tag:theconversation.com,2011:/africa/topics/ocean-chemistry-6170/articlesOcean chemistry – The Conversation2015-08-12T10:18:34Ztag:theconversation.com,2011:article/449542015-08-12T10:18:34Z2015-08-12T10:18:34ZTemporary ban on fishing reflects how fragile Arctic ecosystem is<figure><img src="https://images.theconversation.com/files/90491/original/image-20150731-17151-6qzm4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Time to get cracking: a Canadian research vessel in the Arctic. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/usnavyresearch/16417228361/in/photolist-s7UQS-5nz4hW-fbMuv1-fbxe3i-r1JA2p-8F3QBD-8F3QD2-3pVDAV-vTdKiB-4ExGtv-hivLP7-vTFrYH-vBdM8u-vTdYC2-vT2AeU-vTc9rV-vAB4Z7-vB4N1Q-uWD4cJ-vTETBi-g6rTRS-fy5A8i-vRivSG-vB7N5v-uWH8ec-6RxWZJ-5nozeL-oTHfgF-98wPFT-98zYwU">John F. Williams/Office of Naval Research</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>As climate change melts the ice in the Arctic, areas that had previously been closed in the Arctic Ocean are becoming available to fishing. Five countries bordering the Arctic – Canada, Russia, the United States, Norway and Denmark – recently agreed to a <a href="https://www.regjeringen.no/globalassets/departementene/ud/vedlegg/folkerett/declaration-on-arctic-fisheries-16-july-2015.pdf">temporary fishing ban</a> in the region.</p>
<p>The decision shows how a warming Arctic raises a number of unanswered economic and scientific issues as fishing expands, questions I’ve studied as a researcher in fisheries economics. </p>
<p>Many scientists applaud the temporary ban decision because it signals the willingness of political leaders to be proactive rather than <a href="http://www.nature.com/nclimate/journal/v1/n9/nclimate1301/metrics/blogs">reactive</a> in ensuring that we have the science in place to support sustainable use of the resources.</p>
<p>What is more, the agreement is a beautiful application of the precautionary approach whereby prudent action is being taken early enough in the face of uncertainty and potentially serious risk. </p>
<p>Ultimately, what’s needed is a fisheries management regime that includes closing of a substantial part of the Arctic ocean to commercial fishing. In the meantime, this temporal decision will buy time to allow scientific information to be gathered before the inevitable expansion of commercial scale fishing to the area becomes a reality. </p>
<p>So what are the risks of commercial fishing in the Arctic and what kind of information will scientists be gathering? </p>
<h2>Impact on the locals</h2>
<p>First off, this agreement will help avoid the usual “gold rush” that follows “newly” found natural resources and the mess it usually leaves behind.</p>
<p>In the 1990s, a number of deep-sea fish species, such as orange roughy, were discovered in different parts of the global ocean, from Namibia to South Africa and Australia. A big rush of commercial fishing followed before we understood that these fishes grow very slowly and live several decades, which resulted in their <a href="http://www.marine-conservation.org/media/filer_public/2011/09/01/lenfest_deep_sea_rsr.pdf">depletion in many parts of the world</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/90478/original/image-20150731-17146-z42o8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/90478/original/image-20150731-17146-z42o8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/90478/original/image-20150731-17146-z42o8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/90478/original/image-20150731-17146-z42o8h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/90478/original/image-20150731-17146-z42o8h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/90478/original/image-20150731-17146-z42o8h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/90478/original/image-20150731-17146-z42o8h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/90478/original/image-20150731-17146-z42o8h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="attribution"><a class="source" href="https://www.flickr.com/photos/duncan/478985951/in/photolist-5VGgsm-k4aHAm-3bk6r4-3bkcgk-3bpEWm-3bkapv-5t1VPj-9pw42e-5t1V9C-5t1VHL-5sWwzP-4W7BtL-8vfJ6-JjW9n-45RX3Z-45S2ez-5oZLLL-45RUT2-45RZkT-4zqXs5-bbkYW4-JjVQt-tNMNn-edutH8-31JVUd-7EAwi3-6dMJfV-9ArCMz-9GVZfY-618GF9-5i3oMR-8zSREe-fg5xr8-acgvKm">duncan c/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
