p>
<p>As this waste accumulates, it could even spread into the water column, scaring away sensitive species and increasing deoxygenation. </p>
<p>When and under what conditions would this happen? This is the question we now need to answer. </p>
<p>Deoxygenation of the bottom waters of the St. Lawrence is of particular concern because it is likely to lead to changes in the abundance and distribution of fishery resources. Indirectly, therefore, it could have socio-economic effects that have yet to be fully assessed.</p><img src="https://counter.theconversation.com/content/217856/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ludovic Pascal is a member of the Québec Océan inter-institutional group and the Nereis Park scientific association. He has received funding from the FRQNT, the MEOPAR Network of Centres of Excellence, and the Québec government (Réseau Québec Maritime, MEIE, MELCCFP).</span></em></p><p class="fine-print"><em><span>Gwénaëlle Chaillou has received funding from the Natural Sciences and Engineering Research Council of Canada (NSERC), Fonds de Recherche du Québec, Canada Research Chairs, and the Government of Québec (Réseau Québec Maritime, MEIE, MELCCFP). She is a member of the Québec Océan inter-institutional group, ACFAS, the Geochemical Society and the International Association of Hydrogeologists - Canadian National Committee (IAH-CNC).</span></em></p>The waters of the St. Lawrence are running out of breath and bottom-dwelling organisms are already feeling the effects. Here’s how ecosystems are reacting.Ludovic Pascal, Postdoctorant en biogéochimie marine, Université du Québec à Rimouski (UQAR)Gwénaëlle Chaillou, Professeure de chimie marine à l'Institut des sciences de la mer de Rimouski (ISMER-UQAR), Université du Québec à Rimouski (UQAR)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2152222023-11-21T13:27:15Z2023-11-21T13:27:15ZClimate change is already forcing lizards, insects and other species to evolve – and most can’t keep up<figure><img src="https://images.theconversation.com/files/558259/original/file-20231108-29-upppm0.jpg?ixlib=rb-1.1.0&rect=2%2C2%2C1615%2C1069&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Temperature sensitivity makes western fence lizards vulnerable to climate change.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/blmoregon/47961427128">Greg Shine/BLM</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Climate change is threatening the survival of plants and animals around the globe as temperatures rise and habitats change.</p>
<p>Some species have been able to meet the challenge with rapid evolutionary adaptation and other changes in behavior or physiology. Dark-colored dragonflies are <a href="https://doi.org/10.1073/pnas.2101458118">getting paler</a> in order to reduce the amount of heat they absorb from the sun. Mustard plants are <a href="https://doi.org/10.1098/rspb.2012.1051">flowering earlier</a> to take advantage of earlier snowmelt. Lizards are <a href="https://doi.org/10.1098/rsbl.2020.0625">becoming more cold-tolerant</a> to handle the extreme variability of our new climate.</p>
<p>However, scientific studies show that climate change is occurring much faster than species are changing.</p>
<figure class="align-center ">
<img alt="A tiny, royal blue fish with gold stripes looks into the camera. The downward slant of its mouth and shadow at the top of its eye give it an annoyed look." src="https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5599%2C3724&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Zebrafish have evolved to thrive in water a degree or so warmer than normal, but they struggle to survive at higher temperatures.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/brachydanio-rerio-royalty-free-image/154930602?adppopup=true">isoft/E+ Getty Images</a></span>
</figcaption>
</figure>
<h2>What is evolutionary adaptation?</h2>
<p>The word “adaptation” is used in many ways by climate scientists, but it has a very specific meaning to biologists: It refers to genetic changes that are passed on from one generation to the next and improve a species’ ability to survive in its environment.</p>
<p>These genetic modifications make evolutionary adaptation different from “acclimation” or “acclimatization,” which involve advantages that are not passed on to offspring. For example, when people move to high-altitude cities, they <a href="http://dx.doi.org/10.1136/bjsports-2013-092840">start producing more red blood cells</a> as they acclimate to the low oxygen.</p>
<p>All over the world, plants and animals have adapted to many different warm and dry habitats, prompting scientists to <a href="https://doi.org/10.1098/rstb.2018.0176">question</a> <a href="https://doi.org/10.1038/s41586-019-1520-9">whether</a> <a href="https://doi.org/10.1111/gcb.14881">species</a> <a href="https://doi.org/10.1073/pnas.1406314111">might</a> <a href="https://doi.org/10.1111/evo.13862">also</a> <a href="https://doi.org/10.1126/science.1063656">adapt</a> <a href="https://doi.org/10.1073/pnas.0608379104">to</a> <a href="https://doi.org/10.1111/ele.14072">our</a> <a href="https://doi.org/10.1126/science.aba9287">rapidly</a> <a href="https://doi.org/10.1126/science.abj7484">changing</a> <a href="https://doi.org/10.1126/science.aaf3343">climate</a>, <a href="https://doi.org/10.1038/nclimate2628">too</a>.</p>
<p>Thus far, the answer <a href="https://doi.org/10.1002/wcc.852">seems to be no</a> for most species.</p>
<h2>Evolving, fast and slow</h2>
<p>A <a href="https://doi.org/10.1038/s41467-019-10924-4">recent study</a> of the populations of 19 bird and mammal species, including owls and deer, shows one potential barrier to adaptation. </p>
<p>In animals that take several years to reach breeding age, the climate has already shifted by the time their offspring are born. Genes that gave the parents an advantage – like hatching at exactly the right time or growing to the best size – are no longer as beneficial for the offspring.</p>
<p>Populations of these slow-maturing animals are adapting to climate change, but not enough during each generation to thrive in the changing conditions. In fact, the rate of evolution is so mismatched to the rate of global warming that the study’s authors estimate that nearly 70% of the local populations they studied are already vulnerable to climate-driven extinction over the coming decades.</p>
<figure class="align-center ">
<img alt="A dragonfly with dark bands on its wings." src="https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Black bands on dragonflies heat up their bodies. Research shows some dragonflies have evolved smaller black bands as the climate warms.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A heat map clearly shows that the dark bands on the wings absorb more heat." src="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.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">In this heat map of the same dragonfly, white areas are the warmest and purple areas are cooler. The dark bands on the wings stand out.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<p>Small-bodied animals, such as many fish, insects and plankton, typically mature quickly. Yet, recent research on <a href="https://doi.org/10.1073/pnas.2011419117">small fish</a> and a type of <a href="https://doi.org/10.1098/rspb.2011.0542">fast-maturing plankton called a copepod</a> revealed another hurdle for rapid genetic adaptation to climate change.</p>
<p>Many species possess genes that permit them to live in environments that are 1 to 2 degrees Celsius (about 2 to 4 Fahrenheit) warmer than today, but new genetic mutations must arise to enable survival if climates reach 4 to 5 C (about 7 to 9 F) warmer, as is possible in some regions, particularly if greenhouse gas emissions continue at a high rate.</p>
<p>To test species’ resilience, scientists warmed populations of these fast-maturing species over many generations to observe their genetic changes. They found that both the copepods and the small fish were able to adapt to the first couple degrees of warming, but populations soon went extinct above that. This was because genetic mutations that increased their ability to live in hotter conditions occurred at a slower rate than the temperatures rose.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A tiny nearly translucent oval creature with a tail and egg sacks trailing behind it." src="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A live copepod with egg sacs at 10 times magnification. These ocean creatures produce new generations quickly, allowing for speedier evolution.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/copepod-micrograph-royalty-free-image/170025374?adppopup=true">NNehring/E+ Getty Images</a></span>
