tag:theconversation.com,2011:/us/topics/snailfish-14156/articles
Snailfish – The Conversation
2021-04-27T12:08:37Z
tag:theconversation.com,2011:article/159734
2021-04-27T12:08:37Z
2021-04-27T12:08:37Z
Fish-inspired soft robot survives a trip to the deepest part of the ocean
<p>The deepest regions of the oceans still remain one of the least explored areas on Earth, despite their considerable scientific interest and the richness of lifeforms inhabiting them. </p>
<p>Two reasons for this are the low temperatures and enormous pressures exerted at such depths, which require the exploration equipment be carefully shielded inside high-strength metal or ceramic chambers to withstand them. This makes deep-sea exploration vessels bulky, expensive and unwieldy, as well as difficult to design, manufacture and transport. </p>
<p>But a new small self-powered underwater robotic fish appears to offer an alternative. According to <a href="https://www.nature.com/articles/s41586-020-03153-z">a recent paper</a>, the robot was able to reach the deepest part of the Pacific Ocean – the Mariana Trench – at a depth of almost 11 km (6.8 miles). </p>
<p>The pressure there is more than a thousand times that on the surface of the sea. Yet various animals, including fish, are able to withstand this staggering pressure and have adapted to life in such adverse conditions. The morphology and skull structure of one of these marine organisms, <a href="https://theconversation.com/how-we-found-worlds-deepest-fish-in-the-mariana-trench-and-why-we-must-keep-exploring-35743">the hadal snailfish</a>, reportedly inspired the design of this remarkable robot swimmer.</p>
<p>The main breakthrough that enabled this significant achievement was a specially-designed compliant polymer body which deforms, without breaking, under high pressure. The team of researchers from Hangzhou in China were able to embed the delicate electronic components required for power, movement and control in a protective silicone matrix. </p>
<p>The electronic components were separated from each other, instead of being tightly packed together as is the usual practice, to make them more resilient to the pressure, similar to the skull bones of the snailfish. </p>
<p>The robot also looks like the snailfish, with an elongated body and tail, as well as two large side fins made of thin silicone. The fins flap to propel the small robot, which measures only 22cm (8.7 inches) in length with a wingspan of 28cm. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-do-creatures-living-in-the-deep-sea-stay-alive-given-the-pressure-111940">Curious Kids: how do creatures living in the deep sea stay alive given the pressure?</a>
</strong>
</em>
</p>
<hr>
<p>The fins are not operated by rigid motors, but by soft artificial muscles. The muscles contain dielectric elastomers – a class of smart materials which contract when electrical voltage is applied to create large movements. </p>
<p>Disk-shaped dielectric elastomer elements create the fin flapping motion that propels the robot, reaching speeds of up to about half a body-length per second (around 0.2 km/h), even at significant depths. </p>
<p>However, this type of actuators – the parts that make a machine move – requires very high voltage. A compact high-voltage amplifier multiplies the lithium-ion battery voltage more than a thousand times to meet this requirement, while an infrared receiver allows remote control of the robot. The soft fins and soft actuators were carefully designed to survive and perform well at the low temperatures and high pressures of the deep-sea environment. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/2hVjTG4aYyE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Free swimming in the deep lake.</span></figcaption>
</figure>
<p>The team performed extensive computational studies and laboratory testing of the propulsion methodology and of how the electronics cope under extreme pressures. Then, they conducted free-swimming field tests, first in a deep lake, then at the South China Sea at depths of more than 3km, before deploying it in the Mariana Trench. </p>
<p>In the Mariana field tests, the robot was mounted on a deep-sea lander, so wasn’t allowed to swim freely. But, it was able to maintain its flapping motion, as recorded by the cameras of the lander, for 45 minutes at a depth of 10,900 metres.</p>
<h2>Soft robots</h2>
<p>This deep-sea swimmer is an example of a new generation of robots inspired by living organisms, both animals and plants. They are built exploiting the advantages of compliant materials like silicone and other polymers, gels or even textiles. </p>
<p>These robots can bend, yield and adapt in response to forces from their environment, so are inherently safer to work next to humans compared to the typical rigid industrial robots. On the other hand, their design, actuation, sensing and control can pose significant challenges, which lie at the core of their scientific and technological interest. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ZUNiGuW2Anw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Flapping in the Mariana trench.</span></figcaption>
</figure>
<p>There is currently intense interdisciplinary research activity in this new area, called soft robotics, leading to exciting innovative advances for a host of related applications, ranging from agriculture to medicine and space. The <a href="https://www.nature.com/articles/nature19100">Harvard Octobot</a> is an example of this class of robots, which appears to have been, among others, a source of inspiration for the design and the technologies employed in this deep-sea robot.</p>
<p>The current version of the deep-sea swimmer appears to be relatively slow, not very easy to manoeuvre, and possibly not able to withstand the strong underwater currents which would disturb its course while attempting to follow a desired path. However, its designers already seem to have plans for further improvements that will make it more manoeuvrable, more efficient and smarter. </p>
<p>Despite any shortcomings, we should not underestimate the robotic design principles and technological advances that led to such a dramatic demonstration.</p><img src="https://counter.theconversation.com/content/159734/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dimitris Tsakiris has received funding from HEFCW, CRUK, and EC/EU. </span></em></p>
The device ventured nearly 11km below the surface to the Mariana Trench.