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<p>In the Arctic Ocean, there are already a <a href="http://onlinelibrary.wiley.com/doi/10.1111/faf.12106/abstract">number of species caught</a>, including the Arctic char, sardine cisco, capelin, Atlantic herring, northern prawn and Greenland halibut. Most of the current catch is landed by small-scale fisheries and is used mainly for <a href="http://www.botany.hawaii.edu/basch/uhnpscesu/pdfs/sam/Zeller2006SmallAS.pdf">local consumption</a>.</p>
<p>The indigenous peoples of the Arctic region depend heavily on traditional foods harvested from the local environment, making them vulnerable to the effects of climate change and other environmental stressors acting in the Arctic environment.</p>
<p>Coastal indigenous peoples who harvest large quantities of marine species consume some of the harvest and trade some with inland groups in exchange for other indigenous foods such as plants, berries and terrestrial mammals. </p>
<p>Fish are generally consumed in the summer and marine mammals are consumed in the winter, whereas seabirds are often consumed in the spring. As a result, socially and culturally, these fisheries are of immense importance even if the actual quantity of fish caught is not large in a commercial sense.</p>
<h2>Chemical changes to the ocean</h2>
<p>Climate science and marine ecosystem research inform us that marine fish species are already being <a href="http://www.ncbi.nlm.nih.gov/pubmed/23676754">impacted by climate change</a>. </p>
<p>They will continue to come under increasing pressure over the course of the 21st century as global climate change, ocean acidification and deoxygenation (the <a href="http://www.annualreviews.org/doi/abs/10.1146/annurev.marine.010908.163855">loss of oxygen</a> in oceans from climate change) combine with other stresses on the ocean to change the primary productivity, growth and distribution of fish populations. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/91346/original/image-20150810-11068-1at7okx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/91346/original/image-20150810-11068-1at7okx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/91346/original/image-20150810-11068-1at7okx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/91346/original/image-20150810-11068-1at7okx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/91346/original/image-20150810-11068-1at7okx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/91346/original/image-20150810-11068-1at7okx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/91346/original/image-20150810-11068-1at7okx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/91346/original/image-20150810-11068-1at7okx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Climate change can affect wildlife directly through ocean acidification or indirectly by affecting prey.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/ashokbo/18992030719/in/photolist-uWg84v-iwRLo-rAZoF5-nSaNDg-8oqUZY-rjvCVA-qEiKaX-52Mycw-rjvD3E-rB5UJp-rjvCXu-hjv1wv-5TZfN-6Hq6jh-6Hm3Ck-9irVQv-6e6msP-9QpqvA-58kFqL-fyWfxb-7u8Wzf-7jJ6Xe-hkKqMR-52HjCr-rAZiET-rjD4En-rjD4yF-eVKoh5-fwtaEx-fwHruY-ph3FMd-cVMcum-dXt3Hv-rAZox9-fyWfr3-n9oZp-d3hSmJ-d3hTTd-7u8Wrs-2gVNps-fyFWX4-vZQaJH-fyFX6v-rB5URP-wXerMB-qWAa1n-5TsJz-4qoeQA-vFTtkU-fwtaHr">ashokbo/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Shellfish species, marine mammals and seabirds commonly harvested in the Arctic region for consumption are likely to be affected by climate change and ocean acidification, either by harming the life functions of the organisms or indirectly through their effects on major prey in the ecosystem. </p>
<p>Deoxygenation is already resulting in a change of where some fish species spend their lives: along the Japanese continental slope, decreases in mid-depth oxygen content over the last 60 years have resulted in <a href="http://www.annualreviews.org/doi/abs/10.1146/annurev-marine-120710-100849">Pacific cod shifting </a>their distributions to shallower depths.</p>
<p>Going forward, some key scientific questions that are yet to be comprehensively addressed include:</p>
<ul>
<li><p>As CO2 and other greenhouse gas emissions increase, how could the marine ecosystems and the living marine resources of the Arctic be affected?</p></li>
<li><p>How resilient will the ecosystems and the living resources in them be as the Arctic Ocean becomes warmer? If sea ice melts faster and ocean acidification accelerates, will the the ocean become deoxygenated and sea levels rise?</p></li>