</figcaption>
</figure>
<p>Cold-blooded species, such as lizards, frogs and fish, are especially vulnerable to climate change because they have a limited capacity to regulate their own body temperatures. Their ability to evolve in response to climate change is expected to be critical for their survival.</p>
<p>However, rapid adaptation to climate change often comes <a href="https://doi.org/10.1007/BF02984069">at a cost</a>: Populations get smaller due to the deaths of individuals that cannot tolerate new, hotter temperatures. Therefore, even if species do evolve to survive with climate change, their smaller populations may still go extinct due to problems such as inbreeding, harmful new mutations or plain old bad luck, such as a disease epidemic.</p>
<p><a href="https://doi.org/10.1126/science.1184695">In a now-classic study</a>, researchers studying lizards in Mexico discovered that the high death rates of just the heat-sensitive individuals – representing only a subset of the entire population – caused 12% of all lizard populations in Mexico to go extinct between 1975 and 2009. Even with some heat-tolerant adult lizards surviving in each population under the warmer conditions, the researchers estimated climate change would kill so many heat-sensitive adults within each population that 54% of all populations would go extinct by 2080.</p>
<h2>Evolutionary adaptation isn’t species’ only option</h2>
<p>Another way species adjust to rising temperatures is acclimation, sometimes called “phenotypic plasticity.” For example, <a href="https://doi.org/10.1126/science.1157174">great tits in the U.K.</a> – small birds that are common in yards and forests – lay their eggs earlier in warmer years so that their nestlings hatch right as the winter weather ends, no matter when that happens.</p>
<figure class="align-center ">
<img alt="A small bird with a yellow body and black head with white cheeks sits on a branch." src="https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.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">A great tit – <em>Parus major</em>. In the U.K., these common birds have been laying their eggs earlier in warm years.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/hedera_baltica/49433487712/in">Hedera.Baltica via Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>However, a <a href="https://www.nature.com/articles/s41467-022-32953-2">recent analysis</a> of more than 100 beetle, grasshopper and other insect species all over the world found that acclimation may not help those species enough. The study’s authors found that the species they reviewed gained an average of only 0.1 C (about 0.2 F) greater heat tolerance when acclimating to 1 C (about 2 F) warmer air temperatures during their development. Thus, the rate of global warming seems to be outstripping species’ abilities to acclimate, too.</p>
<p>Plants and animals could also escape the impacts of global warming by migrating to cooler habitats. A <a href="https://doi.org/10.1038/s41559-020-1198-2">global analysis</a> of more than 12,000 different plants and animal species recently showed that many species are migrating toward the poles fast enough to keep pace with rising temperatures, and many <a href="https://doi.org/10.1111/ele.13762">tropical species are moving upslope</a> to higher elevations as well.</p>
<p>Nonetheless, migration has its limits. Research shows that <a href="https://doi.org/10.1073/pnas.1804224115">tropical birds that already live high in the mountains could be doomed</a> because there is no room for them to migrate any farther upward. Tropical species, therefore, may be on what the authors call an “escalator to extinction.”</p>
<figure class="align-center ">
<img alt="A yellow-and-black moth sits on a yellow flower in an alpine field with snow-covered mountains in the background." src="https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=789&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=789&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=789&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=992&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=992&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=992&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Police car moths living at high elevations have little room to migrate to escape increasing heat.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<p>High-latitude and high-elevation habitats also present numerous challenges for species to overcome besides temperature. Our own research across 800 species of insects all over the Earth shows that butterflies, bees and other flying insects are <a href="https://doi.org/10.1038/s41558-023-01794-2">especially hindered from migrating to higher elevations</a> because there is not enough oxygen for them to survive. </p>
<h2>Many species lack obvious climate strategies</h2>
<p>Overall, evolutionary adaptation appears to help lessen the impacts of global warming, but the evidence thus far shows that it is insufficient to overcome current rates of climate change. Acclimation and migration provide faster solutions, but research shows that those may not be enough, either.</p>
<p>Of course, not all evolution is driven by warming temperatures. Plant and animal species appear to be also gradually adapting to other kinds of environments, including <a href="https://doi.org/10.1111/evo.14191">human-created ones like cities</a>. But the fast pace of global warming makes it <a href="https://nca2023.globalchange.gov/chapter/8#fig-8-2">one of the major threats</a> that species must respond to immediately.</p>
<p>The <a href="https://nca2023.globalchange.gov/chapter/8#fig-8-2">evidence indicates</a> that humanity cannot simply assume that plants and animals will be able to save themselves from climate change. To protect these species, humans will have to stop the activities that are fueling climate change.</p><img src="https://counter.theconversation.com/content/215222/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 organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From dark dragonflies becoming paler to plants flowering earlier, some species are slowly evolving with the climate. Evolutionary biologists explain why few will evolve fast enough.Michael P. Moore, Assistant Professor of Biology, University of Colorado DenverJames T. Stroud, Assistant Professor of Ecology and Evolution, Georgia Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163042023-11-15T23:14:16Z2023-11-15T23:14:16ZWhat designers can do to make textiles healthier for people and the planet<figure><img src="https://images.theconversation.com/files/555594/original/file-20230927-29-m4ke9q.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C994%2C720&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The glamourous aspect of fashion obscures the health and socio-environmental issues of the textile industry.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>The <a href="https://www.youtube.com/watch?v=rwp0Bx0awoE">pollution caused by the textile industry</a> is often discussed, but its <a href="https://pubmed.ncbi.nlm.nih.gov/30278363/">impact on health</a> is less emphasized. Nevertheless, the petrochemical compounds used in the manufacturing of our clothes have harmful effects on <a href="https://www.youtube.com/watch?v=onD5UOP5z_c">workers</a>, <a href="https://www.youtube.com/watch?v=IxVq_38BoPE">surrounding communities</a>, and <a href="http://www.cec.org/files/documents/publications/11777-furthering-understanding-migration-chemicals-from-consumer-products-en.pdf">consumers</a>. This issue has a <a href="https://www.greenpeace.org/static/planet4-international-stateless/2012/11/317d2d47-toxicthreads01.pdf">global impact</a>, but its assessment is complex due to our low chronic exposure to a <a href="https://www.leslibraires.ca/livres/perturbateurs-endocriniens-la-menace-invisible-marine-jobert-9782283028179.html">“cocktail” of synthetic substances</a> whose cause-and-effect relationships are difficult to identify.</p>
<p>Moreover, most of these substances prove to be toxic through interaction or degradation, as is the case with <a href="https://www.canada.ca/en/health-canada/services/chemical-substances/substance-groupings-initiative/aromatic-azo-benzidine-based.html">azo dyes</a> that are ubiquitous and persistent in the environment.</p>
