Sophisticated submarines are ready to scan the deepest abysses at the bottom of the oceans and answer age-old questions about the exotic creatures that live there, the origins of tsunami waves and the origin of life on earth
Editors' note: Large parts of the article describe the mission of the robotic submarine "Neraus". At the time of editing the Hebrew edition, the submarine was sent as planned for its mission in the depths of the sea. However, in one of her first dives she was crushed by the water pressure and destroyed.
On April 10, 2014, the Thomas G. Thompson research ship left and moved about 900 kilometers northeast of New Zealand, it anchored in the heart of the Pacific Ocean and lowered "Nereus" into the water - a robotic submarine the size of a small compact car (which began operating in -2009 – the editors). Nareus dived further and further into one of the deepest and most dangerous places in the world: the Karmadak Abyss, which is more than 10,000 meters deep - as high as Everest with Mount Meron resting on it. At the bottom of the abyss there is absolute water pressure and the water pressure is about 1,000 atmospheres, like the pressure that three large off-road vehicles would exert if they were placed on your toe. Nereus was supposed to illuminate the unknown in retirement. Her video camera was supposed to beam images up to the clipper via a thin fiber optic strip as Schnauzer's hair pulled apart and pulled down with her.
The scientists on board expected to see strange living creatures on their computer screens as Nareus' robotic arm scooped up rocks and animals from the bottom of the abyss. The submarine was supposed to insert a rigid tube into the seabed to retrieve cylindrical samples of the sediments contained therein. The robotic submarine was also designed to gulp down large amounts of water in hopes of capturing bacteria and other organisms capable of surviving in these extreme conditions.
The biologists and geologists hoped, and not for nothing, that Raus would make wonderful discoveries. But this research expedition was of even greater importance. Almost no one has ever descended to a depth of more than six kilometers, that is, into the deepest abysses in the world, known as the "Hadalian regions" (after Hades, the god of the underworld - the editors). But this year's April expedition, led by the Woods Hole Oceanographic Institution (WHOI), is meant to mark the beginning of a period scientists have been fighting for and longing for for decades: systematic exploration of the last unknown area left on our planet. The Nareus expedition was "the beginning of the Hadean research enterprise," according to Patricia Fryer, a marine geologist at the University of Hawaii at Manoa. "And this is a plant that can definitely provide us with amazing discoveries."
The study of the Hadelic regions got off the ground thanks to a successful combination of funding, technology and advertising. Public attention was focused on the sea abyss in 2012, when the film director and researcher James Cameron sailed a one-man submarine to the deepest seabed in the world, another abyss called "Mariana". WHOI improved Cameroon's deep-water technology, and the Nareus was supposed to be more powerful yet nimble enough. The funding sources are expanding. And as more submarines are built, the possibility of reaching more and more deep places is becoming more and more realised.
And yet the budgets are tight and the task is great. The total area of the deep abysses is close to the area of Australia. Where should the submarines be sent? What should they look for? From interviews we conducted with more than a dozen marine experts, there is agreement on a limited number of top priority issues, including: understanding how creatures survive under the tremendous water pressure, checking whether the bodies of large and small organisms contain unknown compounds that can be used for new medicines, finding out how earthquakes start to generate tsunamis , and to answer the biggest question of all - did life on earth begin in these abysses, as some scientists believe, a hypothesis that at the moment we don't know how to prove or disprove.
Plenty of new creatures
If the Henreus had survived the water pressure, the mission could have led to significant progress in some of the research priorities. The most important advantages of this robot, which cost about 8 million dollars, was its ability to take videos and broadcast them live to the ship (which it did broadcast until the moment of its crash - the editors), and its ability to collect more rock, sediment and water samples than all those "landers" that researchers have so far lowered to the bottom the sea, and which were nothing more than small, stationary research cells that sink to a single point on the seabed and provide useful, but limited, information. The Henreus could stay underwater for 12 hours, and even when the cable tying her to the ship broke, she knew how to float up on her own.