<li><p>How could these biophysical and ecological impacts of climate change affect peoples of the Arctic through economic social and cultural channels?</p></li>
<li><p>How could the population of marine mammals be affected, and how might this affect the thriving whale-watching industry in the region? </p></li>
</ul>
<h2>Fisheries and protected areas</h2>
<p>Changing marine ecosystem conditions are already redistributing fish species and accelerating the invasion in the Arctic Ocean of species from lower latitudes. This means further scientific exploration of the consequences of changing currents and future management arrangements is needed – including the economic and social effects on the peoples and economies of the Arctic countries.</p>
<p>These key scientific questions relate to how climate change is likely to affect the governance of what would be international fisheries – that is, fisheries targeting fish stocks that migrate between the exclusive economic zones, or EEZs, of two or more countries. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/91345/original/image-20150810-11104-d9gg3m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/91345/original/image-20150810-11104-d9gg3m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/91345/original/image-20150810-11104-d9gg3m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/91345/original/image-20150810-11104-d9gg3m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/91345/original/image-20150810-11104-d9gg3m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/91345/original/image-20150810-11104-d9gg3m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/91345/original/image-20150810-11104-d9gg3m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/91345/original/image-20150810-11104-d9gg3m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">What rules apply when trawlers head to the Arctic?</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/18091975@N00/5204140700/in/photolist-8VSzHN-4msL6A-jSmjJy-e6iPgU-ofiaMZ-ottAM3-2rW2X1-awWumW-qREiBW-5E72Ti-97Mn3q-r4koG3-r6xNB7-48X3bn-2HHBf6-nBmtSp-7QHoVB-97LFYm-eAvdNd-atV4UK-ow7FiV-f2pkCs-6z83Jn-dxKxnU-6zc7QN-93CeDv-vDxs8-ebvWa3-ebvWyJ-ebvXkW-TuKAa-nBnq8g-nBmAbq-2mvCLS-41yiNX-9cxAuy-ebqg78-BSuGo-38PBHq-nV9nUp-x61hz-8Te6Ly-2EYh2A-4hKXaF-4N1ngV-7FoPpc-ocJosC-ediUei-oanHNK-udWzr9">Eoin Gardiner/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>For example, Pacific salmon spend their lives in US and Canadian waters, and highly migratory stocks such as tuna straddle the waters of countries and the high seas. Some stocks spend all their lives in the high seas. </p>
<p>These fish stocks are usually managed jointly by the countries sharing the fish – for example, the US and Canada jointly manage Pacific salmon and halibut. But the increased likelihood of abrupt and unpredictable changes in the productive potential and migratory behavior of exploited fish stocks under climate change may threaten current joint management arrangements. </p>
<p>Another open question is what happens when the temporary ban ends. A permanent ban on commercial fishing and the creation of marine protected areas (MPAs) would buffer the Arctic ecosystem from some of the uncertainty in the future. </p>
<p>Like a diversified portfolio of stocks, MPAs help to protect us from errors and mistakes in the science, policy design and implementation of fisheries regulation. In the event of such mistakes, the fish protected in the MPA could help <a href="http://dx.doi.org/10.1890/1051-0761(1998)8%5BS72:ITPPIF%5D2.0.CO;2">replenish the fished area</a> in the same way that conservative investments in a portfolio can help a portfolio recover faster after a stock market meltdown. </p>
<p>We need to understand what the impact of the Arctic’s melting are for both research and policy development. We already know the Arctic is changing rapidly; better knowledge of those changes will help inform effective multinational fisheries governance.</p><img src="https://counter.theconversation.com/content/44954/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rashid Sumaila receives funding from the Social Science and Humanities Council of Canada -OceanCanada Partnership; the Natural Sciences Research Council of Canada, the Belmont Fund, GenomeCanada.