<p>Through my research in sustainable textile design, I explore how design can contribute to making the textile industry more environmentally friendly, focusing on raising ecological awareness among designers, decision-makers, and the general public.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551518/original/file-20231002-15-cu6ppt.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="textile dyes" src="https://images.theconversation.com/files/551518/original/file-20231002-15-cu6ppt.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551518/original/file-20231002-15-cu6ppt.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=221&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551518/original/file-20231002-15-cu6ppt.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=221&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551518/original/file-20231002-15-cu6ppt.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=221&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551518/original/file-20231002-15-cu6ppt.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=277&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551518/original/file-20231002-15-cu6ppt.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=277&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551518/original/file-20231002-15-cu6ppt.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=277&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dyes made from agri-food waste and inspired by Pantone.</span>
<span class="attribution"><span class="source">(Vanessa Mardirossian)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<h2>Design-led solutions</h2>
<p>In the 1960s, designer <a href="https://papanek.org/archivelibrary/victor-papanek/">Victor Papanek</a> was the first to address <a href="https://www.goodreads.com/book/show/190560.Design_for_the_Real_World">environmental issues related to industrial product design</a>. Meanwhile, biologist <a href="https://www.rachelcarson.org/silent-spring">Rachel Carson</a> initiated the emergence of ecological consciousness, shedding light on the profound impact of human activity on the environment. </p>
<p>Then in the 1990s, <a href="https://www.epa.gov/greenchemistry/basics-green-chemistry">green chemistry</a> facilitated collaboration between design and biology to develop <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1278402">ecological textiles</a>. Aligned with <a href="https://mcdonough.com/wp-content/uploads/2013/03/Hannover-Principles-1992.pdf">The Hannover Principles</a>, these textiles aimed to enhance waste management and preserve water purity. Intending to harmonize the interdependence between human activity and the natural world by eliminating toxic inputs at their source, these principles also gave rise to the “<a href="https://us.macmillan.com/books/9780865475878/cradletocradle">Cradle to Cradle</a>” ecodesign philosophy that popularized the concept of circular design in the early 2000s.</p>
<h2>An inspired approach from nature</h2>
<p>Humanity has always drawn inspiration from nature to create. </p>
<p>However, in the late 20th century, biologist <a href="https://biomimicry.org/janine-benyus/">Janine Benyus</a> invited us to <a href="https://biomimicry.org">observe the operating mechanisms of living organisms</a>, encouraging a reevaluation of manufacturing processes through <a href="https://biomimicry.org/chapterone/">biomimicry</a> — a concept that draws inspiration from nature’s designs and processes to create more sustainable technologies.</p>
<p>Could we, for example, produce dyes at room temperature and without toxic molecules? This approach leads to a shared reflection between design, science and engineering. This multidisciplinary vision of design, where ecology, medicine, and politics play a role in the design process to better meet the needs of society, was already advocated by Papanek in 1969.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551520/original/file-20231002-30-2h1680.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="diagram" src="https://images.theconversation.com/files/551520/original/file-20231002-30-2h1680.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551520/original/file-20231002-30-2h1680.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551520/original/file-20231002-30-2h1680.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551520/original/file-20231002-30-2h1680.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551520/original/file-20231002-30-2h1680.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551520/original/file-20231002-30-2h1680.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551520/original/file-20231002-30-2h1680.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">Concept of ‘minimal design,’ by Victor Papanek.</span>
<span class="attribution"><span class="source">(Diagram taken from the work of Victor Papanek)</span></span>
</figcaption>
</figure>
<h2>Developing ecological literacy</h2>
<p>In 1990, educator <a href="https://blogs.ubc.ca/lled3662017/files/2017/08/Orr_Environmental-Literacy-Ecoliteracy.pdf">David Orr</a> introduced the concept of ecoliteracy to address a major gap in traditional education, centered on humans and ignoring their interconnectedness with nature. He advocated for environmental education to develop a sense of belonging to one’s living environment and establish production models that promote the resilience of ecosystems. This concept helps to understand the intricate connections between human activities and ecological systems, to foster a sense of responsibility and informed decision-making.</p>
<p>In the 2000s, fashion design researcher <a href="https://katefletcher.com">Kate Fletcher</a> supported the development of this ecological literacy to help stakeholders in the industry (designers, consumers and manufacturers) understand the implicit interconnection of industrial and living systems, showing that fashion maintains a vital relationship with nature. </p>
<p>Then, in 2018, the sustainable design researcher <a href="https://www.bloomsbury.com/ca/design-ecology-politics-9781350258778/">Joanna Boehnert </a>emphasized that ecological literacy not only promotes the development of new, more sustainable ways of producing, but also broadens our social, political, and economic vision to systemically address transdisciplinary sustainability challenges. </p>
<p>This is also supported by biologist Emmanuel Delannoy who offers a <a href="http://permaeconomie.fr/author/edelannoy">permaeconomy</a> model, blending permaculture and economics to establish a symbiotic relationship between economic systems and the natural environment, fostering resilience and prompting a reevaluation of our connection with living organisms</p>
<h2>A colourful heritage to rediscover</h2>
<p>My <a href="https://hexagram.ca/fr/qu-est-ce-que-la-recherche-creation/">research-creation</a> proposes a critical reflection on textile dyeing. </p>
<p>This field of investigation leads me to explore colouring beyond its aesthetic to raise ecological, economic and pedagogical questions. </p>
<p>While the glamourous aspect of fashion obscures the health and socio-environmental issues of the textile industry, I direct my thinking toward a more global understanding of dyeing, including its origins, manufacturing methods and interactions with living organisms. </p>
<p>I explore the development of non-toxic dyes by studying, on one hand, literature on <a href="https://www.belin-editeur.com/le-monde-des-teintures-naturelles">natural dyes since prehistory</a>, and, on the other hand, by meeting experts in the field such as scientific historian <a href="https://www.cnrs.fr/sites/default/files/download-file/CardonD.pdf">Dominique Cardon</a> or ecoliterate artisan <a href="https://fibershed.org/staff-board/">Rebecca Burgess</a>, founder of the <a href="https://fibershed.org">Fibershed</a> concept, which aims to produce biodegradable clothing in a limited geographical space. </p>
<p>I also study field practices, including those of the Textile Laboratory of <a href="https://www.luma.org/arles/atelierluma.html">Atelier Luma</a>, which works at the intersection of ecology, textiles and regional economic development. </p>
<p>And, I keep an eye on <a href="https://www.arts.ac.uk/subjects/textiles-and-materials/postgraduate?collection=ual-courses-meta-prod&query=!nullquery&start_rank=1&sort=relevance&f.Subject-test%7Csubject=Textiles%20and%20materials&f.Course%20level%7Clevel=Postgraduate">design education programs </a>that offer an art-science approach where deep ecology is integrated into the design process. </p>
<h2>Symbiosis between nature and the textile industry</h2>
<p>Additionally, in the <a href="https://speculativelifebiolab.com/2022/04/03/cooking-and-culturing-colour-part-iv/">research laboratory</a> where I work, I experiment with the intersection of traditional and prospective dyeing recipes.</p>