Dimitris Tsakiris, Reader in Intelligent Robotics, Aberystwyth University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/103003
2018-09-11T13:45:37Z
2018-09-11T13:45:37Z
Snailfish: how we found a new species in one of the ocean’s deepest places
<figure><img src="https://images.theconversation.com/files/235841/original/file-20180911-144461-140bl6z.png?ixlib=rb-1.1.0&rect=7%2C0%2C994%2C515&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Inside a snailfish.</span> <span class="attribution"><span class="source">Newcastle University / Natural History Museum, London</span>, <span class="license">Author provided</span></span></figcaption></figure><p>From an unmanned submersible, protected by a casing of stainless steel almost an inch thick and a window made from super strong sapphire crystal, we can observe the life that thrives at our planet’s most extreme and darkest depths. Thanks to technology and sheer material strength, we can temporarily trespass into this high pressure environment. But in stark contrast to the robust deep sea imaging equipment we rely on, the creatures our camera records look extremely fragile. </p>
<p>Four-and-a-half miles beneath our research vessel, which was floating on the surface of the Pacific Ocean, we captured footage of several previously undiscovered species of hadal snailfish. With delicate fins and transparent, gelatinous bodies, they are some of this environment’s most <a href="https://www.sciencedirect.com/science/article/pii/S0967063716300656?via%3Dihub">enigmatic inhabitants</a>, fish that – at first glance – look like they should be incapable of surviving under such enormous pressures. And yet, it appears they are thriving in this strange world.</p>
<p>In spring, a team of 40 scientists from 17 different nations conducted an expedition to the Atacama Trench, which runs along the west coast of South America. We were there to find a particular snailfish. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/235810/original/file-20180911-144461-n5s8e3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/235810/original/file-20180911-144461-n5s8e3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/235810/original/file-20180911-144461-n5s8e3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/235810/original/file-20180911-144461-n5s8e3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/235810/original/file-20180911-144461-n5s8e3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/235810/original/file-20180911-144461-n5s8e3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/235810/original/file-20180911-144461-n5s8e3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/235810/original/file-20180911-144461-n5s8e3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Atacama trench is the dark blue line off the coast of Chile and Peru.</span>
<span class="attribution"><a class="source" href="https://www.ngdc.noaa.gov/mgg/image/2minsurface/1350/00N090W.jpg">NOAA</a></span>
</figcaption>
</figure>
<p>On a previous expedition, our principal investigator (Alan Jamieson) had <a href="https://news.nationalgeographic.com/news/2010/10/photogalleries/101014-deep-fish-seen-snailfish-eel-ocean-pictures/">photographed a snailfish with long, wing-like fins</a> at a depth of 7,000 metres. Only one species, <a href="http://www.fishbase.org/summary/Notoliparis-antonbruuni.html"><em>Notoliparis antonbruuni</em></a> was known to inhabit this area at such a depth. It had been described from a single specimen, so badly damaged that we are not able to use it to identify our images of living animals. We wanted to find this elusive winged snailfish again to learn more about it and observe it in its natural habitat.</p>
<p>These hadal snailfish tend to live at depths between 7,000 and 8,200 metres (“hadal” simply means anywhere below 6,000 metres), but their apparent rarity is perhaps misunderstood. Because of their extreme habitat (at least for humans), they are difficult to observe rather than actually “rare” as we know it. And with the right equipment and opportunity, we were confident, after ten years of study, that we knew where and how to find them. </p>
<p>The Atacama Trench is part of the Peru-Chile subduction zone, a large 590,000 square kilometre area where one tectonic plate is being forced under another and the ocean floor quickly plunges to more than 8,000 metres. Its volume is almost the same as the neighbouring Andes mountain range, which the tectonic subduction zone also creates, and exploring it is no easy feat.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/235830/original/file-20180911-144473-q5ur5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/235830/original/file-20180911-144473-q5ur5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=324&fit=crop&dpr=1 600w, https://images.theconversation.com/files/235830/original/file-20180911-144473-q5ur5i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=324&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/235830/original/file-20180911-144473-q5ur5i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=324&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/235830/original/file-20180911-144473-q5ur5i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=407&fit=crop&dpr=1 754w, https://images.theconversation.com/files/235830/original/file-20180911-144473-q5ur5i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=407&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/235830/original/file-20180911-144473-q5ur5i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=407&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Deep dive.</span>
