tag:theconversation.com,2011:/us/topics/kelp-forests-36723/articleskelp forests – The Conversation2023-11-03T08:15:53Ztag:theconversation.com,2011:article/2143892023-11-03T08:15:53Z2023-11-03T08:15:53ZCan we eat our way through an exploding sea urchin problem?<figure><img src="https://images.theconversation.com/files/557013/original/file-20231101-21-pz1lh7.PNG?ixlib=rb-1.1.0&rect=3%2C11%2C2583%2C1082&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">John Keane on an extensive urchin barren</span> <span class="attribution"><span class="source">John Keane</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Longspined sea urchins are native to temperate waters around New South Wales. But as oceans heat up, their range has expanded more than 650km, through eastern Victoria and south to Tasmania. Their numbers are exploding in the process, clear-felling kelp forests and leaving “urchin barrens” behind.</p>
<p>The species (<em>Centrostephanus rodgersii</em>) is now the single largest and most <a href="https://www.sciencedirect.com/science/article/pii/S0022098111000803">urgent threat</a> to kelp forests along the southeastern coast of Australia’s <a href="https://greatsouthernreef.com/learn">Great Southern Reef</a>. </p>
<p>What can we do? Here’s one excellent solution: eat their roe, a buttery delicacy that can fetch hundreds of dollars per kilogram. Tasmania already has a government-backed urchin fishery. When combined with a mix of other tools, as outlined in <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0011/1623593/IMAS-Submission-to-the-senate-inquiry-on-climate-related-marine-and-invasive-species_Final.pdf">our submission</a> to the invasive marine species <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/Invasivemarinespecies">Senate inquiry</a>, harvesting urchins can put the brakes on this overabundant, range-extending marine species. </p>
<p>Today, the <a href="https://www.aph.gov.au/Parliamentary_Business/Committees/Senate/Environment_and_Communications/Invasivemarinespecies/Report">Senate handed down its findings</a>, identifying <a href="https://parlinfo.aph.gov.au/parlInfo/download/committees/reportsen/RB000056/toc_pdf/Win-winunderouroceansClimate-relatedmarineinvasivespecies.pdf">investment in commercial harvesting</a> as a frontline climate-ready tool to combat the urchin. It presents a win-win opportunity by maximising socioeconomic and environmental returns for kelp ecosystems, while lessening the ongoing cost of control.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/nsLLLT908Kk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Strategies for urchin control.</span></figcaption>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-great-southern-reef-is-in-more-trouble-than-the-great-barrier-reef-201235">The Great Southern Reef is in more trouble than the Great Barrier Reef</a>
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<h2>Dealing with urchins is urgent</h2>
<p><a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15634">Almost 200 marine species</a> have been documented shifting range in Australian seas as climate change heats the oceans. But longspined sea urchins are the most damaging so far. </p>
<p>The waters along hundreds of kilometres of coastline have now warmed above a winter average of 12°C. This is the temperature at which <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2486.2008.01543.x">urchin larvae can develop</a> during spawning. The ocean is warming faster than land, heating at a rate of <a href="https://www.sciencedirect.com/science/article/pii/S0079661123000897">4°C per century</a>.</p>
<p>The Senate inquiry shows the government is listening. The inquiry and accompanying <a href="https://www.aph.gov.au/DocumentStore.ashx?id=7ceb303f-b642-4674-82cc-0195ba034fb3">five-year plan</a> for control methods are based on more than <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0011/1623593/IMAS-Submission-to-the-senate-inquiry-on-climate-related-marine-and-invasive-species_Final.pdf">two decades</a> of scientific research. </p>
<h2>The tragedy of the barrens</h2>
<p>Urchins chew through entire forests of kelp. Once the big kelp is gone, they switch to feeding on tiny encrusting seaweeds that can regrow rapidly and persist in the face of intensive grazing. This creates <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.2013.0269">“hyper-stable” urchin barrens</a>. </p>
<p>The damage is dramatic, with the local loss of <a href="https://link.springer.com/article/10.1007/s00442-008-1043-9">hundreds of kelp-associated species</a> ranging from valuable abalone to the iconic leafy seadragon. </p>
<p>Barrens in southern NSW, eastern Victoria and Tasmania can now be measured in the scale of kilometres, with whole reefs turned into <a href="https://hiddendeserts.com/the-project/">underwater deserts</a>. </p>
<p>They expand fast, too. In Tasmania, early sightings off the northeast in 1978 have turned into a population <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0005/1176026/129569-Resurvey-of-the-Longspined-Sea-Urchin-Centrostephanus-rodgersii-and-associated-barren-reef-in-Tasmania.pdf">estimated at 20 million</a> around the eastern coastline. Barren areas now cover 15% of Tasmanian reefs. If left unchecked, 50% of reef habitat could be lost by the 2030s, as we’ve seen in southern NSW and eastern Victoria. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="diver in a kelp forest looking for sea urchins" src="https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557021/original/file-20231101-21-8uhhst.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Research divers assessing sea urchin spread off St Helens in Tasmania’s northeast.</span>
<span class="attribution"><span class="source">Matt Testoni</span></span>
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<h2>Correcting an imbalance of nature</h2>
<p>Rock lobsters are a natural predator of urchins. They boost <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0008/1556522/Centro_lobster_exp_site_resurvey_final_report.pdf">kelp bed resilience</a> and even prevent barren expansion in some areas off limits to lobster fisheries. </p>
<p>The Tasmanian East Coast Rock Lobster Rebuilding Strategy focuses on rebuilding stocks to help combat the urchin. However, the lobsters’ strong preference for <a href="https://academic.oup.com/icesjms/article/79/4/1353/6565266">local prey</a> such as abalone, their <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0008/1556522/Centro_lobster_exp_site_resurvey_final_report.pdf">negligible capacity to rehabilitate extensive barrens</a> once urchins reach hyperabundance, and high recreational and commercial fisheries value, constrains the scale of effectiveness. </p>
<p>Another option is culling, where divers kill urchins underwater. The upshot is that kelp can grow back quickly, within just 18 months, if all visible urchins are culled. But it’s <a href="https://www.frdc.com.au/sites/default/files/products/2011-087-DLD.pdf">extremely expensive</a> and urchins can reemerge, meaning culling needs to be ongoing. </p>
<h2>An affordable, scalable, long-term solution?</h2>
<p>Yes. Make it profitable. The main game here isn’t the urchins themselves but their roe, known as “uni” in Japan. Urchin roe is a delicacy, renowned for its sweet, buttery, umami flavours and bright golden colour. Premium roe returns top dollar in markets from across South East Asia, the United States and the Middle East.</p>
<p>If commercial fisheries are viable, we can remove vast quantities of urchins from reefs in a low-cost urchin control program over large areas. </p>
<p>But there are challenges here too. Extracting the roe is labour-intensive. Roe quality can vary greatly, dropping as overgrazing ensues. To date, infrastructure, access to markets, and detailed knowledge of processing techniques has been a limiting factor. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A commercial diver bags a haul of sea urchins destined for international markets" src="https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556999/original/file-20231101-15-pghp65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A commercial diver removes a haul of sea urchins destined for international markets.</span>
<span class="attribution"><span class="source">Matt Testoni</span></span>
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</figure>
<p>Tasmania is showing it can be done. In 2018, the state government invested in a <a href="https://fishing.tas.gov.au/community/long-spined-sea-urchin-management/abalone-industry-reinvestment-fund">fledgling urchin fishery</a> in conjunction with the abalone industry by offering <a href="https://tasfisheriesresearch.org/wp-content/uploads/2022/11/Cresswell-et-al.-Centrostephanus-Subsidy-Program-Initial-Evaluatio.pdf">harvest subsidies</a>.</p>
<p>These gave urchin processors the financial certainty to invest. In a few years, annual urchin fishery yields have grown from <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0010/1659268/TASMANIAN-LONGSPINED-SEA-URCHIN-FISHERY-ASSESSMENT-2021-22.pdf">40 tonnes to 500 tonnes</a>, all harvested by hand by divers.</p>
<p>To date, the fishery has created more than 100 jobs and boosted regional economies. It’s <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0011/1623593/IMAS-Submission-to-the-senate-inquiry-on-climate-related-marine-and-invasive-species_Final.pdf">starting to work too</a>. The fishery has not only slowed the expansion of urchin barrens, but allowed recovery of kelp habitats in some heavily fished areas. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sea-urchins-have-invaded-tasmania-and-victoria-but-we-cant-work-out-what-to-do-with-them-194534">Sea urchins have invaded Tasmania and Victoria, but we can’t work out what to do with them</a>
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</em>
</p>
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<h2>Expanding urchin fisheries</h2>
<p>Tasmania’s example shows the potential of fishery-led control of overabundant, problematic species. Making the most of it means adding value, such as by expanding the international market, developing new uses for low-grade urchin roe and <a href="https://www.mdpi.com/2073-4395/12/12/2919">selling waste products</a>. If it’s more profitable, divers will be able to travel farther from port and fish down urchin stocks.</p>
<p>We can also direct fishery efforts for better urchin control by offering subsidies to <a href="https://www.imas.utas.edu.au/__data/assets/pdf_file/0010/1659268/TASMANIAN-LONGSPINED-SEA-URCHIN-FISHERY-ASSESSMENT-2021-22.pdf">fish high priority areas</a>. </p>
<p>Other states hit hard by urchins too, such as Victoria, could benefit from control-by-fishery. </p>
<p>Achieving national, widespread urchin control will require challenging coordination. We need to:</p>
<ul>
<li>support dive fisheries to become the heavy lifter of urchin control</li>
<li>add <a href="https://www.youtube.com/watch?v=vFbB0bPHUDQ">extra urchin control measures</a> on high-value reefs</li>
<li>begin restoring degraded barrens to a mosaic of urchin fisheries or kelp forests</li>
<li>boost populations of urchin predators on healthy reefs, to increase resilience in the first place.<br></li>
</ul>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo showing a healthy kelp ecosystem" src="https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557026/original/file-20231101-19-e51xgv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Healthy kelp ecosystems are vital for abalone.</span>
<span class="attribution"><span class="source">Matt Testoni</span></span>
</figcaption>
</figure>
<p>If we do this right, Australia’s control of the longspined sea urchin could be a global exemplar of <a href="https://www.climatereadyaustralia.com.au/">climate-ready</a> management of overabundant and range extending species, boosting <a href="https://www.frdc.com.au/project/2014-301">rural economies</a> and <a href="https://www.csiro.au/en/research/natural-environment/land/regional-prosperity">social wellbeing</a>. As species keep moving, finding low- or zero-cost control measures will be essential to keeping ecosystems intact. </p>
<p>Controlling troublesome species is often seen as a major cost to government. Our work and the work of many others has shown it doesn’t have to be. Creating viable urchin fisheries turns a cost into a benefit. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/marine-species-are-being-pushed-towards-the-poles-from-dugong-to-octopuses-here-are-8-marine-species-you-might-spot-in-new-places-207115">Marine species are being pushed towards the poles. From dugong to octopuses, here are 8 marine species you might spot in new places</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/214389/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Keane receives funding from the Fisheries Research Development Corporation and the Tasmanian Government.</span></em></p><p class="fine-print"><em><span>Scott Ling receives funding from the Australian Research Council. </span></em></p>Controlling invasive sea urchins is expensive. Why not make it profitable by fishing for them and selling their roe as a delicacy?John Keane, Research Fellow (Dive Fisheries), University of TasmaniaScott Ling, Associate professor, University of TasmaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2129562023-09-12T01:26:13Z2023-09-12T01:26:13ZNZ’s vital kelp forests are in peril from ocean warming – threatening the important species that rely on them<figure><img src="https://images.theconversation.com/files/546764/original/file-20230906-15-pjv6o8.JPG?ixlib=rb-1.1.0&rect=21%2C109%2C3620%2C2621&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Christopher Cornwall</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Years of almost non-stop marine heatwaves are stressing New Zealand’s kelp forests. But as we show in our new <a href="https://www.tandfonline.com/doi/full/10.1080/0028825X.2023.2245786">research</a>, ongoing ocean warming is only one of several threats to these unique and important coastal seaweed ecosystems.</p>
<p>Many seaweed species are sensitive to changes in the ocean’s acidity and coastal “darkening” – changes in colour and clarity – is forcing some to retreat to shallower waters. All these stress factors combined place these crucial habitats in peril, with consequences for all species that depend on them.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1699221261497561442"}"></div></p>
<p>New Zealand has the ninth longest coastline in the world (at about 15,000 kilometres). This is almost twice the length of Australia’s great southern reef, which has been <a href="https://www.publish.csiro.au/mf/mf15232">valued</a> at AUS$10 billion annually. </p>
<p>No equivalent valuation has been calculated for New Zealand’s seaweed-dominated rocky reefs, but we know they provide crucial habitat for economically and culturally important species such as pāua (abalone), kina (sea urchins), rock lobster and near-shore finfish.</p>
<p>Our ability to predict the future impacts on these species depends on our understanding of how the coastal habitats they require are changing. </p>
<h2>Rising heat and dimming light</h2>
<p>New Zealand’s seaweed ecosystems include canopy-forming large brown algae as well as several understorey species. Driven by rising ocean temperatures, more frequent, intense and longer marine heatwaves already place these kelp forests under thermal stress. </p>
<p>We predict that marine heatwaves will change the range and basic physiology of many seaweed species, removing sensitive ones from the northern edges of their <a href="https://www.frontiersin.org/articles/10.3389/fmars.2021.721087/full">ranges</a> and slowing growth rates of most. </p>
<p>Seaweeds require sunlight to photosynthesise and grow. But increasingly frequent erosion events from extreme weather like cyclone Gabrielle raise sediment levels in coastal seawater, leading to coastal darkening.</p>
<figure class="align-center ">
<img alt="An underwater image of a site with few, smaller seaweeds." src="https://images.theconversation.com/files/546765/original/file-20230906-35257-qps39o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546765/original/file-20230906-35257-qps39o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546765/original/file-20230906-35257-qps39o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546765/original/file-20230906-35257-qps39o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546765/original/file-20230906-35257-qps39o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546765/original/file-20230906-35257-qps39o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546765/original/file-20230906-35257-qps39o.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">Coastal darkening results in reduced cover of large brown algae, including kelp and native fucoids.</span>
<span class="attribution"><span class="source">Christopher Cornwall</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Sediment running off the land, made worse by storm events, has already lowered photosynthetic rates of seaweeds in several regions. New Zealand’s geologically young landmass is eroding rapidly in some areas and research shows seaweed communities are <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15837">creeping further up the reef</a> into shallow waters. They can no longer survive in deeper reefs because of low light. </p>
<p>This darkening will intensify if we don’t halt erosion and remediate lands. The effects of sedimentation have likely already limited the distribution of some seaweeds and will continue to do so in future.</p>
<h2>When the sea becomes more acidic</h2>
<p>Ocean acidification, which makes seawater more acidic because of the excess carbon dioxide it is absorbing, threatens the ability of calcareous seaweeds to grow. It puts the survival of sensitive coralline algae (the pink algae covering coastal rocky reefs) at <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15899">risk</a>, slowing their growth and ability to spread to new space. </p>
<figure class="align-center ">
<img alt="An underwater image of pink encrusting algae." src="https://images.theconversation.com/files/546763/original/file-20230906-26-qy5q2k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546763/original/file-20230906-26-qy5q2k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546763/original/file-20230906-26-qy5q2k.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546763/original/file-20230906-26-qy5q2k.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546763/original/file-20230906-26-qy5q2k.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546763/original/file-20230906-26-qy5q2k.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546763/original/file-20230906-26-qy5q2k.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">Coralline algae provide a surface for pāua larvae to settle on but they are extremely sensitive to ocean acidification.</span>
<span class="attribution"><span class="source">Christopher Cornwall</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>These red seaweeds form skeletons made of calcium carbonate and represent the seaweed group most sensitive to ocean acidification. Within coralline algae, some species are more sensitive than others. </p>