<p>Inspired by the concept of <a href="https://www.scirp.org/(S(lz5mqp453edsnp55rrgjct55))/reference/ReferencesPapers.aspx?ReferenceID=1999041">industrial ecology</a> (precursor of the <a href="https://www.canada.ca/en/services/environment/conservation/sustainability/circular-economy.html">circular economy</a>), that values the waste of one industry as resources for another, I use <a href="https://www.lapresse.ca/societe/mode-et-beaute/2021-03-30/quand-les-dechets-se-melent-de-la-mode.php">agri-food waste</a> as a colouring source, combined with the use of <a href="https://hexagram.ca/en/demo2-vanessa-mardirossian-the-culture-of-color-an-ecoliteracy-of-textile-design/">pigment-producing bacteria</a> to expand the colour palette. </p>
<p>Thus, tannins from various waste materials can be used in dye recipes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551537/original/file-20231002-25-qtiisx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="bits of coloured fabric" src="https://images.theconversation.com/files/551537/original/file-20231002-25-qtiisx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551537/original/file-20231002-25-qtiisx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551537/original/file-20231002-25-qtiisx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551537/original/file-20231002-25-qtiisx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551537/original/file-20231002-25-qtiisx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551537/original/file-20231002-25-qtiisx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551537/original/file-20231002-25-qtiisx.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">Fabric dyed from waste and bacteria.</span>
<span class="attribution"><span class="source">(Vanessa Mardirossian)</span>, <span class="license">Fourni par l'auteur</span></span>
</figcaption>
</figure>
<p>But colouring a textile is only the visible part of the iceberg, as fibre preparation takes place upstream to ensure the colour’s resistance to light and washing, known as “mordanting.” Whether the fibre is animal or vegetable, different mordants will be used. </p>
<p>This expertise acquired iteratively between theory, prototyping, and results analysis contributes to gaining “textile ecoliteracy.” Coupled with a knowledge of biology, this allows for understanding the deleterious interactions between the material and living worlds. </p>
<p>Ultimately, the synthesis of ecoliteracy and biomimicry concepts has led me to reflect on a macro-vision of the fashion industry ecosystem, and to consider the concept of “textile ecoliteracy” as a means to deploy a network of intersectoral collaborations between design, health, education, and industry. </p>
<p>My research aims to show that <a href="https://www.tandfonline.com/doi/abs/10.2752/175693810X12774625387594">textile materiality must harmonize symbiotically with natural ecosystems</a> so that both parties benefit from their interaction.</p>
<p>In conclusion, the textile industry’s environmental and health impacts necessitate urgent attention and innovative solutions. This article has delved into the historical context, explored interdisciplinary approaches, and proposed the concept of “textile ecoliteracy” as a collaborative means to address these challenges. </p>
<p>By focusing on sustainable design, education, and the utilization of innovative practices, designers can play a pivotal role in reshaping the industry. The synthesis of ecological awareness and biomimicry principles highlights the potential for a harmonious coexistence between textile materiality and natural ecosystems. </p>
<p>As we move forward, fostering a symbiotic relationship between the textile industry and the environment is not just a choice but a collective responsibility — one that promises a healthier future for both people and the planet.</p><img src="https://counter.theconversation.com/content/216304/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vanessa Mardirossian is a member of Acfas, Hexagram and Concordia University's Textiles & Materiality and Critical Practices in Material and Materiality research laboratories. She has received funding from the Social Sciences and Humanities Research Council of Canada (SSHRC), Concordia University and Université du Québec à Montréal.</span></em></p>The production, use and end-of-life of clothing all have an impact on our health. But greater ecological awareness could turn the tide.Vanessa Mardirossian, PhD Candidate and educator in sustainable fashion, Concordia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2166392023-11-09T19:09:59Z2023-11-09T19:09:59ZA new theory linking evolution and physics has scientists baffled – but is it solving a problem that doesn’t exist?<figure><img src="https://images.theconversation.com/files/558544/original/file-20231109-17-qp5bsl.jpg?ixlib=rb-1.1.0&rect=10%2C42%2C7130%2C4710&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/leafless-tree-with-water-droplets-TYnHpsuAkBg">Tim Johnson / Unsplash</a></span></figcaption></figure><p>In October, a paper titled “<a href="https://www.nature.com/articles/s41586-023-06600-9">Assembly theory explains and quantifies selection and evolution</a>” appeared in the top science journal Nature. The authors – a team led by Lee Cronin at the University of Glasgow and Sara Walker at Arizona State University – claim their theory is an “interface between physics and biology” which explains how complex biological forms can evolve.</p>
<p>The paper provoked strong responses. On the one hand were headlines like “<a href="https://www.sciencealert.com/assembly-theory-bold-new-theory-of-everything-could-unite-physics-and-evolution">Bold New ‘Theory of Everything’ Could Unite Physics And Evolution</a>”.</p>
<p>On the other were reactions from scientists. One evolutionary biologist <a href="https://twitter.com/baym/status/1710815658890432679">tweeted</a> “after multiple reads I still have absolutely no idea what [this paper] is doing”. Another <a href="https://twitter.com/Irishpalaeo/status/1712450672476512424">said</a> “I read the paper and I feel more confused […] I think reading that paper has made me forget my own name.”</p>
<p>As a biologist who studies evolution, I felt I had to read the paper myself. Was assembly theory really the radical new paradigm its authors suggested? Or was it the “<a href="https://twitter.com/AdamRutherford/status/1711160807453569404">abject wankwaffle</a>” its critics decried?</p>
<h2>Hackle-raising claims</h2>
<p>When I sat down to read the paper, the very first sentence of the abstract had my hackles up: </p>
<blockquote>
<p>Scientists have grappled with reconciling biological evolution with the immutable laws of the Universe defined by physics.</p>
</blockquote>
<p>I had no idea we scientists grappled with this. No biologist I know has a problem with the laws of physics or sees any problem with reconciling them with evolution. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/life-modern-physics-cant-explain-it-but-our-new-theory-which-says-time-is-fundamental-might-203129">Life: modern physics can't explain it – but our new theory, which says time is fundamental, might</a>
</strong>
</em>
</p>
<hr>
<p>The abstract goes on to note that the laws of physics do not predict “life’s origin, evolution and the development of human culture and technology”, and claims we need a “new approach” to understand “how diverse, open-ended forms can emerge from physics without an inherent design blueprint”.</p>
<p>The complaint that biological evolution seems incompatible with the laws of physics, taken with the use of loaded terms like “design blueprint”, is reminiscent of creationist arguments against evolution. No wonder the blood pressure of evolutionary biologists was spiking.</p>
<p>In the words of <a href="https://www.nature.com/articles/s41586-023-06600-9#comment-6296992737">one Nature commenter</a>: “Why so many creationist tropes in the first few sentences?”</p>
<h2>Biology and physics</h2>
<p>Before I go further, I should note that I may, along with some of scientists quoted above, not fully understand the aim of the paper. But I have problems with what I do understand of it. </p>
<p>First of all, the claim that evolution is at odds with the immutable laws of physics does not seem to be supported. </p>
<p>The paper says “the open-ended generation of novelty does not fit cleanly in the paradigmatic frameworks of either biology or physics”, which doesn’t seem to make much sense. </p>
<figure class="align-center ">