</span></em></p>A melting Arctic means new areas will be open to commercial fishing but scientists – and bordering countries – say they need time to study the ecological and economic risks.Rashid Sumaila, Director & Professor, Fisheries Economics Research Unit, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/303922014-08-15T15:39:04Z2014-08-15T15:39:04ZThe way the wind blows may not be enough to prevent ocean ‘dead zones’ growing<figure><img src="https://images.theconversation.com/files/56609/original/rjgvxz7b-1408105600.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Enormous algal blooms off Cornwall, which can lead to low oxygen waters.</span> <span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File:Cwall99_lg.jpg">NASA</a></span></figcaption></figure><p>The world’s oceans are plagued with the problem of “dead zones”, areas of high nutrients (such as nitrogen and phosphorus) in which plankton blooms cause a major reduction of oxygen levels in the water. Sea creatures need oxygen to breathe just as we do, and if oxygen levels fall low enough <a href="http://www.newscientist.com/article/dn14835-marine-dead-zones-leave-crabs-gasping.html">marine animals can suffocate</a>. This commonly happens around coastlines where fertilisers are washed from fields into rivers and the sea, but also mid-ocean, where currents trap waters in gyres (large systems of rotating ocean currents).</p>
<p>To date most studies have shown that these dead zones have been growing with global warming. But a <a href="http://www.sciencemag.org/content/345/6197/665">recent study</a> published in Science by Curtis Deutsch and colleagues suggests that the ocean’s largest anoxic zone – where there has been a total depletion of oxygen – in the eastern tropical North Pacific, may in fact shrink due to weakening trade winds caused by global warming. </p>
<p>The <a href="http://oceanservice.noaa.gov/education/kits/currents/05currents2.html">trade winds</a> drive water away from the coast, and the gap is filled by new cold and nutrient-rich waters that come up from the deep. These nutrients trigger algae and plankton blooms upon which larger animals feed, which builds up an accumulation of organic matter. As bacteria decompose this organic matter the oxygen in the water is depleted. This causes low oxygen areas, such as the <a href="http://depts.washington.edu/aog/oxygen-minimum-zones/">oxygen minimum zones</a> (OMZs) with very low oxygen content found at intermediate ocean depths.</p>
<p>Weaker trade winds would mean less upwelling of these deep nutrient-rich waters, and consequently less plankton and less oxygen depletion. Deutsch and colleagues affirm that although initial oxygen content will be lower due to higher temperatures, oxygen demand will decrease as trade winds do. So, the result would be that low oxygen areas in the tropical north Pacific would shrink.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/56547/original/2ktvn4dh-1408028153.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/56547/original/2ktvn4dh-1408028153.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=354&fit=crop&dpr=1 600w, https://images.theconversation.com/files/56547/original/2ktvn4dh-1408028153.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=354&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/56547/original/2ktvn4dh-1408028153.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=354&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/56547/original/2ktvn4dh-1408028153.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=445&fit=crop&dpr=1 754w, https://images.theconversation.com/files/56547/original/2ktvn4dh-1408028153.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=445&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/56547/original/2ktvn4dh-1408028153.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=445&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Map showing low oxygen areas (in blue).</span>
<span class="attribution"><a class="source" href="http://www.washington.edu/news/2014/08/07/oceans-most-oxygen-deprived-zones-to-shrink-under-climate-change/">C. Deutsch/University of Washington</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A natural problem exacerbated by man</h2>
<p>Natural dead zones can be found worldwide, particularly near regions where strong upwelling occurs. These natural dead zones have typically had low oxygen levels over huge lengths of time, due to ocean circulation patterns that prevent mixing. Although these OMZs are natural, they can become larger and more intense due to human activities, such as prolonged and intensive use of fertilisers, changes in land use, deforestation, soil erosion, global warming, and waste waters from cities or industry. All these are well known to cause algal blooms and so drive the expansion of oxygen-depleted areas. In fact, dead zones caused by these human factors have <a href="https://theconversation.com/coastal-dead-zones-on-the-rise-15496">increased over time</a>. Naturally occurring OMZs have also been expanding <a href="http://www.newscientist.com/article/dn16477-global-warming-could-suffocate-the-sea.html">as temperature rises</a>, so the paper’s prediction that such oxygen minimum zones would shrink flies in the face of previous studies.</p>
<h2>Rising temperatures pose problems</h2>
<p>Animals increase their respiration rates as temperature rises, so they need more oxygen to breathe at higher temperatures. Warmer water also dissolves less oxygen, so as climate change warms the oceans the amount of oxygen decreases, making the effects on marine life even more acute.</p>
<p>Warming also encourages <a href="http://centerforoceansolutions.org/climate/impacts/ocean-warming/water-column-stratafi/">water stratification</a>, where the water separates into layers based on temperature or salinity, creating a physical barrier that prevents oxygen reaching deeper waters.</p>
<p><a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2009.02094.x/abstract">Previous studies</a> have predicted a weakening of trade winds in tropical areas, but have also forecasted changes to low-pressure weather fronts over coastlines that would lead to stronger winds, sufficient to replace any upwelling effect lost by weaker trade winds. </p>
<p>It seems likely that, in the same way, greater water stratification will lead to a worsening and expansion of dead zones, counteracting any effect the weakening trade winds might have to halt the process of de-oxygenation, and the paper’s authors acknowledge that this is possible.</p>
<p>Taking everything into account, it seems that the process of warming oceans under climate change will inexorably lead to larger areas of oxygen-poor ocean, with all the knock-on effects for marine life that entails.</p><img src="https://counter.theconversation.com/content/30392/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Raquel Vaquer-Sunyer does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The world’s oceans are plagued with the problem of “dead zones”, areas of high nutrients (such as nitrogen and phosphorus) in which plankton blooms cause a major reduction of oxygen levels in the water…Raquel Vaquer-Sunyer, Marie Curie post-doctoral researcher, Lund UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/299162014-07-31T14:39:05Z2014-07-31T14:39:05ZBefore we plunder the deep ocean further we must take stock of what could be lost<figure><img src="https://images.theconversation.com/files/55335/original/ht9g9xdx-1406734833.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Will what lies beneath still be there once we've finished with it?</span> <span class="attribution"><a class="source" href="http://pixabay.com/en/animal-asia-blue-dark-deep-depth-18719/">PublicDomainPictures</a></span></figcaption></figure><p>The deep sea is the largest habitat on earth and incredibly important to humans, but it faces many threats – from increased human exploitation to the effects of climate change. As this exploitation expands we need to decide to what extent we will try to conserve the oceans, and this is a decision that must be informed by what the oceans provide. This was the motivation for <a href="http://www.biogeosciences.net/11/3941/2014/bg-11-3941-2014.html">our study</a>, published in the journal Biogeosciences.</p>
<p>One of the constant challenges faced by deep-sea researchers is the impression often held that the deep-sea is too unknown and remote to be important to humans. This makes it an uphill battle to explain why our research is of more than just scientific interest. The fact that the deep oceans are largely in international waters outside national jurisdiction means that its importance is truly global, because it is only at a planet-wide level that they can be properly managed.</p>
<p>We are on the verge of expanding the range of what we take from the sea: developments such as <a href="http://worldoceanreview.com/en/wor-1/energy/marine-minerals/">manganese nodule mining</a> are closer to fruition, terrestrial supplies of rare earth elements are dwindling making the massive reservoirs under the ocean more attractive, and <a href="http://www.nytimes.com/2010/11/09/science/09seafloor.html?_r=0">mining claims</a> for massive sulfides, rich in elements used in electronics, are likely to start in the next year. </p>