<p>In New Zealand, coralline algae provide important surfaces for larval settlement of many species, including pāua and kina. Whether the species of coralline algae that provide vital settlement substrates are sensitive or robust to ocean acidification remains unknown.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ocean-acidification-will-increase-the-iodine-content-of-seaweeds-and-the-billions-of-people-who-eat-them-106568">Ocean acidification will increase the iodine content of seaweeds – and the billions of people who eat them</a>
</strong>
</em>
</p>
<hr>
<h2>Ecological impacts on seaweed ecosystems</h2>
<p>Seaweed communities provide enormous benefits to New Zealand. They provide food and habitat for several marine invertebrates and finfish species of both cultural and commercial value, including pāua, kina, moki, snapper, rocklobster, blue cod and butterfish. </p>
<p>If seaweed ecosystems are altered, these species will experience changes in food supply and habitat availability.</p>
<figure class="align-center ">
<img alt="A giant kelp forest in Wellington Harbour, which provides both food and shelter for other species." src="https://images.theconversation.com/files/546766/original/file-20230906-28-rad0l9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546766/original/file-20230906-28-rad0l9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546766/original/file-20230906-28-rad0l9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546766/original/file-20230906-28-rad0l9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546766/original/file-20230906-28-rad0l9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546766/original/file-20230906-28-rad0l9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546766/original/file-20230906-28-rad0l9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A giant kelp forest in Wellington Harbour.</span>
<span class="attribution"><span class="source">Valerio Micaroni</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Giant kelp (<em>Macrocystis pyrifera</em>) and bull kelp (<em>Durvillaea spp.</em>) are important habitat formers and food suppliers for other species. But they are also extremely sensitive to the impacts of temperature stress. </p>
<p><a href="https://www.frontiersin.org/articles/10.3389/fmars.2019.00084/full">Marine heatwaves</a> and ongoing <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0278268">ocean warming</a> likely threaten them throughout their ranges, especially at their northern limit. </p>
<h2>Shifting population ranges and invasions</h2>
<p>Warming oceans also facilitate the spread of Australian long-spined urchins (<em>Centrostephanus rodgersii</em>) which will threaten seaweed communities in northern New Zealand. </p>
<p>Populations of this warm-water species have already expanded in some parts of New Zealand, similar to Tasmania where it invaded during the 1950s and caused widespread “urchin barrens” where the urchins graze through kelp beds, leaving few seaweeds.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sea-urchins-have-invaded-tasmania-and-victoria-but-we-cant-work-out-what-to-do-with-them-194534">Sea urchins have invaded Tasmania and Victoria, but we can’t work out what to do with them</a>
</strong>
</em>
</p>
<hr>
<p>New Zealand is home to around <a href="https://www.tepapa.govt.nz/about/te-papa-press/natural-history/new-zealand-seaweeds-illustrated-guide-0">1,100 species of seaweeds</a>. Many are poorly documented and with unknown ranges. </p>
<p>The combined effects of climate change will likely result in the extinction of some species with very narrow ranges. This is especially true for species that are sensitive to changes in light or temperature and currently live near the edges of their physiological limits. </p>
<figure class="align-center ">
<img alt="An underwater image of a small read seaweed." src="https://images.theconversation.com/files/546767/original/file-20230906-23-qpz8ds.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546767/original/file-20230906-23-qpz8ds.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546767/original/file-20230906-23-qpz8ds.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546767/original/file-20230906-23-qpz8ds.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546767/original/file-20230906-23-qpz8ds.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546767/original/file-20230906-23-qpz8ds.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546767/original/file-20230906-23-qpz8ds.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">Many of New Zealand’s seaweeds are small red algae with poorly described ranges.</span>
<span class="attribution"><span class="source">Christopher Cornwall</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>To add to all of this, we don’t know how the impacts of the invasive caulerpa seaweeds <a href="https://www.mpi.govt.nz/biosecurity/exotic-pests-and-diseases-in-new-zealand/pests-and-diseases-under-response/exotic-caulerpa-seaweeds-caulerpa-brachypus-and-caulerpa-parvifolia-in-new-zealand/"><em>Caulerpa brachypus</em> and <em>Caulerpa parvifolia</em></a> will interact with climate change.</p>
<p>The degradation of coastal ecosystems is another reminder that we must move to eliminate the use of fossil fuels, as well as limiting overfishing and sedimentation. </p>
<p>There is potential to breed high-temperature, low-light and low-pH resistant strains of major species to help restore these ecosystems in the future, but we need strategic government investment in integrated coastal management and climate adaptation to save them in the first place.</p><img src="https://counter.theconversation.com/content/212956/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Cornwall receives funding from The Tertiary Education Commission of New Zealand, Victoria University of Wellington, The French Embassy in New Zealand, Mountains to the Sea Wellington, and Te Apārangi The Royal Society of New Zealand. </span></em></p><p class="fine-print"><em><span>Wendy Nelson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New Zealand’s kelp forests provide food and shelter for many marine species of commercial and cultural value. But they are at risk from warming oceans, run-off from land and marine invaders.Christopher Cornwall, Lecturer, Te Herenga Waka — Victoria University of WellingtonWendy Nelson, Senior Research Fellow, Auckland War Memorial MuseumLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2039082023-04-18T20:01:01Z2023-04-18T20:01:01ZA forgotten and neglected ecosystem covers a third of Earth’s coastlines, with a collective value of $500 billion<figure><img src="https://images.theconversation.com/files/521495/original/file-20230418-20-ivxgck.jpg?ixlib=rb-1.1.0&rect=67%2C40%2C2874%2C1935&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Joe Belanger/Shutterstock</span></span></figcaption></figure><p>Underwater forests known as kelp have been sustaining people and cultures for millennia. However, most of us are only vaguely aware of the vibrant masses of seaweed hugging the ocean shores around Earth. Furthermore, we don’t realise how valuable and necessary they really are.</p>
<p>In a new study <a href="https://doi.org/10.1038/s41467-023-37385-0">published today in Nature Communications</a>, we have produced the first global estimate of the economic value of kelp forests – revealing they provide hundreds of billions of dollars in value to humans across the world.</p>
<h2>A human history of kelp</h2>
<p>Along the Pacific, kelp harvest has long played an important role in Asian societies. In Japan, seaweed was among the marine products people could use to pay taxes, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/raq.12524">according to a law code from the year 701</a>.</p>
<p>In Medieval Europe, kelp was used to fertilise soil and increase crop yields, to treat <a href="https://www.healthdirect.gov.au/goitre#:%7E:text=Goitre%20is%20an%20enlarged%20thyroid,hard%20to%20breathe%20or%20swallow.">goitre</a>, and was used to fortify building materials <a href="https://link.springer.com/chapter/10.1007/978-94-009-4057-4_24">for centuries</a>. In the 21st century kelp forests have become the <a href="https://link.springer.com/chapter/10.1007/978-981-10-6910-9_2">main source for alginate</a>, a common food and medical additive.</p>
<p>And throughout this time, kelps have supported <a href="https://www.cambridge.org/core/journals/environmental-conservation/article/kelp-forest-ecosystems-biodiversity-stability-resilience-and-future/105EB05670376912F180E116D64135D6">teeming ecosystems</a> and important <a href="https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.12483">fisheries</a> of abalone, lobsters and many different types of fishes. Through their prolific productivity, kelp forests <a href="https://link.springer.com/article/10.1007/s12601-015-0001-9">draw carbon from the atmosphere</a>, exude oxygen, and help reduce <a href="https://www.int-res.com/abstracts/meps/v531/p155-166/">nutrient pollution in our oceans</a>.</p>
<p>A marine marvel, hidden kelp forests spread across <a href="https://www.researchgate.net/publication/327606143_Status_and_Trends_for_the_World%27s_Kelp_Forests">almost one third of our world’s coastlines</a> and lie within 50km of 740 million people. If you live in London, Tokyo, New York, Vancouver, Santiago, Cape Town, Los Angeles or Lisbon, you have one of these ecosystems on your doorstep.</p>
<p>Yet they tend to be forgotten or misunderstood. People often aren’t even aware of a kelp forest, and if they are, they might be most familiar with a pile of decomposing seaweed on the beach after a storm.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An underwater view of seaweed in blue water with fishes swimming through" src="https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521237/original/file-20230417-22-w9r1p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A kelp forest is a rich habitat, a provider of oxygen and a sequester of carbon.</span>
<span class="attribution"><span class="source">Andrew b Stowe/Shutterstock</span></span>
</figcaption>
</figure>
<p>This disconnect has real-world implications. Despite sitting next to some of the biggest research centres on the planet and likely covering <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/geb.13515">more seafloor than any other biotic habitat</a>, research and conservation of kelp forests is <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/jpy.13239">terribly behind</a> other ecosystems.</p>
<p>This knowledge gap impedes desperately needed action and conservation. Kelp populations in <a href="https://www.nature.com/articles/s41598-019-51114-y">northern California</a>, <a href="https://www.int-res.com/abstracts/meps/v653/p1-18/">Tasmania</a>, and the <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0229703">Salish Sea</a> have all but disappeared in living memory. Elsewhere, kelp populations have been <a href="https://www.pnas.org/doi/10.1073/pnas.1606102113">continually declining</a> over the last 50 years.</p>
<p>What we value and how we value it is actually quite a complicated process. And despite the fact we make value judgements over and over each day, we have a really poor understanding of something’s value if it doesn’t have a price tag on it.</p>
<p>Our natural world is perhaps the ultimate value provider – everything we do in our societies is ultimately tied to nature, ecosystems, and a healthy planet. But because these processes and benefits happen with or without humans, they are often taken for granted.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A white sandy beach with masses of black seaweed lying in the sun" src="https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521236/original/file-20230417-24-w9r1p8.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 seaweed we step over on our beaches is just a small fraction of the vibrant kelp ecosystems beneath the waves.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/1Y-x8lPnqDU">Andrew Dawes/Unsplash</a></span>
</figcaption>
</figure>
<h2>So, what is the ‘value’ of a kelp forest?</h2>
<p>Our research has brought together data from all across our oceans to produce a global estimate of the economic value of kelp forest ecosystems. Looking at six key genera of kelp – <em>Macrocystis</em>, <em>Nereocystis</em>, <em>Laminaria</em>, <em>Saccharina</em>, <em>Ecklonia</em>, and <em>Lessonia</em> – and the potential economic value of the fisheries they support, the carbon they pull from the atmosphere, and the nutrient pollution they remove from the water, we found that kelp forests are valued at US$500 billion per year.</p>
<p>The highest of these values was the removal of excess nitrogen from the water, which can trigger blooms of algae, reduced water quality, and <a href="https://www.usgs.gov/mission-areas/water-resources/science/nutrients-and-eutrophication">ultimately oxygen-depleted dead zones</a>.</p>
<p>A close second was the fisheries values – kelp forests support some of our most iconic fisheries, including lobster and abalone.</p>
<p>Lastly, despite finding the carbon sequestration of kelp forests was comparable to other terrestrial and marine ecosystems, the economic value was much lower, as society has yet to place a high price on carbon. This finding suggests that carbon credits may not be an economic driver of kelp conservation, but kelp forests still play an important role in the blue carbon cycle.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An orange fish with a long snout and limbs swimming among kelp" src="https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=405&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=405&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=405&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521498/original/file-20230418-14-zqggqg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Weedy seadragons are just one of many fishes living in kelp forests.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/johnwturnbull/41749070410/in/album-72157703596928075/">John Turnbull/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>The future of kelp</h2>
<p>When nature is treated as a freebie, where we can take what we want and not pay for the damages, this attitude has direct consequences; people and the environment suffer.</p>
<p>First, it can mean that people and government don’t see the value in protecting and restoring ecosystems. Second, development projects are <a href="https://theconversation.com/environment-laws-have-failed-to-tackle-the-extinction-emergency-heres-the-proof-122936">able to destroy nature</a> without compensating for those damages.</p>
<p>Lastly, it leads to poor management. How can we manage something if we cannot quantify it? Imagine if you didn’t know where your bank account was, or how much money was in it.</p>
<p>The battle to save our kelp forests is just getting started, and we need greater action to protect these intrinsically and economically valuable marine ecosystems.</p>
<p>That is why researchers like me have started the not-for-profit <a href="https://kelpforestalliance.com/who-we-are">Kelp Forest Alliance</a>, and have now launched the <a href="https://kelpforestalliance.com/kelp-forest-challenge">Kelp Forest Challenge</a>, a global call to protect and restore 4 million hectares of kelp forest by 2040. This is a call for governments to meet their commitments to the <a href="https://www.unep.org/resources/kunming-montreal-global-biodiversity-framework">Kunming-Montreal Global Biodiversity Framework</a> and act now to save these ecosystems and #HelpTheKelp.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whether-youre-a-snorkeller-or-ceo-you-can-help-save-our-vital-kelp-forests-202620">Whether you're a snorkeller or CEO, you can help save our vital kelp forests</a>
</strong>
</em>
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<img src="https://counter.theconversation.com/content/203908/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aaron Eger is the Founder and Program Director of the Kelp Forest Alliance, a research driven not-for-profit organization. He is also a Postdoctoral Research Fellow at the University of New South Wales Sydney. The Kelp Forest Alliance is supported by the Nature Conservancy, The Banner Foundation, the Van Dyson Foundation, and UNSW Sydney.</span></em></p>We cannot afford to ignore kelp – these vibrant underwater forests have sustained people and ecosystems for centuries, and continue to do so today.Aaron Eger, Postdoctoral research fellow, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2026202023-03-30T04:04:02Z2023-03-30T04:04:02ZWhether you’re a snorkeller or CEO, you can help save our vital kelp forests<figure><img src="https://images.theconversation.com/files/518366/original/file-20230330-21-mdwwxo.jpg?ixlib=rb-1.1.0&rect=40%2C8%2C5422%2C3628&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>What if we told you the world has forests harbouring creatures with three hearts and where the canopy can grow by a foot a day? What if we told you it was silently disappearing? What if we told you we now have the chance to bring it back?</p>
<p>These wonder-filled and remarkably productive ecosystems are kelp forests. They wrap around <a href="https://www.researchgate.net/publication/327606143_Status_and_Trends_for_the_World%27s_Kelp_Forests">almost a third</a> of the world’s coastlines. If you live in New York, Los Angeles, Sydney or Tokyo, you can snorkel over a kelp forest on a day trip, and potentially spot a seahorse or three-hearted octopus. </p>
<p>Kelp forests have even influenced human migration patterns. The so-called “<a href="https://www.tandfonline.com/doi/full/10.1080/15564890701628612">kelp highway</a>” suggests the first Americans settled on the continent by following the kelp-dominated coastline of the Pacific Rim, feeding on plentiful fish and molluscs. </p>
<p>But these vast forests of the sea are little known compared to coral reefs. That’s a tragedy, given they support some of our most lucrative fisheries such as lobster and abalone, house thousands of species, and can capture great amounts of carbon. </p>
<p>Kelp forests are dying at a rate similar to <a href="https://onlinelibrary.wiley.com/doi/10.1111/jpy.13239">coral reefs or rainforests</a>. In some areas, we have seen near total loss of kelp forests in living memory, and sometimes in just a few years. This includes losing 95% of bull kelp in northern California and 95% of giant kelp <a href="https://theconversation.com/can-selective-breeding-of-super-kelp-save-our-cold-water-reefs-from-hotter-seas-170271">in Tasmania</a>.</p>
<p>But this is not a bad news story. This is about you and your ability to help. You might think – what can I do? I’m not a scientist. But all around the world, communities and individuals are working to restore these ecosystems. It might be planting out baby kelp with mask and snorkel, removing destructive sea urchin swarms or even creating art to draw attention to these forgotten forests. </p>