<img alt="A microscope photo of fluorescent cells" src="https://images.theconversation.com/files/558547/original/file-20231109-15-kojsc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558547/original/file-20231109-15-kojsc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558547/original/file-20231109-15-kojsc4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558547/original/file-20231109-15-kojsc4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558547/original/file-20231109-15-kojsc4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558547/original/file-20231109-15-kojsc4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558547/original/file-20231109-15-kojsc4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Is there a conflict between biology and physics that needs to be explained?</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/a-close-up-of-a-cell-phone-case-sIqWYiNLiJU">National Cancer Institute / Unsplash</a></span>
</figcaption>
</figure>
<p>In the paradigm of biology, we understand there is a variation in biological forms through genetic drift, mutation and selection. Does this <em>need</em> to “fit the paradigm of physics”, as long as it doesn’t break any laws of physics?</p>
<p>Another troubling statement: “To comprehend how diverse, open-ended forms can emerge from physics without an inherent design blueprint, a new approach to understanding and quantifying selection is necessary.” </p>
<p>Is it? One of the tenets of evolutionary theory is that there is no “teleology” – no goal or aimed-for endpoint – in the process. So how could there be a “design blueprint”? Why would its absence need to be explained?</p>
<h2>Putting numbers on the odds of evolution</h2>
<p>So what is assembly theory trying to do? <a href="https://twitter.com/leecronin/status/1711356692720501103">According to Cronin</a>, it “aims to explain selection & evolution before biology”; as such its goal is a theory that unifies inert and living matter and seeks to explain their complexity or otherwise, in the same way.</p>
<p>The paper itself says it is a “framework that does not alter the laws of physics, but redefines the concept of an ‘object’ on which these laws act”. </p>
<blockquote>
<p>[Assembly theory] conceptualizes objects not as point particles, but as entities defined by their possible formation histories. This allows objects to show evidence of selection, within well-defined boundaries of individuals or selected units. </p>
</blockquote>
<p>The “object” in assembly theory is then what “laws of physics” act on. For any object, we can calculate its “assembly index”, a number that measures how complex the object would be to make. </p>
<p>Any object that is both abundant and has a high assembly index is unlikely to have arisen by chance, so it must be a product of evolution and selection. This, in itself, is neither problematic nor new – apart from this calculated “index”.</p>
<p>How do we figure out that assembly index? We count the number of steps it would take to build a molecule, say, or a bodily organ, or a whole organism. The higher the index, the more likely it is to have evolved. </p>
<p>So assembly theory is an attempt to quantify the complexity of something and the likelihood of it having evolved. </p>
<h2>A problem that doesn’t exist?</h2>
<p>Is this useful? It’s hard to say. </p>
<p>For one thing, it implies there is only one pathway to produce a complicated (high assembly index) object such as a biochemical molecule, which is simply not the case.</p>
<p>Also, as <a href="https://twitter.com/professor_dave/status/1710914156612710503">another scientist pointed out</a>: </p>
<blockquote>
<p>it’s obvious that if a molecule is complex and there are lots of copies of it, then it likely emerged from some process of evolution. And most chemists could spot such cases without the need for assembly theory. Although trying to put numbers on it is very neat.</p>
</blockquote>
<p>My own feeling is that this is a poorly written paper, as evidenced by the inability of many biologists to understand what it is trying to do, and much of the negative reaction to the work springs from the hard-to-follow framing and use of phrases that echo creationist talking points. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/physics-has-long-failed-to-explain-life-but-were-testing-a-groundbreaking-new-theory-in-the-lab-215636">Physics has long failed to explain life – but we're testing a groundbreaking new theory in the lab</a>
</strong>
</em>
</p>
<hr>
<p>As for assembly theory itself, it seems to have been <a href="https://www.quantamagazine.org/a-new-theory-for-the-assembly-of-life-in-the-universe-20230504/">developed</a> in the course of Cronin and Walker’s efforts to find a general way to <a href="https://www.nature.com/articles/s41467-021-23258-x">recognise signs of life on alien planets</a>, and even <a href="https://www.mdpi.com/1099-4300/24/7/884">create artificial life</a>. And perhaps, in those contexts, it may prove useful.</p>
<p>However, as a sweeping new paradigm aiming to unify evolution and physics, assembly theory appears – to me and many others – to be addressing a problem that does not exist.</p><img src="https://counter.theconversation.com/content/216639/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bill Bateman 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>‘Assembly theory’ aims to explain evolution without biology. Is it a dazzling breakthrough or an attempt to answer questions nobody asked?Bill Bateman, Associate professor, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2170352023-11-08T19:05:23Z2023-11-08T19:05:23ZHow animals get their skin patterns is a matter of physics – new research clarifying how could improve medical diagnostics and synthetic materials<figure><img src="https://images.theconversation.com/files/558150/original/file-20231107-15-ksvdj8.png?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Color patterns seen in fish and other animals evolved to serve various purposes.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/close-up-of-the-eye-of-a-yellowspot-rabbitfish-royalty-free-image/691700228">Lagunatic Photo/iStock via Getty Images Plus</a></span></figcaption></figure><p>Patterns on animal skin, such as zebra stripes and poison frog color patches, serve various biological functions, including <a href="https://doi.org/10.1080/00222933.2019.1607600">temperature regulation</a>, <a href="https://doi.org/10.1098/rsos.160824">camouflage</a> and <a href="https://doi.org/10.1111/j.1558-5646.2011.01257.x">warning signals</a>. The colors making up these patterns must be distinct and well separated to be effective. For instance, as a warning signal, distinct colors make them clearly visible to other animals. And as camouflage, well-separated colors allow animals to better blend into their surroundings.</p>
<p>In our newly published research in Science Advances, my student <a href="https://scholar.google.com/citations?user=ZYQyHkYAAAAJ&hl=en">Ben Alessio</a> <a href="https://scholar.google.com/citations?user=oiMqxxoAAAAJ&hl=en">and I</a> propose a <a href="http://www.science.org/doi/10.1126/sciadv.adj2457">potential mechanism</a> explaining how these distinctive patterns form – that could potentially be applied to medical diagnostics and synthetic materials.</p>
<p>A thought experiment can help visualize the challenge of achieving distinctive color patterns. Imagine gently adding a drop of blue and red dye to a cup of water. The drops will slowly disperse throughout the water due to the <a href="https://bio.libretexts.org/Learning_Objects/Worksheets/Biology_Tutorials/Diffusion_and_Osmosis">process of diffusion</a>, where molecules move from an area of higher concentration to lower concentration. Eventually, the water will have an even concentration of blue and red dyes and become purple. Thus, diffusion tends to create color uniformity.</p>
<p>A question naturally arises: How can distinct color patterns form in the presence of diffusion?</p>
<h2>Movement and boundaries</h2>
<p>Mathematician Alan Turing first addressed this question in his seminal 1952 paper, “<a href="https://doi.org/10.1098/rstb.1952.0012">The Chemical Basis of Morphogenesis</a>.” Turing showed that under appropriate conditions, the chemical reactions involved in producing color can interact with each other in a way that counteracts diffusion. This makes it possible for colors to self-organize and create interconnected regions with different colors, forming what are now called Turing patterns. </p>