<span class="attribution"><span class="source">Newcastle University</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A trio of snailfish</h2>
<p>We deployed our freefalling cameras 27 times – from the <em>relative</em> shallows at 2,500 metres to the trench’s deepest point, Richard’s Deep, at just over 8,000 metres. This enabled us to take more than 100 hours of video and 11,000 photographs at the seabed – and the results did not disappoint. The snailfish we were looking for made an appearance – and it wasn’t alone. Two other previously unknown hadal snailfish species were present in the footage. In fact, all three species appeared in the same shot on one occasion. Out of necessity, they were given quick, stand-in names: we called them the “purple”, the “pink” and the “blue” Atacama snailfishes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/235816/original/file-20180911-144458-58n4o4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/235816/original/file-20180911-144458-58n4o4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/235816/original/file-20180911-144458-58n4o4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=155&fit=crop&dpr=1 600w, https://images.theconversation.com/files/235816/original/file-20180911-144458-58n4o4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=155&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/235816/original/file-20180911-144458-58n4o4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=155&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/235816/original/file-20180911-144458-58n4o4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=194&fit=crop&dpr=1 754w, https://images.theconversation.com/files/235816/original/file-20180911-144458-58n4o4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=194&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/235816/original/file-20180911-144458-58n4o4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=194&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Left to right: purple, pink and blue.</span>
<span class="attribution"><span class="source">Newcastle University</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The “blue” appeared to be the “winged” species Jamieson had recorded previously. Its long trailing fins and prominent snout resembled the <a href="https://youtu.be/6rU3sSDII7A">Ethereal snailfish</a> we had recorded on another expedition to the <a href="https://theconversation.com/how-we-found-worlds-deepest-fish-in-the-mariana-trench-and-why-we-must-keep-exploring-35743">Mariana Trench</a>, far away on the other side of the Pacific. </p>
<p>The “pink” species, meanwhile, was more robust and was closer in appearance to the <a href="http://www.mapress.com/j/zt/article/view/zootaxa.4358.1.7">Mariana snailfish (<em>Pseudoliparis swirei</em>)</a> that we described in 2017 and which also inhabits the Mariana Trench. To see these two species – with such different body plans – sharing a trench again got us thinking: they must be doing something different to one another down there to both carve themselves a niche.</p>
<p>The third species, a small purple fish, looked more like the snailfish we would expect to see on the shallower abyssal plains – at a depth of around 3,500 metres. But one of these purple snailfish, just 9cm long, followed its invertebrate prey into one of our traps. This small fragile fish is currently the only physical specimen of the new species and should eventually allow us to give it a formal scientific name. And while we much prefer our video of the living animal, only a physical specimen can be deposited in a museum and used to formally describe a new species.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/235817/original/file-20180911-144461-1pohi28.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/235817/original/file-20180911-144461-1pohi28.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/235817/original/file-20180911-144461-1pohi28.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/235817/original/file-20180911-144461-1pohi28.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/235817/original/file-20180911-144461-1pohi28.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/235817/original/file-20180911-144461-1pohi28.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/235817/original/file-20180911-144461-1pohi28.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/235817/original/file-20180911-144461-1pohi28.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">Meet the specimen. It died due to warm temperatures and low pressure long before it reached the surface.</span>