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<img alt="Scuba diver planting kelp forest underwater" src="https://images.theconversation.com/files/517601/original/file-20230327-28-y6a0wp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517601/original/file-20230327-28-y6a0wp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517601/original/file-20230327-28-y6a0wp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517601/original/file-20230327-28-y6a0wp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517601/original/file-20230327-28-y6a0wp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517601/original/file-20230327-28-y6a0wp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517601/original/file-20230327-28-y6a0wp.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">
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<span class="caption">This diver is replanting a kelp forest.</span>
<span class="attribution"><span class="source">John Turnbull</span></span>
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<h2>From citizen science to community-led recovery</h2>
<p>This year, we issued the <a href="https://kelpforestalliance.com/kelp-forest-challenge">Kelp Forest Challenge</a> to communities around the world: let’s aim to protect 3 million hectares of surviving kelp and restore one million more hectares by 2040.</p>
<p>A task this size can’t be achieved just by scientists and researchers. We need communities to play an active part. Just as people turn out in droves for Clean Up Australia Day to replant native plants along creeks or fish out introduced carp, we believe community backing is the only way we will be able to regenerate the oceans.</p>
<p>We’re not alone in this. Many other groups are looking to community help to expand restoration efforts. Think of South Australia’s <a href="https://ozfish.org.au/projects/seeds-for-snapper-south-australia/">Seeds for Snapper program</a>, which relies on beachcombers collecting seagrass fruit to aid replanting of the seagrass meadows which act as fish nurseries. </p>
<p>The stakes are high. Last year, nations signed the Kunming-Montreal <a href="https://www.cbd.int/article/cop15-final-text-kunming-montreal-gbf-221222">biodiversity pact</a>, which included pledging to protect 30% of the world’s oceans by 2030. </p>
<p>We have to ensure our remaining kelp forests are covered. At present, very few kelp forests have any measure of protection. They’re often forgotten or excluded from marine management plans.</p>
<p>But they are vital. Australia’s Great Southern Reef, for instance, is the <a href="https://www.science.org.au/curious/earth-environment/whos-heard-great-southern-reef#:%7E:text=The%20Great%20Southern%20Reef%20is,to%20Kalbarri%20in%20Western%20Australia.">kelp counterpart</a> to the far better known Great Barrier Reef. Where the coral peters out in northern New South Wales, the kelp starts, spanning thousands of kilometres across Australia and stopping only in Kalbarri, Western Australia. </p>
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Read more:
<a href="https://theconversation.com/the-great-southern-reef-is-in-more-trouble-than-the-great-barrier-reef-201235">The Great Southern Reef is in more trouble than the Great Barrier Reef</a>
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<p>Some countries are tackling this at a national level. South Korea <a href="https://kelpforestalliance.com/restoration-projects/korea-fisheries-resources-agency-fira-south-korea">has pledged</a> to restore an additional 30,000 hectares of kelp forest by 2030. We now need other countries to follow suit.</p>
<p>Yet, there are many ways to help kelp. In Tasmania, for instance, the government subsidised a <a href="https://fishing.tas.gov.au/community/long-spined-sea-urchin-management/long-spined-sea-urchin-strategy">sea urchin fishery</a>. Why? Because as climate change brings warmer waters, kelp-munching, long-spined sea urchins have migrated from the mainland and now number in the millions. Recreational divers have also been asked to help by removing urchins they spot. </p>
<h2>Is it possible?</h2>
<p>Stopping environmental collapse can seem like an impossible task. But take heart. Remember – we’ve already overcome other seemingly unachievable conservation challenges.</p>
<p>We once used whale oil to fuel our lamps, soap up in the bath and even make sandwiches. But our demand for this oily product soon outstripped supply. Whalers with harpoons drove them almost to extinction. Once considered inexhaustible, humpbacks were hunted down to <a href="https://www.elsevier.com/books/encyclopedia-of-marine-mammals/wursig/978-0-12-804327-1">just 5%</a> of their previous population size. </p>
<p>This ecological tragedy gave way to one of our <a href="https://theconversation.com/the-big-comeback-its-time-to-declare-victory-for-australian-humpback-whale-conservation-44970">greatest conservation successes</a>. After getting together, coordinating and acting, we banned whaling. The humpback population has soared to <a href="https://www.iucnredlist.org/species/13006/50362794#population">over 135,000</a>.</p>
<p>In this case, simply stopping what we were doing allowed the whales to rebound from near extinction. But we’re not so lucky with our kelp forests.</p>
<p>We have tried cleaning up water pollution, removing pest species and even stopping local harvests. But in many cases, stopping the original cause of decline hasn’t been enough to entice these ecosystems to return. This sobering fact means it’s time to put on our wetsuits and get to work actively restoring undersea forests.</p>
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<p>So what can you do? </p>
<p>Do you run a business? Stopping pollution from flowing into rivers is one way to help kelp, as well as avoiding development in sensitive coastal areas. </p>
<p>Even better, some businesses are moving towards being nature positive. That is, their work regenerates nature rather than depletes it. Think of the people in Moreton Bay fisheries active in <a href="https://ozfish.org.au/projects/moreton-bay-shellfish-reef-restoration/">restoring local oyster reefs</a>. </p>
<p>Tech companies can help by monitoring marine forest health. Kelp farmers can provide seed stock and baby kelp for restoration. Tourism operators can promote kelp forests and their creatures – think of the <a href="https://www.whyalla.com/cuttlefish">growing fame</a> of the giant cuttlefish breeding season in Whyalla. </p>
<p>And if you’re a keen community member? You can help by volunteering your time with citizen science projects like the <a href="https://reeflifesurvey.com/">Reef Life Survey</a>, forming community groups to steward and protect your patch of the ocean or contributing to existing restoration projects like Sydney’s <a href="http://www.operationcrayweed.com/">Operation Crayweed</a>.</p>
<p>We can no longer rely on the oceans to heal themselves. We’ll need help from all levels of society to make it happen.</p>
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Read more:
<a href="https://theconversation.com/can-selective-breeding-of-super-kelp-save-our-cold-water-reefs-from-hotter-seas-170271">Can selective breeding of 'super kelp' save our cold water reefs from hotter seas?</a>
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<img src="https://counter.theconversation.com/content/202620/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aaron Eger is the Founder and Program Director of the Kelp Forest Alliance, a research driven not-for-profit organization. The Kelp Forest Alliance is supported by the Nature Conservancy, The Banner Foundation, the Van Dyson Foundation, and UNSW Sydney.</span></em></p><p class="fine-print"><em><span>Adriana Vergés is one of the lead scientists of Operation Crayweed, a kelp restoration project that has received funding from the Australian Research Council, the NSW Fishing Trust, the NSW Environmental Trust, Sustainable Surf and Patagonia as well as private philanthropists. She is one of the Directors of the Kelp Forest Alliance, a newly established not-for-profit organisation. The Kelp Forest Alliance is supported by The Nature Conservancy, the Banner Foundation, the Van Dyson Foundation and UNSW Sydney.</span></em></p>When we stopped whaling, the whales recovered. But our vital kelp forests won’t return without our helpAaron Eger, Postdoctoral research fellow, UNSW SydneyAdriana Vergés, Professor in marine ecology, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1565262021-03-05T17:51:30Z2021-03-05T17:51:30ZClimate change is flooding the Arctic Ocean with light – what it means for the species that live there<p><em>This is a transcript of episode 5 of The Conversation Weekly podcast, <a href="https://theconversation.com/diving-in-the-icy-depths-the-scientists-studying-what-climate-change-is-doing-to-the-arctic-ocean-the-conversation-weekly-podcast-156417">How climate change if flooding the Arctic Ocean with light</a>. In this episode, two experts explain how melting ice in the far north is bringing more light to the Arctic Ocean and what this means for the species that live there. And we hear from a team of archaeologists on their new research in Tanzania’s Olduvai Gorge that found evidence of just how adaptable early humans were to the changing environment.</em> </p>
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<p><em>NOTE: Transcripts may contain errors. Please check the corresponding audio before quoting in print.</em></p>
<p>Dan Merino: Hello and welcome back. From The Conversation, I’m Dan Merino in San Francisco. </p>
<p>Gemma Ware: And I’m Gemma Ware in London and you’re listening to <a href="https://theconversation.com/global/topics/the-conversation-weekly-98901">The Conversation Weekly</a>, the world explained by experts. </p>
<p>Dan: In this episode, two Arctic Ocean researchers explain how melting ice in the far north leads to more light in the Arctic – and what that means for sea life.</p>
<p>Karen Filbee-Dexter: Our ecosystems are responding, because these changes are really dramatic and they’re noticeable. </p>
<p>Gemma: And we talk to a team of archaeologists about the early humans who lived in Tanzania’s Olduvai Gorge 2 million years ago. </p>
<p>Makarius Peter Itambu: In this scenario, hominims from Oldupa maintained the very same toolkit. </p>
<p>Dan: So Gemma, today we’re going on a journey up to just about as far north as we can go, all the way up to the Arctic. What do you imagine when I say the word Arctic? </p>
<p>Gemma: I feel a bit cold already, and I guess I think of big expanses of snow and ice, drifting, like wind. Maybe the odd polar bear. And I guess in winter it’s just dark. </p>
<p>Dan: That’s a great example if you were to stay on top of the ice, but there’s a whole different world beneath it. And it’s full of ocean, like teeming alive. </p>
<p>Gemma: We know climate change is causing some of this ice to melt though, right? </p>
<p>Dan: Yeah totally… well some of the ice melts every summer. The sun’s up and then in winter when the sun goes away it grows back, but that ice is melting much more than it used to. So in September 2020, Arctic sea ice covered <a href="https://www.nasa.gov/feature/goddard/2020/2020-arctic-sea-ice-minimum-at-second-lowest-on-record/">3.74 million square kilometres</a>. </p>
<p>Gemma: Well that sounds like a lot…</p>
<p>Dan: It does. But it’s the second smallest measurement ever. And only roughly half of what was measured in 1980.</p>
<p>Gemma: So what does that melting sea ice mean for all that teeming sea life living in the Arctic Ocean?</p>
<p>Dan: It’s not clear cut… it’s not all bad news even. Different scientists are studying all sorts of changes to see how it’s going to matter for the life in the Arctic, but one of the things they’re looking at is light. If there’s less and less sea ice, more light gets down into the ocean. And in the dark winter, where ice would normally cover the ice caps, it’s not there, so ships are driving through more and more and bringing with them a lot of artificial light. </p>
<p>I spoke to two researchers who’ve been spending a lot of time in the cold icy waters way up north to study all of this. And let’s just let one of them kind of set the scene. So Gemma, and all you listeners out there, imagine you step off a plane in the far, far north. Here’s what you might see.</p>
<p>Karen: So you have these places that are so covered in snow and ice, that they almost have a moon landscape of just bare rock in the summer. No leaves, no forest, no trees. </p>
<p>Dan: That’s Karen Filbee-Dexter, a research fellow at the university of Western Australia and a scientist at the Institute of Marine Research in Norway. She’s talking about the shoreline there. The long dark winters make it so that even in the sunny summer, the landscape is barren. But in the ocean, there’s a very a different story. </p>
<p>Karen: And then you go under water and you have to go a little bit deeper, but when you dive you sort of past this zone, where all of a sudden these amazing underwater forests appear.</p>
<p>Dan: These forests are not made of trees of course, but of kelp, attached to the sea floor, swaying in the currents.</p>
<p>Karen: So you have these long blades that will float in the water column and then they, just like a forest, shade light and create these understory conditions that fish and animals use and live in the same way as a forest does on land. </p>
<p>Dan: And how big are we talking? And I’m thinking Redwood trees, or am I thinking a bush in my yard kind of size?</p>
<p>Karen: It depends on the species and it depends on the forest. So, the first kelp forest that I dove on in the Arctic was about one to two meters tall. And it was actually in Arctic Norway. But the largest kelp forest that I’ve been in the Arctic has been in Canada. So there is an area in Nunavut where the kelp was about three to five meters tall. And that was spectacular.</p>
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Read more:
<a href="https://theconversation.com/arctic-ocean-climate-change-is-flooding-the-remote-north-with-light-and-new-species-150157">Arctic Ocean: climate change is flooding the remote north with light – and new species</a>
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<p>Dan: Until recently, not too much was known about Arctic kelp. What kind grow where, or even how much there is.</p>
<p>Karen and her colleagues at the Arctic Kelp project, an aptly named group of universities, institutions and NGOs across Canada, are trying to catalogue which kelps are growing in the Arctic today, and how the warming temperatures are going to affect where they grow in the future.</p>
<p>Karen has spent a lot of time underwater using scuba gear to study these kelp ecosystems. But for many of these places, you can only access them in the short window when sea ice disappears. </p>
<p>Karen: So that’s what’s incredible about these habitats. They’re covered by ice. For sometimes more than half of the year and they require light to live. So they’re just growing based on light that reaches the sea floor in this very short period when the ice is not there. </p>
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<img alt="A scuba diver swims through kelp fronds." src="https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A diver explores a four-metre-high sugar kelp forest off Southampton Island, Canada.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
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<p>Dan: Kelps, and well, everything in the Arctic Ocean, spend a huge amount of time in the dark, either because it’s winter the sun hasn’t come up for months, or because the sea surface is covered by ice. When the ice melts and daylight returns, kelps grow really fast. They have to, it’s a short growing season.
But that growing season is getting longer. </p>
<p>Karen: What’s happening now in the Arctic is we have this massive and dramatic loss of sea ice. So this means that a large amount of Arctic coastline, which is normally covered in ice and normally doesn’t get that much light is now suddenly sort of open to, to the sun.</p>
<p>Dan: All you gardeners out there will know this equation: more sunlight, more growth. As Arctic temperatures warm due to climate change and sea shrinks, these underwater forests are expanding, and kelp is now growing in places where it didn’t used to. </p>
<p>Karen: So based on, how the conditions have changed from 1950 to now, we can predict that the migration rate in the Arctic is about, 20km per decade. So this sort of poleward expansion is definitely marching along, and there’s all the evidence that these changes are accelerating.</p>
<p>Daniel: 20km per decade is pretty fast for a bunch of trees</p>
<p>Karen: Yes, the marching forest. It is definitely something out of a Lord of the Rings movie. But the rules are different in the Arctic, right? So, so it’s changing much faster than the rest of the world. Everything happening there is happening at, you know, <a href="https://theconversation.com/siberia-heatwave-why-the-arctic-is-warming-so-much-faster-than-the-rest-of-the-world-141455">two to three times</a> the rate of change. So, we’re already way into the climate change future, along our Arctic coastlines. So it’s not surprising that our ecosystems are responding because these changes are really dramatic and they’re noticeable. And they’re going to put a lot of pressure on marine species to move. </p>
<p>Dan: These changes which are causing kelp to expand and move are not good everywhere though. A lot of the Arctic coastline is made of permafrost. </p>
<p>Karen: This is essentially frozen soil. When that frozen soil thaws all of that dirt and sediment just flushes into the coastal zone and creates a lot of turbidity.</p>
<p>Dan: This murky brown water prevents light from reaching the seafloor and the kelps growing there. </p>
<p>Another side effect of climate change is that glaciers and ice sheets are melting and dumping huge amounts of fresh water into coastal areas, that can also harm kelp. </p>
<p>So while not every change is good for kelps and seaweeds way up north, overall Karen says that predictive models show the future is looking pretty good for Arctic kelp forests.</p>
<p>In many other parts of the world, these ecosystems are shrinking, so it’s kind of cool that, as least to some extent, these losses are being offset up north. And a large expansion of underwater kelps might actually help slow climate change ever so slightly.</p>
<p>Just like trees on land, kelps rely on carbon dioxide to grow. Expanding kelp forests in the Arctic could become a pretty significant carbon sink. When these kelps die, they just drift slowly to the deep dark depths of the ocean, and because it’s so cold, they don’t really rot either. Instead, they just sit there, keeping corbon dioxide locked up at the bottom of the ocean. </p>
<p>There are other more tangible benefits to larger kelp forests too. It’s great habitat for marine life. </p>
<p>Karen: They’re going to have a higher canopy height and a higher biomass. This means that there’s more space for animals to live in. So basically more rooms in the house, more structure, more niches for different species to occupy.</p>
<p>It also probably will mean a shift in species. So most seaweeds and most kelps in the Arctic were almost kicked out in the last ice age and then they’ve been slowly inching their way back in. And some of them have done a better job and have adapted to these really extreme conditions, better than others.</p>
<p>Dan: Kelps aren’t the only thing that likes less sea ice. Us humans do as well.
As sea ice decreases in both summer and winter, the formerly dark polar night that last for weeks or months, is now being lit up like never before by boats and the artificial light they bring in with them. This is a big deal to the multitudes of sea creatures that have adapted over millions of years to the darkness of the polar winter. One group of scientists is studying how this new influx of light is changing the behaviour of these animals. </p>
<p>Jørgen Berge: My name is Jørgen Berge, I’m a professor in marine biology at UIT, the Arctic University of Norway.</p>
<p>Dan: Jørgen, unlike most people, doesn’t actually mind the long dark, polar, winter. I spoke to him late last year, when the polar night in Norway had just begun</p>
<p>Jørgen: We actually just started the polar night items sitting now in Tromsø at 70 degrees north. The sun orbits around our horizon for 24 hours a day for two months in a row. There is still clear difference between day and night. But that difference becomes less and less the further north you get. And then once you get up to around 80 degrees, then the human eye is hardly able to distinguish any difference between night and day during the darkest part of the polar night. </p>
<p>But the polar night is certainly not just dark. It’s actually all about different kinds of light. Both background illumination from the sun, the aurora borealis the moon, also biological light.</p>
<p>Dan: Up until fairly recently, scientists used to think that the darkness of the polar night was uninteresting, devoid of life. But a research project that Jørgen started back in 2006 changed all that – and kind of by accident. His team was actually looking at how retreating sea ice would affect the marine ecosystem in an Arctic Fjord.</p>
<p>Jørgen: So we had to be there in the late autumn to deploy instruments that would then be in place and do measurements when the sun came back. But then as more or less a byproduct, the instruments were also doing measurements during the dark polar night. But when we got these data back, we started to realise that, hang on something, something is actually happening here.</p>
<p>Dan: What him and his team found changed scientists’ understanding of the polar night. The polar night isn’t not boring, far from it in fact. </p>
<p>Jørgen: So it’s a system that is in fact in full operation. Seabirds, fishes, zooplankton. It’s just so fascinatingly full of life during the, during the dark polar night. </p>
<p>Dan: One of the processes Jørgen and his colleagues has studied is called diel vertical migration. </p>
<p>Jørgen: That is the behaviour where organisms – zooplankton and fish – they move up from the deep up into the shallow, during nighttime and go migrate down into the deep, during daytime. </p>
<p>Dan: This is entirely controlled by light, so researchers just assumed it would stop. The polar night is just perpetual darkness after all. </p>
<p>Jørgen: It turns out that it doesn’t stop, it’s ongoing. One of the things that we have started to realise is how extremely intimately, these organisms are connected to the light climate, to ambient light. </p>
<p>Dan: Even with the sun gone during the winter months, light plays a huge role in the Arctic. The sun still brightens the sky ever so slightly as the earth rotates. Moon cycles also change light levels, and so does the aurora borealis. And creatures react to all of this. But when Jørgen and his colleagues were studying these creatures, they got conflicting data between the instruments they left alone over one winter and the data they collected from their boats. The reason was light pollution from the researchers themselves.</p>
<p>Jørgen: The first year we really didn’t fully really understand why the samples we took never matched the data that we got from acoustic instruments that had been deployed autonomously. But it turns out that these organisms, they are able to respond to extreme small levels of light.</p>
<p>Dan: Jørgen and his team need, well, light to work on their boat, so they use headlamps and floodlights and stuff. For ultra light-sensitive sea creatures, these lights are huge signals. Some swim towards them, some swim violently away. And not just animals near the surface. The team found this happening down to depths of 200 metres below the sea level. </p>
<p>The effect of light pollution could be happening on a large scale, thanks to melting sea ice and increased human presence. </p>
<p>Jørgen: As sea ice retreats, as we start fishing further north, oil and gas exploration, shipping, not the least, more and more human presence in the high Arctic during the polar night, then we also bring with us artificial lights. At the moment we are not able to, to, to say to which degree this really is a problem, but, that is one of the things that we are now really starting to look into.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large ship covered in yellow lights illuminates the icy water." src="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Creatures which have adapted to the polar night over millions of years are now suddenly exposed to artificial light.</span>
<span class="attribution"><a class="source" href="https://www.michaelosnyder.com/intothedark">Michael O. Snyder</a>, <span class="license">Author provided</span></span>
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</figure>
<p>Dan: And melting sea ice, well that’s climate change.</p>
<p>Jørgen: So artificial light, it’s not of course a direct effect of climate change, but it’s certainly related to climate change because as it gets warmer, as there is less sea ice then we see more human presence and human presence will, it means there’s more artificial lights involved.</p>
<p>Dan: So what does this all mean for the fish, zooplankton and other sea creatures that are super-sensitive to light and live in this high Arctic environment? Jørgen says that’s a difficult question to answer. </p>
<p>Jørgen: Personally, I think that we have to look at the effects in two ways. One is the direct effect of light pollution. It does affect organisms there and then. Most likely that effect is limited, because it only last while there is artificial light there. And there’s certainly a limit to the, the geographical extent of that impact.</p>
<p>However, I think there’s another effect that is much more important. And that is how it’s affecting our knowledge about the polar night. To take one example, there’s more and more fisheries the high Arctic during the polar night. If you want to do surveys to give an estimate about how much there is of say haddock or cod, you have to do acoustic surveys with research vessels in the polar night, in where we are fishing. And these measurements might be strongly biased and impaired. </p>
<p>Dan: Essentially what Jørgen is saying is that every measure of arctic fisheries even taken in winter could be way off. By bringing in light, the fishermen and researchers change how fish and other animals behave. This is one of the oldest problems in biology: how to study ecosystems without disturbing them. And I asked him he feels as a scientist, to discover that his own presence could be distorting the results of his research. </p>
<p>Jørgen: Yeah, it sorta makes you feel unwanted. You know, that your presence is affecting the organisms, but it also, as a scientist, it also makes me, maybe wonder and questions. And I find it fascinating trying to understand things I cannot see. </p>
<p>It’s difficult to explain, but to me, when you really go, go up into the high Arctic and you allow yourself to be in the darkness and you start to take in all the senses, the sounds, the light, it’s just a, just a miracle sometimes.</p>
<p>I can still remember one on the experience we had. This was one of the first years when we were up on Svalbard in, early January, and I was out in a small boat out in the middle of the fjord and we turned off the engines. We turned off all lights because we wanted to look for seabirds. And we looked down and we saw this upside down sky filled with blue-green light, and that was just an amazing experience to see all this organisms from big jellies to small unicellular organisms blinking and glowing and moving in all directions. That was a beautiful sight.</p>
<p>Dan: What Jørgen saw was bio-luminescence – light produced by creatures in the Arctic night to communicate with each other. When you live in total darkness, light is, almost paradoxically, one of the most important and useful things there could possibly be. Even to the scientists who study it, the darkness of the polar night is so much more complex than anyone even imagined.</p>
<p>Gemma: I love the idea of the ocean blinking back at you, that’s just so beautiful as Jørgen said. </p>
<p>Dan: It made me want to take a vacation to the polar night in the middle of winter, which I’d never thought I’d say before. But, it is also dangerous, both Karen and Jørgen were talking about polar bears and how you actually have to carry guns, so it’s not all blinky lights and gorgeousness. </p>
<p>Dan: Both Karen and Jørgen have written for The Conversation as part of a series we’re running called <a href="https://theconversation.com/uk/topics/oceans-21-96784">Oceans 21</a>. It examines the history and future of the world’s oceans. On The Conversation’s website, we’ve actually got a profile of every ocean on earth and Jørgen and Karen contributed to the one on the Arctic. </p>
<p>Gemma: Yes and our environment editors are publishing really important new research on a regular basis about the ocean. They just published another story about a team of scientists <a href="https://theconversation.com/where-does-plastic-pollution-go-when-it-enters-the-ocean-155182">tracking where plastic pollution</a> goes when it enters the water.</p>
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<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">
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<p><strong><em>This research 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 out for new articles on the state of our oceans in the lead up to the UN’s next climate conference, COP26. The series is brought to you by The Conversation’s international network.</em></p>
<p>Dan: We’ve put a link to that, and the Oceans 21 series, in the show notes.</p>
<p>Gemma: Coming up, a group of archaeologists talk to us about some of their recent finds from Tanzania. But first, we’ve got a message with some recommended reading from Laura Hood, politics editor and assistant editor at The Conversation in London.</p>
<p>Laura Hood: Hello. My name is Laura Hood. I’m a politics editor for The Conversation here in London. I’ve got two recommendations this week. I worked with a <a href="https://theconversation.com/conspiracy-theories-start-to-take-hold-at-age-14-study-suggests-156006">team of psychologists led by Daniel Jolley</a> from the University of Northumbria here in the UK. He told me about some work his team has been doing investigating how young people are being affected by conspiracy theories in the pandemic. Before they got in touch. I hadn’t realised that almost everything we know about conspiracy theories is based on work investigating adults. We know next to nothing about how children encounter and absorb misinformation. So they’ve been conducting surveys with British adolescents to try to work out at what age we’re most vulnerable to conspiracy theories and the extent to which young people are being exposed to them during lockdown. It’s really interesting reading, I think, particularly for parents.</p>
<p>I’d also like to recommend an article written by Mark Toshner, he’s an expert in respiratory medicine at the University of Cambridge. He’s <a href="https://theconversation.com/covid-vaccines-how-to-make-sense-of-reports-on-their-effectiveness-155921">put together a guide</a> for anyone who’s feeling a bit overwhelmed by the scientific information that’s flying around about vaccines right now. He says, he feels really sorry for us trying to absorb all this information and he wants to make it a bit easier. So he’s tackling topics such as what it means when we hear that one vaccine is 90% effective, say, or another one is only 70% effective. Is that something we should be worrying about? Should we be trying to pick and choose our vaccines? He’s also talking about what it means for a vaccine to be potentially less effective against particular types of variant of COVID-19. So it’s useful information at this stage of the pandemic. </p>
<p>Daniel: That was Laura Hood from The Conversation in London. </p>
<p>Gemma: So for our next story, we’re heading to a warmer climate, thankfully, to Tanzania in East Africa and a place called the Olduvai Gorge. It’s known as the birthplace of humanity.</p>
<p>Dan: Birthplace, so how long we talking here? </p>
<p>Gemma: Ages, so about 2 million years or so. And today, archeologists from around the world, come to Olduvai to study the remains of different species of early humans. But scientists are also interested in the ancient environment and what the gorge actually looked like back then. </p>
<p>Dan: So is there a name for studying ancient climates?</p>
<p>Gemma: Yes, and it’s a great one. It’s paleoecology. So basically this is looking for evidence of ancient plants and pollen, and even bits of airborne charcoal by delicately sifting through layers of sediment. So we’ve been talking to a group of researchers who’ve been doing this work in a specific parts of the Olduvai Gorge called Ewass Oldupa, which actually means “the way to the gorge” in the Maa language of the local Masaai and what they’ve found has provided new insights into just how adaptable early humans were to the changing environment around them.</p>
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<a href="https://theconversation.com/finds-in-tanzanias-olduvai-gorge-reveal-how-ancient-humans-adapted-to-change-150755">Finds in Tanzania's Olduvai Gorge reveal how ancient humans adapted to change</a>
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<p>Julio Mercader: I’m Julio Mercader and I’m a professor with the University of Calgary, which is in Western Canada.</p>
<p>Gemma: OK, and we’re talking to you today, Julio, about your most recent research that’s just been published. It’s about an area in Tanzania, in East Africa. Can you just give me a bit of context? Why is this part of the world so important for our history? </p>
<p>Julio: Olduvai Gorge is in East Africa, and if you think of it as a region – there is this reef that is splitting the crust of the earth that is allowing volcanoes to spit out lava and ash. But at the same time as the splitting, it’s making the terrain sink. And when that happens, you have water building up that forms lakes and rivers and swamps. And because of that biodiversity tends to be really, really high because nature is a really productive in these kind of a rfit context.</p>
<p>Now in East Africa, which is where Olduvai is, the rift has been alive, so to speak, for more than 20 million years so that when humanity is forming, several million years ago, early humans, like any other animal, are being attracted to the resources that you find in the rift. </p>
<p>Now life near volcanoes was preserved because the eruptions and the sediments covered that up and then archaeologists exposed it. So now imagine an African Pompeii. But this time is much older. It is two million years. And instead of Romans, you want to imagine humans. But these humans are not like you and I, huh? They are early humans, several species. Unlike today when there is only one species. And among them on Olduvai Gorge, you have the first member of our genus, that we say in biology, and that is the genus homo. Right? And so to sum it up, Olduvai Gorge is important because many aspects of early human life have been buried, covered and preserved for posterity. And it’s not only the human fossils, but what we humans did on a daily basis, our activities. </p>
<p>And as you know, the gorge is like a canyon, it’s like a small version of the Grand Canyon. And because there is like a scar in the terrain, you can see the fossils in the remains, popping out from the walls that create the canyon. </p>
<p>Gemma: So it seems like an incredibly important place for archaeologists like you and your colleagues. How long ago are we talking and is this a period of time when different species are actually competing for dominance? </p>
<p>Julio: Well, there is a lot we don’t know about this, but what we do know is that it was 2 million years ago. And at this point, what you have is humans belonging with a several genera. So for example, various <a href="https://theconversation.com/uk/topics/homo-habilis-17175">homo habilis</a>, and that species belongs with the same genus as you and I. But there is also paranthropus boisei, and other members of the australopithecines. </p>
<p>Now, are they competing directly with one another? From an ecological point of view, maybe not. Maybe not because we know that the adaptations, the morphology of the body, the cranial architecture, the diets may be a little different. So to explain this, imagine different species taking on different niches within the environment. </p>
<p>Gemma: OK, so let’s get into a bit more detail now about the research that you and your colleagues have <a href="https://www.nature.com/articles/s41467-020-20176-2">recently published a paper on</a>. What did you find? </p>
<p>Julio: We uncovered evidence that hominins were coming to a specific location within the gorge, which is on the western side of it. And, they kept coming back.</p>
<p>Gemma: To understand more about what the team of archaeologists found in the gorge, I spoke to two of the Tanzanians who’d worked on the study. Pastory Bushozi and Makarius Peter Itambu. I got them on a slightly dodgy line. So bear with us.</p>
<p>Pastory Bushozi: My name is Pastory Bushozi. I’m a senior lecturer at the University of Dar es Salaam, and archaeologist working on paleoanthropology. </p>
<p>Makarius: My name is Makarius, I’m a lecturer in archaeology, teaching human evolution, paleoenvironment and African stone age. </p>
<p>Gemma: What did you find? What did the ecology of the Olduvai gorge look like when these populations you were studying were living there 2 million years ago? </p>
<p>Makarius: The discovery revealed that the oldest Olduvai hominins used diverse but rapidly changing environments, that range from fern meadows, to woodland mosaics, but also natural band landscape to the lakeside. But also there’s woodland and palm groves, as well as steppes. Those were the kind of environment that looked like during 2 million years ago. </p>
<p>Gemma: So the landscape was changing, you were having forest, you having like a big steppe, you were having grasslands.</p>
<p>Makarius: Right, but the more interesting things, hominims continued to utilise the same toolkit, which is Olduwan. And this is so interesting because we believed that climatic change always trigger technological change, but in this scenario, hominins from Oldupa, it was the Oldupa site, maintain the very same toolkit, the Olduwan stone tools. </p>
<p>Gemma: You were seeing that they were using the same tools throughout that period?</p>
<p>Makarius: Yeah, that was so fascinating that despite of these rapid changes, adaptation to this major geomorphic and ecological transformation did not have any impact. </p>
<p>Gemma: Here’s Julio Mercader again. </p>
<p>Julio: What is interesting here is that over the course of 300,000 years, these Olduwan hominins are coming back to exploit different environments. And so what we have here for the first time is evidence in one place of the diversity of the adaptive tools and strategies that humanity is using to exploit many different ecologies and environments, showing an early example of great adaptability</p>
<p>Gemma: So you were seeing a real ability to use the environment to their benefit?</p>
<p>Julio: That is right. And so to me, this is a real landmark because there is technological dependence, but also the ability to adapt to whatever changes there are happening. And so, in a way it is like the very beginnings of the invasive behaviour typifies any other pioneer. </p>
<p>Gemma: Dr. Bushozi, can I bring you in there. I understand it was you who made one of the oldest discoveries?</p>
<p>Pastory: Yes, it was me, because actually I found those stone tools that were coming on the lower sequence. So I was excited, myself, and I called my colleague to come and see that. That day, everybody was excited. So by then we were collecting everything to see what we were going to do in the lab. </p>
<p>Gemma: And are you able to do research at the moment or is the pandemic stopping your research in the gorge?</p>
<p>Pastory: Because of the pandemic, we are not doing research, but still we are working on the lab. The work I’m doing now is to clean those stone tools by using chemicals so that I can get a good picture on those stone tools, and then after that we are also trying to do get what kind of raw materials, what kind of implement they were using to shape those tools. And then when we go back into the field, we’ll be able to find, trace now where those rocks were coming from. </p>
<p>Gemma: Thank you so much for your time, I really appreciate it.</p>
<p>Makarius and Pastory: Thank you so much.</p>
<p>Gemma: You can read more about the research in a piece that Julio Mercader wrote for The Conversation about their findings.</p>
<p>Alright, that’s it for this week. Thanks to all the academics who’ve spoken to us for this episode - and to The Conversation editors Natasha Joseph, Jack Marley, Hannah Hoag and Laura Hood. </p>
<p>Dan: You can find links to all the expert analysis we’ve mentioned in the episode – and tonnes of other recommended reading – in the show notes. And if you learnt loads and want to read more, click the link to <a href="https://theconversation.com/newsletter?utm_campaign=PodcastTCWeekly&utm_content=newsletter&utm_source=podcast">sign up for our free daily email</a>.</p>
<p>Gemma: This episode is co-produced by Mend Mariwany and me, with sound design by Eloise Stevens.</p>
<p>Dan: Our theme music is by Neeta Sarl. Final thanks also to Alice Mason, Stephen Khan and Imriel Morgan.</p>
<p>Gemma: Thanks for listening everybody. Until next time.</p><img src="https://counter.theconversation.com/content/156526/count.gif" alt="The Conversation" width="1" height="1" />
A transcript of episode 5 of The Conversation Weekly podcast, including stories on the Arctic Ocean and new archaeological finds in Tanzania’s Olduvai Gorge.Gemma Ware, Head of AudioDaniel Merino, Associate Breaking News Editor and Co-Host of The Conversation Weekly PodcastLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1530912021-01-13T05:00:06Z2021-01-13T05:00:06ZWorried about Earth’s future? Well, the outlook is worse than even scientists can grasp<figure><img src="https://images.theconversation.com/files/378461/original/file-20210113-21-rwemte.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5568%2C3692&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Daniel Mariuz/AAP</span></span></figcaption></figure><p>Anyone with even a passing interest in the global environment knows all is not well. But just how bad is the situation? Our new paper shows the outlook for life on Earth is more dire than is generally understood. </p>
<p>The research <a href="https://www.frontiersin.org/articles/10.3389/fcosc.2020.615419/full">published today</a> reviews more than 150 studies to produce a stark summary of the state of the natural world. We outline the likely future trends in biodiversity decline, mass extinction, climate disruption and planetary toxification. We clarify the gravity of the human predicament and provide a timely snapshot of the crises that must be addressed now. </p>
<p>The problems, all tied to human consumption and population growth, will almost certainly worsen over coming decades. The damage will be felt for centuries and threatens the survival of all species, including our own.</p>
<p>Our paper was authored by 17 leading scientists, including those from Flinders University, Stanford University and the University of California, Los Angeles. Our message might not be popular, and indeed is frightening. But scientists must be candid and accurate if humanity is to understand the enormity of the challenges we face.</p>
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<img alt="Girl in breathing mask attached ot plant in container" src="https://images.theconversation.com/files/378462/original/file-20210113-21-1vk2ung.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378462/original/file-20210113-21-1vk2ung.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378462/original/file-20210113-21-1vk2ung.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378462/original/file-20210113-21-1vk2ung.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378462/original/file-20210113-21-1vk2ung.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378462/original/file-20210113-21-1vk2ung.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378462/original/file-20210113-21-1vk2ung.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Humanity must come to terms with the future we and future generations face.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>Getting to grips with the problem</h2>
<p>First, we reviewed the extent to which experts grasp the scale of the threats to the biosphere and its lifeforms, including humanity. Alarmingly, the research shows future environmental conditions will be far more dangerous than experts currently believe.</p>
<p>This is largely because academics tend to specialise in <a href="https://www.tandfonline.com/doi/abs/10.1080/15487733.2007.11907989">one discipline</a>, which means they’re in many cases unfamiliar with the <a href="https://www.dymocks.com.au/book/fragile-dominion-by-simon-levin-and-simon-a-levin-9780738203195">complex system</a> in which planetary-scale problems — and their potential solutions — exist. </p>
<p>What’s more, positive change can be impeded by governments <a href="https://www.embopress.org/doi/full/10.15252/embr.201643381">rejecting</a> or ignoring scientific advice, and <a href="https://www.nature.com/articles/s41562-020-0884-z">ignorance of human behaviour</a> by both technical experts and policymakers.</p>
<p>More broadly, the human <a href="https://www.nature.com/articles/s41562-020-0884-z">optimism bias</a> – thinking bad things are more likely to befall others than yourself – means many people underestimate the environmental crisis. </p>
<h2>Numbers don’t lie</h2>
<p>Our research also reviewed the current state of the global environment. While the problems are too numerous to cover in full here, they include:</p>
<ul>
<li><p>a <a href="https://www.nature.com/articles/nature25138">halving</a> of vegetation biomass since the agricultural revolution around 11,000 years ago. Overall, humans have altered almost <a href="https://ipbes.net/global-assessment">two-thirds</a> of Earth’s land surface</p></li>
<li><p>about <a href="https://science.sciencemag.org/content/366/6471/eaax3100">1,300 documented</a> <a href="https://www.nature.com/articles/s41559-019-0906-2">species extinctions</a> over the past 500 years, with many more unrecorded. More broadly, population sizes of animal species have declined by more than <a href="https://www.worldwildlife.org/publications/living-planet-report-2020">two-thirds</a> over the last 50 years, suggesting more extinctions are imminent</p></li>
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<strong>
Read more:
<a href="https://theconversation.com/what-is-a-mass-extinction-and-are-we-in-one-now-122535">What is a 'mass extinction' and are we in one now?</a>
</strong>
</em>
</p>
<hr>
<ul>
<li><p>about <a href="https://www.un.org/sustainabledevelopment/blog/2019/05/nature-decline-unprecedented-report/">one million</a> plant and animal species globally threatened with extinction. The combined mass of wild mammals today is less than <a href="https://www.pnas.org/content/115/25/6506">one-quarter</a> the mass before humans started colonising the planet. Insects are also <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev-ento-011019-025151">disappearing rapidly</a> in many regions</p></li>
<li><p>85% of the global wetland area <a href="https://www.publish.csiro.au/mf/mf14173">lost</a> in 300 years, and more than 65% of the oceans <a href="https://www.nature.com/articles/ncomms8615">compromised</a> to some extent by humans</p></li>
<li><p>a halving of live coral cover on reefs in less than <a href="https://www.nature.com/articles/nclimate1674">200 years</a> and a decrease in seagrass extent by <a href="https://science.sciencemag.org/content/366/6471/eaax3100">10% per decade</a> over the last century. <a href="https://www.pnas.org/content/113/48/13785">About 40%</a> of kelp forests have declined in abundance, and the number of large predatory fishes is <a href="https://onlinelibrary.wiley.com/doi/full/10.1046/j.1467-2979.2003.00103.x">fewer than 30%</a> of that a century ago.</p></li>
</ul>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/378178/original/file-20210112-15-1ornvrk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="State of the Earth's environment" src="https://images.theconversation.com/files/378178/original/file-20210112-15-1ornvrk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378178/original/file-20210112-15-1ornvrk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=521&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378178/original/file-20210112-15-1ornvrk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=521&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378178/original/file-20210112-15-1ornvrk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=521&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378178/original/file-20210112-15-1ornvrk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=654&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378178/original/file-20210112-15-1ornvrk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=654&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378178/original/file-20210112-15-1ornvrk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=654&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Major environmental-change categories expressed as a percentage relative to intact baseline. Red indicates percentage of category damaged, lost or otherwise affected; blue indicates percentage intact, remaining or unaffected.</span>
<span class="attribution"><span class="source">Frontiers in Conservation Science</span></span>
</figcaption>
</figure>
<h2>A bad situation only getting worse</h2>
<p>The human population has reached <a href="https://www.prb.org/2020-world-population-data-sheet/">7.8 billion</a> – double what it was in 1970 – and is set to reach about 10 billion by 2050. More people equals more food insecurity, soil degradation, plastic pollution and biodiversity loss. </p>
<p>High population densities make pandemics more likely. They also drive overcrowding, unemployment, housing shortages and deteriorating infrastructure, and can spark conflicts leading to <a href="https://theconversation.com/by-inciting-capitol-mob-trump-pushes-u-s-closer-to-a-banana-republic-152850">insurrections</a>, terrorism, and war.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-explained-why-we-need-to-focus-on-increased-consumption-as-much-as-population-growth-138602">Climate explained: why we need to focus on increased consumption as much as population growth</a>
</strong>
</em>
</p>
<hr>
<p>Essentially, humans have created an ecological <a href="https://www.investopedia.com/terms/p/ponzischeme.asp">Ponzi scheme</a>. Consumption, as a percentage of Earth’s <a href="https://www.footprintnetwork.org">capacity to regenerate itself</a>, has grown from 73% in 1960 to <a href="https://www.mdpi.com/2079-9276/7/3/58">more than 170% today</a>. </p>
<p>High-consuming countries like Australia, Canada and the US use multiple units of fossil-fuel energy to produce one energy unit of food. Energy consumption will therefore increase in the near future, especially as the global middle class grows.</p>
<p>Then there’s climate change. Humanity has already exceeded global warming of 1°C this century, and will almost assuredly <a href="https://www.ipcc.ch/sr15/chapter/spm/">exceed 1.5 °C</a> between 2030 and 2052. Even if all nations party to the <a href="https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement">Paris Agreement</a> ratify their commitments, warming would still reach between 2.6°C and 3.1°C by 2100.</p>
<figure class="align-center ">
<img alt="people walking on a crowded street" src="https://images.theconversation.com/files/364900/original/file-20201022-18-iwc4eu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/364900/original/file-20201022-18-iwc4eu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/364900/original/file-20201022-18-iwc4eu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/364900/original/file-20201022-18-iwc4eu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/364900/original/file-20201022-18-iwc4eu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/364900/original/file-20201022-18-iwc4eu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/364900/original/file-20201022-18-iwc4eu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The human population is set to reach 10 billion by 2050.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>The danger of political impotence</h2>
<p>Our paper found global policymaking falls far short of addressing these existential threats. Securing Earth’s future requires prudent, long-term decisions. However this is impeded by short-term interests, and an economic system that <a href="https://theconversation.com/piketty-challenges-us-to-consider-if-we-need-to-rein-in-wealth-inequality-67552">concentrates wealth among a few individuals</a>.</p>
<p>Right-wing populist leaders with <a href="https://www.nature.com/articles/d41586-018-07236-w">anti-environment agendas</a> are on the rise, and in many countries, environmental protest groups have been labelled “<a href="https://theconversation.com/extinction-rebellion-terror-threat-is-a-wake-up-call-for-how-the-state-treats-environmental-activism-129804">terrorists</a>”. Environmentalism has become weaponised as a political ideology, rather than properly viewed as a universal mode of self-preservation.</p>
<p>Financed <a href="https://theconversation.com/a-brief-history-of-fossil-fuelled-climate-denial-61273">disinformation campaigns</a>, such as those against climate action and <a href="http://alert-conservation.org/issues-research-highlights/2014/11/27/progress-in-the-battle-against-illegal-logging">forest protection</a>, protect short-term profits and claim meaningful environmental action is too costly – while ignoring the broader cost of not acting. By and large, it appears unlikely business investments <a href="https://www.un.org/press/en/2019/ecosoc6972.doc.htm">will shift at sufficient scale</a> to avoid environmental catastrophe.</p>
<h2>Changing course</h2>
<p>Fundamental change is required to avoid this ghastly future. Specifically, we and many others suggest: </p>
<ul>
<li><p><a href="https://theconversation.com/life-in-a-degrowth-economy-and-why-you-might-actually-enjoy-it-32224">abolishing</a> the goal of perpetual economic growth</p></li>
<li><p>revealing the true cost of products and activities by forcing those who damage the environment to pay for its restoration, such as through <a href="https://theconversation.com/carbon-pricing-works-the-largest-ever-study-puts-it-beyond-doubt-142034">carbon pricing</a></p></li>
<li><p>rapidly eliminating fossil fuels</p></li>
<li><p>regulating markets by curtailing monopolisation and limiting undue corporate influence on policy</p></li>
<li><p>reigning in corporate lobbying of political representatives</p></li>
<li><p>educating and <a href="https://www.ted.com/talks/katharine_wilkinson_how_empowering_women_and_girls_can_help_stop_global_warming">empowering women</a> across the globe, including giving them control over family planning.</p></li>
</ul>
<figure class="align-center ">
<img alt="A coal plant" src="https://images.theconversation.com/files/378465/original/file-20210113-15-6b1vqv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378465/original/file-20210113-15-6b1vqv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378465/original/file-20210113-15-6b1vqv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378465/original/file-20210113-15-6b1vqv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378465/original/file-20210113-15-6b1vqv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378465/original/file-20210113-15-6b1vqv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378465/original/file-20210113-15-6b1vqv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The true cost of environmental damage should be borne by those responsible.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Don’t look away</h2>
<p>Many organisations and individuals are devoted to achieving these aims. However their messages have not sufficiently penetrated the policy, economic, political and academic realms to make much difference.</p>
<p>Failing to acknowledge the magnitude of problems facing humanity is not just naïve, it’s dangerous. And science has a big role to play here. </p>
<p>Scientists must not sugarcoat the overwhelming challenges ahead. Instead, they should <em>tell it like it is</em>. Anything else is at best misleading, and at worst potentially lethal for the human enterprise.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mass-extinctions-and-climate-change-why-the-speed-of-rising-greenhouse-gases-matters-56675">Mass extinctions and climate change: why the speed of rising greenhouse gases matters</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/153091/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Corey J. A. Bradshaw receives funding from the Australian Research Council. The Rockefeller Foundation provided funding for elements of this research via a Bellagio Writer's Fellowship to CJAB and PRE.</span></em></p><p class="fine-print"><em><span>Daniel T. Blumstein receives funding from the US National Science Foundation and the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Paul Ehrlich does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Humanity is destroying Earth’s ability to support complex life. But coming to grips with the magnitude of the problem is hard, even for experts.Corey J. A. Bradshaw, Matthew Flinders Professor of Global Ecology and Models Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders UniversityDaniel T. Blumstein, Professor in the Department of Ecology and Evolutionary Biology and the Institute of the Environment and Sustainability, University of California, Los AngelesPaul Ehrlich, President, Center for Conservation Biology, Bing Professor of Population Studies, Stanford UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1501572020-12-06T10:01:21Z2020-12-06T10:01:21ZArctic Ocean: climate change is flooding the remote north with light – and new species<figure><img src="https://images.theconversation.com/files/372024/original/file-20201130-15-bi9r3q.jpg?ixlib=rb-1.1.0&rect=62%2C62%2C2932%2C1926&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A boat navigates at night next to large icebergs in eastern Greenland.</span> <span class="attribution"><span class="source">(AP Photo/Felipe Dana)</span></span></figcaption></figure><p>At just over 14 million square kilometres, the Arctic Ocean is the smallest and shallowest of the world’s oceans. It is also the coldest. An expansive raft of sea ice floats near its centre, expanding in the long, cold, dark winter, and contracting in the summer, as the Sun climbs higher in the sky. </p>
<p>Every year, usually in September, the sea ice cover shrinks to its lowest level. The tally in 2020 was a meagre <a href="https://www.nasa.gov/feature/goddard/2020/2020-arctic-sea-ice-minimum-at-second-lowest-on-record">3.74 million square kilometres</a>, the second-smallest measurement in 42 years, and roughly half of what it was in 1980. Each year, as the climate warms, the Arctic is holding onto less and less ice. </p>
<p>The effects of global warming are being felt around the world, but nowhere on Earth are they as dramatic as they are in the Arctic. The Arctic is warming <a href="https://theconversation.com/siberia-heatwave-why-the-arctic-is-warming-so-much-faster-than-the-rest-of-the-world-141455">two to three times faster</a> than any other place on Earth, ushering in far-reaching changes to the Arctic Ocean, its ecosystems and the 4 million people who live in the Arctic.</p>
<hr>
<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><a href="https://oceans21.netlify.app/">Five profiles open our series on the global ocean</a>, delving into ancient <a href="https://theconversation.com/exploring-the-indian-ocean-as-a-rich-archive-of-history-above-and-below-the-water-line-133817">Indian Ocean</a> trade networks, <a href="https://theconversation.com/it-might-be-the-worlds-biggest-ocean-but-the-mighty-pacific-is-in-peril-150745">Pacific</a> plastic pollution, <a href="https://theconversation.com/arctic-ocean-climate-change-is-flooding-the-remote-north-with-light-and-new-species-150157">Arctic</a> light and life, <a href="https://theconversation.com/the-atlantic-the-driving-force-behind-ocean-circulation-and-our-taste-for-cod-146534">Atlantic</a> fisheries and the <a href="https://theconversation.com/an-ocean-like-no-other-the-southern-oceans-ecological-richness-and-significance-for-global-climate-151084">Southern Ocean</a>’s impact on global climate. Look out for new articles in the lead up to COP26. Brought to you by The Conversation’s international network.</em></p>
<p>Some of them are unexpected. The warmer water is pulling some species further north, into higher latitudes. The thinner ice is carrying more people through the Arctic on cruise ships, cargo ships and research vessels. Ice and snow can almost entirely black out the water beneath it, but climate change is allowing more light to flood in.</p>
<h2>Artificial light in the polar night</h2>
<p>Light is very important in the Arctic. The algae which form the foundation of the Arctic Ocean’s food web convert sunlight into sugar and fat, feeding fish and, ultimately, whales, polar bears and humans.</p>