Thanks to these features, the Henreus was best suited for scanning and searching for strange animals, the first task on the agenda. Until now, the scientists had been looking in specific locations, and Nareus was supposed to take them on a wide-ranging virtual tour of the Carmadec Abyss, collecting biological samples along the way. "I think we're in for some surprises," said Timothy Shank, a WHOI deep-water biologist and the expedition's chief scientist in April, before setting off. "These will be things we didn't think of, even though we think we've thought of everything. That's what drives me."
Anyone who visits Shank's laboratory, where he keeps preserved samples of starfish, shrimp, "tubeworms" and other deep-dwellers, will see shelves marked with intriguing names of places around the globe, such as "Galapagos Rift" or "Mid-Atlantic Ridge". But it doesn't even have a single shelf marked with the name of the Adelite Abyss. There are so few examples from these depths.
With the exception of a few rare and unusual submarines, manned and robotic submarines are designed to dive at most a little deeper than the upper limit of what is defined as the Hadley zone: that is, all areas of the ocean that are more than 6,000 meters deep. The high pressure and other factors complicate and increase the operation of submarines at depths greater than this.
Only four diving vessels have reached the deepest point in the world: "Challenger Dip" in the "Mariana" Abyss off the coast of Guam, which is 10,989 meters deep. US Navy officer Don Walsh and Swiss marine engineer Jacques Piccard dived there in 1960 in the Trieste - an oval diving bell and heavily reinforced. No one returned there until 1995, when the "Japan Agency for Science and Technology of the Exploration of the Earth and the Seas" (JAMSTEC), sent there a remotely controlled submarine called "Kaiko". After Kaiko, Nareus herself visited the Challenger socket in 2009. Three years later, James Cameron dived there in his private deep-sea submarine DEEPSEA CHALLENGER [see "Divers to the Deep", Scientific American Israel, October 2013].
Most of the dives came with samples for research purposes, but they were mainly intended to test the engineering aspects of the mission, to prove that it is possible to survive there, and if there then anywhere. The scientists hoped that Caico would serve science for a long time, but in 2003, after a few short and limited missions in the Adelian regions, it was swept away and lost in a big storm. Its main replacement is only capable of going as deep as seven kilometers. Another vessel, Abismo, is capable of diving to a depth of ten kilometers, but its capabilities are much more limited and it is not used much.
Shank hoped that with the help of the Henraus, he would soon be able to fill another shelf, which would be marked with the label "Kramdak". The expedition was part of the "Program for the Study of Ecosystems in the Adelian Regions" (HADES) funded by the American National Science Foundation (NSF). The program brings together scientists from the USA, the UK, New Zealand and Japan, and within the framework of it they will promote the study of the Hadean regions.
Previous expeditions concentrated on the flat center of the Challenger Trough, a plain whose bottom is composed of sedimentary materials, due to its great depth. But the deepest point is not the most scientifically interesting point in the depression. The more intriguing parts of the chasms are the edges and the rocky slopes on the sides.
The researchers chose to focus on the cliffs on the sides of Carmadak because the water above them is teeming with life, and it is likely that more food sinks down from them to the bottom-dwelling animals. (The Mariana Trench, on the other hand, lies beneath a relatively barren area of the ocean.) Since Nareus could dive for hours, researchers hoped it would not only observe animals, but also capture some for genetic analysis, if they weren't too large or elusive.
The Karmadak expedition "being the first systematic review, should be a landmark and a touchstone for future studies," Schank said before the Nereus was lost. "Then we'll go to other chasms for comparison." He was confident that they would get it: "The issue is in a period of tremendous momentum."
It is possible that in each such abyss resides a unique group of animals, but the heads of HADES are not in a hurry to hold on to this hypothesis. Before, researchers believed that different species resided in each underwater mountain, but later the hypothesis was disproved as it was not sufficiently based.
Thrive under pressure
The second issue in the biologists' order of priorities is almost as fundamental as the first issue: understanding the way the cells of the creatures of the great and small deeps function under these enormous pressures. Understanding these mechanisms may allow new drugs to be concocted.