<span class="attribution"><span class="source">Newcastle University</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Preservation</h2>
<p>Once on the surface, we photographed this specimen while it was suspended in chilled seawater – its body is simply too fragile to support itself in air and we didn’t want it to suffer the same fate as the <a href="https://www.theguardian.com/environment/2013/sep/12/blobfish-world-ugliest-animal">poor blobfish</a>, which, for the record, really aren’t that sad-looking (their jelly-like bodies just collapse when exposed at the surface).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/235821/original/file-20180911-144470-11o5448.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/235821/original/file-20180911-144470-11o5448.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/235821/original/file-20180911-144470-11o5448.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=297&fit=crop&dpr=1 600w, https://images.theconversation.com/files/235821/original/file-20180911-144470-11o5448.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=297&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/235821/original/file-20180911-144470-11o5448.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=297&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/235821/original/file-20180911-144470-11o5448.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=374&fit=crop&dpr=1 754w, https://images.theconversation.com/files/235821/original/file-20180911-144470-11o5448.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=374&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/235821/original/file-20180911-144470-11o5448.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=374&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blobfish aren’t sad at all in their natural habitat.</span>
<span class="attribution"><span class="source">Newcastle University</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Over the following months, we then put the specimen through several stages of preservation to avoid shrinking its largely gelatinous body. So that scientists (and the interested public) don’t have to fight over access to a single, fragile specimen, it was also CT scanned at the <a href="http://www.nhm.ac.uk/iac">Natural History Museum, London</a>, creating a detailed 3D digital model of it, inside and out. Such digital back ups are gaining traction in science – take the <a href="https://www.washington.edu/news/2016/07/19/uw-professor-is-digitizing-every-fish-species-in-the-world/">Scan All Fishes</a> project, for example. And disasters like the recent fire at <a href="https://www.theatlantic.com/science/archive/2018/09/brazil-rio-de-janeiro-museum-fire/569299/">Brazil’s National Museum</a>, which will have wiped out many unique specimens, also show why they are so important.</p>
<p>But what have we discovered about these mysterious creatures? First, as fish approach the absolute extremes of the environmental conditions that they can cope with, they do not simply eke out an existence but thrive. It is also emerging that some trenches support not only a single specialist species but multiple species with body plans that hint at different lifestyles within the trench. </p>
<p>Second, the snailfish family (<em>Liparidae</em>) is not only the absolute winner of the <a href="https://theconversation.com/how-we-found-worlds-deepest-fish-in-the-mariana-trench-and-why-we-must-keep-exploring-35743">deepest fish award</a> (having been found in multiple other trenches), but species are living in trenches that at times are over 10,000km apart and entirely isolated from one another. Incredibly, snailfish exist at these extreme depths, wherever these extreme depths are, and in numbers never thought possible.</p>
<p>And the snailfish is just one story that emerged from our expedition. Over the coming months, we will continue to process the huge amount of data we collected, the most we have ever gathered on a single voyage. Our assessment of the large mobile animals we filmed will feed into the <a href="https://www.sdu.dk/en/om_sdu/institutter_centre/i_biologi/forskning/forskningsprojekter/benthic+diagenesis+and+microbiology+of+hadal+trenches/project/voyage+march+2018">project’s larger goal</a> to understand the biological and chemical processes within the trench as a whole.</p><img src="https://counter.theconversation.com/content/103003/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The expedition to the Atacama Trench was funded by BMBF (for ship time) and the ERC project HADES (European Research Council Advanced Investigator Grant-Nr. 669947; Benthic diagenesis and microbiology of hadal trenches”), the University of Southern Denmark and Max Planck Society and will be featured as part of the 2018 Challenger Conference being held at Newcastle University September 10-14.</span></em></p>
These ‘snailfish’ look too fragile to exist several miles below the waves.
Thomas Linley, Research Associate, Marine Ecology, Newcastle University
Alan Jamieson, Senior Lecturer in Marine Ecology, Newcastle University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/88991
2018-02-01T11:39:17Z
2018-02-01T11:39:17Z
The deepest-dwelling fish in the sea is small, pink and delicate
<figure><img src="https://images.theconversation.com/files/203477/original/file-20180125-100902-h0oik.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Image from video of Mariana snailfish. </span> <span class="attribution"><span class="source">SOI/HADES/University of Aberdeen (Dr. Alan Jamieson) </span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Thanks to movies and nature videos, many people know that bizarre creatures live in the ocean’s deepest, darkest regions. They include <a href="http://ocean.si.edu/ocean-photos/midnight-hunter">viperfish</a> with huge mouths and big teeth, and <a href="http://ocean.si.edu/ocean-news/meet-tiny-bacteria-give-anglerfishes-their-spooky-glow">anglerfish</a>, which have bioluminescent lures that make their own light in a dark world. </p>
<p>However, the world’s deepest-dwelling fish – known as a hadal snailfish – is small, pink and completely scaleless. Its skin is so transparent that you can see right through to its liver. Nonetheless, hadal snailfish are some of the most successful animals found in the ocean’s deepest places. </p>
<p>Our research team, which includes scientists from the United States, United Kingdom and New Zealand, found a new species of hadal snailfish in 2014 in the Mariana Trench. It has been seen living <a href="https://www.jamstec.go.jp/e/about/press_release/20170824/">at depths of almost 27,000 feet</a> (8,200 meters). We recently published its <a href="https://biotaxa.org/Zootaxa/article/view/zootaxa.4358.1.7">scientific description</a> and officially christened it <em>Pseudoliparis swirei</em>. Studying its adaptations for living at such great depths has provided new insights about what kinds of life can survive in the deep ocean.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/EuaAMHuAfuA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Mariana snailfish, <em>Pseudoliparis swirei</em>, the deepest-living fish. Video by Alan Jamieson and Thomas Linley, University of Aberdeen. Schmidt Ocean Institute.</span></figcaption>
</figure>
<h2>Exploring the hadal zone</h2>
<p>We discovered this fish during a survey of the Mariana Trench in the western Pacific Ocean. Deep-sea trenches form at subduction zones, where one of the tectonic plates that form the Earth’s crust slides beneath another plate. They extend 20,000 to 36,000 feet deep below the ocean’s surface. The Mariana Trench is deeper than Mount Everest is tall. </p>
<p>Ocean waters in these trenches are known as the hadal zone. Our team set out to explore the Mariana Trench from top to bottom in an effort to understand what lives in the hadal zone; how organisms there interact; how they survive under enormous pressure created by six to seven miles of water above them; and what role hadal trenches play in the global ocean ecosystem. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/202888/original/file-20180122-182948-y5fckv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/202888/original/file-20180122-182948-y5fckv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/202888/original/file-20180122-182948-y5fckv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/202888/original/file-20180122-182948-y5fckv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/202888/original/file-20180122-182948-y5fckv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/202888/original/file-20180122-182948-y5fckv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/202888/original/file-20180122-182948-y5fckv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/202888/original/file-20180122-182948-y5fckv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mariana Trench location.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Mariana_trench_location.jpg">Dcfleck</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Getting to the bottom</h2>
<p>Sending instruments to the ocean floor is pretty straightforward. Bringing them back up is not. Researchers studying the deep sea often use nets, cameras or robots connected to ships by cables. But a 7-mile-long cable, even if it is very strong, can break under its own weight. </p>
<p>We used <a href="https://schmidtocean.org/11000-meters-under-the-sea-meet-schmidt-ocean-institutes-new-landers-part-one/">free-falling landers</a> – mechanical platforms that carry instruments and steel weights and are not connected to the ship. When we deploy landers, it takes about four hours for them to sink to the bottom. To call them back, we use an acoustic signal that causes them to release their ballast and float to the surface. Then we search for them in the water (each carries an orange flag), retrieve them and collect their data. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/202497/original/file-20180118-158525-pekw6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/202497/original/file-20180118-158525-pekw6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/202497/original/file-20180118-158525-pekw6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/202497/original/file-20180118-158525-pekw6t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/202497/original/file-20180118-158525-pekw6t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/202497/original/file-20180118-158525-pekw6t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/202497/original/file-20180118-158525-pekw6t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/202497/original/file-20180118-158525-pekw6t.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">Deploying the fish trap in the Mariana Trench from the R/V Falkor. © Schmidt Ocean Institute.</span>
<span class="attribution"><span class="source">Paul Yancey, Whitman College.</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Life in the trenches</h2>
<p>Hadal trenches are named after Hades, the Greek god of the underworld. To humans, they are harsh, extreme environments. Pressure is as high as 15,000 pounds per square inch – equivalent to a large elephant standing on your thumb, and 1,100 times greater than atmospheric pressure at sea level. Water temperatures are as low as 33 degrees Fahrenheit (1 degree Celsius). Yet, a host of animals thrive under these conditions.</p>
<p>Our team put down cameras baited with mackerel to attract mobile animals in the trench. At shallower depths, from approximately 16,000 to 21,000 feet (5,000-6,500 meters) on the abyssal plain, we saw large fish such as rattails, cusk eels and eel pouts. At the upper edges of the trench, below 21,000 feet, we found decapod shrimp, supergiant amphipods (swimming crustaceans), and small pink snailfish. This newly discovered species of snailfish that lives to near 27,000 feet (8,200 meters), is now the world’s deepest living fish. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/6N4xmNGeCVU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Video footage captured from the University of Aberdeen’s Hadal-Lander in the Mariana Trench from 16,000 to 35,000 feet deep. Video by Alan Jamieson and Thomas Linley.</span></figcaption>
</figure>
<p>At the trench’s greatest depths, near 36,000 feet (11,000 meters), we saw only large swarms of small scavenging amphipods, which are somewhat similar to garden pill bugs. Amphipods live all over the ocean but are highly abundant in trenches. The Mariana snailfish that we filmed were eating these amphipods, which make up most of their <a href="https://www.sciencedirect.com/science/article/pii/S0967063716302540">diet</a>.</p>
<p>The Mariana Trench houses the ocean’s deepest point, at Challenger Deep, named for the <a href="http://www.divediscover.whoi.edu/history-ocean/challenger.html">HMS Challenger expedition</a>, which discovered the trench in 1875. Their deepest sounding, at nearly 27,000 feet (8,184 meters), was the greatest known ocean depth at that time. The site was named Swire Deep, after Herbert Swire, an officer on the voyage. We named the Mariana snailfish <em>Pseudoliparis swirei</em> in his honor, to acknowledge and thank crew members who have supported oceanographic research throughout history. </p>
<h2>Life under pressure</h2>
<p>Hadal snailfish have several adaptations to help them live under high pressure. Their bodies do not contain any air spaces, such as the swim bladders that bony fish use to ascend and descend in the water. Instead, hadal snailfish have a layer of <a href="http://dx.doi.org/10.1098/rsos.171063">gelatinous goo</a> under their skins that aids buoyancy and also makes them more streamlined.</p>
<p>Hadal animals have also adapted to pressure on a molecular level. We’ve even found that some enzymes in the muscles of hadal fish are <a href="https://doi.org/10.1016/j.dsr.2017.05.010">adapted to function better under high pressure</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/203582/original/file-20180126-100926-5f86t5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/203582/original/file-20180126-100926-5f86t5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/203582/original/file-20180126-100926-5f86t5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=150&fit=crop&dpr=1 600w, https://images.theconversation.com/files/203582/original/file-20180126-100926-5f86t5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=150&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/203582/original/file-20180126-100926-5f86t5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=150&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/203582/original/file-20180126-100926-5f86t5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=188&fit=crop&dpr=1 754w, https://images.theconversation.com/files/203582/original/file-20180126-100926-5f86t5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=188&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/203582/original/file-20180126-100926-5f86t5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=188&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scientific drawing of <em>Pseudoliparis swirei</em>, the Mariana snailfish.</span>