<p>At high latitudes in the Arctic during the depths of winter, the Sun stays below the horizon for 24 hours. This is called the polar night, and at the North Pole, the year is simply one day lasting six months, followed by one equally long night.</p>
<p>Researchers studying the effects of ice loss deployed moored observatories – anchored instruments with a buoy — in an Arctic fjord in the autumn of 2006, before the fjord froze. When sampling started in the spring of 2007, the moorings had been in place for almost six months, collecting data throughout the long and bitter polar night.</p>
<p>What they detected changed everything.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man on a boat stands with a torch, looking into the polar night." src="https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354039/original/file-20200821-24-142ql6l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The polar night can last for weeks and even months in the high Arctic.</span>
<span class="attribution"><a class="source" href="https://www.michaelosnyder.com/intothedark">Michael O. Snyder</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Life in the dark</h2>
<p>At that time, scientists assumed the polar night was utterly uninteresting. A dead period in which life lies dormant and the ecosystem sinks into a dark and frigid standby mode. Not much was expected to come of these measurements, so researchers were surprised when the data showed that life doesn’t pause at all. </p>
<p>Arctic zooplankton — tiny microscopic animals that eat algae — take part in something called diel vertical migration beneath the ice and in the dead of the polar night. Sea creatures in all the oceans of the world do this, migrating to depth during the day to hide from potential predators in the dark, and surfacing at night to feed. </p>
<p>Organisms use light as a cue to do this, so they shouldn’t logically be able to during the polar night. We now understand the polar night to be a riot of <a href="https://www.springer.com/gp/book/9783030332075">ecological activity</a>. The normal rhythms of daily life continue in the gloom. Clams open and close cyclically, seabirds hunt in almost total darkness, ghost shrimps and sea snails gather in kelp forests to reproduce, and deep-water species such as the <a href="http://www.seawater.no/fauna/cnidaria/periphylla.html">helmet jellyfish</a> surface when it’s dark enough to stay safe from predators. </p>
<p>For most of the organisms active during this period, the Moon, stars and aurora borealis likely give important cues that guide their behaviour, especially in parts of the Arctic not covered by sea ice. But as the <a href="https://theconversation.com/siberia-heatwave-why-the-arctic-is-warming-so-much-faster-than-the-rest-of-the-world-141455">Arctic climate warms</a> and human activities in the region ramp up, these natural light sources will in many places be invisible, crowded out by much stronger artificial light.</p>
<figure class="align-center ">
<img alt="A band of turquoise light in the sky is reflected in the Norwegian fjord below." src="https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=345&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=345&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=345&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=434&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=434&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369805/original/file-20201117-21-1w6y3lv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=434&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The northern lights dance in the sky over Tromsø, Norway.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/northern-lights-aurora-borealis-sky-over-1667574898">Muratart/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Artificial light</h2>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/27386582/">Almost a quarter</a> of all land masses are exposed to scattered artificial light at night, as it’s <a href="https://theconversation.com/the-moon-and-stars-are-a-compass-for-nocturnal-animals-but-light-pollution-is-leading-them-astray-142301">reflected back</a> to the ground from the atmosphere. Few truly dark places remain, and light from cities, coastlines, roads and ships is visible as far as <a href="https://theconversation.com/aliens-could-light-and-noise-from-earth-attract-attention-from-outer-space-121073">outer space</a>. </p>
<p>Even in sparsely populated areas of the Arctic, light pollution is noticeable. Shipping routes, oil and gas exploration and fisheries extend into the region as the sea ice retreats, drawing artificial light into the otherwise inky black polar night. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A large ship covered in yellow lights illuminates the icy water." src="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354037/original/file-20200821-20-1br36v1.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">Creatures which have adapted to the polar night over millions of years are now suddenly exposed to artificial light.</span>
<span class="attribution"><a class="source" href="https://www.michaelosnyder.com/intothedark">Michael O. Snyder</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>No organisms have had the opportunity to properly adapt to these changes – evolution works on a much longer timescale. Meanwhile, the harmonic movements of the Earth, Moon and Sun have provided reliable cues to Arctic animals for millennia. Many biological events, such as migration, foraging and breeding are highly attuned to their gentle predictability.</p>
<p>In <a href="https://www.nature.com/articles/s42003-020-0807-6.epdf?author_access_token=AhjhVJ9T-Ho3FU8ewme7A9RgN0jAjWel9jnR3ZoTv0NEMXGytZWyu7pRWgNA-Ls9S-OwEeIlQT_1cG84LQxJkHVlTII3ANzs3zXmrS-cLPS7or6UYLjEnyWFmnSN748A-DMYCYQKXSVtuY0VaRAieg%253D%253D">a recent study</a> carried out in the high Arctic archipelago of Svalbard, between mainland Norway and the north pole, the onboard lights of a research vessel were found to affect fish and zooplankton at least 200 metres down. Disturbed by the sudden intrusion of light, the creatures swirling beneath the surface reacted dramatically, with some swimming towards the beam, and others swimming violently away. </p>
<p>It’s difficult to predict the effect artificial light from ships newly navigating the ice-free Arctic will have on polar night ecosystems that have known darkness for longer than modern humans have existed. How the rapidly growing human presence in the Arctic will affect the ecosystem is concerning, but there are also unpleasant questions for researchers. If much of the information we’ve gathered about the Arctic came from scientists stationed on brightly lit boats, how “natural” is the state of the ecosystem we have reported?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Seen from a sea ice floe, a large ship on the horizon beams white light into the sky." src="https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/354036/original/file-20200821-22-54wul0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Research in the Arctic could change considerably over the coming years to reduce light pollution.</span>
<span class="attribution"><a class="source" href="https://www.michaelosnyder.com/intothedark">Michael O. Snyder</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Arctic marine science is about to enter a new era with autonomous and remotely operated platforms, capable of operating without any light, making measurements in complete darkness.</p>
<hr>
<p><em>Listen to interviews with two the scientists studying artificial light and kelp forests in the Arctic Ocean in <a href="https://theconversation.com/diving-in-the-icy-depths-the-scientists-studying-what-climate-change-is-doing-to-the-arctic-ocean-the-conversation-weekly-podcast-156417">The Conversation Weekly podcast</a>.</em> </p>
<iframe src="https://embed.acast.com/60087127b9687759d637bade/603fd2cb60fb3d4ddced9015?cover=true&ga=false" frameborder="0" allow="autoplay" width="100%" height="110"></iframe>
<hr>
<h2>Underwater forests</h2>
<p>As sea ice retreats from the shores of Greenland, Norway, North America and Russia, periods with open water are getting longer, and more light is reaching the sea floor. Suddenly, coastal ecosystems that have been hidden under ice for 200,000 years are seeing the light of day. This could be very good news for marine plants like kelp – large brown seaweeds that thrive in cold water with enough light and nutrients. </p>
<p>Anchored to the sea floor and floating with the tide and currents, some species of kelp can grow up to <a href="https://www.montereybayaquarium.org/animals/animals-a-to-z/giant-kelp#:%7E:text=Giant%20kelp%20often%20grows%20in,to%20sway%20in%20ocean%20currents.">50 metres</a> (175 feet) – about the same height as Nelson’s Column in Trafalgar Square, London. But kelp are typically excluded from the highest latitudes because of the shade cast by sea ice and its scouring effect on the seabed. </p>
<figure class="align-center ">
<img alt="Large greeny-brown and frilled fronds of seaweed snake across a gravelly seabed." src="https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361496/original/file-20201004-16-v7supj.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">Badderlocks, or winged kelp, off the coast of Nunavut in the Canadian Arctic.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These lush underwater forests are set to grow and thrive as sea ice shrinks. <a href="https://deeply.thenewhumanitarian.org/arctic/articles/2016/04/13/let-them-eat-kelp-spinning-gold-from-seaweed">Kelp are not a new arrival to the Arctic though</a>. They were once part of the traditional Greenlandic diet, and polar researchers and explorers observed them along northern coasts more than a century ago. </p>
<p>Some species of kelp may have colonised Arctic coasts after the last ice age, or <a href="https://www.pnas.org/content/117/36/22590">spread out from small pockets</a> where they’d held on. But most kelp forests in the Arctic are smaller and more restricted to patches in deeper waters, compared to the vast swathes of seaweed that line coasts like California’s in the US.</p>
<figure class="align-center ">
<img alt="A scuba diver swims through kelp fronds." src="https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360011/original/file-20200925-14-iifn5y.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 explores a four-metre-high sugar kelp forest off Southampton Island, Canada.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Recent evidence from <a href="https://www.pnas.org/content/109/35/14052">Norway</a> and <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2486.2012.02765.x">Greenland</a> shows kelp forests are already expanding and increasing their ranges poleward, and these ocean plants are expected to get bigger and grow faster as the Arctic <a href="https://doi.org/10.1016/j.gloplacha.2018.09.005">warms</a>, creating more nooks for species to live in and around. The full extent of Arctic kelp forests remains largely unseen and uncharted, but modelling can help determine how much they have shifted and grown in the Arctic since the 1950s.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of the Arctic Circle showing how kelp forests will expand further north as the world warms." src="https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=534&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=534&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=534&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=671&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=671&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361844/original/file-20201006-14-1saik96.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=671&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Known locations of kelp forests and global trends in predicted average summer surface temperature increase over next two decades, according to IPCC models.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1016/j.gloplacha.2018.09.005">Filbee-Dexter et al. (2018)</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A new carbon sink</h2>
<p>Although large seaweeds come in all shapes and sizes, many are remarkably similar to trees, with long, trunk-like but flexible bodies called stipes. The kelp forest canopy is filled with the flat blades like leaves, while holdfasts act like roots by anchoring the seaweed to rocks below.</p>
<p>Some types of Arctic kelp can grow over <a href="https://www.arctickelp.ca/post/finding-forests">ten metres</a> and form large and complex canopies suspended in the water column, with a shaded and protected understorey. Much like forests on land, these marine forests provide habitats, nursery areas and feeding grounds for many animals and fish, including cod, pollack, crabs, lobsters and sea urchins. </p>
<figure class="align-center ">
<img alt="A cloud of shrimp surrounds a large path of kelp." src="https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361494/original/file-20201004-14-xo1kq7.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">Kelp forests offer lots of nooks and crannies and surfaces to settle on, making them rich in wildlife.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Kelp are fast growers, storing carbon in their leathery tissue as they do. So what does their expansion in the Arctic mean for the global climate? Like restoring forests on land, growing underwater kelp forests can help to slow climate change by diverting carbon from the atmosphere.</p>
<p>Better yet, some kelp material breaks off and is swept out of shallow coastal waters and into the deep ocean where it’s effectively removed from the Earth’s carbon cycle. Expanding kelp forests along the Earth’s extensive Arctic coasts could become a growing carbon sink that captures the CO₂ humans emit and locks it away in the deep sea. </p>
<p>What’s happening with kelp in the Arctic is fairly unique – these ocean forests are <a href="https://www.pnas.org/content/113/48/13785.short">embattled</a> in most other parts of the world. Overall, the global extent of kelp forests is on a <a href="https://www.washingtonpost.com/news/theworldpost/wp/2018/10/23/ocean/">downward trend</a> because of ocean heatwaves, pollution, warming temperatures, and outbreaks of grazers like <a href="https://theconversation.com/restore-large-carnivores-to-save-struggling-ecosystems-21828">sea urchins</a>.</p>
<p>Unsurprisingly, it’s not all good news. Encroaching kelp forests could push out unique wildlife in the high Arctic. Algae living under the ice will have nowhere to go, and could disappear altogether. More temperate kelp species may replace endemic Arctic kelps such as <em>Laminaria solidungula</em>.</p>
<figure class="align-center ">
<img alt="A bright orange crab nestles in a thicket of dark brown seaweed." src="https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/361497/original/file-20201004-14-hzvj8d.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 crab finds refuge on <em>Laminaria solidungula</em> – the only kelp species endemic to the Arctic.</span>
<span class="attribution"><span class="source">Ignacio Garrido/ArcticKelp</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>But kelp are just one set of species among many pushing further and deeper into the region as the ice melts.</p>
<h2>Arctic invasions</h2>
<p>Milne Inlet, on north Baffin Island, Nunavut, Canada, sees <a href="https://doi.org/10.1371/journal.pone.0211815">more marine traffic than any other port in Arctic Canada</a>. Most days during the open-water period, 300-metre-long ships leave the port laden with iron ore from the nearby Mary River Mine. Between <a href="https://www.baffinland.com/_resources/2019_NIRB_AnnualReport.pdf">71 and 82 ships</a> pass through the area annually, most heading to — or coming from <a href="https://tc.canada.ca/en/marine-transportation/marine-safety/ship-safety-bulletins/updates-canadian-ballast-water-reporting-form-ssb-no-07-2018">ports in northern Europe</a>.</p>
<p>Cruise ships, coast guard vessels, pleasure yachts, research icebreakers, cargo supply ships and rigid inflatable boats full of tourists also glide through the area. Unprecedented warming and declining sea ice has attracted new industries and other activities to the Arctic. Communities like Pond Inlet have seen marine traffic <a href="https://doi.org/10.14430/arctic4698">triple in the past two decades</a>.</p>
<figure class="align-center ">
<img alt="Ships anchored offshore in icy water with small group of passengers standing on a point of land." src="https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370614/original/file-20201121-15-injscx.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">Passengers from a cruise ship arrive in Pond Inlet, Nunavut.</span>
<span class="attribution"><span class="source">Kimberly Howland</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These ships come to the Arctic from all over the world, carrying a host of aquatic hitchhikers picked up in Rotterdam, Hamburg, Dunkirk and elsewhere. These species — some too small to see with the naked eye — are hidden in the ballast water pumped into on-board tanks to stabilise the ship. They also <a href="https://cdnsciencepub.com/doi/10.1139/cjfas-2014-0473">stick to the hull and other outer surfaces</a>, called “biofouling.” </p>
<p>Some survive the voyage to the Arctic and are released into the environment when the ballast water <a href="http://semaphore.uqar.ca/id/eprint/1481/1/Antoine_Dispas_fevrier2019.pdf">is discharged and cargo loaded</a>. Those that maintain their hold on the outer surface may release eggs, sperm or larvae.</p>
<p>Many of these organisms are innocuous, but some may be invasive newcomers that can cause harm. <a href="https://cdnsciencepub.com/doi/10.1139/cjfas-2014-0473">Research in Canada</a> and <a href="https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2664.12566">Norway</a> has already shown non-native invasive species like bay and acorn barnacles can survive ship transits to the Arctic. This raises a risk for Arctic ecosystems given that invasive species are <a href="http://dx.doi.org/10.1098/rsbl.2015.0623">one of the top causes for extinctions worldwide</a>. </p>
<h2>Expanded routes</h2>
<p>Concern about invasive species extends far beyond the community of Pond Inlet. Around 4 million people live in the Arctic, many of them along the coasts that provide nutrients and critical habitat for a wide array of animals, from Arctic char and ringed seals to polar bear, bowhead whales and millions of migratory birds.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=694&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=694&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=694&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=872&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=872&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369441/original/file-20201115-21-q49248.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=872&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">As the Arctic sea ice melts during the summer months, shipping routes are opening up along the Russian coast and through the Northwest Passage. Some say a trans-Arctic route might soon be navigable.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>As waters warm, the shipping season is becoming longer, and new routes, like the Northwest Passage and the Northern Sea Route (along Russia’s Arctic coast), are opening up. Some researchers expect a <a href="https://doi.org/10.1002/2016GL069315">trans-Arctic route across the North Pole might be navigable by mid-century</a>. The increased ship traffic <a href="https://doi.org/10.1111/gcb.15159">magnifies the numbers and kinds of organisms transported into Arctic waters</a>, and the progressively more hospitable conditions improve their odds of survival.</p>
<p>Prevention is the number one way to <a href="https://doi.org/10.1016/j.marpolbul.2007.01.005">keep invasive species out</a> of the Arctic. Most ships must treat their ballast water, using <a href="https://www.imo.org/en/About/Conventions/Pages/International-Convention-for-the-Control-and-Management-of-Ships%27-Ballast-Water-and-Sediments-(BWM).aspx">chemicals or other processes, and/or exchange it</a> to limit the movement of harmful organisms to new locations. Guidelines also recommend ships use special coatings on the hulls and clean them regularly <a href="https://wwwcdn.imo.org/localresources/en/OurWork/Environment/Documents/RESOLUTIONMEPC.207%5B62%5D.pdf">to prevent biofouling</a>. But these prevention measures are not always reliable, and their efficacy in colder environments is <a href="https://waves-vagues.dfo-mpo.gc.ca/Library/40817817.pdf">poorly understood</a>. </p>
<p>The next best approach is to <a href="http://www.stoppinginvasives.com/dotAsset/3a05e4d0-bb25-40ff-a72a-c25a486bb90f.pdf">detect invaders as soon as possible once they arrive</a>, to improve chances for eradication or suppression. But early detection requires widespread monitoring, which can be challenging in the Arctic. Keeping an eye out for the arrival of a new species can be akin to searching for a needle in a haystack, but northern communities may offer a solution.</p>
<p>Researchers in Norway, <a href="https://accs.uaa.alaska.edu/invasive-species/bering-sea-marine-invasives/">Alaska</a> and Canada have found a way to make that search easier by singling out species that have <a href="https://doi.org/10.1007/s10530-017-1553-7">caused harm elsewhere</a> and that could endure Arctic environmental conditions. Nearly two dozen potential invaders show a high chance for <a href="https://doi.org/10.1111/gcb.15159">taking hold in Arctic Canada</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/369444/original/file-20201115-21-qt4axk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The red king crab was intentionally introduced to the Barents Sea in the 1960s, but is now spreading south along the Norwegian coast.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Among these is the cold-adapted red king crab, native to the Sea of Japan, Bering Sea and North Pacific. It was intentionally introduced to the Barents Sea in the 1960s to establish a fishery and is now spreading south <a href="https://www.researchgate.net/publication/226380427_The_Invasive_History_Impact_and_Management_of_the_Red_King_Crab_Paralithodes_camtschaticus_off_the_Coast_of_Norway">along the Norwegian coast and in the White Sea</a>. It is a large, voracious predator <a href="https://www.cabi.org/isc/datasheet/71549">implicated in substantial declines</a> of harvested shellfish, sea urchins and other larger, slow moving bottom species, with a high likelihood of <a href="https://doi.org/10.1371/journal.pone.0211815">surviving transport in ballast water</a>. </p>
<p>Another is the common periwinkle, which <a href="https://www.cabi.org/isc/datasheet/76460">ruthlessly grazes on lush aquatic plants</a> in shoreline habitats, leaving behind bare or encrusted rock. It has also introduced a parasite on the east coast of North America that causes <a href="https://invasions.si.edu/nemesis/calnemo/SpeciesSummary.jsp?TSN=70419">black spot disease in fishes</a>, which stresses adult fishes and makes them unpalatable, kills juveniles and causes intestinal damage to birds and mammals that eat them. </p>
<h2>Tracking genetic remnants</h2>
<p>New species like these could affect the fish and mammals people hunt and eat, if they were to arrive in Pond Inlet. After just a few years of shipping, a handful of possibly non-native species have <a href="https://www.baffinland.com/_resources/document_portal/1663724-197-R-Rev0-24000-BIM-2019-MEEMP-27AUG-20-cs.pdf">already been discovered</a>, including the invasive <a href="https://invasions.si.edu/nemesis/browseDB/SpeciesSummary.jsp?TSN=-47">red-gilled mudworm (<em>Marenzellaria viridis</em>)</a>, and a <a href="https://invasions.si.edu/nemesis/browseDB/SpeciesSummary.jsp?TSN=93600">potentially invasive tube dwelling amphipod</a>. Both are known to reach high densities, alter the characteristics of the seafloor sediment and compete with native species.</p>
<figure class="align-center ">
<img alt="An orange ship sits in icy water with a rocky slope behind it." src="https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370615/original/file-20201121-17-tn68en.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A cargo ship passes through Milne Inlet, Nunavut.</span>
<span class="attribution"><span class="source">Kimberly Howland</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Baffinland, the company that runs the Mary River Mine, is seeking to <a href="https://www.cbc.ca/news/canada/north/hunters-inuit-knowledge-ignored-nunavut-mine-environmental-study-1.5726454">double its annual output</a> of iron ore. If the expansion proceeds, up to 176 ore carriers will pass through Milne Inlet during the open-water season. </p>
<p>Although the future of Arctic shipping remains uncertain, it’s an upward trend that needs to be watched. In Canada, researchers are working with Indigenous partners in communities with high shipping activity — including Churchill, Manitoba; Pond Inlet and Iqaluit in Nunavut; Salluit, Quebec and Nain, Newfoundland — to establish an invasive species monitoring network. One of the approaches includes collecting water and testing it for <a href="https://doi.org/10.1038/s41598-018-27048-2">genetic remnants</a> shed from scales, faeces, sperm and other biological material. </p>
<figure class="align-center ">
<img alt="A group of people sit on shore learning to use sampling equipment." src="https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370616/original/file-20201121-13-1mcbfik.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">Members of the 2019 field team from Pond Inlet and Salluit filter eDNA from water samples collected from Milne Inlet.</span>
<span class="attribution"><span class="source">Christopher Mckindsey</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This environmental DNA (eDNA) is easy to collect and can help detect organisms that might otherwise be difficult to capture or are in low abundance. The technique has also <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/edn3.35">improved baseline knowledge of coastal biodiversity</a> in other areas of high shipping, a fundamental step in detecting future change. </p>
<p>Some non-native species have already been detected in the Port of Churchill using eDNA surveillance and other sampling methods, including <a href="http://semaphore.uqar.ca/id/eprint/1481/1/Antoine_Dispas_fevrier2019.pdf">jellyfish, rainbow smelt and an invasive copepod species</a>.</p>
<p>Efforts are underway to expand the network across the Arctic as part of the Arctic Council’s <a href="https://arctic-council.org/en/projects/invasive/">Arctic Invasive Alien Species Strategy</a> to reduce the spread of invasive species. </p>
<p>The Arctic is often called the frontline of the climate crisis, and because of its rapid rate of warming, the region is beset by invasions of all kinds, from new species to new shipping routes. These forces could entirely remake the ocean basin within the lifetimes of people alive today, from frozen, star-lit vistas, populated by unique communities of highly adapted organisms, to something quite different.</p>
<p>The Arctic is changing faster than scientists can document, yet there will be opportunities, such as growing carbon sinks, that could benefit the wildlife and people who live there. Not all changes to our warming world will be wholly negative. In the Arctic, as elsewhere, there are winners and losers.</p><img src="https://counter.theconversation.com/content/150157/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jørgen Berge receives funding from the Norwegian Research Council (300333).</span></em></p><p class="fine-print"><em><span>Carlos Duarte receives funding from King Abdullah University of Science and Technology and the Independent Research Fund of Denmark.</span></em></p><p class="fine-print"><em><span>Dorte Krause-Jensen receives funding from various governmental research funds, such as the Independent Research Fund, Denmark, and private research funds, including the Velux Foundations.</span></em></p><p class="fine-print"><em><span>Karen Filbee-Dexter receives funding from ArcticNet, the Norwegian Blue Forest Network, the Australian Research Council, and the Norwegian Research Council (BlueConnect).</span></em></p><p class="fine-print"><em><span>Kimberly Howland receives funding from Fisheries and Ocean Canada; Natural Resources Canada and Polar Knowledge Canada.</span></em></p><p class="fine-print"><em><span>Philippe Archambault receives funding from ArcticNet.</span></em></p>The Arctic has been a remote place for much of its history. But climate change is bringing global problems and opportunities to its door.Jørgen Berge, Vice Dean for Research, Arctic and Marine Biology, University of TromsøCarlos M. Duarte, Adjunct Professor of Marine Ecology, King Abdullah University of Science and TechnologyDorte Krause-Jensen, Professor, Marine Ecology, Aarhus UniversityKaren Filbee-Dexter, Research Fellow, School of Biological Sciences, The University of Western AustraliaKimberly Howland, Research Scientist/Adjunct University Professor, Université du Québec à Rimouski (UQAR)Philippe Archambault, Professor & CoScientific Director of ArcticNet, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1504602020-11-26T19:01:08Z2020-11-26T19:01:08ZHow will sharks respond to climate change? It might depend on where they grew up<figure><img src="https://images.theconversation.com/files/371438/original/file-20201126-21-124xran.jpg?ixlib=rb-1.1.0&rect=0%2C55%2C4606%2C3006&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>They may have been around for <a href="https://www.sea.museum/2020/01/16/ten-interesting-facts-about-sharks">hundreds of millions of years</a> — long before trees — but today sharks and rays are are among <a href="https://www.iucn.org/content/a-quarter-sharks-and-rays-threatened-extinction">the most threatened</a> animals in the world, largely because of overfishing and habitat loss. </p>
<p>Climate change adds another overarching stressor to the mix. So how will sharks cope as the ocean heats up?</p>
<p>Our <a href="https://doi.org/10.1111/gcb.15422">new research</a> looked at Port Jackson sharks to find out. We found individual sharks adapt in different ways, depending where they came from.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/371446/original/file-20201126-17-10kqzy6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A Port Jackson shark swimming on the sea bed" src="https://images.theconversation.com/files/371446/original/file-20201126-17-10kqzy6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/371446/original/file-20201126-17-10kqzy6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=826&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371446/original/file-20201126-17-10kqzy6.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=826&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371446/original/file-20201126-17-10kqzy6.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=826&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371446/original/file-20201126-17-10kqzy6.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1038&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371446/original/file-20201126-17-10kqzy6.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1038&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371446/original/file-20201126-17-10kqzy6.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1038&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Port Jackson sharks in Jervis Bay may be better at responding to climate change than those from The Great Australian Bight.</span>
<span class="attribution"><span class="source">Connor Gervais</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Port Jackson sharks from cooler waters in the Great Australian Bight found it harder to cope with rising temperatures than those living in the warmer water from Jervis Bay in New South Wales. </p>
<p>This is important because it goes against the general assumption that species in warmer, tropical waters are at the greatest risk of climate change. It also illustrates that we shouldn’t assume all populations in one species respond to climate change in the same way, as it can lead to over- or underestimating their sensitivity. </p>
<p>But before we explore this further, let’s look at what exactly sharks will be exposed to in the coming years. </p>
<h2>An existential threat</h2>
<p>In Australia, the grim reality of climate change is already upon us: we’re seeing intense <a href="https://doi.org/10.1038/s41558-019-0412-1">marine heat waves</a> and <a href="https://www.doi.org/10.1126/science.aan8048">coral bleaching</a> events, the disappearance of entire <a href="https://doi.org/10.1111/nph.16107">kelp forests</a>, <a href="https://doi.org/10.1071/MF16322">mangrove forest dieback</a> and the continent-wide <a href="https://doi.org/10.1016/j.jembe.2011.02.021">shifting of marine life</a>. </p>
<p>The southeast of Australia is a global change hotspot, with water temperatures rising at three to <a href="https://soe.environment.gov.au/theme/marine-environment/topic/2016/climate-change#:%7E:text=Ocean%20temperature,per%20decade%20(Figure%20MAR5).">four times the global average</a>. In addition to rising water temperatures, oceans are becoming <a href="https://www.ipcc.ch/srocc/home">more acidic</a> and the amount of oxygen is declining. </p>
<p>Any one of these factors is cause for concern, but all three may also be acting together. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/371449/original/file-20201126-23-17fty0j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Coral bleaching" src="https://images.theconversation.com/files/371449/original/file-20201126-23-17fty0j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371449/original/file-20201126-23-17fty0j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371449/original/file-20201126-23-17fty0j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371449/original/file-20201126-23-17fty0j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371449/original/file-20201126-23-17fty0j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371449/original/file-20201126-23-17fty0j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371449/original/file-20201126-23-17fty0j.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">Oceans act like a heat sink, absorbing 90% of the heat in the atmosphere. This makes marine environments highly susceptible to climate change.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>One may argue sharks have been around for millions of years and survived multiple climate catastrophes, including <a href="https://www.sea.museum/2020/01/16/ten-interesting-facts-about-sharks">several global mass extinctions events</a>. </p>
<p>To that, we say life in the anthropocene is characterised by changes in temperature and levels of carbon dioxide on a scale not seen for more than three million years. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/weve-just-discovered-two-new-shark-species-but-they-may-already-be-threatened-by-fishing-134067">We've just discovered two new shark species – but they may already be threatened by fishing</a>
</strong>
</em>
</p>
<hr>
<p>Rapid climate change represents an existential threat to all life on Earth and sharks can’t evolve fast enough to keep up because they tend to be long-lived with low reproductive output (they don’t have many pups). The time between generations is just too long to respond via natural selection.</p>
<h2>Dealing with rising temperatures</h2>
<p>When it comes to dealing with rising water temperature, sharks have two options: they can change their physiology to adapt, or <a href="https://doi.org/10.3354/meps13322">move towards the poles</a> to cooler waters. </p>
<p>Moving to cooler waters is one of the more obvious responses to climate change, while subtle impacts on physiology, as we studied, have largely been ignored to date. However, they can have big impacts on individual, and ultimately species, distributions and survival. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/371447/original/file-20201126-23-1p7kp58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Juvenile Port Jackson sharks" src="https://images.theconversation.com/files/371447/original/file-20201126-23-1p7kp58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371447/original/file-20201126-23-1p7kp58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371447/original/file-20201126-23-1p7kp58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371447/original/file-20201126-23-1p7kp58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371447/original/file-20201126-23-1p7kp58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371447/original/file-20201126-23-1p7kp58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371447/original/file-20201126-23-1p7kp58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Juvenile Port Jackson sharks from our study.</span>
<span class="attribution"><span class="source">Connor Gervais</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We collected Port Jackson sharks from cold water around Adelaide and warm water in Jervis Bay. After increasing temperatures by 3°C, we studied their thermal limits (how much heat the sharks could take before losing equilibrium), swimming activity and their resting metabolic rate. </p>
<p>While all populations could adjust their thermal limits, their metabolic rate and swimming activity depended on where the sharks were originally collected from.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/photos-from-the-field-these-magnificent-whales-are-adapting-to-warming-water-but-how-much-can-they-take-148329">Photos from the field: these magnificent whales are adapting to warming water, but how much can they take?</a>
</strong>
</em>
</p>
<hr>
<p>With a rise in water temperature of just 3°C, the energy required to survive is more than twice that of current day temperatures for the Port Jackson sharks in Adelaide. </p>
<p>The massive shift in energy demand we observed in the Adelaide sharks means they have to prioritise survival (coping mechanisms) over other processes, such as growth and reproduction. This is consistent with several other shark species that have slower growth when exposed to warmer waters, including <a href="https://doi.org/10.1007/s00227-018-3427-7">epaulette sharks</a> and <a href="https://doi.org/10.1071/MF03023">bonnethead sharks</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/371440/original/file-20201126-15-kkfr7c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two brown, spiralled shark eggs: one is about half the size of the other" src="https://images.theconversation.com/files/371440/original/file-20201126-15-kkfr7c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371440/original/file-20201126-15-kkfr7c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371440/original/file-20201126-15-kkfr7c.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371440/original/file-20201126-15-kkfr7c.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371440/original/file-20201126-15-kkfr7c.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371440/original/file-20201126-15-kkfr7c.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371440/original/file-20201126-15-kkfr7c.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 smaller egg to the left is from Port Jackson sharks near Adelaide, while the right egg is from sharks in Jervis Bay.</span>
<span class="attribution"><span class="source">Connor Gervais</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>On the other hand, a 3°C temperature rise hardly affected the energy demands of the Port Jackson sharks from Jervis Bay at all. </p>
<h2>Threatening the whole ecosystem</h2>
<p>Discovering what drives responses to heat is important for identifying broader patterns. For example, the decreased sensitivity of the Jervis Bay sharks likely reflects the thermal history of the region. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sharks-one-in-four-habitats-in-remote-open-ocean-threatened-by-longline-fishing-120849">Sharks: one in four habitats in remote open ocean threatened by longline fishing</a>
</strong>
</em>
</p>
<hr>
<p>Australia’s southeastern coastline is warmed by the East Australian Current, which varies in strength both throughout the year and from year to year. With each generation exposed to these naturally variable conditions, populations along this coastline have likely become more tolerant to heat. </p>
<p>Populations in the Great Australian Bight, in contrast, don’t experience such variability, which may make them more susceptible to climate change.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/JK-5VtIuC0g?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>So why is this important? When sharks change their behaviour it affects the whole ecosystem. </p>
<p>The implications range from shifts in fish stocks to conservation management, such as where marine reserves are assigned. </p>
<p>Sharks and rays generally rank at the top or in the middle of the food chain, and<br>
have <a href="https://doi.org/10.1016/j.tree.2019.01.005">critical ecosystem functions</a>. </p>
<p>Port Jackson sharks, for example, are predators of urchins, and urchins feed on kelp forests — a rich habitat for hundreds of marine species. If the number of sharks decline in a region and the number of urchins increase, then it could lead to the loss of kelp forests. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/371445/original/file-20201126-19-1ovbrse.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The top of a swimming Port Jackson shark" src="https://images.theconversation.com/files/371445/original/file-20201126-19-1ovbrse.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371445/original/file-20201126-19-1ovbrse.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371445/original/file-20201126-19-1ovbrse.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371445/original/file-20201126-19-1ovbrse.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371445/original/file-20201126-19-1ovbrse.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371445/original/file-20201126-19-1ovbrse.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371445/original/file-20201126-19-1ovbrse.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">Port Jackson sharks feed on feed on urchins in kelp forests.</span>
<span class="attribution"><span class="source">Connor Gervais</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>What’s next?</h2>
<p>There’s little research dedicated to understanding how individuals from different populations within species respond to climate change. </p>
<p>We need more of this kind of research, because it can help identify hidden resilience within species, and also highlight populations at greatest risk. We have seen this in action in <a href="https://theconversation.com/heat-tolerant-corals-can-create-nurseries-that-are-resistant-to-bleaching-116675">coral bleaching events</a> in different parts of Australia, for example. </p>
<p>We also need a better handle on how a wide range of species will respond to a changing climate. This will help us understand how communities and ecosystems might fragment, as each ecosystem component responds to warming in different ways and at different speeds. </p>
<p>Steps need to be taken to address these holes in our knowledge base if we’re to prepare for what follows. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/one-fifth-of-ecosystems-in-danger-of-collapse-heres-what-that-might-look-like-148137">One-fifth of ecosystems in danger of collapse – here’s what that might look like</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/150460/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Even within a species, animals will suffer climate change differently. For sharks, it pays to live in warmer waters.Culum Brown, Professor, Macquarie UniversityConnor Gervais, Connor GervaisLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1105772019-01-29T01:20:43Z2019-01-29T01:20:43ZFarmed fish dying, grape harvest weeks early – just some of the effects of last summer’s heatwave in NZ<figure><img src="https://images.theconversation.com/files/255735/original/file-20190128-108348-ycw7kr.jpg?ixlib=rb-1.1.0&rect=395%2C309%2C2591%2C1657&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Queensland groper, typical of coral reefs off Queensland at 27°S were found in the Bay of Islands, north of Auckland, at 35°S.</span> <span class="attribution"><span class="source">from www.shutterstock.com</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>As the Australian heatwave is spilling across the Tasman and <a href="https://about.metservice.com/homepagerss/">pushing up temperatures in New Zealand</a>, we take a look at the conditions that caused a similar event last year and the impacts it had. </p>
<p>Last summer’s heatwave gave New Zealand its warmest summer and the warmest January on record. It covered an area of four million square kilometres (comparable to the Indian subcontinent), including the land, the eastern Tasman Sea and the Pacific east of New Zealand to the Chatham Islands.</p>
<p>In our <a href="https://iopscience.iop.org/article/10.1088/1748-9326/ab012a">research</a>, we looked at what happened and why, and found that the heatwave affected many sectors, leading to early grape harvests and killing farmed fish in parts of the country. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/coastal-seas-around-new-zealand-are-heading-into-a-marine-heatwave-again-110028">Coastal seas around New Zealand are heading into a marine heatwave, again</a>
</strong>
</em>
</p>
<hr>
<h2>Drivers of warmer than average conditions</h2>
<p>We used a combination of land and ocean temperature observations, large-scale analyses of the atmospheric circulation, and ocean modelling to understand the drivers of the 2017/18 summer heatwave. It was memorable for a number of extreme events and statistics. </p>
<p>The average air temperature was <a href="https://www.niwa.co.nz/news/the-record-summer-of-2017-18">2.2°C above the 1981-2010 normal</a> of 16.7°C, and it was the <a href="https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11985980">warmest summer ever recorded in more than 150 years</a>. The number of extreme warm days and warm nights was also the highest recorded, going back several decades. </p>
<p>The peak month was January 2018, 3.2°C above normal and the warmest month recorded in observations as far back as 1867. Ocean surface temperatures were similarly extreme, with a <a href="https://www.radionz.co.nz/national/programmes/up-this-way/audio/2018628386/marine-heatwave-it-s-never-been-that-hot-before">marine heatwave that lasted about five months</a>, at 2.0°C above normal at its peak. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/255986/original/file-20190129-108338-19sp0aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255986/original/file-20190129-108338-19sp0aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255986/original/file-20190129-108338-19sp0aj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255986/original/file-20190129-108338-19sp0aj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255986/original/file-20190129-108338-19sp0aj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255986/original/file-20190129-108338-19sp0aj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255986/original/file-20190129-108338-19sp0aj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The combined New Zealand annual land and sea surface temperature record, in °C, from 1867 to 2018, compared with the 1981-2010 average. The blue bars represent individual years, and the red line trends over groups of years.</span>
<span class="attribution"><span class="source">Jim Salinger</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The warming was mostly the result of very settled conditions over the country, especially to the east, bringing light winds, plenty of sun, and warm air from the subtropics. Such conditions in summer are associated with the positive phase of a <a href="https://www.niwa.co.nz/sites/niwa.co.nz/files/import/attachments/sam.pdf">polar ring of climate variability known as the Southern Annular Mode</a> (SAM), which brings high pressures (anticyclones) to New Zealand and parts of other southern hemisphere countries in the mid-latitudes, including southern Australia and Tasmania, southern Chile and Argentina. </p>
<p>The SAM was <a href="https://journals.ametsoc.org/doi/10.1175/JCLI-D-11-00474.1">strongly positive throughout last summer</a>, especially in January, and weak La Niña conditions were prevalent in the tropics. The light winds in the New Zealand region allowed the ocean surface to warm rapidly, without the usual turbulent mixing to transport the heat away. The warmest waters in the Tasman Sea formed an unusually thin layer near the surface.</p>
<h2>Impacts and repercussions</h2>
<p>New Zealand was affected by <a href="https://www.radionz.co.nz/news/on-the-inside/349437/from-unbelievable-summer-to-biblical-storm">more than its normal share of ex-tropical cyclones</a>, notably <a href="https://www.stuff.co.nz/business/102453304/cyclone-fehi-cost-insurers-39-million">Fehi</a> and <a href="https://www.stuff.co.nz/national/101624537/former-cyclone-gita-crosses-new-zealand-leaving-destruction-in-its-wake">Gita</a>. They brought strong winds, storm surges and <a href="https://www.bbc.com/news/world-asia-43123148">heavy rainfalls that caused flooding</a> as they passed through. The warm ocean waters around New Zealand would have helped maintain the intensity of the storms and supply moisture to drive the heavy downpours.</p>
<p>The warm conditions caused massive ice loss in South Island glaciers, estimated to be the largest annual loss of glacier ice in nearly 60 years of records for the Southern Alps. Satellite data from end-of-summer snowline measurements at the Tasman Glacier suggest that the Southern Alps lost 9% of glacier ice during last summer alone.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/255945/original/file-20190128-108364-14te30j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255945/original/file-20190128-108364-14te30j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=785&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255945/original/file-20190128-108364-14te30j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=785&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255945/original/file-20190128-108364-14te30j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=785&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255945/original/file-20190128-108364-14te30j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=987&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255945/original/file-20190128-108364-14te30j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=987&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255945/original/file-20190128-108364-14te30j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=987&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Franz Josef glacier on New Zealand’s West Coast advanced during the 1980s and 1990s but is now retreating.</span>
<span class="attribution"><span class="source">Andrew Lorrey/NIWA</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-birds-eye-view-of-new-zealands-changing-glaciers-97074">A bird’s eye view of New Zealand's changing glaciers</a>
</strong>
</em>
</p>
<hr>
<p>Warm air temperatures had a marked effect on managed and natural ecosystems. The Marlborough <a href="https://www.stuff.co.nz/business/100313102/hot-dry-weather-signals-early-grape-harvest-in-marlborough">grape harvest was unusually early</a> in 2018, two to three weeks ahead of the normal maturation time. Marine ecosystems were significantly disrupted. Coastal <a href="https://www.sciencedaily.com/releases/2016/07/160707151113.htm">kelp forests struggled to grow in the warm sea</a>. In southern New Zealand, the temperature threshold was breached three times, resulting in substantial losses of kelp canopies. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-marine-heatwave-has-wiped-out-a-swathe-of-was-undersea-kelp-forest-62042">A marine heatwave has wiped out a swathe of WA's undersea kelp forest</a>
</strong>
</em>
</p>
<hr>
<p>For the first time, <a href="https://www.stuff.co.nz/business/farming/aquaculture/104189647/salmon-industry-in-short-supply-turns-to-atlantic-seas-for-help">Atlantic salmon had to be imported</a> as <a href="https://www.stuff.co.nz/business/farming/aquaculture/101031695/hotterthannormal-water-kills-off-salmon-in-the-sounds">farmed fish died in salmon farms</a> in the Marlborough Sounds. Commercial fishers reported that snapper was spawning approximately six weeks early off the South Island coast, and <a href="https://www.stuff.co.nz/environment/104306474/rare-tropical-aussie-grouper-spotted-in-new-zealand-waters-after-summers-marine-heatwave">Queensland groper was reported in northern New Zealand</a>, 3000km out of range.</p>
<h2>Past and future</h2>
<p>The summer of 2017/18 shared some characteristics with another hot summer, way back in 1934/35. That season was so warm that it prompted a <a href="https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11983565">special report by the New Zealand Meteorological Service</a>. Conditions were similar: persistent high-pressure systems in the New Zealand region, positive SAM conditions, light winds over and around New Zealand, warm ocean surface and air temperatures. While those two summers shared some natural variations in the local climate, the recent summer was warmer for two reasons. </p>
<p>First, climate in the region is now more than half a degree warmer now than in the 1930s. Second, the <a href="https://journals.ametsoc.org/doi/abs/10.1175/1520-0442%282003%29016%3C4134%3ATITSAM%3E2.0.CO%3B2">SAM has been trending towards its positive phase</a> over the last few decades, making settled conditions over New Zealand more frequent now than in the 1930s. That trend is mostly related to the ozone hole that occurs in spring and early summer, cooling the polar atmosphere and <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010GL045384">driving the strongest winds farther south towards Antarctica</a>, leaving lighter winds and higher pressures over New Zealand.</p>
<p>Looking to the future, we can compare the conditions experienced in 2017/18 with what climate models predict for the future. We estimate that the extreme warm conditions of New Zealand’s last summer would be typical summer conditions by the end of the century, for an emissions scenario associated with a couple of degrees of global warming above pre-industrial temperatures. If emissions keep increasing as they have done in recent years, last summer will seem cool by the standards of 2100.</p><img src="https://counter.theconversation.com/content/110577/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Renwick receives funding from Victoria University of Wellington, the Ministry for Business, Innovation and Employment, and has received funding from the Marsden Fund administered by the Royal Society of NZ. </span></em></p><p class="fine-print"><em><span>Jim Salinger does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Analysis of last summer’s heatwave shows it killed farmed salmon and decimated kelp forests, as well as shifting grape harvests and fish spawning times forward by several weeks.Jim Salinger, Honorary Associate, Tasmanian Institute for Agriculture, University of TasmaniaJames Renwick, Professor, Physical Geography (climate science), Te Herenga Waka — Victoria University of WellingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/730692017-03-14T18:56:26Z2017-03-14T18:56:26ZKelps in southern Africa are thriving, but some key inhabitants of kelp forests are not<figure><img src="https://images.theconversation.com/files/160143/original/image-20170309-21020-ur795r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Kelp forests in South Africa are thriving but the marine life relying on it aren't. </span> <span class="attribution"><span class="source">Steven Benjamin</span></span></figcaption></figure><blockquote>
<p>……while far below</p>
<p>The sea-blooms and the oozy woods which wear</p>
<p>The sapless foliage of the ocean, know </p>
<p>Thy voice, and suddenly grow gray with fear</p>
</blockquote>
<p><em><a href="https://www.poetryfoundation.org/poems-and-poets/poems/detail/45134">PB Shelley (Ode to the West Wind)</a></em></p>
<p>There’s a forest in the extreme west of South Africa which very few people know much about. It’s 1000km long but only around 100m wide, and also extends along the rocky coastline of Namibia. This forest is a kelp forest. Kelps are <a href="http://www.geol.utas.edu.au/kelpwatch/facts_w.html">large brown seaweeds</a> and there are two main species in southern Africa, <em>Ecklonia maxima</em> and <em>Laminaria pallida</em>. These form the canopy, and they are mostly a few metres tall, although <em>Ecklonia</em> can reach 17m. </p>
<p>The forest is as productive per unit area as a tropical rain forest, and has a variety of diverse organisms. Many of the people who live on its fringes provide for themselves by extracting and selling food items from it, in a sense being modern “hunter-gatherers”. Some of these resources that live within kelp ecosystems are almost gone, and much of what is left is now collected illegally.</p>
<p>Around a quarter of the worlds coastlines, along cool-water rocky coasts, are populated by kelp forests. With climate change, they are on the move. As a result, a <a href="http://www.kelpecosystems.org/projects/">working group</a> was formed by the National Center for Ecological Analysis and Synthesis <a href="http://www.pnas.org/cgi/doi/10.1073/pnas.1606102113">to study these changes</a> on a global scale. The study showed that kelp abundance is declining in 38% of world regions, but increasing in 27%. This means that almost two-thirds of global kelp forests are changing.</p>
<p>Seawater temperature is critical for kelp survival, and the cooler the water the higher the amounts of dissolved nutrients necessary for kelp growth. Global seas are reacting to climate change differently on different continents. In Europe, considerable warming is causing kelp forests to disappear in the south, like Portugal for example, but increase in abundance towards the Arctic. But in southern Africa, for example, kelps are thriving.</p>
<p>While kelps themselves are doing quite well, some of their inhabitants are not.</p>
<h2>Not the same everywhere</h2>
<p>Perhaps the most severe effects of climate change on kelp are in Australia. Here, the edges of the kelp-dominated Great Southern Reef <a href="https://theconversation.com/australias-other-reef-is-worth-more-than-10-billion-a-year-but-have-you-heard-of-it-45600">have seen considerable diebacks</a> of kelp due to large warming events. These are also associated with southward movement of <a href="https://theconversation.com/sydneys-waters-could-be-tropical-in-decades-heres-the-bad-news-31523">kelp-eating tropical fish</a> and <a href="http://www.pnas.org/content/106/52/22341.short">urchins</a>. </p>
<p>In the extreme south of Australia, in Tasmania, beautiful forests of the giant kelp <em>Macrocystis pyrifera</em> have nowhere to go following considerable warming and increased grazing. And its seems likely they will soon <a href="http://www.themercury.com.au/lifestyle/tasweekend-tassies-disappearing-underwater-forests/news-story/a62e76e745b46e6a69caadac50181bcc">cease to exist</a>.</p>
<p>In South Africa, kelps are having a more productive time, for now. If there was a poem on these forests, it should perhaps be called “Ode to the Southeast Wind”. These winds, which cause large-scale upwelling of cool, nutrient-rich water, have been increasing in intensity and duration in recent years <a href="http://www.sciencedirect.com/science/article/pii/S092479631400311X">in southwestern South Africa</a>.</p>
<p>There’s evidence that kelp forests have become more abundant at the southern <a href="http://www.tandfonline.com/doi/abs/10.2989/1814232X.2014.954618">end of their range</a>, and also a dispersal event around 2006 meant that a kelp forest of <em>Ecklonia maxima</em> appeared at De Hoop Nature Reserve, around 70km east of where <a href="http://www.tandfonline.com/doi/abs/10.2989/1814232X.2012.675125">forests previously grew</a>.</p>
<p>Sea water climate change scenarios suggest that further north, in Namibia and the Northern Cape province of South Africa, warming is occurring and conditions may become gradually less favourable for kelp forests in this region.</p>
<h2>Ripple effect</h2>
<p>Kelps in South Africa are actually doing quite well because of cooling waters and increased nutrients. But some of the major iconic species of kelp ecosystems, like lobster and abalone are not doing well. This could be for a number of reasons such as fishing and climate change. </p>
<p>Major marine resources that live in these kelp forests are abalone (<em>Haliotis midae</em>) and rock lobster (<em>Jasus lalandii</em>), and they too have undergone notable changes, and unlike kelp, are not doing so well. Both abalone and rock lobster are now in great trouble due to overfishing, with populations estimated at a few percent of original abundances. In addition, shifts in the abundance of some species (rock lobster) have seriously impacted other species (abalone).</p>
<p>In the early 1990s a major eastward shift brought lobsters east of False Bay, while illegal fishing of abalone was on the rise. This resulted in considerable changes <a href="http://www.tandfonline.com/doi/abs/10.2989/1814232X.2010.538138">in the kelp forests</a>, given that lobsters are predators that eat major kelp grazers, especially the spiny sea urchin (<em>Parechinus angulosus</em>), but also juvenile abalone that hide beneath the urchin spines. Following a decline in these grazers, due to lobster predation, kelps and seaweeds became more abundant, while many animal groups, that are eaten by lobsters, were reduced massively. </p>
<p>The kelp forests of South Africa were extensively studied in the 1970s, but little biological study has gone on since then. There’s a dire need to understand the country’s altered kelp forests; how they work, the effects of environmental change, and the dynamics of these changed systems, with new patterns of dominance of different species.</p><img src="https://counter.theconversation.com/content/73069/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Bolton receives funding from the National Research Foundation (South Africa).</span></em></p><p class="fine-print"><em><span>Laura Blamey receives funding from the National Research Foundation (South Africa).</span></em></p>Climate change affects kelp forests all over the world differently. In southern Africa, they seem to be thriving which should be good news. The marine life relying on kelp, are however struggling.John Bolton, Professor of Biology and a marine plant biologist, University of Cape TownLaura Blamey, Marine Ecologist in the Department of Biological Sciences, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.