The mystery began back in Walsh and Picard's dive in 1960. They stayed on the bottom for about 20 minutes and reported that they saw a "flatfish" there. But they didn't have cameras and biologists today doubt this observation.
"There's no way they've seen a fish like that, there's just no way," says Jeffrey K. Dreizen, a deep-water fishing expert and one of the heads of HADES. Studies show that fish simply cannot withstand such pressure. The fish that were definitely observed at the deepest depth can be seen in a video taken at a depth of about 7,700 meters. Walsh admits he's no fish expert, but stands by what he saw. “I can only say that I think I saw some fish. But they keep telling me that I haven't seen a single fish."
In the 90s, biologist Paul Yancey from Whitman College discovered that the deeper the water, the higher the concentration of the compound trimethylamine N-oxide (TMAO) in fish cells. This compound is responsible for the unpleasant smell that emanates from fish. This correlation is valid down to a depth of about 7,000 meters, the maximum depth from which Linsey and Dreisen, his current research partner, have samples.
The mechanism by which TMAO stabilizes the proteins and makes them resistant to stress is not clear, and there may be a limit to its effect. The role of TMAO in the blood system of the fish is similar to the role of salt: it helps maintain the osmotic pressure that determines whether water will enter or leave the cells. At a depth of about 8,000 meters, the salinity in the fish's body should be close to that of sea water. The scientists therefore hypothesize that if the fish dives to a greater depth, an amount of water will enter its body cells that will kill it. Science cannot prove the non-existence of anything, but if fish are not found in the great depths of the Hadean regions, this would largely confirm the hypothesis that fish cannot survive there. And yet, Yancey hoped that Raus would prove him wrong. "I would really like to catch this fish, to understand how it works."
According to the little information we have, it seems that other creatures, such as crabs and snails, are also limited to a depth of about 8,000 meters. But in the few dives that were to greater depths than that, the researchers saw large organisms such as sea cucumbers and amphipods, which belong to the crustacean family. However, microscopic creatures were found in abundance. Yancey thinks these life forms may be aided by other protein-stabilizing chemicals, called phaseolites, like those he found in the amphipods collected by James Cameron's team.
Researchers in the field of biomedicine have already studied another compound found by Yancey called scyllo-inositol. They hope to use it to treat Alzheimer's disease, which is one of the diseases associated with protein folding problems. Because of this context, biologists are eager to discover protein stabilizers in the organisms that exist in the Hadellan Abyss that might be used as drugs.
Doug Bartlett, a microbiologist from the Scripps Institution of Oceanography, also did preliminary studies on deep-sea bacteria collected by the landers and found in the mud brought up by Cameron Ladella from the bottom. Bartlett hoped to study bacteria found in the water, mud samples and animals that Reuss planned to collect, and he hopes to one day get samples stored in tanks with pressure similar to that at Hadley's depth, so he can observe the cells while they are still alive.
carbon and tsunami
Since only a few studies have been done in the Hadean regions, a single data set delivered by one of the future submarines may be sufficient to illuminate priority issues in several different fields. As for example, in the crucial question: how much carbon falls, or sinks, into these abysses.
For sea creatures, carbon-containing molecules are food. And the cascade of molecules falling from above includes all kinds of delicacies, such as algae, dead fish and excrement of the inhabitants of the shallower water. The amount of fallout may decrease as you go deeper, as a large part of what sinks is eaten on its way down. But it is also possible that the chasms act as funnels that collect all the organic matter that comes from above and from the mud sliding down the slopes. If the biologists knew where the carbon was concentrated, they would also know where the widest variety of animals could be found. And if there is enough food, there may also be larger animals than expected.
The eyes of geochemists are also on this carbon, because the oceans absorb about 40% to 50% of the carbon dioxide emitted into the atmosphere naturally and due to human activities, which slows down the increase of the greenhouse effect. The researchers speculate that much of this carbon is buried at the bottom of the sea, but they do not even know the order of magnitude of the amount reaching the abyss.