<p>However, in mathematical models, the boundaries between color regions are fuzzy due to diffusion. This is unlike in nature, where boundaries are often sharp and colors are well separated.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558105/original/file-20231107-20-d6d55o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of head of moray eel with dark brown patches separated by uneven white boundaries." src="https://images.theconversation.com/files/558105/original/file-20231107-20-d6d55o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558105/original/file-20231107-20-d6d55o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558105/original/file-20231107-20-d6d55o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558105/original/file-20231107-20-d6d55o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558105/original/file-20231107-20-d6d55o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558105/original/file-20231107-20-d6d55o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558105/original/file-20231107-20-d6d55o.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">Moray eels have distinctive patterns on their skin.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/laced-leopard-moray-in-indian-ocean-during-a-scuba-royalty-free-image/1306632894">Asergieiev/iStock via Getty Images</a></span>
</figcaption>
</figure>
<p>Our team thought a clue to figuring out how animals create distinctive color patterns could be found in lab experiments on micron-sized particles, such as the <a href="https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Biology_(Kimball)/03%3A_The_Cellular_Basis_of_Life/3.22%3A_Chromatophores">cells involved in producing the colors</a> of an animal’s skin. <a href="https://doi.org/10.1039/D0SM00899K">My work</a> and work from <a href="https://doi.org/10.1073/pnas.1511484112">other labs</a> found that micron-sized particles form <a href="https://doi.org/10.1103/PhysRevLett.117.258001">banded structures</a> when placed between a region with a high concentration of other dissolved solutes and a region with a low concentration of other dissolved solutes.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/558109/original/file-20231107-17-u1tewc.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of a large blue circle moving to the right as it's swept along with the medium-sized red circles surrounding it also moving to the right, where there is a higher concentration of small green circles" src="https://images.theconversation.com/files/558109/original/file-20231107-17-u1tewc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/558109/original/file-20231107-17-u1tewc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=551&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558109/original/file-20231107-17-u1tewc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=551&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558109/original/file-20231107-17-u1tewc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=551&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558109/original/file-20231107-17-u1tewc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=693&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558109/original/file-20231107-17-u1tewc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=693&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558109/original/file-20231107-17-u1tewc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=693&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 blue circle in this diagram is moving to the right due to diffusiophoresis, as it is swept along with the motion of the red circles moving into an area where there are more green circles.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Schematic_of_particle_illustrating_diffusiophoresis.png">Richard Sear/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>In the context of our thought experiment, changes in the concentration of blue and red dyes in water can propel other particles in the liquid to move in certain directions. As the red dye moves into an area where it is at a lower concentration, nearby particles will be carried along with it. This phenomenon is <a href="https://doi.org/10.1039/C6SM00052E">called diffusiophoresis</a>. </p>
<p>You benefit from diffusiophoresis whenever you <a href="https://doi.org/10.1103/PhysRevApplied.9.034012">do your laundry</a>: Dirt particles move away from your clothing as soap molecules diffuse out from your shirt and into the water.</p>
<h2>Drawing sharp boundaries</h2>
<p>We wondered whether Turing patterns composed of regions of concentration differences could also move micron-sized particles. If so, would the resulting patterns from these particles be sharp and not fuzzy? </p>
<p>To answer this question, we <a href="http://www.science.org/doi/10.1126/sciadv.adj2457">conducted computer simulations</a> of Turing patterns – including hexagons, stripes and double spots – and found that diffusiophoresis makes the resulting patterns significantly more distinctive in all cases. These diffusiophoresis simulations were able to replicate the intricate patterns on the skin of the ornate boxfish and jewel moray eel, which isn’t possible through Turing’s theory alone.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/pU-EB6fa0As?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">This video shows small particles moving due to a related phenomenon called diffusioosmosis.</span></figcaption>
</figure>
<p>Further supporting our hypothesis, our model was able to reproduce the findings of a <a href="https://doi.org/10.1038/s41567-021-01213-3">lab study</a> on how the bacterium <em>E. coli</em> moves molecular cargo within themselves. Diffusiophoresis resulted in sharper movement patterns, confirming its role as a physical mechanism behind biological pattern formation. </p>
<p>Because the cells that produce the pigments that make up the colors of an animal’s skin are also micron-sized, our findings suggest that diffusiophoresis may play a key role in creating distinctive color patterns more broadly in nature.</p>
<h2>Learning nature’s trick</h2>
<p>Understanding how nature programs specific functions can help researchers design synthetic systems that perform similar tasks. </p>
<p>Lab experiments have shown that scientists can use diffusiophoresis to create <a href="https://doi.org/10.1038/ncomms15181">membraneless water filters</a> and <a href="https://doi.org/10.1002/adma.201701516">low-cost drug development tools</a>.</p>
<p>Our work suggests that combining the conditions that form Turing patterns with diffusiophoresis could also form the basis of artificial skin patches. Just like adaptive skin patterns in animals, when Turing patterns change – say from hexagons to stripes – this indicates underlying differences in chemical concentrations inside or outside the body. </p>
<p>Skin patches that can sense these changes could diagnose medical conditions and monitor a patient’s health by detecting changes in biochemical markers. These skin patches could also sense changes in the concentration of harmful chemicals in the environment.</p>
<h2>The work ahead</h2>
<p>Our simulations exclusively focused on spherical particles, while the cells that create pigments in skin come in varying shapes. The effect of shape on the formation of intricate patterns remains unclear. </p>
<p>Furthermore, pigment cells move in a complicated biological environment. More research is needed to understand how that environment inhibits motion and potentially freezes patterns in place.</p>
<p>Besides animal skin patterns, Turing patterns are also crucial to other processes such as <a href="https://doi.org/10.1042%2FBST20200013">embryonic development</a> and <a href="https://doi.org/10.1016/j.neo.2020.09.008">tumor formation</a>. Our work suggests that diffusiophoresis may play an underappreciated but important role in these natural processes.</p>
<p>Studying how biological patterns form will help researchers move one step closer to mimicking their functions in the lab – <a href="https://doi.org/10.1038/s41427-021-00322-y">an age-old endeavor</a> that could benefit society.</p><img src="https://counter.theconversation.com/content/217035/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ankur Gupta receives funding from NSF (CBET - 2238412) and ACS Petroleum Research Fund (65836 - DNI9). </span></em></p>Understanding how the intricate spots and stripes, or Turing patterns, of many animals form can help scientists mimic those processes in the lab.Ankur Gupta, Assistant Professor of Chemical and Biological Engineering, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2133262023-11-07T13:38:21Z2023-11-07T13:38:21ZEngineered ‘living materials’ could help clean up water pollution one day<figure><img src="https://images.theconversation.com/files/556959/original/file-20231031-27-mncpgs.jpg?ixlib=rb-1.1.0&rect=18%2C0%2C2048%2C1358&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers at the University of California, San Diego have developed a new 'living' material.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/jsoe/53172954946/in/album-72177720311058323/">David Baillot/UC San Diego Jacobs School of Engineering</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Water pollution is a growing concern globally, with <a href="https://doi.org/10.1016/j.oneear.2022.01.005">research estimating</a> that chemical industries discharge <a href="https://cleanwaterinternational.org/water-pollution-everything-we-need-to-know/amp/">300-400 megatonnes</a> (600-800 billion pounds) of industrial waste into bodies of water each year. </p>
<p>As a <a href="https://www.pokorskilab.com/">team of materials scientists</a>, we’re working on an engineered “living material” that may be able to transform chemical dye pollutants from the <a href="https://www.cnn.com/2023/04/21/middleeast/textile-wastewater-pollutant-cleaner-hnk-scn-spc-intl/index.html">textile industry</a> into harmless substances.</p>
<p><a href="https://www.safewater.org/fact-sheets-1/2017/1/23/industrial-waste">Water pollution</a> is both an environmental and humanitarian issue that can affect ecosystems and human health alike. We’re hopeful that the materials we’re developing could be one tool available to help combat this problem.</p>
<h2>Engineering a living material</h2>
<p>The “<a href="https://www.nature.com/collections/fhcabedjaa">engineered living material</a>” our team has been working on <a href="https://my.clevelandclinic.org/health/articles/24494-bacteria">contains programmed bacteria</a> embedded in a soft hydrogel material. We first published a paper showing the potential effectiveness of this material in <a href="https://doi.org/10.1038/s41467-023-40265-2">Nature Communications</a> in August 2023.</p>
<p><a href="https://www.snexplores.org/article/explainer-what-is-a-hydrogel">The hydrogel</a> that forms the base of the material has similar properties to Jell-O – it’s soft and made mostly of water. Our particular hydrogel is made from a natural and biodegradable <a href="https://dalchem.com.au/how-to/what-is-alginate/">seaweed-based polymer called alginate</a>, an ingredient common <a href="https://kitchen-theory.com/sodium-alginate-spherification/">in some foods</a>.</p>
<p>The alginate hydrogel provides a solid physical support for bacterial cells, similar to how <a href="https://theconversation.com/mapping-the-100-trillion-cells-that-make-up-your-body-103078">tissues support cells</a> in the human body. We intentionally chose this material so that the bacteria we embedded could grow and flourish. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A green polymer, arranged in a square with a 5 by 5 grid of smaller squares, sits on a clear surface." src="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The grid shape of the material helps the bacteria take in carbon dioxide.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/jsoe/53173442373/in/album-72177720311058323/">David Baillot/UC San Diego Jacobs School of Engineering</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>We picked the seaweed-based alginate as the material base because it’s porous and can retain water. It also allows the <a href="https://www.microscopemaster.com/photosynthetic-bacteria.html">bacterial cells</a> to take in nutrients from the surrounding environment.</p>
<p>After we prepared the hydrogel, we embedded photosynthetic – or sunlight-capturing – bacteria called <a href="https://www.britannica.com/science/blue-green-algae">cyanobacteria</a> into the gel.</p>
<p>The cyanobacteria embedded in the material still needed to take in light and carbon dioxide <a href="https://education.nationalgeographic.org/resource/photosynthesis/">to perform photosynthesis</a>, which keeps them alive. The hydrogel was porous enough to allow that, but to make the configuration as efficient as possible, we <a href="https://www.cellink.com/3d-bioprinting/">3D-printed</a> the gel into custom shapes – grids and honeycombs. These structures have a higher surface-to-volume ratio that allow more light, CO₂ and nutrients to come into the material. </p>
<p>The cells were happy in that geometry. We observed higher cell growth and density over time in the alginate gels in the grid or honeycomb structures when compared with the default disc shape.</p>
<h2>Cleaning up dye</h2>
<p>Like all other bacteria, cyanobacteria has different <a href="https://www.ibiology.org/bioengineering/genetic-circuits/">genetic circuits</a>, which tell the cells what outputs to produce. Our team <a href="https://www.britannica.com/science/genetic-engineering/Process-and-techniques">genetically engineered</a> the bacterial <a href="https://www.newscientist.com/definition/dna/">DNA</a> so that the cells created a specific enzyme <a href="https://en.wikipedia.org/wiki/Laccase">called laccase</a>. </p>
<p>The laccase enzyme produced by the cyanobacteria works by performing a chemical reaction with a pollutant that transforms it into a form that’s no longer functional. By breaking the chemical bonds, it can make a toxic pollutant nontoxic. The enzyme is regenerated at the end of the reaction, and it goes off to complete more reactions. </p>
<p>Once we’d embedded these laccase-creating cyanobacteria into the alginate hydrogel, we put them in a solution made up of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10532910/">industrial dye pollutant</a> to see if they could clean up the dye. In this test, we wanted to see if our material could change the structure of the dye so that it went from being colored to uncolored. But, in other cases, the material could potentially change a chemical structure to go from toxic to nontoxic. </p>
<p>The dye we used, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10532910/">indigo carmine</a>, is a common industrial wastewater pollutant usually found in the water near textile plants – it’s the main pigment in blue jeans. We found that our material took all the color out of the bulk of the dye over about 10 days.</p>
<p>This is good news, but we wanted to make sure that our material wasn’t adding waste to polluted water by leaching bacterial cells. So, we also engineered the bacteria to produce a protein that could damage the cell membrane of the bacteria – a programmable kill switch. </p>
<p>The genetic circuit was programmed to respond to a harmless chemical, called <a href="https://academic.oup.com/pcp/article/54/10/1724/1908151">theophylline</a>, commonly found in caffeine, tea and chocolate. By adding theophylline, we could destroy bacterial cells at will. </p>
<p>The field of engineered living materials is still developing, but this just means there are plenty of opportunities to develop new materials with both living and nonliving components.</p><img src="https://counter.theconversation.com/content/213326/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan K. Pokorski receives funding from the National Science Foundation and Department of Energy.</span></em></p><p class="fine-print"><em><span>Debika Datta does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>‘Living materials’ made with genetically engineered bacteria and Jell-O-like gel could make pollutants in water bodies nontoxic.Jonathan K. Pokorski, Professor of Nanoengineering, University of California, San DiegoDebika Datta, Postdoctoral Scholar in Nanoengineering, University of California, San DiegoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2161772023-10-30T03:31:01Z2023-10-30T03:31:01ZTwo questions, hundreds of scientists, no easy answers: how small differences in data analysis make huge differences in results<figure><img src="https://images.theconversation.com/files/556512/original/file-20231030-25-sz3v30.jpg?ixlib=rb-1.1.0&rect=0%2C17%2C3872%2C2567&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How do siblings affect the size of baby blue tits? It depends whom you ask.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blue-tit-cyanisties-caeruleus-being-gaping-1700866117">Shutterstock</a></span></figcaption></figure><p>Over the past 20 years or so, there has been growing concern that <a href="https://theconversation.com/science-is-in-a-reproducibility-crisis-how-do-we-resolve-it-16998">many results published in scientific journals can’t be reproduced</a>. </p>
<p>Depending on the field of research, studies have found efforts to redo published studies lead to different results in between <a href="https://news.virginia.edu/content/after-10-years-many-labs-comes-end-its-success-replicable">23%</a> and <a href="https://www.nature.com/articles/483531a">89%</a> of cases.</p>
<p>To understand how different researchers might arrive at different results, we asked hundreds of ecologists and evolutionary biologists to answer two questions by analysing given sets of data. They arrived at a huge range of answers.</p>
<p>Our study has been accepted by BMC Biology as a stage 1 <a href="https://www.cos.io/initiatives/registered-reports">registered report</a> and is <a href="https://ecoevorxiv.org/repository/view/6000/">currently available as a preprint</a> ahead of peer review for stage 2.</p>
<h2>Why is reproducibility a problem?</h2>
<p>The <a href="https://theconversation.com/putting-psychological-research-to-the-test-with-the-reproducibility-project-7052">causes of problems with reproducibility</a> are common across science. They include an over-reliance on simplistic measures of
“statistical significance” rather than nuanced evaluations, the fact journals prefer to publish “exciting” findings, and <a href="https://theconversation.com/our-survey-found-questionable-research-practices-by-ecologists-and-biologists-heres-what-that-means-94421">questionable research practices</a> that make articles more exciting at the expense of transparency and increase the rate of false results in the literature.</p>
<p>Much of the research on reproducibility and ways it can be improved (such as <a href="https://theconversation.com/the-science-reproducibility-crisis-and-what-can-be-done-about-it-74198">“open science” initiatives</a>) has been slow to spread between different fields of science. </p>
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Read more:
<a href="https://theconversation.com/our-survey-found-questionable-research-practices-by-ecologists-and-biologists-heres-what-that-means-94421">Our survey found 'questionable research practices' by ecologists and biologists – here's what that means</a>
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<p>Interest in these ideas has been <a href="https://www.science.org/content/article/psychology-s-replication-crisis-inspires-ecologists-push-more-reliable-research">growing among ecologists</a>, but so far there has been little research evaluating replicability in ecology. One reason for this is the difficulty of disentangling environmental differences from the influence of researchers’ choices.</p>
<p>One way to get at the replicability of ecological research, separate from environmental effects, is to focus on what happens after the data is collected.</p>
<h2>Birds and siblings, grass and seedlings</h2>
<p>We were inspired by <a href="https://www.nature.com/articles/526189a">work led by Raphael Silberzahn</a> which asked social scientists to analyse a dataset to determine whether soccer players’ skin tone predicted the number of red cards they received. The study found a wide range of results.</p>
<p>We emulated this approach in ecology and evolutionary biology with an open call to help us answer two research questions:</p>
<ul>
<li><p>“To what extent is the growth of nestling blue tits (<em>Cyanistes caeruleus</em>) influenced by competition with siblings?” </p></li>
<li><p>“How does grass cover influence <em>Eucalyptus</em> spp. seedling recruitment?” (“<em>Eucalyptus</em> spp. seedling recruitment” means how many seedlings of trees from the genus <em>Eucalyptus</em> there are.)</p></li>
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<img alt="A photo of eucalyptus seedlings outdoors" src="https://images.theconversation.com/files/556514/original/file-20231030-17-mh6uxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556514/original/file-20231030-17-mh6uxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556514/original/file-20231030-17-mh6uxm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556514/original/file-20231030-17-mh6uxm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556514/original/file-20231030-17-mh6uxm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556514/original/file-20231030-17-mh6uxm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556514/original/file-20231030-17-mh6uxm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Researchers disagreed over whether grass cover encourages or discourages Eucalyptus seedlings.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-growing-eucalyptus-seedling-650020558">Shutterstock</a></span>
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<p>Two hundred and forty-six ecologists and evolutionary biologists answered our call. Some worked alone and some in teams, producing 137 written descriptions of their overall answer to the research questions (alongside numeric results). These answers varied substantially for both datasets.</p>
<p>Looking at the effect of grass cover on the number of <em>Eucalyptus</em> seedlings, we had 63 responses. Eighteen described a negative effect (more grass means fewer seedlings), 31 described no effect, six teams described a positive effect (more grass means more seedlings), and eight described a mixed effect (some analyses found positive effects and some found negative effects). </p>
<p>For the effect of sibling competition on blue tit growth, we had 74 responses. Sixty-four teams described a negative effect (more competition means slower growth, though only 37 of these teams thought this negative effect was conclusive), five described no effect, and five described a mixed effect.</p>
<h2>What the results mean</h2>
<p>Perhaps unsurprisingly, we and our coauthors had a range of views on how these results should be interpreted.</p>
<p>We have asked three of our coauthors to comment on what struck them most.</p>
<p>Peter Vesk, who was the source of the <em>Eucalyptus</em> data, said: </p>
<blockquote>
<p>Looking at the mean of all the analyses, it makes sense. Grass has essentially a negligible effect on [the number of] eucalypt tree seedlings, compared to the distance from the nearest mother tree. But the range of estimated effects is gobsmacking. It fits with my own experience that lots of small differences in the analysis workflow can add to large variation [in results].</p>
</blockquote>
<p>Simon Griffith collected the blue tit data more than 20 years ago, and it was not previously analysed due to the complexity of decisions about the right analytical pathway. He said: </p>
<blockquote>
<p>This study demonstrates that there isn’t one answer from any set of data. There are a wide range of different outcomes and understanding the underlying biology needs to account for that diversity.</p>
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<p>Meta-researcher Fiona Fidler, who studies research itself, said: </p>
<blockquote>
<p>The point of these studies isn’t to scare people or to create a crisis. It is to help build our understanding of heterogeneity and what it means for the practice of science. Through metaresearch projects like this we can develop better intuitions about uncertainty and make better calibrated conclusions from our research.</p>
</blockquote>
<h2>What should we do about it?</h2>
<p>In our view, the results suggest three courses of action for researchers, publishers, funders and the broader science community.</p>
<p>First, we should avoid treating published research as fact. A single scientific article is just one piece of evidence, existing in a broader context of limitations and biases. </p>
<p>The push for “novel” science means studying something that has already been investigated is discouraged, and consequently we inflate the value of individual studies. We need to take a step back and consider each article in context, rather than treating them as the final word on the matter.</p>
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Read more:
<a href="https://theconversation.com/the-science-reproducibility-crisis-and-what-can-be-done-about-it-74198">The science 'reproducibility crisis' – and what can be done about it</a>
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<p>Second, we should conduct more analyses per article and report all of them. If research depends on what analytic choices are made, it makes sense to present multiple analyses to build a fuller picture of the result.</p>
<p>And third, each study should include a description of how the results depend on data analysis decision. Research publications tend to focus on discussing the ecological implications of their findings, but they should also talk about how different analysis choices influenced the results, and what that means for interpreting the findings.</p><img src="https://counter.theconversation.com/content/216177/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elliot Gould receives funding from an Australian Government Research Training Program Scholarship.</span></em></p><p class="fine-print"><em><span>Hannah Fraser and Timothy H. Parker 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>246 scientists looked at the same data sets and drew very different conclusions.Hannah Fraser, Postdoctoral Researcher , The University of MelbourneElliot Gould, PhD student, School of Biosciences, The University of MelbourneTimothy H. Parker, Professor of Biology and Environmental Studies, Whitman CollegeLicensed as Creative Commons – attribution, no derivatives.