<p>This is the time to discuss deep-sea stewardship before it is already underway. Already commercial fishing has expanded to encompass more species, taking more from the sea with ramifications for the entire marine ecosystem. We need to realise how these ecosystems are important to human society now, so that those who are beginning to harvest yet more resources from the oceans can see what impact that may have. </p>
<p>In addition to summarising what the deep sea provides to society already, we also emphasise that a different approach needs to be taken. For example, manganese nodules take centuries or longer to form and are not renewable. Many commercial fish stocks are in decline – even with precautionary management. Fishing is often treated more as mining than management of a living resource; no time is allowed for certain slow-growing deep-sea fish stocks to recover resulting in the complete loss of the stock.</p>
<h2>Much more than just fish and fuel</h2>
<p>It’s not just the biological resources that are important. Because of its vast size, the physical and chemical aspects of the ocean essentially shape and regulate the way the planet works. </p>
<p>One of the most important services provided by the deep sea is its role in gas cycling: as one of the largest sinks for greenhouse gases on the planet, the world would not look like it does now without the deep sea. Already the ocean has <a href="http://www.pmel.noaa.gov/co2/story/Ocean+Carbon+Uptake">absorbed a massive amount</a> of the CO<sub>2</sub> we have released, bearing the brunt of the human impact on the climate. There are also <a href="https://theconversation.com/japans-quest-to-tap-the-natural-gas-beneath-the-ocean-floor-26770">vast reservoirs of methane</a> under the seafloor, which is consumed by bacterial and biological processes when it is released, preventing it from reaching the atmosphere and exacerbating the effects of global warming.</p>
<p>Also vital is the <a href="http://www.soest.hawaii.edu/oceanography/courses/OCN626/respiration%20and%20efficiency.pdf">remineralisation of nutrients</a> which provides the nitrogen, phosphate, and other nutrients needed to sustain the most productive surface fisheries on the planet. When that deep, nutrient rich water comes to the surface it stimulates plankton to create the base of the most productive marine food webs, which in turn feed billions of humans.</p>
<p>The most important result of this study is to highlight the diversity of what ocean habitats offer to humans for our benefit, from the deep-sea trenches to vents and seeps. While this vast environment still contains a staggering list of unknowns, what we do know highlights the extent of what it provides to society. From materials for jewellery or electronics to oil and gas and other future potential energy reserves or novel pharmaceuticals, its value should be recognised. In this way, as we decide to use it more in the future we work to avoid damaging or losing the services it already provides. </p>
<p>What the ocean provides reaches all across humankind, from fishers providing food or income from the sea, directly or indirectly, or those far removed from the ocean whose climates are changing less fast than they would if the deep ocean was not absorbing 25-50% of all the CO<sub>2</sub> already released into the atmosphere since the industrial revolution.</p>
<p>The importance of these services makes it less like many of the other systems that are managed and so the traditional methods and frameworks need to be changed. We hope that the managers, stakeholders and scientists involved with the ocean’s resources will be able to use our work to develop their understanding of the interconnected nature of everything the deep sea has to offer.</p><img src="https://counter.theconversation.com/content/29916/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>The deep sea is the largest habitat on earth and incredibly important to humans, but it faces many threats – from increased human exploitation to the effects of climate change. As this exploitation expands…Jeroen Ingels, Postdoctoral Research Fellow, Plymouth Marine LaboratoryAndrew Thurber, Assistant Professor (Sr. Research) in Ocean Ecology and Biogeochemistry, Oregon State UniversityLicensed as Creative Commons – attribution, no derivatives.