The future submersibles will collect sediment samples that scientists will analyze to measure the amount of carbon in them, as scientists from the Nareus mission were supposed to do. They will also measure the amounts of oxygen, to assess the degree of biological activity occurring there. "My oxygen sensors are designed for the deepest abysses in the world, and I'm dying to get them down," Dreizen said before the accident.
Geologists, on the other hand, are interested in another aspect of the bottom of the abyss, an aspect that can affect us much more directly.
The epicenter of the magnitude 9 earthquake that struck the Tohoku region of Japan in 2011 and caused the devastating tsunami wave that brought about the collapse of the Fukushima nuclear reactor was in the abyss of Japan. Many scientists were amazed to find that noise of such intensity was possible there, says Hiroshi Kitzato of JAMSTEC. Researchers have drill cores of sediment collected on the sea floor in this area, and rock samples brought up by a robot that dived to a depth of 7,000 meters.
But the abyss is 1,500 meters deeper than that, and the earthquake started deep below the sea floor. Experts don't even know the best way to scan such areas, says Gerard Freire, a geophysicist at the Honolulu-based Pacific Tsunami Warning Center. "We can learn a lot if we can see what's going on down there." Rock samples from greater depths will be able to improve our understanding of the propagation of stress in the underground areas, and additional sediment samples will help researchers determine if the type of sediment in the abysses can affect the intensity of the noises.
Another process on the geologists' wish list regarding the Hadean regions is serpentinization. This process is very important in understanding the long-term balance between the formation of tectonic plates and their destruction. The destruction happens in chasms, in places where two plates collide and one slides under the other. Most of the material has melted, and the process of serpentinization, which is a chemical reaction between water and a certain type of rock, is a decisive factor in maintaining this balance.
At least that's what the scientists think. Rock and sediment samples from the abysses, along with a detailed visual review of the environment in which they were found, can help a lot in proving hypotheses and disproving them, says geologist Daniel Lizerald from WHOI. He hoped that Raus could provide such information from the Keramdak Trench or, in its next mission, from the Mariana Trench planned for later in 2014. "This will be the first confirmation that processes that seem plausible to us are actually occurring in reality," says Patricia Freire.
cradle of life
The serpentinization reaction may also hold part of the answer to the question: "Did life on Earth begin in these deepest depths?". The reaction releases heat, hydrogen, methane and various minerals into the water, all the ingredients necessary for life based on chemical processes, or "chemo-synthetic life". There are some deep places where organisms get the energy they need from chemical reactions, rather than through photosynthesis from the sun. Some scientists claim that life may have started in hydrothermal vents, holes in the ocean floor from which seawater emerges, which seeped elsewhere into the rock layer, and which return to the sea when they are hot and rich in chemicals and minerals. Most of us have seen pictures of giant worms found near these vents.
But hydrothermal vents don't usually last long, so some scientists today question the idea that they are the source of life. A more recent hypothesis suggests that sperantinization in the abyss may be better suited to fuel the beginnings of life, since it spans a much larger area, and lasts a much longer time, on geological orders of magnitude. Cameron says that it was this hypothesis that pushed him more than anything else on his journey into the Challenger sinkhole: "I felt as if I was looking at the cradle of life itself."
In fact, during Cameron's test dives, before going down to full depth, his men dropped off a landing craft equipped for the Siren hole, a place not far from the Challenger hole and almost as deep as it. The fiberglass box, which was about the size of a refrigerator, was equipped with water samples, a baited trap, a video camera and other devices. On one of the dives, she landed right in front of what appeared to be a white fibrous mat of microorganisms. "It was like playing darts blindfolded and hitting a ball in the middle," says Cameron.
Kevin Hand, an Earth scientist and astrobiologist from NASA's Jet Propulsion Laboratory (JPL), who participated in the expedition, discovered the carpet when examining the videos taken by the craft. The box must have startled the tiny creatures when it landed on the bottom, which is what the model caught. Preliminary results show that these bacteria may have genetics that allow them to produce energy from compounds released by serpentinization.
Of course, there is no reason why there should not also be hydrothermal vents in the deep abysses. In any case, the animals found near the openings in shallower water are quite strange. So that also taking into account the enormous pressure in the depths of the abyss, there is no telling what strange creatures will be found near the hydrothermal vents there.
Underwater space race
The agenda for the researchers of the Hadean regions is fascinating, but for now, it will be difficult to implement after the main tool, Nareus, is lost. Cameron gave WHOI rights to use his submarine and the technologies developed for it, but the agency does not intend to use it for now, partly due to insurance issues.
The range of options may expand toward the end of 2015. The Schmidt Institute for the Study of the Sea, founded by Google CEO Eric Schmidt and his wife Wendy Schmidt, is working with WHOI to build Nareus' successor, the N11K. This sub will be able to carry a larger sample payload, and will have two robotic arms instead of just one, so it can hold onto the bottom with one arm and dig well with the other. [Disclosure: I advise the Schmidt Institute on media communication matters.]
Manned submarines probably won't play an important role, at least not in the next few years. Similar to what is happening in the American space program, there is also a discussion going on here about the question of the relative merits of manned vehicles. Shank and Patricia Freire argue that videography cannot replace the human ability to perceive the visible in the dark depths in XNUMXD.
Cameron adds that manned dives provide inspiration [see box on opposite page]. Indeed, the founder of the Virgin Group, Richard Branson, and his partner, the entrepreneur Chris Walsh, intend to sail a submarine with one person in it to the deepest point in each of the five oceans of the planet. Problems with the transparent dome on their prototype vessel slowed the project's progress.
At the Triton Submarine Company in Vero Beach, Florida, we have planned a submarine for three people capable of reaching the deepest abysses, but the financing for its construction has not yet been found. China, which recently launched a manned submarine that can reach a depth of 7,000 meters, is planning another submarine that will reach the full Hadley depth, as is Japan. But it will be years before these two ventures are completed.
At JPL, Hand is designing a small robotic submarine that can be maneuvered in groups from a small vessel. He says that the planned cost is about $10,000 per submarine, so that it would be possible to assemble a fleet of such submarines, and if one were lost it would not be a terrible disaster. He, JPL engineers and engineers from Cameron's group hope to get funding for the project from NASA. "We want to import some of the capabilities and lessons learned in the robotic exploration missions to other worlds, such as Mars and beyond, and recruit those capabilities and talents to explore the oceans here," Hand says.
With the improvement of research technology and the increase in budgets, researchers are faced with the blessed issue: which chasm and which furrow to plow first. It is possible that completely different creatures inhabit the highly isolated conditions of the 8,428-meter-deep South Sandwich Abyss off the coast of Antarctica. The Puerto Rico Abyss can offer valuable information about the connections between the abysses. And there are also some open plains deep in the Hadley that researchers would like to compare to abysses.
Patricia Freire is trying to get funding for a workshop where deep water scientists from all over the world will participate to discuss priorities and determine the best way forward. The research so far has been done bit by bit, and similar to the exploration of outer space, here too coordinated international cooperation can make better use of resources and expert knowledge than a competitive race to the ground between countries. "It seems to me that the community of ocean scientists is ready" to set a systematic agenda for the study of the Hadean regions, says Freire. Dreizen agrees: "We now have the technology to explore these places. And we are impatiently ready to go."
About the author
Mark Schrope is a freelance writer and editor from Florida, who spent more than seven months on ocean exploration cruises. He also works as a communications consultant at the Schmidt Institute for Marine Research.
in brief
In April 2014, the vessel "Nerous" dived to the bottom of the Karmadak Abyss, which is 10,047 meters deep. It was planned to take live videos of strange creatures and collect samples of sediment, rocks and water - but drowned.
Even after the accident, the technology, funding and public opinion are ready for a systematic survey of the underwater chasms. The researchers want to understand how organisms survive under the tremendous water pressure and to examine whether life on Earth began in such places and was fed there by chemical energy and not by solar energy.
Extraordinary compounds found in the creatures of the depths could lead to innovations in the field of medicine, and rocks from there might reveal why tsunami waves reach such great power. There is already a debate about which is more profitable: manned or robotic submarines.
Deep Thoughts by James Cameron / