tag:theconversation.com,2011:/africa/topics/sea-life-10221/articlesSea life – The Conversation2023-07-14T12:49:06Ztag:theconversation.com,2011:article/2097702023-07-14T12:49:06Z2023-07-14T12:49:06ZCorals are starting to bleach as global ocean temperatures hit record highs<figure><img src="https://images.theconversation.com/files/537483/original/file-20230714-23-yzqhp8.png?ixlib=rb-1.1.0&rect=0%2C23%2C5176%2C3422&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mass coral bleaching in 2014 left the Coral Reef Monitoring Program monitoring site at Cheeca Rocks off the Florida Keys a blanket of white.</span> <span class="attribution"><a class="source" href="https://www.aoml.noaa.gov/coral-bleaching-cheeca-rocks/">NOAA</a></span></figcaption></figure><p>The water off South Florida is <a href="https://coralreefwatch.noaa.gov/data/vs/ts_figures/ts_multi_year/vs_ts_multiyr_florida_keys.png">over 90 degrees Fahrenheit</a> (32 Celsius) in mid-July, and scientists are already seeing signs of coral bleaching off Central and South America. Particularly concerning is how early in the summer we are seeing these high ocean temperatures. If the <a href="https://theconversation.com/ocean-heat-is-off-the-charts-heres-what-that-means-for-humans-and-ecosystems-around-the-world-207902">extreme heat</a> persists, it could have dire consequences for coral reefs.</p>
<p>Just like humans, corals can handle some degree of stress, but the longer it lasts, the more harm it can do. Corals can’t move to cooler areas when water temperatures rise to dangerous levels. They are stuck in it. For those that are <a href="https://doi.org/10.1007/s00338-022-02232-z">particularly sensitive to temperature stress</a>, that can be devastating.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/537405/original/file-20230713-21-o01eyh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two photos shows a coral on two different dates, one healthy and reddish in color, the other white." src="https://images.theconversation.com/files/537405/original/file-20230713-21-o01eyh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537405/original/file-20230713-21-o01eyh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=246&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537405/original/file-20230713-21-o01eyh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=246&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537405/original/file-20230713-21-o01eyh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=246&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537405/original/file-20230713-21-o01eyh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=310&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537405/original/file-20230713-21-o01eyh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=310&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537405/original/file-20230713-21-o01eyh.png?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">A transplanted coral in the Port of Miami that was healthy in early 2023 had bleached in the warm water by July 11, 2023.</span>
<span class="attribution"><span class="source">NOAA/University of Miami</span></span>
</figcaption>
</figure>
<p><a href="https://scholar.google.com/citations?user=WS4sEzgAAAAJ&hl=en">I lead</a> the <a href="https://www.aoml.noaa.gov/coral-reef-ecosystems/">Coral Program</a> at the National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Lab in Miami, Florida. Healthy coral reef ecosystems are important for humans in numerous ways. Unfortunately, <a href="https://theconversation.com/el-nino-is-coming-and-ocean-temps-are-already-at-record-highs-that-can-spell-disaster-for-fish-and-corals-202424">marine heat waves are becoming more common</a> and more extreme, with potentially devastating consequences for reefs around the world that are already in a fragile state.</p>
<h2>Why coral reefs matter to everyone</h2>
<p>Coral reefs are hot spots of biodiversity. They are often referred to as the <a href="https://oceanexplorer.noaa.gov/okeanos/explorations/10index/background/biodiversity/biodiversity.html">rainforests of the sea</a> because they are home to the highest concentrations of species in the ocean.</p>
<p>Healthy reefs are vibrant ecosystems that support fish and fisheries, which in turn <a href="https://www.noaa.gov/education/resource-collections/marine-life/coral-reef-ecosystems#">support economies and food for millions of people</a>. Additionally, they provide billions of dollars in economic activity every year through tourism, particularly in places like the Florida Keys, where people go to scuba dive, snorkel, fish and experience the natural beauty of coral reefs.</p>
<p>If that isn’t enough, <a href="https://www.usgs.gov/centers/pcmsc/science/role-reefs-coastal-protection">reefs also protect shorelines</a>, beaches and billions of dollars in coastal infrastructure by buffering wave energy, particularly during storms and hurricanes. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IEWJAEkGeNk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What goes into a coral reef?</span></figcaption>
</figure>
<p>But corals are quite <a href="https://scied.ucar.edu/learning-zone/climate-change-impacts/corals-and-climate">sensitive to warming water</a>. They host a microscopic symbiotic <a href="https://oceanservice.noaa.gov/education/tutorial_corals/coral02_zooxanthellae.html">algae called zooxanthella</a> that photosynthesizes just like plants, providing food to the coral. When the surrounding waters get too warm for too long, the zooxanthellae leave the coral, and the coral can turn pale or white – a process known as bleaching.</p>
<p>If corals stay bleached, they can become energetically compromised and ultimately die.</p>
<p>When corals die or their growth slows, these beautiful, complex reef habitats start disappearing and can eventually erode to sand. A recent paper by <a href="https://www.aoml.noaa.gov/tag/john-morris/">John Morris</a>, a scientist in my lab in Florida, shows that around <a href="https://doi.org/10.1038/s41598-022-23394-4">70% of reefs are now net erosional in the Florida Keys</a>, meaning they are losing more habitat than they build.</p>
<figure class="align-center ">
<img alt="Two maps show large areas of above average heat, particularly along the equator in the Pacific, which is an indicator of El Nino, and in much of the Atlantic." src="https://images.theconversation.com/files/537391/original/file-20230713-21-xyfqps.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537391/original/file-20230713-21-xyfqps.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=670&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537391/original/file-20230713-21-xyfqps.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=670&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537391/original/file-20230713-21-xyfqps.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=670&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537391/original/file-20230713-21-xyfqps.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=842&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537391/original/file-20230713-21-xyfqps.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=842&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537391/original/file-20230713-21-xyfqps.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=842&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">About 40% of the global ocean was experiencing a marine heat wave in July 2023. NOAA’s experimental forecasts for August and October show sea surface temperatures well above average in many regions. An increase of 1 degree Celsius = 1.8 degrees Fahrenheit.</span>
<span class="attribution"><a class="source" href="https://psl.noaa.gov/marine-heatwaves/#report">NOAA PSL</a></span>
</figcaption>
</figure>
<p>Unfortunately, these critical coral reef habitats are in decline around the world because of extreme bleaching events, disease and numerous other human-caused stressors. In the Florida Keys, coral cover has decline by about <a href="https://www.climate.gov/news-features/features/mission-iconic-reefs-noaa-aims-restore-florida-keys-climate-resilient-corals">90% over the past several decades</a>.</p>
<h2>Coral bleaching in 2023</h2>
<p>In the Port of Miami, where we have found <a href="https://doi.org/10.1038/s41598-023-33467-7">particularly resilient coral communities</a>, a doctoral candidate in my lab, <a href="https://www.researchgate.net/profile/Allyson-Demerlis">Allyson DeMerlis</a>, documented the first coral bleaching of her experimentally <a href="https://reefresilience.org/management-strategies/restoration/coral-populations/coral-gardening/outplanting/">outplanted corals</a> on July 11, 2023.</p>
<p>Other scientists we work with have reported coral bleaching off of Colombia, El Salvador, Costa Rica and Mexico in the eastern Pacific, as well as along the Caribbean coasts of Panama, Mexico and Belize.</p>
<p>We have yet to see widespread coral death associated with this particular marine heat wave, so it is possible the corals could recover if sea surface temperatures cool down soon. However, global sea surface <a href="https://theconversation.com/ocean-heat-is-off-the-charts-heres-what-that-means-for-humans-and-ecosystems-around-the-world-207902">temperatures are at record highs</a>, and large parts of the Atlantic and eastern Pacific are <a href="https://coralreefwatch.noaa.gov/satellite/bleachingoutlook_cfs/index.php">under bleaching alerts</a>. At this point, the evidence points to the potential for a very negative outcome.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/537387/original/file-20230713-29-3fo0qw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A chart of every year's global daily average sea surface temperature shows 2023 far above all other years since satellite records started in 1981." src="https://images.theconversation.com/files/537387/original/file-20230713-29-3fo0qw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537387/original/file-20230713-29-3fo0qw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537387/original/file-20230713-29-3fo0qw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537387/original/file-20230713-29-3fo0qw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537387/original/file-20230713-29-3fo0qw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537387/original/file-20230713-29-3fo0qw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537387/original/file-20230713-29-3fo0qw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sea surface temperatures have been off the charts. The thick black line is 2023. The orange line is 2022. The 1982-2011 average is the middle dashed line.</span>
<span class="attribution"><a class="source" href="https://climatereanalyzer.org/clim/sst_daily/">ClimateReanalyzer.org/NOAA OISST v2.1</a></span>
</figcaption>
</figure>
<p><a href="https://theconversation.com/el-nino-is-back-thats-good-news-or-bad-news-depending-on-where-you-live-205974">El Niño</a> is contributing to the problem this year, but the longer-term trends of rising ocean heat are <a href="https://climate.nasa.gov/">driven by global warming</a> fueled by human activities.</p>
<p>To put that into context, <a href="https://doi.org/10.1038/srep16762">a paper</a> by NOAA scientist <a href="https://scholar.google.com/citations?user=rEv8BNoAAAAJ&hl=en">Derek Manzello</a> showed that in the Florida Keys, the number of days per year in which water temperatures were higher than 90 F (32 C) had increased by more than 2,500% in the two decades following the mid-1990s relative to the prior 20 years. That is a remarkable increase in the number of days that corals are experiencing particularly stressful warm water.</p>
<h2>What can we do to protect corals?</h2>
<p>First, we cannot give up on corals.</p>
<p><a href="https://www.aoml.noaa.gov/people/alice-webb/">Alice Webb</a>, a coral reef scientist working with our group, recently published <a href="https://doi.org/10.1038/s41598-022-26930-4">a study</a> based on years of our research in the Florida Keys. She modeled reef habitat persistence under climate, restoration and adaptation scenarios and found that protecting reefs is going to take everything – active restoration of reefs, helping corals acclimate or adapt to changing temperatures, and, importantly, human curbing of greenhouse gas emissions.</p>
<figure class="align-center ">
<img alt="A map shows warm ocean temperatures across a large part of the Atlantic and Pacific around North America." src="https://images.theconversation.com/files/537410/original/file-20230713-17-5rc865.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537410/original/file-20230713-17-5rc865.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=504&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537410/original/file-20230713-17-5rc865.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=504&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537410/original/file-20230713-17-5rc865.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=504&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537410/original/file-20230713-17-5rc865.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=634&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537410/original/file-20230713-17-5rc865.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=634&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537410/original/file-20230713-17-5rc865.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=634&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sea surface temperatures off South Florida were abnormally high in mid-July 2023.</span>
<span class="attribution"><a class="source" href="https://coralreefwatch.noaa.gov/product/5km/index_5km_sst.php">Coral Reef Watch/NOAA</a></span>
</figcaption>
</figure>
<p>Major restoration efforts are underway in the Florida Keys as part of the NOAA-led <a href="https://marinesanctuary.org/mission-iconic-reefs/">Mission Iconic Reefs</a>. We are also assessing how different coral individuals perform under stress, hoping to identify those that are particularly stress-tolerant by combing through the massive amounts of <a href="https://www.ingentaconnect.com/contentone/umrsmas/bullmar/2023/00000099/00000002/art00006">data from restoration projects and coral nurseries</a>.</p>
<p>We are also evaluating stress-hardening techniques. For example, in tide pools, corals are exposed to large swings in temperature over short periods, making them more resilient to subsequent thermal stress events. We are exploring whether it’s possible to replicate that natural process in the lab, before corals are planted onto reefs, to better <a href="https://doi.org/10.1007/s00338-022-02232-z">prepare them for stressful summers in the wild</a>.</p>
<p>Coral bleaching on a large scale has really been documented only since the early 1980s. When I talk to people who have been fishing and diving in the Florida Keys since before I was born, they have amazing stories of how vibrant the reefs used to be. They know firsthand how bad things have become because they have lived it.</p>
<p>There isn’t currently a single silver-bullet solution, but ignoring the harm being done is not an option. There is simply too much at stake.</p><img src="https://counter.theconversation.com/content/209770/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Enochs receives funding from NOAA. </span></em></p>Water temperatures in the 90s off Florida in July are alarming, a NOAA coral scientist writes. Scientists in several North American countries have already spotted coral bleaching off their coasts.Ian Enochs, Research Ecologist, National Oceanic and Atmospheric AdministrationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1883402022-10-24T12:27:57Z2022-10-24T12:27:57ZGeoengineering the ocean to fight climate change raises serious environmental justice questions<figure><img src="https://images.theconversation.com/files/489457/original/file-20221012-17-7piebk.jpg?ixlib=rb-1.1.0&rect=816%2C0%2C5465%2C3559&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We could sink more carbon in the ocean to fight climate change, but should we?</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/fishermen-coming-back-to-the-beach-sland-of-mozambique-news-photo/617964338?phrase=ocean%20fishermen%20island">Eric Lafforgue/Art in All of Us/Corbis via Getty Images</a></span></figcaption></figure><p>Heat waves, droughts and extreme weather are <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">endangering people and ecosystems</a> somewhere in the world almost every day. These extremes are exacerbated by climate change, driven primarily by increasing emissions of greenhouse gases that build up in the atmosphere and trap heat at the Earth’s surface. </p>
<p>With that in mind, researchers are <a href="https://www.bostonglobe.com/2022/10/20/business/hubspots-brian-halligan-gets-real-about-climate-change/">exploring ways</a> to pull carbon dioxide out of the atmosphere and lock it away – <a href="https://nap.nationalacademies.org/catalog/26278/a-research-strategy-for-ocean-based-carbon-dioxide-removal-and-sequestration">including using the ocean</a>. But while these techniques might work, they raise serious technical, social and ethical questions, many of which have no clear answers yet.</p>
<p>We study climate change <a href="https://scholar.google.com/citations?user=1nrd2msAAAAJ&hl=en">policy, sustainability</a> and <a href="https://scholar.google.com/citations?user=VADzLZAAAAAJ&hl=en">environmental justice</a>. Before people start experimenting with the health of the ocean, there are several key questions to consider.</p>
<h2>Ocean carbon dioxide removal 101</h2>
<p>The ocean covers about 70% of the planet, and it <a href="https://earthobservatory.nasa.gov/features/OceanCarbon">naturally takes up carbon dioxide</a>. In fact, <a href="https://www.nature.com/articles/s41467-020-18203-3#Sec2">about a quarter</a> of human-produced carbon dioxide ends up in the ocean.</p>
<p>Ocean carbon dioxide removal is any action designed to use the ocean to remove even more carbon dioxide from the atmosphere than it already does and store it. </p>
<p>It spans a wide range of techniques – from increasing the amount and vitality of carbon dioxide-absorbing <a href="https://doi.org/10.1002/wcc.529">mangrove forests</a> to using <a href="https://nap.nationalacademies.org/catalog/26278/a-research-strategy-for-ocean-based-carbon-dioxide-removal-and-sequestration">ocean fertilization</a> to stimulate the growth of phytoplankton that absorb carbon dioxide to building pipelines that pump <a href="https://digitalcommons.mainelaw.maine.edu/oclj/vol12/iss2/3/">liquid carbon dioxide into formations under the seabed</a>, where it can eventually solidify as carbonate rock.</p>
<figure class="align-center ">
<img alt="A cross-section of ocean showing different types of carbon capture, like ocean fertilization" src="https://images.theconversation.com/files/483878/original/file-20220912-10060-hpa6op.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483878/original/file-20220912-10060-hpa6op.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=324&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483878/original/file-20220912-10060-hpa6op.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=324&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483878/original/file-20220912-10060-hpa6op.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=324&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483878/original/file-20220912-10060-hpa6op.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=408&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483878/original/file-20220912-10060-hpa6op.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=408&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483878/original/file-20220912-10060-hpa6op.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=408&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Methods of ocean direct carbon removal.</span>
<span class="attribution"><a class="source" href="https://www.frontiersin.org/articles/10.3389/fclim.2021.664456/full">2021 Boettcher, Brent, Buck, Low, McLaren and Mengis, Frontiers, 2021</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>There are other forms of carbon dioxide removal – planting trees, for example. But they <a href="https://www.ipcc.ch/srccl/">require large amounts of land</a> that is needed for other essential uses, such as agriculture.</p>
<p>That’s why <a href="https://www.nationalacademies.org/news/2021/12/new-report-assesses-the-feasibility-cost-and-potential-impacts-of-ocean-based-carbon-dioxide-removal-approaches-recommends-u-s-research-program">interest in using the vast ocean is growing</a>.</p>
<h2>Would these methods store enough carbon?</h2>
<p>The first crucial question is whether ocean carbon dioxide removal techniques could significantly reduce atmospheric carbon dioxide and store it long term, beyond what the ocean already does. Greenhouse gas <a href="https://www.ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_SPM.pdf">emissions are still increasing globally</a>, which means that ocean carbon dioxide removal would need to keep carbon dioxide out of the atmosphere for a long time, at least until greenhouse gas emissions have fallen.</p>
<p>Initial evidence suggests that some forms of ocean carbon dioxide removal, such as those that rely on short-lived biomass like kelp forests or phytoplankton, <a href="https://doi.org/10.1098/rsbl.2018.0781">may not keep captured carbon stored</a> for more than a few decades. That’s because most plant tissues are quickly recycled by decay or by sea creatures grazing on them.</p>
<p>In contrast, mechanisms that form minerals, like the interaction when carbon dioxide is pumped into basalt formations, or that alter the way seawater retains carbon dioxide, such as <a href="https://www.american.edu/sis/centers/carbon-removal/fact-sheet-ocean-alkalinization.cfm">increasing its alkalinity</a>, prevent carbon from escaping and are much more likely to keep it out of the atmosphere for hundreds or thousands of years.</p>
<h2>Ecological risks and benefits</h2>
<p>Another key question is what ecological benefits or risks accompany different ocean carbon dioxide removal approaches.</p>
<p>Research shows that some options, such as supporting mangrove forests, <a href="https://doi.org/10.1016/j.ecolecon.2020.106758">may promote biodiversity and benefit nearby human communities</a>.</p>
<p>However, other options could introduce novel risks. For example, growing and then sinking large amounts of kelp or algae <a href="https://doi.org/10.3389/fmars.2019.00107">could bring in invasive species</a>. Dissolving certain types of rock in the ocean could reduce ocean acidity. This would enhance the ocean’s ability to store carbon dioxide, but these rocks could also contain trace amounts of metals that could harm marine life, and these risks are <a href="https://doi.org/10.5194/bg-19-3683-2022">not well understood</a>.</p>
<figure class="align-center ">
<img alt="Satellite view of the coast showing swirls of phytoplankton" src="https://images.theconversation.com/files/483924/original/file-20220912-24-7r0v1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483924/original/file-20220912-24-7r0v1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483924/original/file-20220912-24-7r0v1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483924/original/file-20220912-24-7r0v1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483924/original/file-20220912-24-7r0v1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483924/original/file-20220912-24-7r0v1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483924/original/file-20220912-24-7r0v1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Phytoplankton can grow explosively over a few days or weeks. Ocean fertilization is designed to supercharge that process to capture carbon dioxide, but it can have harmful affects for other marine life.</span>
<span class="attribution"><a class="source" href="https://earthobservatory.nasa.gov/features/Phytoplankton">Robert Simmon and Jesse Allen/NOAA/MODIS</a></span>
</figcaption>
</figure>
<p>Each process could also release some greenhouse gases, reducing its overall effectiveness.</p>
<h2>Interfering with nature is a social question</h2>
<p>The ocean affects everyone on the planet, but not everyone will have the same relationship to it or the same opportunities to have their opinions heard. </p>
<p>Much of the global population lives near the ocean, and some interventions <a href="https://doi.org/10.3389/fclim.2021.684063">might impinge on places that support jobs and communities</a>. For example, boosting algae growth could affect nearby wild fisheries or interfere with recreation. People and communities are going to evaluate these risks differently depending on how they are personally affected.</p>
<p>In addition, people’s trust in decision-makers often <a href="https://www.sciencedirect.com/science/article/pii/S0921800921000161">shapes their views of technologies</a>. Some ways of using the ocean to remove carbon, such as those close to the shore, could be governed locally. It’s less clear how decisions about the <a href="https://nap.nationalacademies.org/download/26278">high seas or deep ocean</a> would be made, since these areas are not under the jurisdiction of any one country or global governing body.</p>
<p>People’s perceptions will likely also be shaped by such factors as whether or not they see ocean carbon dioxide removal as <a href="https://doi.org/10.1016/j.gloenvcha.2013.06.002">interfering with nature or protecting it</a>. However, views of what is acceptable or not can change. As the impacts of climate change increase, <a href="https://doi.org/10.1111/cobi.13759">tolerance for some unconventional interventions seems to be growing</a>.</p>
<h2>It’s also an ethical question</h2>
<p>Ocean carbon dioxide removal also raises a variety of ethical questions that do not have straightforward answers.</p>
<p>For example, it forces people to consider the <a href="https://doi.org/10.5840/ijap201024221">relationship between humans and nonhumans</a>. Are humans obliged to intervene to reduce the impact on the climate, or ought we avoid ocean interventions? Do people have the right to purposefully intervene in the ocean or not? Are there specific obligations that humans ought to recognize when considering such options? </p>
<figure class="align-center ">
<img alt="People crouch down to plant mangroves." src="https://images.theconversation.com/files/489449/original/file-20221012-18-7t7a2q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489449/original/file-20221012-18-7t7a2q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489449/original/file-20221012-18-7t7a2q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489449/original/file-20221012-18-7t7a2q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489449/original/file-20221012-18-7t7a2q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489449/original/file-20221012-18-7t7a2q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489449/original/file-20221012-18-7t7a2q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Volunteers plant mangrove saplings in the Philippines.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/filipino-volunteers-plant-mangrove-saplings-during-the-news-photo/73318400?phrase=philippines%20planting%20mangroves&adppopup=true">Romeo Gacad/AFP via Getty Images</a></span>
</figcaption>
</figure>
<p>Other ethical questions revolve around who makes decisions about ocean carbon dioxide removal and the consequences. For example, <a href="https://doi.org/10.1111/1758-5899.12921">who should be involved in decision-making</a> about the ocean? Could relying on ocean carbon dioxide removal <a href="https://doi.org/10.1016/j.crm.2021.100324">reduce societies’ commitment</a> to reducing emissions through other means, such as by reducing consumption, increasing efficiency and transforming energy systems?</p>
<h2>Who pays?</h2>
<p>Finally, ocean carbon dioxide removal could be very expensive. </p>
<p>For example, mining and then adding rocks to reduce the ocean’s acidity has been <a href="https://doi.org/10.1088/1748-9326/aaa9c4">estimated to cost</a> between US$60 and $200 per ton of carbon dioxide removed. To put that into context, the world produced <a href="https://www.iea.org/news/global-co2-emissions-rebounded-to-their-highest-level-in-history-in-2021">more than 36 billion metric tons</a> of carbon dioxide from energy alone in 2021.</p>
<p>Even macroalgae cultivation could be in the <a href="https://doi.org/10.1146/annurev-marine-032122-113850">tens of billions of dollars</a> if done at the scale likely necessary to have an impact.</p>
<p>These methods are more expensive than many actions that reduce emissions right now. For instance, using solar panels to avoid carbon emissions can range from saving money to a cost of $50 per ton of carbon dioxide, while actions like reducing methane emissions are <a href="https://www.iea.org/data-and-statistics/charts/ghg-abatement-costs-for-selected-measures-of-the-sustainable-recovery-plan">even less expensive</a>. But the harm from continued climate change has been estimated to be in the <a href="https://www.nature.com/articles/s41558-019-0444-6">hundreds of billions annually</a> in the United States alone.</p>
<p>These costs raise more questions. For example, how much debt is fair for future generations to carry, and how should the costs be distributed globally to fix a global problem? </p>
<p>Ocean carbon dioxide removal <a href="https://nap.nationalacademies.org/download/26278">could become a useful method</a> for keeping global warming in check, but it should not be seen as a silver bullet, especially since there isn’t an effective global system for making decisions about the ocean.</p>
<p><em>Sarah Cooley, a former research scientist at Woods Hole Oceanographic Institution and director of climate science at the Ocean Conservancy, contributed to this article.</em></p><img src="https://counter.theconversation.com/content/188340/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Terre Satterfield receives funding from Pacific Institute for Climate Solutions
(F20-00333) to explore public attitudes toward OCDR</span></em></p><p class="fine-print"><em><span>Sonja Klinsky 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>From planting mangroves to dumping minerals in the ocean, there are lots of ideas for ocean carbon dioxide removal – and even more questions.Sonja Klinsky, Associate Professor and Senior Global Futures Scientist, Arizona State UniversityTerre Satterfield, Professor of Culture, Risk and the Environment, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1597922021-04-29T14:38:49Z2021-04-29T14:38:49ZWatching a coral reef die as climate change devastates one of the most pristine tropical island areas on Earth<figure><img src="https://images.theconversation.com/files/397728/original/file-20210429-13-1cf9nq9.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C1917%2C1212&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Chagos Reef was vibrant before the heat wave.</span> <span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Ken Marks/Khaled bin Sultan Living Oceans Foundation</a></span></figcaption></figure><p>The <a href="https://en.wikipedia.org/wiki/Chagos_Archipelago#/media/File:Chagos_map.PNG">Chagos Archipelago</a> is one of the most remote, seemingly idyllic places on Earth. Coconut-covered sandy beaches with incredible bird life rim tropical islands in the Indian Ocean, hundreds of miles from any continent. Just below the waves, coral reefs stretch for miles along an <a href="https://www.researchgate.net/figure/Satellite-bathymetry-map-of-the-western-Indian-Ocean-basin-Approximate-aerial-extent-of_fig1_320835153">underwater mountain chain</a>.</p>
<p>It’s a paradise. At least it was before the heat wave.</p>
<p>When I first explored the Chagos Archipelago 15 years ago, the underwater view was incredible. Schools of brilliantly colored fish in blues, yellows and oranges darted among the corals of a vast, healthy reef system. Sharks and other large predators swam overhead. Because the archipelago is so remote and sits in one of the largest <a href="https://chagos-trust.org/chagos/overview">marine protected areas</a> on the planet, it has been sheltered from industrial fishing fleets and other activities that can harm the coastal environment.</p>
<p>But it can’t be protected from climate change.</p>
<figure class="align-center ">
<img alt="A diver carries a plastic pipe for measuring while swimming over a variety of corals" src="https://images.theconversation.com/files/397204/original/file-20210426-15-ng6gsy.jpg?ixlib=rb-1.1.0&rect=480%2C586%2C1097%2C689&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397204/original/file-20210426-15-ng6gsy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397204/original/file-20210426-15-ng6gsy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397204/original/file-20210426-15-ng6gsy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397204/original/file-20210426-15-ng6gsy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397204/original/file-20210426-15-ng6gsy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397204/original/file-20210426-15-ng6gsy.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 diver documents the coral reefs in the Chagos Archipelago.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<p>In 2015, a marine heat wave struck, harming coral reefs worldwide. <a href="https://people.miami.edu/profile/spurkis@rsmas.miami.edu">I’m a marine biologist</a> at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, and I was with a team of researchers on a <a href="https://www.livingoceansfoundation.org/global-reef-expedition/global-reef-expedition-final-reports/">10-year global expedition to map the world’s reefs</a>, led by the <a href="https://www.livingoceansfoundation.org/">Khaled bin Sultan Living Oceans Foundation</a>, wrapping up our work in the Chagos Archipelago at the time. Our report on the state of the reefs there <a href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">was just published</a> in spring 2021.</p>
<p>As the water temperature rose, the corals began to bleach. To the untrained eye, the scene would have looked fantastic. When the water heats up, corals become stressed and they expel the tiny algae called dinoflagellates that live in their tissue. Bleaching isn’t as simple as going from a living coral to a bleached white one, though. After they expel the algae, the corals turn fluorescent pinks and blues and yellows as they produce chemicals to <a href="https://doi.org/10.1016/j.cub.2020.04.055">protect themselves from the Sun’s harmful rays</a>. The entire reef was turning psychedelic colors.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397178/original/file-20210426-13-v15dqm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two bright pink coral mounds" src="https://images.theconversation.com/files/397178/original/file-20210426-13-v15dqm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397178/original/file-20210426-13-v15dqm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397178/original/file-20210426-13-v15dqm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397178/original/file-20210426-13-v15dqm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397178/original/file-20210426-13-v15dqm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397178/original/file-20210426-13-v15dqm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397178/original/file-20210426-13-v15dqm.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">Just before they turned white, the corals turned abnormally bright shades.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Phil Renaud/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Large fish and schools of fish swimming above the reef" src="https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.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 Chagos archipelago is home to some 800 species of fish, including rays, skates and dozens of varieties of shark.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Phil Renaud/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<p>That explosion of color is rare, and it doesn’t last long. Over the following week, we watched the corals turn white and start to die. It wasn’t just small pieces of the reef that were bleaching – it was happening across hundreds of square miles.</p>
<p>What most people think of as a coral is actually many tiny colonial polyps that build calcium carbonate skeletons. With their algae gone, the coral polyps could still feed by plucking morsels out of the water, but their metabolism slows without the algae, which provide more nutrients <a href="https://oceanservice.noaa.gov/education/tutorial_corals/coral02_zooxanthellae.html">through photosynthesis</a>. They were left desperately weakened and more vulnerable to diseases. We could see diseases taking hold, and that’s what finished them off.</p>
<p>We were witnessing the death of a reef.</p>
<figure class="align-center ">
<img alt="A large mushroom-shaped coral structure, half of it turned white from bleaching" src="https://images.theconversation.com/files/397197/original/file-20210426-19-2eyjzx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397197/original/file-20210426-19-2eyjzx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397197/original/file-20210426-19-2eyjzx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397197/original/file-20210426-19-2eyjzx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397197/original/file-20210426-19-2eyjzx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397197/original/file-20210426-19-2eyjzx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397197/original/file-20210426-19-2eyjzx.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">Corals beginning to bleach in the Chagos archipelago.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Phil Renaud/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<h2>Rising temperatures increase the heat wave risk</h2>
<p>The devastation of the Chagos Reef wasn’t happening in isolation.</p>
<p>Over the past century, <a href="https://www.ncdc.noaa.gov/cag/global/time-series/globe/ocean/ytd/12/1880-2017">sea surface temperatures</a> have risen by an average of <a href="https://www.epa.gov/climate-indicators/climate-change-indicators-sea-surface-temperature">about 0.13 degrees Celsius</a> (0.23 F) per decade as the oceans absorb the vast majority of greenhouse gas emissions from human activities, largely from the burning of fossil fuels. The temperature increase and changing ocean chemistry affects sea life of all kinds, from <a href="https://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F">deteriorating the shells of oysters and tiny pteropods</a>, an essential part of the food chain, to causing fish populations to migrate to cooler water. </p>
<p>Corals can become stressed when temperatures around them <a href="https://coralreefwatch.noaa.gov/satellite/methodology/methodology.php">rise just 1 C</a> (1.8 F) above their tolerance level. With water temperature elevated from global warming, even a minor heat wave can become devastating.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IEWJAEkGeNk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>In 2015, the ocean heat from a strong <a href="https://oceanservice.noaa.gov/facts/ninonina.html">El Niño</a> event triggered the mass bleaching in the Chagos reefs and <a href="https://www.climate.gov/news-features/event-tracker/survey-photos-reveal-damage-year%E2%80%99s-global-coral-bleaching-event">around the world</a>. It was the third global bleaching on record, following events in <a href="http://www.reefcheck.org/wp-content/uploads/2020/07/Ambio1999.pdf">1998</a> and <a href="https://www.climate.gov/news-features/videos/coral-bleaching-alarm-2010">2010</a>.</p>
<p>Bleaching doesn’t just affect the corals – entire reef systems and the fish that feed, spawn and live among the coral branches suffer. One <a href="https://doi.org/10.1073/pnas.0401277101">study of reefs</a> around Papua New Guinea in the southwest Pacific found that about 75% of the reef fish species declined after the 1998 bleaching, and many of those species declined by more than half.</p>
<figure class="align-center ">
<img alt="Two bright orange fish with white bands swim past an anemone" src="https://images.theconversation.com/files/397200/original/file-20210426-21-24e0zc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397200/original/file-20210426-21-24e0zc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397200/original/file-20210426-21-24e0zc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397200/original/file-20210426-21-24e0zc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397200/original/file-20210426-21-24e0zc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397200/original/file-20210426-21-24e0zc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397200/original/file-20210426-21-24e0zc.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">Most corals are brown or green. Fish and anemones bring color to the reefs.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Ken Marks/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<figure class="align-center ">
<img alt="Starfish on a coral" src="https://images.theconversation.com/files/397603/original/file-20210428-19-1j2eryy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397603/original/file-20210428-19-1j2eryy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397603/original/file-20210428-19-1j2eryy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397603/original/file-20210428-19-1j2eryy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397603/original/file-20210428-19-1j2eryy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397603/original/file-20210428-19-1j2eryy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397603/original/file-20210428-19-1j2eryy.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">Noduled sea stars are among the reef’s diverse species.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/global-reef-expedition/">Ken Marks/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<p>Research shows marine heat waves are now about <a href="http://doi.org/10.1126/science.aba0690">20 times more likely</a> than they were just four decades ago, and they tend to be hotter and last longer. We’re at the point now that some places in the world are anticipating coral bleaching every couple of years.</p>
<p>That increasing frequency of heat waves is a death knell for reefs. They don’t have time to recover before they get hit again.</p>
<p><iframe id="IS1fT" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/IS1fT/4/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Where we saw signs of hope</h2>
<p>During the <a href="https://www.livingoceansfoundation.org/global-reef-expedition/global-reef-expedition-final-reports/">Global Reef Expedition</a>, we visited over 1,000 reefs around the world. Our mission was to conduct standardized surveys to assess the state of the reefs and map the reefs in detail so scientists could document and hopefully respond to changes in the future. With that knowledge, countries can plan more effectively to protect the reefs, important national resources, providing <a href="https://reefresilience.org/value-of-reefs/">hundreds of billions of dollars a year</a> in economic value while also <a href="https://oceanservice.noaa.gov/facts/coral_protect.html">protecting coastlines</a> from waves and storms.</p>
<p>We saw damage almost everywhere, from the <a href="https://www.livingoceansfoundation.org/global-reef-expedition/atlantic-ocean/inaguas-bahamas/">Bahamas</a> to the <a href="https://www.youtube.com/watch?v=7yisyMO-Xi0">Great Barrier Reef</a>.</p>
<p>Some reefs are able to survive heat waves better than others. Cooler, stronger currents, and even storms and cloudier areas can help prevent heat building up. But the global trend is not promising. The world has already <a href="https://www.nationalacademies.org/news/2019/06/protecting-coral-reefs-in-a-deteriorating-environment">lost 30% to 50% of its reefs</a> in the last 40 years, and scientists have warned that most of the remaining reefs <a href="https://www.ipcc.ch/2018/10/08/summary-for-policymakers-of-ipcc-special-report-on-global-warming-of-1-5c-approved-by-governments/">could be gone within decades</a>.</p>
<figure class="align-center ">
<img alt="Flat corals turning white as they bleach" src="https://images.theconversation.com/files/397202/original/file-20210426-21-nq77pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397202/original/file-20210426-21-nq77pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397202/original/file-20210426-21-nq77pb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397202/original/file-20210426-21-nq77pb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397202/original/file-20210426-21-nq77pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397202/original/file-20210426-21-nq77pb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397202/original/file-20210426-21-nq77pb.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">Table corals bleaching in the Chagos Reef.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Derek Manzello/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397179/original/file-20210426-21-1l2ahj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diver with large sea turtle swimming over corals." src="https://images.theconversation.com/files/397179/original/file-20210426-21-1l2ahj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397179/original/file-20210426-21-1l2ahj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397179/original/file-20210426-21-1l2ahj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397179/original/file-20210426-21-1l2ahj7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397179/original/file-20210426-21-1l2ahj7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397179/original/file-20210426-21-1l2ahj7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397179/original/file-20210426-21-1l2ahj7.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 author, Sam Purkis, dives near a hawksbill turtle in the Chagos Archipelago.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Derek Manzello/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<p>While we see some evidence that certain marine species are <a href="https://phys.org/news/2021-04-climate-marine-species-poleward.html">moving to cooler waters</a> as the planet warms, a reef takes thousands of years to establish and grow, and it is limited by geography.</p>
<p>In the areas where we saw glimmers of hope, it was mostly due to good management. When a region can control other harmful human factors – such as overfishing, extensive coastal development, pollution and runoff – the <a href="https://blogs.scientificamerican.com/observations/a-bulwark-against-reef-destruction-in-a-warming-world/">reefs are healthier</a> and better able to handle the global pressures from climate change.</p>
<p>Establishing large marine protected areas is one of the most effective ways I’ve seen to <a href="http://doi.org/10.1098/rstb.2015.0210">protect coral reefs</a> because it limits those other harms.</p>
<figure class="align-center ">
<img alt="Pointed-nose fish among coral branches" src="https://images.theconversation.com/files/397195/original/file-20210426-19-7dtogm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397195/original/file-20210426-19-7dtogm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397195/original/file-20210426-19-7dtogm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397195/original/file-20210426-19-7dtogm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397195/original/file-20210426-19-7dtogm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397195/original/file-20210426-19-7dtogm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397195/original/file-20210426-19-7dtogm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Coral reefs are fish nurseries and feeding grounds. They also protect coast lines from storms and waves.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Stephan Andrews/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<figure class="align-center ">
<img alt="Brilliant blue fish swim in a coral reef" src="https://images.theconversation.com/files/397205/original/file-20210426-15-15m16st.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397205/original/file-20210426-15-15m16st.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397205/original/file-20210426-15-15m16st.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397205/original/file-20210426-15-15m16st.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397205/original/file-20210426-15-15m16st.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397205/original/file-20210426-15-15m16st.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397205/original/file-20210426-15-15m16st.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">Some of the diversity of the Chagos Reef.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Derek Manzello/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<p>The Chagos marine protected area covers 640,000 square kilometers (250,000 square miles) with only one island currently inhabited – Diego Garcia, which houses a U.S. military base. The British government, which created the marine protected area in 2010, has been <a href="https://www.lawfareblog.com/chagos-archipelago-dispute-law-diplomacy-and-military-basing">under pressure to turn over control of the region</a> to the country of Mauritius, where former Chagos residents now live and which won a challenge over it in the International Court of Justice in 2020. Whatever happens with jurisdiction, the region would benefit from maintaining a high level of marine protection.</p>
<h2>A warning for other ecosystems</h2>
<p>The Chagos reefs could potentially recover – if they are spared from more heat waves. Even a 10% recovery would make the reefs stronger for when the next bleaching occurs. But recovery of a reef is measured in decades, not years.</p>
<p>So far, research missions that have returned to the Chagos reefs have found only meager recovery, if any at all.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Large fish and schools of fish swimming above the reef" src="https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397198/original/file-20210426-21-txmdaj.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 Chagos Archipelago is home to some 800 species of fish, including rays, skates and dozens of varieties of shark.</span>
<span class="attribution"><a class="source" href="https://www.livingoceansfoundation.org/publication/global-reef-expedition-chagos-archipelago-final-report/">Phil Renaud/Khaled bin Sultan Living Oceans Foundation</a></span>
</figcaption>
</figure>
<p>We knew the reefs weren’t doing well under the insidious march of climate change in 2011, when the global reef expedition started. But it’s nothing like the intensity of worry we have now in 2021.</p>
<p>Coral reefs are the canary in the coal mine. Humans have collapsed other ecosystems before through overfishing, overhunting and development, but this is the first unequivocally tied to climate change. It’s a harbinger of what can happen to other ecosystems as they reach their survival thresholds.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369797/original/file-20201117-13-180ibt9.png?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">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>This story is part of <a href="https://theconversation.com/uk/topics/oceans-21-96784">Oceans 21</a></em></strong>
<br><em>Our series on the global ocean opened with <a href="https://oceans21.netlify.app/">five in-depth profiles</a>. Look for new articles on the state of our oceans in the lead-up to the U.N.’s next climate conference, COP26. The series is brought to you by The Conversation’s international network.</em></p><img src="https://counter.theconversation.com/content/159792/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sam Purkis 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>Scientists watched in real time as rising ocean heat transformed the sprawling reef. It was a harbinger for ecosystems everywhere as the planet warms.Sam Purkis, Professor and Chair of the Department of Marine Sciences, University of MiamiLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1557952021-03-03T13:44:58Z2021-03-03T13:44:58ZClever cuttlefish show advanced self-control, like chimps and crows<figure><img src="https://images.theconversation.com/files/385555/original/file-20210222-15-10wxcxe.jpg?ixlib=rb-1.1.0&rect=42%2C158%2C7016%2C4285&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Courtesy of the Grass Foundation</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>When I enter the marine laboratory in the morning, there’s always a chance I’m about to get soaked. You see, our crankiest common cuttlefish, called Franklin, has recently taken to squirting a water jet at me from her tank. I’ve decided it’s her grumpy way of saying she doesn’t want to participate in experiments, because Franklin never hoses me during my evening visits, which is when I’m only in the lab to give her dinner.</p>
<p>Cuttlefish are clever creatures, and squirting saltwater is not their only party trick. They’re <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(07)01138-4">experts at camouflage</a>, adjusting the colour and texture of their skin to match their environment. Plus, cuttlefish possess a range of <a href="https://onlinelibrary.wiley.com/doi/10.1111/brv.12651">advanced cognitive abilities</a>, including a <a href="https://www.sciencedirect.com/science/article/pii/S0960982213012621">sophisticated memory</a>, to help them <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2019.0743">optimise their foraging behaviour</a> and adapt to changing prey conditions.</p>
<p>But Franklin’s selective squirting inspired me to test for another cognitive ability in cuttlefish: self-control, which might be what stops Franklin’s impulse to drench me during my evening visits. </p>
<p>The ability to exert self-control varies across species. <a href="https://pubmed.ncbi.nlm.nih.gov/9163939/">Rats</a>, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0003347205000412">chickens</a>, and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1333221/">pigeons</a> find it difficult to resist food and can only delay gratification for a handful of seconds. <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/wcs.1504">Primates and brainy birds</a>, meanwhile, can tolerate delays of up to several minutes to obtain food of higher quality or quantity. </p>
<p>My team, including colleagues Nicky Clayton and Roger Hanlon, decided to test the self-control of cuttlefish by adapting a famous psychology experiment used to test toddlers’ willpower. We found a significant capacity for <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2020.3161">self-control in cuttlefish</a>, which is the first evidence of this cognitive ability in an invertebrate. </p>
<h2>Marine marshmallows</h2>
<p>To test our cuttlefish, we adapted the <a href="https://science.sciencemag.org/content/244/4907/933">Stanford marshmallow experiment</a>, in which children are presented with a choice of taking an immediate reward – a single marshmallow – or waiting for the superior but delayed reward of two marshmallows. In human children aged between three and five years old, about half cave in and take the first marshmallow, and half wait to receive both marshmallows. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/4y6R5boDqh4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The marshmallow test was first designed to test the willpower of children, not cephalopods.</span></figcaption>
</figure>
<p>We presented cuttlefish with a similar dilemma. To test their willpower, our cuttlefish were presented with two desirable prey items, each contained within a separate Perspex chamber. </p>
<p>One chamber was baited with a piece of king prawn, their second preference, which they could eat immediately. The other chamber was baited with a tastier live grass shrimp, their first preference, which they could only eat if they waited and did not eat the piece of prawn. </p>
<p>We tested a range of delays starting from ten seconds and increasing the delay by increments of ten seconds. All six cuttlefish waited for the better live shrimp and were able to tolerate delays up to 130 seconds, which is comparable to what we see in long-lived social species such as chimpanzees, crows and parrots.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/clever-crows-can-plan-for-the-future-like-humans-do-80627">Clever crows can plan for the future like humans do</a>
</strong>
</em>
</p>
<hr>
<p>Long-lived social species – species that live for many years and form social bonds – draw a number of obvious <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/wcs.1504">benefits from self-control</a>. Temporarily denying their impulses could lead to a longer and better life. Resisting temptation so that they can help a social partner could strengthen social bonds that lead to reciprocated favours in the future. </p>
<p>The same rules don’t apply for cuttlefish. They’re not social, and they’re short-lived. The average cuttlefish lifespan is just two years. So why would a cuttlefish be a discerning eater, prepared to exert self-control? </p>
<h2>Fine-tuned foraging</h2>
<p>Perhaps the answer lies in their eating habits. Cuttlefish stay motionless in camouflage for long periods to avoid detection from predators. This “sit-and-wait” behaviour is punctuated by <a href="https://www.sciencedirect.com/science/article/abs/pii/S0022098105000092">brief bouts of foraging</a>.</p>
<p>The need to optimise these foraging bouts might have influenced the evolutionary expression of self-control in cuttlefish, because individuals who wait for better-quality prey could forage more efficiently at the same time as limiting their exposure to predators. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/mW4PbW893ik?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">My colleague Roger Hanlon explains how cuttlefish use camouflage.</span></figcaption>
</figure>
<p>The concept of “less is sometimes more” is not something that all animals can appreciate. Those that have learned to avoid temptation in the present to enjoy a better outcome in the future – like <a href="https://psycnet.apa.org/record/2012-33753-006">humans</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0960982217316767">chimpanzees</a> – perform better in tests of general intelligence, too.</p>
<p>We decided to test the <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2020.3161">learning performance</a> of our cuttlefish, an indicator of intelligence, in a separate reversal-learning task. We placed two markers that differed in colour in two random locations in their tank. </p>
<p>First, we had the cuttlefish associate one of the coloured markers with food, by rewarding them with food when they went to it. Then, we reversed the experiment. That meant the cuttlefish had to associate the other coloured marker with an edible reward. Cuttlefish that were quicker at learning both the first association and the reversed association were also better at resisting temptation in our marine marshmallow test. </p>
<h2>A parallel with chimpanzees</h2>
<p>These findings are the first demonstration of a link between self-control and learning performance outside of the primate lineage. </p>
<p>Finding that cuttlefish are capable of some of the facets that are thought to be fundamental to the evolution of human intelligence is an extreme example of convergent evolution, where animals with completely different evolutionary histories possess the same cognitive feature. </p>
<p>Finding cognitive similarities between such distantly related animals is an important piece of the evolutionary puzzle. It could bring us one step closer to pinpointing the origins of intelligence. And it gives me a newfound appreciation for Franklin, despite her insistence on drenching me each morning.</p><img src="https://counter.theconversation.com/content/155795/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexandra Schnell receives funding from the Royal Society. </span></em></p>A marine version of the Stanford marshmallow experiment helped show cuttlefish can delay gratification.Alexandra Schnell, Research Fellow, Darwin College, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1542662021-03-01T19:10:42Z2021-03-01T19:10:42ZLife on the hidden doughnuts of the Great Barrier Reef is also threatened by climate change<figure><img src="https://images.theconversation.com/files/386318/original/file-20210225-13-1xhk1ej.jpg?ixlib=rb-1.1.0&rect=0%2C155%2C4448%2C3219&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A sea cucumber living on the Great Barrier Reef inter-reef seafloor.</span> <span class="attribution"><span class="source">Kent Holmes/Nature Ecology and Evolution</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Mention the Great Barrier Reef, and most people think of the rich beauty and colour of corals, fish and other sea life that are increasingly <a href="https://www.gbrmpa.gov.au/our-work/threats-to-the-reef/climate-change">threatened by climate change</a>.</p>
<p>But there is another part of the Great Barrier Reef that until recently was largely hidden and under-explored. </p>
<p>In the northern section of the Great Barrier Reef Marine Park there are large <em>Halimeda</em> algal habitats called <a href="https://link.springer.com/article/10.1007%2FBF00302010" title="Halimeda bioherms of the northern Great Barrier Reef">bioherms</a> (also known as doughnuts because of their shape).</p>
<p>They are constructed by a type of algae (<em>Halimeda</em>) with a limestone skeleton. The tops of the bioherms are carpeted by a living meadow of the algae, yet much of the plant community includes other types of green, red and brown algae and some seagrasses.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/382110/original/file-20210203-21-qmsn6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A type of green seaweed." src="https://images.theconversation.com/files/382110/original/file-20210203-21-qmsn6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382110/original/file-20210203-21-qmsn6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382110/original/file-20210203-21-qmsn6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382110/original/file-20210203-21-qmsn6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382110/original/file-20210203-21-qmsn6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382110/original/file-20210203-21-qmsn6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382110/original/file-20210203-21-qmsn6y.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"><em>Halimeda</em> is a genus of green macroalgae (seaweed).</span>
<span class="attribution"><span class="source">Mardi McNeil</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The bioherms cover an area greater than <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/dep2.122" title="Morphotype differentiation in the Great Barrier Reef Halimeda bioherm carbonate factory: Internal architecture and surface geomorphometrics">6,000km²</a>, more than twice the area of shallow coral reefs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/385990/original/file-20210223-15-cogh30.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Several maps showing the location of the _Halimeda_ bioherms." src="https://images.theconversation.com/files/385990/original/file-20210223-15-cogh30.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/385990/original/file-20210223-15-cogh30.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=426&fit=crop&dpr=1 600w, https://images.theconversation.com/files/385990/original/file-20210223-15-cogh30.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=426&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/385990/original/file-20210223-15-cogh30.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=426&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/385990/original/file-20210223-15-cogh30.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=536&fit=crop&dpr=1 754w, https://images.theconversation.com/files/385990/original/file-20210223-15-cogh30.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=536&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/385990/original/file-20210223-15-cogh30.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=536&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 distribution of <em>Halimeda</em> bioherms in the Great Barrier Reef.</span>
<span class="attribution"><a class="source" href="https://figshare.com/articles/figure/Distribution_of_mapped_Halimeda_bioherms_-_Great_Barrier_Reef/7506251">Figshare/Mardi McNeil</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Scientists have known <a href="https://link.springer.com/article/10.1007/BF02395280" title="Halimeda biomass, growth rates and sediment generation on reefs in the central great barrier reef province">for decades</a> of this unusual inter-reef seafloor habitat that lies between the coast and the outer barrier reefs. But they’ve never investigated the diversity of marine life that lives there, until now.</p>
<p>In a new study published today in <a href="https://dx.doi.org/10.1038/s41559-021-01400-8" title="Inter-reef Halimeda algal habitats within the Great Barrier Reef support a distinct biotic community and high biodiversity">Nature Ecology and Evolution</a>, scientists examined the community of plants and animals that inhabit these unique areas. </p>
<h2>Let’s go deeper</h2>
<p>Most studies of tropical marine biodiversity come from shallow <a href="https://www.mdpi.com/1424-2818/10/1/1/htm" title="Some Implications of High Biodiversity for Management of Tropical Marine Ecosystems—An Australian Perspective">coastal and coral reef habitats</a>. We know a great deal about the biodiversity of these parts of the Great Barrier Reef.</p>
<p>But beyond the vision of scuba divers, deeper inter-reef habitats on the shelf, such as the bioherms, have been largely under-explored.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/gene-editing-is-revealing-how-corals-respond-to-warming-waters-it-could-transform-how-we-manage-our-reefs-143444">Gene editing is revealing how corals respond to warming waters. It could transform how we manage our reefs</a>
</strong>
</em>
</p>
<hr>
<p>In our study, we used a <a href="https://www.marine.csiro.au/ipt/resource?r=csiro_gbr_sbd" title="CSIRO - Great Barrier Reef seabed biodiversity study 2003-2006">dataset</a> of all the plants and animals recorded from the bioherms and surrounding seafloor habitats. The data came from the <a href="http://www.frdc.com.au/Archived-Reports/FRDC%20Projects/2003-021-DLD.pdf">Seabed Biodiversity Project</a>, a large study published back in 2007 of the inter-reef biodiversity in the Great Barrier Reef World Heritage Area.</p>
<p>What we found was surprising. An exceptional diversity of marine life and a distinct community was found to be living on the bioherms.</p>
<h2>A diverse community</h2>
<p>The biodiversity of marine life was up to 76% higher on the bioherms than the surrounding inter-reef habitats. Species richness was especially high for plants and invertebrates.</p>
<p>The average number of fish species per site was about the same in both <em>Halimeda</em> and non-<em>Halimeda</em> habitats. In total, 265 species of fish were observed in the bioherms, including sharks and rays.</p>
<p>Overall, more than 1,200 species of animals were recorded from the bioherms. The majority of these (78%) are invertebrates.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/382112/original/file-20210203-13-128ayp4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A feather star invertebrate." src="https://images.theconversation.com/files/382112/original/file-20210203-13-128ayp4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382112/original/file-20210203-13-128ayp4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382112/original/file-20210203-13-128ayp4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382112/original/file-20210203-13-128ayp4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382112/original/file-20210203-13-128ayp4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382112/original/file-20210203-13-128ayp4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382112/original/file-20210203-13-128ayp4.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">Most of the animals living on the <em>Halimeda</em> bioherms are invertebrates, such as this feather star.</span>
<span class="attribution"><span class="source">Mardi McNeil</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A distinct community</h2>
<p>The composition of plant and animal communities on the bioherms was also distinctly different to the surrounding inter-reef areas. </p>
<p>Some 40% of bioherm species were unique to that habitat in the study area. The community included many sponges, snails and slugs, crabs and shrimps, brittle stars, sea urchins and sea cucumbers. </p>
<p>The fish community on the bioherms was also distinct from surrounding habitats. The <a href="https://fishesofaustralia.net.au/home/species/261">two-spot wrasse</a>, <a href="https://fishesofaustralia.net.au/home/species/2460">threadfin emperor</a> and <a href="https://fishesofaustralia.net.au/home/species/315">black-banded damselfish</a> were particularly common.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/386068/original/file-20210224-13-10p7wju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small black fish with a yellow tail and a white band near its neck." src="https://images.theconversation.com/files/386068/original/file-20210224-13-10p7wju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/386068/original/file-20210224-13-10p7wju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/386068/original/file-20210224-13-10p7wju.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/386068/original/file-20210224-13-10p7wju.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/386068/original/file-20210224-13-10p7wju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/386068/original/file-20210224-13-10p7wju.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/386068/original/file-20210224-13-10p7wju.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A yellowtail angelfish (<em>Chaetodontoplus meredithi</em>) seen in coral waters of the Great Barrier Reef.</span>