<span class="attribution"><span class="source">Thomas Linley/Zootaxa</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Whitman College biologist <a href="http://people.whitman.edu/%7Eyancey/">Paul Yancey</a>, a member of our team, has found that deep-sea fish use a molecule called trimethyl-amine oxide (TMAO) to help stabilize their proteins under pressure.</p>
<p>However, to survive at the highest water pressures in the ocean, fish would need so much TMAO in their systems that their cells would reach higher concentrations than seawater. At that high concentration, water would tend to flow into the cells due to a process called osmosis, in which water flows from areas of high concentration to low concentration to equalize. To keep these highly concentrated cells from rupturing, fish would have to continually pump water out of their cells to survive. </p>
<p>The evidence suggests that fish don’t actually live all the way to the deepest ocean depths because they are not able to keep enough TMAO in their cells to combat the high pressure at that depth. This means that around 27,000 feet (8,200 meters) may be <a href="http://dx.doi.org/10.1073/pnas.1322003111">a physiological depth limit for fish.</a></p>
<p>There may be fish that live at levels as deep, or even slightly deeper, than the Mariana snailfish. Different species of hadal snailfish are <a href="https://doi.org/10.1016/j.dsr.2016.05.003">found in trenches worldwide</a>, including the <a href="https://www.britannica.com/place/Kermadec-Trench">Kermadec Trench</a> off New Zealand, the <a href="https://www.britannica.com/place/Japan-Trench">Japan</a> and <a href="https://www.britannica.com/place/Kuril-Trench">Kurile-Kamchatka trenches</a> in the northwestern Pacific, and the <a href="https://www.britannica.com/place/Peru-Chile-Trench">Peru-Chile Trench</a>. As a group, hadal snailfish seem to have found an unlikely haven in a place named for the proverbial hell.</p><img src="https://counter.theconversation.com/content/88991/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mackenzie Gerringer does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
The Mariana snailfish lives nearly 27,000 feet underwater, but has features that help it adapt to intense water pressure and cold. Physiological limits may prevent fish from surviving in deeper water.
Mackenzie Gerringer, Postdoctoral Researcher, University of Washington
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/35743
2014-12-19T20:37:51Z
2014-12-19T20:37:51Z
How we found world’s deepest fish in the Mariana Trench – and why we must keep exploring
<figure><img src="https://images.theconversation.com/files/67847/original/image-20141219-31539-f814tv.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The record-breaker poses for the camera, 8,145m below the waves.</span> <span class="attribution"><a class="source" href="https://www.youtube.com/watch?v=6N4xmNGeCVU">Oceanlab, University of Aberdeen</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>It was our 14th expedition to the trenches of the Pacific Ocean, where depths can exceed 10,000m. And it was due to be our last for the foreseeable future.</p>
<p>We had been aboard the Schmidt Ocean Institute’s (SOI) vessel RV Falkor for 30 days. It was almost over. Then, it turned out to be “the big one”.</p>
<p>For this was the expedition in which my colleagues and I discovered a snailfish living some eight kilometres below the waves, deeper than any fish we know of. My colleagues from the University of Hawaii even recovered some in their traps. </p>
<p>In the past six years we have made many discoveries in the depths, such as <a href="http://www.researchgate.net/publication/229303119_First_findings_of_decapod_crustacea_in_the_hadal_zone">the missing order of Decapoda</a> (shrimps) that were long thought absent from the trenches but are actually rather conspicuous. </p>
<p>In the Kermadec Trench off New Zealand we found the “<a href="http://www.sciencedirect.com/science/article/pii/S0967064512001932">supergiant</a>” amphipod, a crustacean 20 times larger than its shallow-sea relatives. We also filmed large numbers of tadpole-like snailfish in multiple trenches, and <a href="http://www.sciencedaily.com/releases/2008/10/081007132552.htm">as deep as 7700m</a> in the Japan Trench.</p>
<h2>Snailfish surprise</h2>
<p>Based on these observations we predicted that when exploring the Mariana Trench – the world’s deepest – we would find the the Mariana’s own personal snailfish, probably living between 6500m and around 7500m, with more being found at the deeper end of that range.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/6N4xmNGeCVU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Exploring the Mariana Trench. The record-breaking fish appears at 1:45.</span></figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/67852/original/image-20141219-31573-uhls7j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/67852/original/image-20141219-31573-uhls7j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/67852/original/image-20141219-31573-uhls7j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=211&fit=crop&dpr=1 600w, https://images.theconversation.com/files/67852/original/image-20141219-31573-uhls7j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=211&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/67852/original/image-20141219-31573-uhls7j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=211&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/67852/original/image-20141219-31573-uhls7j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=265&fit=crop&dpr=1 754w, https://images.theconversation.com/files/67852/original/image-20141219-31573-uhls7j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=265&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/67852/original/image-20141219-31573-uhls7j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=265&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="source" href="https://www.youtube.com/watch?v=6N4xmNGeCVU">Oceanlab, University of Aberdeen</a></span>
</figcaption>
</figure>
<p>We also predicted that we would see the decapods and supergiants in the upper depths of the trench, and right enough there they were.</p>
<p>A device used to gather samples of ocean floor had an inspection camera on it to monitor the equipment. One night after a dive to 7900m when watching the footage coming back in, a strange ethereal little fish swam past. That got our eyebrows raised. It looked like a snailfish, but was extremely fragile (even for a snailfish) and had a very distinctive appearance.</p>
<p>This prompted a case of “game on”, to find it again, and sure enough we did. The deepest we found it was at 8145m, nearly 500m deeper than our personal record from the Japan Trench.</p>
<p>This of course means that our predictions were slightly wrong, but also makes it very exciting: there are still fish, and perhaps other things, down there to discover and this is what drives us to do more. Our work at the deepest place on Earth is not done yet.</p>
<h2>Why we need to keep exploring</h2>
<p>As much as we are excited about finds such as these, we are typically chased up by people who ask “why do we bother?”, and add rather deflating comments such as “what benefit does this have to society?”</p>
<p>In response I explain that such exploration benefits responsible stewardship of the oceans. In the long term, conservation and maintenance of the our seas relies on us really understanding the ocean – that is, the ocean in its entirety from the surface to <a href="https://theconversation.com/just-how-little-do-we-know-about-the-ocean-floor-32751">what lies beneath the deepest seafloor</a>. The anthropocentric opinion of “out of sight, out of mind” simply doesn’t cut it, and is sadly still common place.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/67850/original/image-20141219-31557-5hq32z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/67850/original/image-20141219-31557-5hq32z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/67850/original/image-20141219-31557-5hq32z.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/67850/original/image-20141219-31557-5hq32z.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/67850/original/image-20141219-31557-5hq32z.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/67850/original/image-20141219-31557-5hq32z.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/67850/original/image-20141219-31557-5hq32z.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Deep-sea divers: the author (right) with colleague Thom Linley.</span>
<span class="attribution"><span class="source">Stuart Piertney</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The deep ocean is far deeper than a person can dive to or fish from, but that doesn’t mean that the things down there are of no consequence to society. We must not, however, confuse curiosity-driven exploration with the search for entertainment or stockpiling consumables.</p>
<p>We know that the deep sea is not exempt from a <a href="https://theconversation.com/heat-accumulating-deep-in-the-atlantic-has-put-global-warming-on-hiatus-30805">changing climate</a> or man-made disturbances such as <a href="http://www.theguardian.com/environment/2014/dec/17/microplastic-deposits-found-deep-in-worlds-oceans-and-seas">plastic pollution</a>. The depths are intrinsically linked to processes in the upper ocean that we humans are continually meddling with.</p>
<p>Changes that happen in the upper ocean will have an effect on the largest habitat on Earth, yet people question why we study the deep sea. We say, how can we conserve the largest habitat on Earth if we know nothing about it? In the quest to understand the entire ocean, people have to study the shallow bits, the deepest bits and everything in-between.</p><img src="https://counter.theconversation.com/content/35743/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Jamieson receives funding from SOI</span></em></p>
It was our 14th expedition to the trenches of the Pacific Ocean, where depths can exceed 10,000m. And it was due to be our last for the foreseeable future. We had been aboard the Schmidt Ocean Institute’s…
Alan Jamieson, Senior Lecturer, Oceanlab, University of Aberdeen
Licensed as Creative Commons – attribution, no derivatives.