<span class="attribution"><a class="source" href="https://fishesofaustralia.net.au/home/species/2503">Sascha Schultz/iNaturalist.org/FishofAustralia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Most interesting about the bioherm fish community was the occurrence of some species such as the <a href="https://fishesofaustralia.net.au/home/species/2503">yellowtail angelfish</a> generally thought to live mostly on coral reefs. Some of these reef-associated fishes have been increasingly observed in <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/faf.12383" title="Beyond the reef: The widespread use of non‐reef habitats by coral reef fishes">a range of non-reef habitats</a>.</p>
<p>These multi-habitat users may be using the bioherms for shelter, feeding, spawning or as nursery grounds. Understanding the connections between shallow coral reefs and deeper bioherms is important to better understand how the reef and inter-reef habitats function.</p>
<h2>An unusual habitat</h2>
<p>The <em>Halimeda</em> bioherms are arguably the <a href="https://www.abc.net.au/news/2016-09-01/new-reef-discovered-near-great-barrier-reef/7806580">weirdest habitat</a> in the Great Barrier Reef.</p>
<p>Recent high-resolution <a href="https://link.springer.com/article/10.1007/s00338-016-1492-2" title="New constraints on the spatial distribution and morphology of the Halimeda bioherms of the Great Barrier Reef, Australia">seafloor mapping</a> using <a href="https://www.deepreef.org/technology/52-lidar.html">airborne lasers</a> revealed the bioherms form a seafloor that looks like fields of giant doughnuts 20 metres high and 200 metres across.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/9e9H8jQZUWg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The doughnuts are the connected circles on the seafloor in the yellow/green bioherm part. They look quite small but each circle is about 200 metres across.</span></figcaption>
</figure>
<p>The tops of the bioherms lie some <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/dep2.122" title="Morphotype differentiation in the Great Barrier Reef Halimeda bioherm carbonate factory: Internal architecture and surface geomorphometrics">25-30 metres below the surface</a>, so can’t be seen from boats passing over. </p>
<p>Deeper water and the remote location has meant the bioherms have been mostly invisible to marine biologists that work on the nearby shallow coral reefs. </p>
<h2>Under threat from climate change</h2>
<p>We are only just beginning to understand the importance of <em>Halimeda</em> bioherms as a habitat to support biodiversity in the Great Barrier Reef. </p>
<p>But just as the rest of the Great Barrier Reef is likely to be impacted by the effects of <a href="https://www.nature.com/articles/s41586-018-0041-2" title="Global warming transforms coral reef assemblages">climate change</a>, so too are the bioherms. </p>
<p>Potential threats to the bioherms include <a href="https://link.springer.com/article/10.1007/s00338-015-1377-9" title="Increased temperature mitigates the effects of ocean acidification in calcified green algae (Halimeda spp)">marine heating</a>, <a href="https://www.int-res.com/abstracts/meps/v440/p67-78" title="Species-specific consequences of ocean acidification for the calcareous tropical green algae Halimeda">ocean acidification</a> and changes to <a href="https://www.gbrmpa.gov.au/our-work/threats-to-the-reef/climate-change/ocean-currents">circulation patterns</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/under-the-moonlight-a-little-light-and-shade-helps-larval-fish-to-grow-at-night-153192">Under the moonlight: a little light and shade helps larval fish to grow at night</a>
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<p>It has been more than 15 years since the inter-reef Seabed Biodiversity Project. The five-yearly Great Barrier Reef <a href="https://www.gbrmpa.gov.au/our-work/outlook-report-2019">Outlook Report</a> says little is known about any ecological trends in the bioherm habitat.</p>
<p>Our new study provides a baseline of the biodiversity of <em>Halimeda</em> bioherms at a single point in time. But questions remain about the present state of this ecosystem and its resilience on short and long-term physical and biological cycles.</p>
<p><a href="https://www.aims.gov.au/docs/research/monitoring/reef/reef-monitoring.html">Long-term monitoring</a> of these unique and hidden habitats is critical to more fully understand the overall health of the Great Barrier Reef.</p><img src="https://counter.theconversation.com/content/154266/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mardi McNeil has previously received funding from the National Geographic Society, the NSW Foundation for Parks and Wildlife, and the Great Barrier Reef Marine Park Authority for research on the habitat potential of Halimeda bioherms.</span></em></p><p class="fine-print"><em><span>Andrew Hoey receives funding from the Australian Research Council and Department of Agriculture, Water, and the Environment. He is a councillor of the Australian Coral Reef Society, and member of the Coral Sea Marine Park Advisory Committee. </span></em></p><p class="fine-print"><em><span>Jody Webster has previously received funding from the National Geographic Society for research on the Halimeda bioherms.</span></em></p><p class="fine-print"><em><span>Luke Nothdurft receives funding from the Ian Potter Foundation.</span></em></p>We are only just beginning to understand the importance of this deep and hidden area of the inter-reef that supports a rich diversity of marine life.Mardi McNeil, Postdoctoral researcher, Queensland University of TechnologyAndrew Hoey, Senior Research Fellow, James Cook UniversityJody Webster, Professor of Marine Geoscience, University of SydneyLuke Nothdurft, Senior Lecturer - Earth Science, Queensland University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1109792019-05-28T02:01:26Z2019-05-28T02:01:26ZCurious Kids: how do sea creatures drink sea water and not get sick?<figure><img src="https://images.theconversation.com/files/258421/original/file-20190212-174883-xze1ii.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1599%2C1200&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Everything in an animal's body is made out of cells. And these cells need chemicals, such as salt, in and around them to work properly. The chemical balance needs to be just right. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/boltofblue/16745338741/in/photolist-rvJeNV-sh5JiC-a84jBX-24kQgYF-8yFh8Q-dW4Hx3-dW4HyL-iN5Lv7-ps2vKW-LMyCpf-nccja8-7zyQYQ-dW4Jhy-cT6qpw-ZWZ6e7-8FtVYg-9UED2i-6UwVFF-dKJ3Q3-8ALeTf-H5kYJ-gNPecq-rFQUvC-4QL73f-8FtXX2-btyNmT-7fsng-ndKs5i-ndKkL6-bnkcqi-ntckuf-o6kVJb-7zv79k-dn1k33-MWJnAG-dW4GZL-6yfD2Z-739YNx-6juu1n-dKCCbR-a2WJmR-dR3mYA-7Sr3eo-nx1SQr-DBhPrH-8Fu5UZ-7mrY9C-DR41NU-7zyTu1-deSvZ5">Alyse & Remi/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p><em><a href="https://theconversation.com/au/topics/curious-kids-36782">Curious Kids</a> is a series for children. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.edu.au You might also like the podcast <a href="http://www.abc.net.au/kidslisten/imagine-this/">Imagine This</a>, a co-production between ABC KIDS listen and The Conversation, based on Curious Kids.</em> </p>
<hr>
<blockquote>
<p><strong>How do sea creatures stand the salt? - Marshall, age 9, Murrumbeena.</strong></p>
</blockquote>
<hr>
<p>Everything in our bodies is made of cells. And these cells need chemicals, such as salt, in and around them to work properly. The chemical balance needs to be <em>just right</em>. </p>
<p>If we don’t get enough salt, a lot of our cells won’t work. But too much salt? That’s also a problem. </p>
<p>Drinking enough fresh water will help dilute the salt in our bodies. And depending on what and how much we eat and drink, our kidneys will remove excess salt and put it in our urine so we can get rid of it. </p>
<p>However, our kidneys can only process small amounts of salt. If we drank a lot of salty seawater, we’d feel sick and could even die. </p>
<h2>Sea animals and sea salt</h2>
<p>Animals that live in the sea cope with seawater in different ways, depending on how much salt their bodies can withstand. </p>
<p>Some animals, such as ghost shrimps, can take in large amounts of salt and will maintain a balance similar to the water around them.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/275579/original/file-20190521-23845-15v9rks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275579/original/file-20190521-23845-15v9rks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275579/original/file-20190521-23845-15v9rks.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275579/original/file-20190521-23845-15v9rks.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275579/original/file-20190521-23845-15v9rks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=497&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275579/original/file-20190521-23845-15v9rks.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=497&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275579/original/file-20190521-23845-15v9rks.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=497&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ghost shrimp can live in very salty water.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1368189527?src=bXqrR_9YLB1Qwffm9-yiRg-1-13&size=huge_jpg">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>They can do that even when they are in water that is saltier than seawater.</p>
<p>Animals that do this are known as “osmoconformers”, and the cells in their bodies can withstand big changes in salt concentrations.</p>
<p>They don’t necessarily drink seawater the way we do, but they can suck water and salt through their skin via processes called osmosis and diffusion. </p>
<p>Many invertebrates (animals without backbones, such as jellyfish) survive in salty water like this. They can cope with a level of saltiness that would be dangerous for us.</p>
<p>However, even these animals have their limits. And if the salt concentrations in their bodies get too high, they need to move to less salty water or they will die.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-what-sea-creature-can-attack-and-win-over-a-blue-whale-98551">Curious Kids: What sea creature can attack and win over a blue whale?</a>
</strong>
</em>
</p>
<hr>
<p>Fish and some invertebrates such as some sea snails need to maintain salt concentrations that are <em>less</em> than seawater. </p>
<p>Fish tend to have concentrations that are about a third of that of seawater. They have developed ways to manage the amount of salt in their bodies and are known as “osmoregulators”. </p>
<p>When a fish drinks sea water, its kidneys (like ours) removes excess salt and gets rid of it via their urine. They can also get rid of salt via their gills, and even their skin.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/275531/original/file-20190521-69182-58ed8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275531/original/file-20190521-69182-58ed8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275531/original/file-20190521-69182-58ed8r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275531/original/file-20190521-69182-58ed8r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275531/original/file-20190521-69182-58ed8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275531/original/file-20190521-69182-58ed8r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275531/original/file-20190521-69182-58ed8r.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">Fish have a few ways to get rid of salt.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/667733179?size=huge_jpg">shutterstock</a></span>
</figcaption>
</figure>
<p>But different fish have different limits. Some saltwater species, if they are trapped in more salty water, will die. </p>
<p>Others can live quite happily in saltier water, but even these will die if they get trapped in <em>really</em> salty water.</p>
<h2>Freshwater fish have a different problem</h2>
<p>Fish that live in freshwater have the opposite problem. Their bodies have higher levels of salt compared to the water that surrounds them. These fish needed to evolve a way to stop the salt leaking <em>out</em> of their bodies and into the water.</p>
<p>They do this by eating foods that have salt in them and drinking lots of water and keeping as much salt as they can in their bodies. </p>
<p>They also actively absorb a small amount of salt from the surrounding water through the gills and skin. If you move these freshwater fish into the ocean, however, they would get very sick and die.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/275537/original/file-20190521-69213-1km90ls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275537/original/file-20190521-69213-1km90ls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275537/original/file-20190521-69213-1km90ls.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275537/original/file-20190521-69213-1km90ls.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275537/original/file-20190521-69213-1km90ls.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275537/original/file-20190521-69213-1km90ls.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275537/original/file-20190521-69213-1km90ls.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">If you move these freshwater fish into the ocean, however, they would get very sick and die.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/laurawolfartist/36850734514/in/photolist-C8528S-Z9TWv3-Z9TXeN-Y9nDvC-Ze9iVF-Y9nDuA-95x762-YcY26K-7bwE1x-ZbkFgo-Ze9igK-5XD622-YcY22X-gu7HLi-ZbkG4L-YcY1LX-VJea9F-7Eamhn-5xwwMQ-8nZnLU-5XHo4d-75Ceuz-7DV4sX-VJe85a-6hGdSZ-7DYUAw-7DV89B-5Nkiiu-7Ee6QL-UDcyyb-VJe7LV-VScLuG-VEXtq1-UDcyHu-UDcwK1-aqjGzN-VJe5kn-gHKueY-BX6s6R">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<h2>Seabirds and turtles</h2>
<p>Seabirds and turtles also need to remove salt from their bodies, but they have what we call “glands” to help.</p>
<p>Glands are special organs in their heads that help remove the salt. If you look at seabirds closely, they dribble water out of their beak nostrils. This water is very salty. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/275558/original/file-20190521-23823-zs1ytx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275558/original/file-20190521-23823-zs1ytx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275558/original/file-20190521-23823-zs1ytx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275558/original/file-20190521-23823-zs1ytx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275558/original/file-20190521-23823-zs1ytx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275558/original/file-20190521-23823-zs1ytx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275558/original/file-20190521-23823-zs1ytx.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">Seabirds dribble salty water out of their beak.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Seabirds_of_the_Drake_Passage_crossing_to_the_Antarctic_Peninsula.Wandering_Albatross_(Diomedea_exulans)._(25369795203).jpg">Murray Foubister/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Turtles remove the excess salt from the eyes, which is why they sometimes look like they are crying. </p>
<p>And seabirds and turtles also have kidneys that remove salt in the same way that fish do.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/275577/original/file-20190521-23841-1ucqogj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275577/original/file-20190521-23841-1ucqogj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275577/original/file-20190521-23841-1ucqogj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275577/original/file-20190521-23841-1ucqogj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275577/original/file-20190521-23841-1ucqogj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275577/original/file-20190521-23841-1ucqogj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275577/original/file-20190521-23841-1ucqogj.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">Turtles ‘cry’ unwanted salt out of their eyes.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/reiner/2951389738/in/photolist-5uNDkY-5uJa5M-5kRG4r-5uNBho-5uJ7Rt-o7S1o8-oZxQ9S-nQoJ8w-dH9gFY-5mgUGU-5kVVRL-5uNEcd-aHGmTx-qwM8ii-5uJfcn-q6wQgY-f8TTe-7L8oZS-aHGneX-5CX7G4-6pyKh4-rzRzyk-4HqQ2S-apyZQ4-JomJnp-8WPXVE-5uJey4-5uJgdX-KD2vD-aHGm1n-d3Wxnu-5ezHWv-sgcVGD-776bPN-8WPYLj-nxXpPZ-cuJfgq-aHGntn-RM92wA-JFgB7H-aHGkxx-4GywvQ-82dHQH-aHGjT8-wjGZhS-aHGnZx-5ezJgn-YW1ZQj-5eE7PS-5eE77S/">Reiner Kraft/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>So, the reason marine animals don’t get sick when they drink seawater is because the species have lived in marine water for a very long time and are adapted to living in that environment. </p>
<p>It comes down to what levels our bodies have evolved to cope with.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-you-blink-when-there-is-a-sudden-loud-noise-close-by-99437">Curious Kids: Why do you blink when there is a sudden loud noise close by?</a>
</strong>
</em>
</p>
<hr>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/168011/original/file-20170505-21620-huq4lj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><em>Please tell us your name, age and which city you live in. We won’t be able to answer every question but we will do our best.</em></p><img src="https://counter.theconversation.com/content/110979/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Glenn Hyndes receives funding from the ARC. He is a member of the Wilderness Society, Australian Marine Science Association, Coast and Estuaries Research Federation and International Seagrass Association.
</span></em></p>Some animals, such as ghost shrimps can even cope with water that is saltier than normal seawater. It’s all down to evolution.Glenn Hyndes, Professor in Coastal Ecology, Edith Cowan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1035932018-09-20T05:39:48Z2018-09-20T05:39:48ZDesal plants might do less damage to marine environments than we thought<figure><img src="https://images.theconversation.com/files/237248/original/file-20180920-10496-zlu726.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some sea creatures are displaced by the desalination plant, but others actually grow.</span> <span class="attribution"><span class="source">Supplied</span></span></figcaption></figure><p>Millions of people all over the world rely on desalinated water. Closer to home, Australia has desalination plants in Melbourne, Adelaide, Perth, the Gold Coast, and many remote and regional locations.</p>
<p>But despite the growing size and number of desalination plants, the environmental impacts are little understood. Our six-year study, <a href="https://authors.elsevier.com/a/1XjIa9pi-IH74">published recently in the journal Water Research</a>, looked at the health the marine environment before, during and after the Sydney Desalination Plant was operating.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fixing-cities-water-crises-could-send-our-climate-targets-down-the-gurgler-82822">Fixing cities' water crises could send our climate targets down the gurgler</a>
</strong>
</em>
</p>
<hr>
<p>Our research tested the effect of pumping and “diffusing” highly concentrated salt water (a byproduct of desalination) back into the ocean.</p>
<p>Contrary to our expectation that high salt levels would impact sea creatures, we found that ecological changes were largely confined to an area within 100m of the discharge point, and reduced shortly after the plant was turned off. We also found the changes were likely a result of strong currents created by the outfall jets, rather than high salinity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/237234/original/file-20180920-107704-1g4df97.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/237234/original/file-20180920-107704-1g4df97.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/237234/original/file-20180920-107704-1g4df97.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=385&fit=crop&dpr=1 600w, https://images.theconversation.com/files/237234/original/file-20180920-107704-1g4df97.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=385&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/237234/original/file-20180920-107704-1g4df97.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=385&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/237234/original/file-20180920-107704-1g4df97.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=484&fit=crop&dpr=1 754w, https://images.theconversation.com/files/237234/original/file-20180920-107704-1g4df97.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=484&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/237234/original/file-20180920-107704-1g4df97.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=484&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
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</figure>
<h2>Desalination is growing</h2>
<p>We examined six underwater locations at about 25m depth over a six-year period during which the plant was under construction, then operating, and then idle. This let us rigorously monitor impacts to and recovery of marine life from the effects of pumping large volumes of hypersaline water back into the ocean. We tested for impacts and recovery at two distances (30m and 100m) from the outfall.</p>
<p>This study provides the first before-and-after test of ecological impacts of desalination brine on marine communities, and a rare insight into mechanisms behind the potential impacts of a growing form of human disturbance.</p>
<p>About 1% of the world’s population now depends on desalinated water for daily use, supplied by almost <a href="https://www.globalwaterintel.com/market-intelligence-reports/ida-desalination-yearbook-2017-2018">20,000 desalination plants</a> that produce more than 90 million cubic meters of water per day.</p>
<p>Increasingly frequent and severe water shortages are projected to accelerate the growth in desalination around the world. By 2025, more than 2.8 billion people in 48 countries are likely to experience water scarcity, with desalination <a href="https://www.globalwaterintel.com/market-intelligence-reports/ida-desalination-yearbook-2017-2018">expected</a> to become an increasingly crucial water source for many coastal populations.</p>
<h2>Effect of the diffusers</h2>
<p>The diffusers that pump concentrated salt water into the ocean at a high velocity (to increase dilution) are so effective that salinity was almost at background levels within 100m of the outfall. However, the diffusion process increased the speed of currents close to the outfall.</p>
<p>This strong current affects species differently, depending on how they settle and feed. Marine species with strong swimming larvae, such as barnacles, can easily settle in high flow and then benefit from faster delivery of food particles. These animals increased in number and size near the outfall. In contrast, species with slow swimming larvae, such as tubeworms, lace corals and sponges, prefer settling and feeding in low current and became less abundant near the outfall.</p>
<p>Therefore, the high-pressure diffusers designed to reduce hypersalinity may have inadvertently caused impacts due to flow. However, these ecological changes may be less concerning than those caused by hypersalinity, as the currents were still within the range that marine communities experience naturally.</p>
<p>Our findings are important, because as drought conditions around the nation worsen and domestic water supplies are coming under strain, desalination is starting to ramp up in eastern and southern Australia.</p>
<p>For instance, water levels at Sydney’s primary dam at Warragamba have dropped to around 65% and the desalination plant is contracted to start supplying drinking water back into the system when dam levels fall <a href="https://www.metrowater.nsw.gov.au/2017-metropolitan-water-plan">below 60%</a>. This plant can potentially double in capacity if needed.</p>
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<strong>
Read more:
<a href="https://theconversation.com/melbournes-desalination-plant-is-just-one-part-of-drought-proofing-water-supply-55934">Melbourne's desalination plant is just one part of drought-proofing water supply</a>
</strong>
</em>
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<p>There is a rapid expansion of the use of desalination, with global capacity increasing by 57% between <a href="http://idadesal.org/desalination-101/desalination-by-the-numbers/">2008 and 2013</a>. Our results will help designers and researchers in this area ensure desalination plants minimise their effect on local coastal systems.</p><img src="https://counter.theconversation.com/content/103593/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Graeme Clark received funding from Sydney Water and Sydney Desalination Plant to conduct this research.</span></em></p><p class="fine-print"><em><span>Emma Johnston received funding from Sydney Water and Sydney Desalination Plant to conduct this research.
</span></em></p>Pumping very salty water into the ocean has surprisingly little impact on marine life.Graeme Clark, Senior Research Associate in Ecology, UNSW SydneyEmma Johnston, Professor and Dean of Science, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/978732018-06-06T11:35:13Z2018-06-06T11:35:13ZThe threats behind the plight of the puffin<figure><img src="https://images.theconversation.com/files/221965/original/file-20180606-137312-1g137u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">shutterstock</span> </figcaption></figure><p>Puffins are facing a perilous future. Population numbers have fallen sharply, and there are even fears the sea bird could be <a href="https://www.theguardian.com/environment/2018/may/24/fears-puffins-die-out-farne-islands-numbers-plummet">heading towards extinction</a> within the next 100 years. </p>
<p>A much loved and enigmatic creature, puffins are easily identified by their wonderfully coloured beaks. They waddle around in a characterful fashion and make the strangest of noises. Their endearing features have been used as the <a href="https://www.penguin.co.uk/books/59910/puffin-by-design/">symbol of children’s books</a>, and to illustrate many stamps – but they are now also appearing on lists of endangered species. </p>
<p>On Britain’s Farne Islands, numbers have gone down 12% on average over just five years, with one island’s population falling by 42%.</p>
<p>The common puffin, named after its puffed-up swollen appearance (although its scientific name, <em>Fratercula arctica</em>, arises from its resemblance to a friar wearing robes) has an extensive range across the northern hemisphere, with breeding colonies from Norway to Newfoundland. </p>
<p>Around 90% of the global population is <a href="http://www.iucnredlist.org/details/22694927/0">found in Europe</a>, with 60% of the population breeding in Iceland (which is also <a href="https://www.icelandontheweb.com/articles-on-iceland/nature/wildlife/puffins/">home to a tradition</a> which involves children rescuing young, wayward puffins – “pufflings” – and returning them to the safety of the sea). The UK is home to 10% of the global puffin population, breeding on many islands and mainland coastal areas.</p>
<p>Although there are around 450,000 puffins in the UK, the species is threatened with extinction due to their rapid and ongoing population decline. <a href="https://www.bbc.co.uk/news/uk-england-tyne-44236755">Recent surveys</a> of the Farne Islands revealed that despite a steady increase over the previous 70 years, numbers have declined by as much as 42% over the past five years.</p>
<p>Unfortunately, we know very little about the ecology of the puffin outside the breeding season. Although the birds amass in large numbers to breed, they spend two-thirds of their life alone, out in the north Atlantic sea. Consequently, they are very difficult to monitor.</p>
<h2>What’s causing the decline?</h2>
<p>Firstly, although puffins live for a fairly long time (the <a href="http://news.bbc.co.uk/1/hi/scotland/8156866.stm">oldest recorded so far</a> reached the age of 34), their breeding population is limited to a small number of sites. They also have a low reproductive rate, laying just one egg a year, which makes them particularly vulnerable to adverse changes in the environment and means they can take a long while to recover from negative impacts.</p>
<p>They are also hunted – by humans and other animals. Smoked or dried puffin is considered a delicacy (or a <a href="http://qi.com/infocloud/puffins">flavouring for porridge</a>) in some places, such as Iceland and the Faroe Islands. But although they were once over harvested by people, hunting is now maintained at a sustainable level.</p>
<p>During the breeding season, puffins nest in burrows on clifftops. Although this offers the nest protection from aerial predators, such as gulls, chicks and eggs are not safe from mammals, including weasels and foxes. On Lundy Island in the Bristol Channel, the population of puffins fell to just 10 pairs, but since the <a href="http://news.bbc.co.uk/1/hi/england/devon/5079426.stm">eradication of rats there</a>, things are looking up. Nevertheless, the Arctic skua can be a <a href="https://twitter.com/BBCEarth/status/937419565155409920">particular problem</a> as it steals food from adult puffins which is intended for their young.</p>
<p>Living on the open ocean makes the puffin highly susceptible to pollution such as oil spills. After the <a href="https://www.bbc.co.uk/news/uk-england-39223308">Torrey Canyon oil spill</a> in 1967, the number of puffins breeding in France the following year decreased by a massive 85%.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"937419565155409920"}"></div></p>
<p>The puffin feeds almost entirely on small fish, including sandeels, herring and capelin, which <a href="https://www.tandfonline.com/doi/abs/10.1080/00063658909477022">make up over 90%</a> of the diet of pufflings. </p>
<p>The birds have a specialised beak with backwards facing spines, which prevents their prey (<a href="http://projectpuffin.audubon.org/birds/puffin-faqs">up to around 60 fish</a> at a time) from falling out of their mouths when foraging. But in years where the main food source is low, many chicks starve to death. </p>
<p>Puffins have also suffered increased mortality from the rising frequency and intensity of extreme weather events associated with climate change. A recent succession of severe storms <a href="http://jncc.defra.gov.uk/page-2966">caused 54,000 seabirds</a>, half of which were puffins, to be washed up along coasts. Starvation was cited as the main cause of death. </p>
<h2>On a cliff edge</h2>
<p>Sea temperatures have increased over the past 30 years, causing indirect effects on puffin survival. The rise in temperature decreases the abundance of plankton, which in turn <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2656.2006.01148.x">leads to a reduction</a> in the growth and survival of young sandeel and herring on which the <a href="https://www.researchgate.net/publication/250218384_Effect_of_wintering_area_and_climate_on_the_survival_of_adult_Atlantic_Puffins_Fratercula_arctica_in_the_eastern_Atlantic">puffins rely</a>, particularly during the breeding season. Conditions in the North Sea are even causing some puffins <a href="https://www.sciencedaily.com/releases/2010/01/100108111229.htm">to travel into the Atlantic</a>, rather than the North Sea, in search of food – a perilous trek involving greater distances and different habitats.</p>
<p>It seems that a combination of factors are to blame for the decline in puffins, but the reduction in their food supply, particularly as a result of increased sea temperatures, appears to be the main culprit. </p>
<p>We need to continue monitoring puffins worldwide to better understand factors affecting populations. Hopefully, we can put measures in place to minimise pollution, reduce introduced predators and promote sustainable harvesting to try and ensure that the fate of this wonderful bird is not the same as that of the dodo.</p><img src="https://counter.theconversation.com/content/97873/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Louise Gentle works for Nottingham Trent University </span></em></p>The bird faces a wave of challenges – from climate change to human hunters.Louise Gentle, Senior Lecturer in Behavioural Ecology, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/737702017-03-01T19:13:14Z2017-03-01T19:13:14ZWhen mammals took to water they needed a few tricks to eat their underwater prey<figure><img src="https://images.theconversation.com/files/158680/original/image-20170228-29942-vui9en.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A baleen whale feeding in the Hauraki Gulf, New Zealand.</span> <span class="attribution"><span class="source">Dr Krista Hupman</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Have you ever watched a dog retrieve a ball thrown into water? On land, dogs are swift and agile, but in water they become slow and ungainly.</p>
<p>Kicking relentlessly at the water, they snap at the ball with their jaws, only to find that they are pushing it further away. Having eventually caught the ball, they inevitably go into a fit of coughing and sneezing, as they try to shake off water from their nose and face. </p>
<p>Most other mammals have a similarly hard time in water. Yet a select few have come to dominate the world’s rivers and seas, from the poles to the Equator and from the water’s surface to the depths of the abyss. </p>
<p>To achieve this, mammals had to learn to swim, to keep warm, and to find, capture and handle their prey in water. </p>
<p>How aquatic mammals have adapted to feed underwater is the subject of a new research article published this week in <a href="http://rspb.royalsocietypublishing.org/content/284/1850/20162750">Proceedings of the Royal Society B</a>. </p>
<p>In this study, we originally set out to review the feeding behaviours of all carnivorous aquatic mammals – creatures as varied as sleek otters, agile seals and dolphins, and filter-feeding whales. To our surprise, we discovered that all of these animals are linked by a simple evolutionary pattern. </p>
<h2>The need to feed in water</h2>
<p>Despite their obvious differences, when feeding in water all mammals appear to follow just six well-defined, interrelated and increasingly specialised strategies. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/158681/original/image-20170228-29906-kh5i1p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/158681/original/image-20170228-29906-kh5i1p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/158681/original/image-20170228-29906-kh5i1p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=265&fit=crop&dpr=1 600w, https://images.theconversation.com/files/158681/original/image-20170228-29906-kh5i1p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=265&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/158681/original/image-20170228-29906-kh5i1p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=265&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/158681/original/image-20170228-29906-kh5i1p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=334&fit=crop&dpr=1 754w, https://images.theconversation.com/files/158681/original/image-20170228-29906-kh5i1p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=334&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/158681/original/image-20170228-29906-kh5i1p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=334&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sequence of increasingly aquatic feeding strategies used by mammals when eating underwater.</span>
<span class="attribution"><span class="source"> Illustrations by Carl Buell</span></span>
</figcaption>
</figure>
<p>The ancestors of aquatic mammals started out as terrestrial feeders, using their teeth and claws to catch and process their food entirely on land. </p>
<p>Over time, some parts of the feeding process began to happen underwater, while others still occurred at the surface, giving rise to semi-aquatic feeding.</p>
<p>For example, modern otters hunt fish underwater using their jaws and paws, but they then bring their catch to the surface to process it with their teeth. </p>
<p>As mammals became more aquatic, they began feeding entirely underwater. Seals and dolphins are capable of catching, handling and swallowing food beneath the waves. Like their terrestrial and semi-aquatic cousins, these raptorial feeders still primarily rely on their teeth to pierce and hold their prey.</p>
<p>To make sure that captured prey does not float away before swallowing, they then suck their food deeper into the mouth by pulling back their tongue.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/158807/original/image-20170228-13104-l74cs0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/158807/original/image-20170228-13104-l74cs0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/158807/original/image-20170228-13104-l74cs0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=568&fit=crop&dpr=1 600w, https://images.theconversation.com/files/158807/original/image-20170228-13104-l74cs0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=568&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/158807/original/image-20170228-13104-l74cs0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=568&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/158807/original/image-20170228-13104-l74cs0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=713&fit=crop&dpr=1 754w, https://images.theconversation.com/files/158807/original/image-20170228-13104-l74cs0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=713&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/158807/original/image-20170228-13104-l74cs0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=713&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Australian sea lion capturing a fish in its teeth during underwater feeding.</span>
<span class="attribution"><span class="source">David Hocking</span></span>
</figcaption>
</figure>
<h2>The suckers</h2>
<p>Building on this need to generate suction, some species took advantage of the ability to manipulate water flow, and became specialist suction feeders.</p>
<p>Animals that use this strategy – including certain seals, sperm whales and beaked whales – largely do away with teeth. Instead they “hoover” prey directly into their mouth, often from a considerable distance, or even from the sea floor. </p>
<p>Because suction feeding does not rely on teeth to pierce individual prey items, it allows the capture of relatively small prey. But as prey gets smaller, it also becomes more difficult to retain inside the mouth.</p>
<h2>The filterers</h2>
<p>Suction filter feeders solve this problem by using a specialised filter, such as the elaborate teeth of crabeater and <a href="https://link.springer.com/article/10.1007/s00300-012-1253-9">leopard seals</a>, or the comb-like baleen plates of grey whales. They then strain small prey like krill from water sucked into the mouth. </p>
<figure>
<iframe src="https://player.vimeo.com/video/206018882" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Leopard seal using suction feeding to capture a small fish and semi-aquatic feeding to process a large fur seal.</span></figcaption>
</figure>
<p>Ram-based filter feeders, including rorquals like the blue and humpback whales, retain a specialised filter but do away with suction. They filter small prey directly from large mouthfuls of seawater.</p>
<p>All of these strategies are flexible in that a single animal may switch between them when feeding on different kinds of prey. For example, a leopard seal may use semi-aquatic or raptorial feeding when hunting penguins, but suction filter feeding when preying on krill.</p>
<p>Nevertheless, any single feeding event will only follow one feeding strategy at a time: after all, a leopard seal cannot filter a penguin.</p>
<h2>Behaviour informs evolution</h2>
<p>The six strategies defined here naturally grade into each other, and together form a sequence that recalls the evolutionary transition of mammals back to the sea. </p>
<p>Some species can cross the boundaries between strategies, but only when one strategy is derived from the next, like semi-aquatic from terrestrial, or suction from raptorial feeding. Thus, for example, fur seals can <a href="http://onlinelibrary.wiley.com/doi/10.1111/mms.12285/full">switch between the semi-aquatic, raptorial and suction strategies</a> when targeting prey of different sizes. </p>
<figure>
<iframe src="https://player.vimeo.com/video/206017099" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Australian fur seals vary their feeding strategy when targeting different sized prey.</span></figcaption>
</figure>
<p>Being able to read evolutionary history from the feeding behaviour of living mammals allows us to explain and make predictions about how the fossil ancestors of these modern species may have behaved. </p>
<p>For example, we might predict that modern baleen whales must have evolved from raptorial ancestors via a suction-feeding intermediate. Recent discoveries, such as that of a <a href="https://theconversation.com/how-alfred-the-whale-lost-its-teeth-to-become-a-giant-filter-feeder-69489">suction feeding, toothed fossil “baleen” whale</a>, seem to bear this out.</p>
<p>So imagine again a dog, struggling with the ball in the water. If we wanted to engineer it to perform better next time, these are the stages we’d have to go through: teach Rex to capture the ball underwater; next, teach him to handle the excess seawater; finally, teach him to suck the ball towards his snout, rather than accidentally pushing it away. </p>
<p>The same process happened for real at least three times in the evolutionary history of mammals. Who knows where it might go next – suction-feeding otters, anyone?</p><img src="https://counter.theconversation.com/content/73770/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Hocking receives funding from an Australian Research Council Linkage Project (LP150100403). He is affiliated with Monash University and Museums Victoria, Melbourne, Australia.</span></em></p><p class="fine-print"><em><span>Felix Georg Marx receives funding through an EU Marie Skłodowska-Curie Global Postdoctoral fellowship (656010/MYSTICETI).
He is affiliated with the Royal Belgian Institute of Natural Sciences, Brussels, Belgium; Monash University, Melbourne, Australia; and Museums Victoria, Melbourne, Australia.</span></em></p><p class="fine-print"><em><span>Travis Park is affiliated with Monash University, Melbourne, Australia and Museums Victoria, Melbourne, Australia. </span></em></p>There are plenty of mammals that have adapted to life in water, some more than others. That meant they also had to adapt the way they feed.David Hocking, Research associate, Monash UniversityFelix Georg Marx, Post doctoral research fellow in evolutionary biology, Monash UniversityTravis Park, PhD student, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/564492016-03-21T16:52:53Z2016-03-21T16:52:53ZHistoric UN talks could save the high seas<figure><img src="https://images.theconversation.com/files/115451/original/image-20160317-30211-1r1knyt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">www.shutterstock.com</span></span></figcaption></figure><p>You wouldn’t know it from land, but <a href="http://www.globaloceancommission.org/the-global-ocean/the-global-governance-gap/">45% of the surface of the globe</a> lies outside the control of any government. The high seas (and seabed) are designated as “Areas Beyond National Jurisdiction” by the UN, with little regulation and few environmental safeguards.</p>
<p>Now, after a <a href="http://www.un.org/Depts/los/biodiversityworkinggroup/biodiversityworkinggroup.htm">decade of discussions</a>, a new treaty will be <a href="http://www.un.org/depts/los/biodiversity/prepcom.htm">negotiated</a> to ensure the conservation and sustainable use of the biodiversity in these areas.</p>
<p>The <a href="http://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf">United Nations Convention on the Law of the Sea</a> (UNCLOS), adopted in 1982, already provides a “Constitution for the Ocean”, but it doesn’t say much about the high seas or the seabed that lies beyond our borders. </p>
<p>Indeed, we used to believe that these areas were not worth exploiting or protecting, but scientific and technological advancements are opening up a world of possibilities.</p>
<h2>What lies beneath</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/115470/original/image-20160317-30219-1bbqd90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/115470/original/image-20160317-30219-1bbqd90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/115470/original/image-20160317-30219-1bbqd90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/115470/original/image-20160317-30219-1bbqd90.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/115470/original/image-20160317-30219-1bbqd90.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/115470/original/image-20160317-30219-1bbqd90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/115470/original/image-20160317-30219-1bbqd90.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/115470/original/image-20160317-30219-1bbqd90.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">Keep to your lane.</span>
<span class="attribution"><span class="source">www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>In recent decades, cargo shipping has grown rapidly and industrial fishing has moved into ever deeper and more distant waters. At the same time, a range of novel activities are under development. Contracts have been signed with the <a href="https://www.isa.org.jm/deep-seabed-minerals-contractors">International Seabed Authority</a> to mine valuable minerals from the seabed, and scientists and entrepreneurs are dreaming up new ways to use the ocean to <a href="http://www.nature.com/news/ocean-fertilization-project-off-canada-sparks-furore-1.11631">mitigate climate change</a> through “geoengineering”. One such idea is to “fertilise” the ocean with iron, stimulating algal blooms that can lock away carbon. </p>
<p>We have also found a wealth of potential uses for the unusual genes contained in unique deep sea organisms. “Marine genetic resources” taken from these organisms are now <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3944531/">turning up in everything</a> from anti-cancer drugs to high-end skin creams. The search to find such genes, known as “bioprospecting”, has begun in earnest, with the US, Germany, and Japan, <a href="http://imedea.uib-csic.es/%7Etxetxu/Publications/Arnaud-Haond_2011_Marine.pdf">leading the charge</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/115473/original/image-20160317-30247-vaw5bn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/115473/original/image-20160317-30247-vaw5bn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/115473/original/image-20160317-30247-vaw5bn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/115473/original/image-20160317-30247-vaw5bn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/115473/original/image-20160317-30247-vaw5bn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/115473/original/image-20160317-30247-vaw5bn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/115473/original/image-20160317-30247-vaw5bn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/115473/original/image-20160317-30247-vaw5bn.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">Marine organism or latest cancer advance?</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/oceanexplorergov/16517340751/in/album-72157622522489576/">NOAA Ocean Explorer</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>All this activity puts further pressure on already stressed and fragile marine ecosystems, and will only be exacerbated by <a href="http://www.iddri.org/Publications/Collections/Analyses/ST0215.pdf">climate change and ocean acidification</a>.</p>
<p>This is a problem. Though we are not always aware of the vast ocean expanse beyond the horizon, the high seas provide us with a range of <a href="http://www.grida.no/graphicslib/detail/estimated-ecosystem-services-value_4f0c">invaluable</a> resources, not least seafood, clean air, and the global sea routes that deliver goods from across the globe to our doorstep.</p>
<p>The high seas contain unique habitats - such as huge underwater mountains and vents that spew boiling water into the icy depths - and we are constantly discovering new flora and fauna making their homes in these extreme environments. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/115823/original/image-20160321-30908-krbwxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/115823/original/image-20160321-30908-krbwxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/115823/original/image-20160321-30908-krbwxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/115823/original/image-20160321-30908-krbwxk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/115823/original/image-20160321-30908-krbwxk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/115823/original/image-20160321-30908-krbwxk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/115823/original/image-20160321-30908-krbwxk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/115823/original/image-20160321-30908-krbwxk.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">Just one of the many hydrothermal vents that line the ocean floor.</span>
<span class="attribution"><a class="source" href="http://www.pmel.noaa.gov/vents/gallery/smoker-images.html">NOAA</a></span>
</figcaption>
</figure>
<p>At the same time, high seas ecosystems are highly interconnected with the seas and coasts that do happen to fall within national jurisdiction, with species constantly criss-crossing the arbitrary lines we have drawn on the map.</p>
<p>If we fail to to properly manage our global ocean, we have a lot to lose.</p>
<h2>Tangled net</h2>
<p>Unfortunately the global regulatory framework for these areas is a hodgepodge of different legal instruments and organisations that mostly <a href="http://www.globaloceancommission.org/wp-content/uploads/GOC-paper10-governance.pdf">do not work well together</a>. Even when they do, huge gaps remain. </p>
<p>There is currently no way to create internationally recognised marine protected areas (MPAs) on the high seas, while the exploitation of marine genetic resources has been a thorny issue because their status under international law is unclear. There are no global rules requiring the assessment of the environmental impacts of a range of activities, including bioprospecting.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/115437/original/image-20160317-30234-viosrz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/115437/original/image-20160317-30234-viosrz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/115437/original/image-20160317-30234-viosrz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=299&fit=crop&dpr=1 600w, https://images.theconversation.com/files/115437/original/image-20160317-30234-viosrz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=299&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/115437/original/image-20160317-30234-viosrz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=299&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/115437/original/image-20160317-30234-viosrz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=376&fit=crop&dpr=1 754w, https://images.theconversation.com/files/115437/original/image-20160317-30234-viosrz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=376&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/115437/original/image-20160317-30234-viosrz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=376&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">No-man’s-land.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/International_waters#/media/File:International_waters.svg">B1mbo</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Despite a consensus decision to press on with negotiations, states haven’t always seen eye to eye. In particular, there has been intense ideological debate about the status of marine genetic resources: developing countries are concerned that only the wealthiest countries can afford to exploit this common resource, while many developed countries don’t want their potentially profitable activities to be subject to regulation.</p>
<p>States agree on some issues, such as the need to provide developing countries with the know-how and technology to conduct marine scientific research. <a href="http://unesdoc.unesco.org/images/0013/001391/139193m.pdf">International guidelines</a> are already in place, but states have been slow to act. <a href="http://unesdoc.unesco.org/images/0023/002325/232586e.pdf">Some efforts</a> have been made, such as the provision of training for early career scientists in developing countries and shared scientific cruises, but such efforts are limited, ad hoc, and uncoordinated. It is unclear how a new agreement could kickstart a new era of assistance and cooperation.</p>
<p>Even issues that initially appear easy to address may ultimately prove tough to resolve in the context of charged negotiations. For example, while almost all states have their own environmental impact assessment laws at home, agreeing a similar process for the high seas is likely to be far more complicated. </p>
<h2>Stormy weather</h2>
<p>The current consensus is already an uneasy one, and this meeting is only the first of four that will take place in 2016 and 2017. It won’t be until 2018 that the UN General Assembly decides on the convening of an intergovernmental conference to adopt a new treaty.</p>
<p>This is undoubtedly an historic and optimistic moment, and an important first step to ensuring that our global ocean gets the protection it so badly needs. Nonetheless it seems likely that there will be many more <a href="http://www.iddri.org/Publications/Collections/Analyses/ST0116_GW%20et%20al._high%20seas.pdf">storms ahead</a> before any heads of state are signing on the dotted line.</p><img src="https://counter.theconversation.com/content/56449/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Les auteurs ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur organisme de recherche.</span></em></p>The next cancer breakthrough could be found in international waters – but who’s in charge of the high seas?Glen Wright, Research Fellow, IddriJulien Rochette, Coordinateur du programme « Océans et zones côtières », IddriLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/533372016-01-19T12:50:50Z2016-01-19T12:50:50ZTen years after the Thames whale, how are Britain’s sea mammals faring?<p>The British Isles are blessed with a wide variety of sea mammals, with records showing 29 species of whales, porpoises and dolphins and seven species of seals in its waters. But only some of these are regular inhabitants, and when the more unusual species make an appearance it can cause considerable public interest – as happened ten years ago when a northern bottlenose whale, normally found in the deep Atlantic, instead <a href="http://news.bbc.co.uk/1/hi/england/london/4631396.stm">swam up the River Thames</a> in front of the Houses of Parliament and tens of thousands of fascinated onlookers.</p>
<p>While few in the city can have been unaware of what was unfolding in the river, attempts to rescue the whale failed, and <a href="http://news.bbc.co.uk/1/hi/england/london/4635874.stm">it died two days later</a>. The whale, far from its normal habitat, had probably entered the North Sea in pursuit of squid, its principal prey, before becoming lost and, hungry and disoriented, ended up in the Thames Estuary. A <a href="http://www.thameswhale.info/">post-mortem by pathologists</a> from the Zoological Society of London found the cause of death to be a combination of dehydration, physiological stress, cardiovascular collapse and multiple organ failure induced by the stress of repeated strandings and the attempted rescue. </p>
<p>In truth, the tale of the Thames whale says more about human behaviour than whales themselves. But a decade on, it’s interesting to reflect on what we know about the changing fortunes of the remarkable creatures that live in Britain’s waters.</p>
<h2>Cetaceans – whales, dolphins and porpoise</h2>
<p>Of the 29 cetacean species recorded around Britain, 15 are regular inhabitants. But we know very little about all but the most common species. Some species such as fin and <a href="http://www.seawatchfoundation.org.uk/humpback-hooray/">humpback whales</a>, among the principal targets of the early 20th century whaling industry, show signs of recovery, with a marked increase in sightings. </p>
<p><a href="http://seawatchfoundation.org.uk/wp-content/uploads/2012/07/Minke_Whale.pdf">Minke whales</a>, which are still taken in Norwegian waters but in smaller numbers, also show signs of population growth since the 1980s. This may be related partly to ecosystem changes during the 1960s-70s when fish stocks of herring and mackerel collapsed, seemingly taking the pressure off prey fish such as sandeel and sprat for which the whales competed. However, since the mid-1990s, the abundance of minke whales as assessed by large-scale surveys (<a href="http://gcmd.gsfc.nasa.gov/KeywordSearch/Metadata.do?Portal=GCMD&MetadataType=0&MetadataView=Full&KeywordPath=&EntryId=seamap103">SCANS in July 1994</a> and <a href="http://biology.st-andrews.ac.uk/scans2/">SCANS II in July 2005</a>) has shown no significant change.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/108579/original/image-20160119-29783-1s4hf3c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/108579/original/image-20160119-29783-1s4hf3c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/108579/original/image-20160119-29783-1s4hf3c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/108579/original/image-20160119-29783-1s4hf3c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/108579/original/image-20160119-29783-1s4hf3c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=452&fit=crop&dpr=1 754w, https://images.theconversation.com/files/108579/original/image-20160119-29783-1s4hf3c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=452&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/108579/original/image-20160119-29783-1s4hf3c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=452&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A minke whale lunging through a shoal of sprat in the Inner Hebrides.</span>
<span class="attribution"><span class="source">P Anderwald</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The same applies to <a href="http://seawatchfoundation.org.uk/wp-content/uploads/2012/07/White-beaked_Dolphin.pdf">white-beaked dolphin</a> and <a href="http://seawatchfoundation.org.uk/wp-content/uploads/2012/07/Harbour_Porpoise.pdf">harbour porpoise</a> – although the porpoise is now found more abundantly in the southern North Sea and English Channel, with a corresponding decrease in the northwestern North Sea. This change in distribution may well be related to the abundance of certain prey – sandeel is an obvious candidate since stocks in the northwestern North Sea have declined over the last 20 years.</p>
<p>During the 1990s, deaths of porpoises from accidental capture in fishing gear such as gill nets were thought to be unsustainable, which led to the introduction in 2004 of an <a href="http://jncc.defra.gov.uk/page-5214">EU Regulation (812/2004) aimed at reducing bycatch</a>. At the same time, fishing in the North and Celtic Seas where porpoise bycatch was greatest also declined. However, porpoise deaths from fishing vessels continue, with insufficient monitoring for us to be truly confident of the scale. </p>
<p>Another problem facing marine mammals is that of pollutants: contaminant levels in top predators, which bioaccumulate through the food chain, have declined substantially from when PCBs (polychlorinated biphenyls) and pesticides (DDT and dieldrin) were widespread during the mid-20th century. But they persist in the oceans, with <a href="http://www.nature.com/articles/srep18573">PCB levels in particular around the UK linked with disease</a> among harbour porpoises. Other top predators like bottlenose dolphin and <a href="http://seawatchfoundation.org.uk/wp-content/uploads/2012/07/Killer_Whale.pdf">orca</a> (killer whale) may also be especially vulnerable. That said, there is no clear evidence of significant overall population declines. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/108480/original/image-20160118-31821-1ns8ray.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/108480/original/image-20160118-31821-1ns8ray.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=369&fit=crop&dpr=1 600w, https://images.theconversation.com/files/108480/original/image-20160118-31821-1ns8ray.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=369&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/108480/original/image-20160118-31821-1ns8ray.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=369&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/108480/original/image-20160118-31821-1ns8ray.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=463&fit=crop&dpr=1 754w, https://images.theconversation.com/files/108480/original/image-20160118-31821-1ns8ray.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=463&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/108480/original/image-20160118-31821-1ns8ray.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=463&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Harbour seals have been declining in several areas in Britain.</span>
<span class="attribution"><span class="source">Peter Evans</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Pinnipeds – seals</h2>
<p>We know much more about seal populations than whales, thanks mainly to the monitoring efforts of the <a href="http://www.smru.st-andrews.ac.uk/">Sea Mammal Research Unit</a> at the University of St Andrews. With an estimated population size of around 112,000, the UK accounts for 38% of the world’s Atlantic grey seals, which appear to be thriving. The majority (88%) breed in Scotland where, since the 1990s, they have been growing in numbers, particularly around Orkney and parts of the North Sea. Only in the Hebrides have pup birth rates remained fairly static.</p>
<p>By contrast, harbour seals have not fared so well over the same period. At 36,500, Britain’s harbour seals represent around 30% of the European population. Harbour seal counts (made during the autumn moult) were stable or rising until around 2000 when they began to decline in Shetland (down by 30%), Orkney (down 78%) and the Firth of Tay (down 93%). Other regions have been more stable, with those further south recovering from the devastating effect of the <a href="http://www.ncbi.nlm.nih.gov/pubmed/16532603">PDV morbillivirus epidemic in 1988</a> which wiped out more than half their population. We don’t really know what’s behind these changes, but competition for food and the impact of toxins from harmful algae are possible causes. </p>
<p>The effects of climate change on sea mammals is also an issue, due to the effects it has on prey species. The last ten years have seen greater numbers of warm water species such as <a href="http://seawatchfoundation.org.uk/wp-content/uploads/2012/07/Striped_Dolphin.pdf">striped dolphin</a> and <a href="http://uk.whales.org/species-guide/cuviers-beaked-whale">Cuvier’s beaked whale</a>, and a new species, <a href="http://uk.whales.org/species-guide/dwarf-sperm-whale">dwarf sperm whale</a>, added to those species appearing in British waters. Also, in what might seem like a contradictory trend, a bowhead whale, normally closely associated with the Arctic, made its <a href="http://www.bbc.co.uk/news/uk-england-cornwall-31659103">first UK appearance</a> off the Isles of Scilly in February 2015. It’s likely that the next ten years will bring more changes to the status and distribution of different species as they experience changing environmental pressures.</p><img src="https://counter.theconversation.com/content/53337/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>I am Director of a non profit research organisation called Sea Watch Foundation. That organisation receives contracts from government conservation bodies such as JNCC and Natural Resources Wales, to undertake research projects. I am also a member of a consortium of academic institutions funded by NERC participating in a Marine Ecosystems Research Programme. I am a member of a scientific Advisory Panel for the Joint Industry Program on Sound and Marine Life. I have no political affiliation. </span></em></p>It didn’t turn out well for the whale who went to Westminster, but others have made a happy home in British waters.Peter Evans, Honorary Senior Lecturer, Bangor UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/262072014-05-02T05:07:16Z2014-05-02T05:07:16ZSix bizarre feeding tactics from the depths of our oceans<figure><img src="https://images.theconversation.com/files/47576/original/xdzpvgz2-1398962117.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Beautiful outside, monster inside.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/54945394@N00/2445410097">dachalan</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>Sea life can be fascinating and terrifying at the same time. Some creatures look beautiful on the outside but harbour darkness within. Some of the scariest tactics of the deep sea go on display when these creatures eat. Here are six of my favourite feeding strategies:</p>
<h2>1. Jellyfish</h2>
<p>Jellyfish, corals and anemones are all cnidarians that have stinging cells on their tentacles called nematocysts. Jellyfish slowly drift along in the currents, swimming gracefully by inflating and deflating their bells, and catching unsuspecting creatures that drift by in these stinging tentacles. Food is then transferred into the digestive tract by oral tentacles that ring the mouth.</p>
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<span class="attribution"><span class="source">Brad Erisman and NOAA</span></span>
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<h2>2. Pink and yellow sea cucumber</h2>
<p>Speaking of tentacles, another cool way to catch a meal can be seen in the <a href="http://galleries.neaq.org/2011/05/pink-and-yellow-sea-cucumber.html">pink and yellow sea cucumber</a> and its relatives. This type of sea cucumber finds a good spot where water is flowing then holds its frilly tentacles out to capture food particles as they float by. It then gracefully plunges each tentacle individually into its mouth and pulls off all of the delicious edible bits. It’s like eating with a rotating collection of flexible forks.</p>
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<h2>3. Feather stars</h2>
<p>Sea cucumber tentacles are akin to the mucus-coated tube feet used by their cousins, the feather stars. They hold their arms aloft, each tube foot stretched out and sticky, ready to catch some snacks. Passing plankton, bacteria and detritus gets trapped in the mucus and after a fair bit of arm waiving it’s time to gather the goods.</p>
<p>The tube foot furthest from the feather star’s mouth bends down to get closer to its neighbouring foot, which wraps itself around the first, sweeping it and bringing with it a sticky picnic. The foot below that does the same: wrapping itself around its neighbour and scraping the food off the end. It then delivers the meal to the feather star’s mouth.</p>
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<h2>4. Larvaceans</h2>
<p>There are more animals that make the most of mucus to catch a meal, such as larvaceans. They tend to be a few centimetres long and look a lot like a tadpole, with a round body at one end and a long tail at the other. On their own they are not the most inspiring of creatures, but the way they dine is definitely worth a mention.</p>
<p>Each larvacean builds it’s own mucus house that serves as a filter for the ocean’s fine foods. Their beating tail creates a current that keeps this sticky net open and brings in the grub. To deal with filters getting clogged, larvaceans simply throw out the old house and create a new one roughly every hour, ready to trap more tasty morsels.</p>
<p>The discarded house goes on to make a delicious meal for deep sea animals, rapidly falling to the deep ocean because all the trapped material makes it pretty heavy. Most material falls slowly to the deep – and it’s often eaten up on the way, but larvacean creations fall so fast that deep sea critters can enjoy a packed lunch of pretty fresh food. </p>
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<h2>5. Humpback whales</h2>
<p>Humpback whales form groups and then carefully coordinate, blowing bubbles to corral schools of fish together into one spot. Once the schools are combined into one big ball of lunch, the whales swim upwards through the school of fish with their mouths open.</p>
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<h2>6. Sea star</h2>
<p>Imagine a mussel feeling safe and secure in its shell. Suddenly, a purple sea star appears and starts prying open that shell, showing every intention of eating the tiny creature inside.</p>
<p>The good news is, mussel muscles are very strong so the sea star can only open the shell of its intended victim a tiny bit. The bad news is, sea stars have the ability to invert their stomachs. Even though it has only opened he mussel’s shell slightly, it can push its stomach out of its body through the tiny space, digesting it in its own home.</p>
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<p class="fine-print"><em><span>Jessica Carilli blogs at Saltwater Science (<a href="http://www.nature.com/scitable/blog/saltwater-science">http://www.nature.com/scitable/blog/saltwater-science</a>)</span></em></p>Sea life can be fascinating and terrifying at the same time. Some creatures look beautiful on the outside but harbour darkness within. Some of the scariest tactics of the deep sea go on display when these…Jessica Carilli, Adjunct Professor, University of California, San DiegoLicensed as Creative Commons – attribution, no derivatives.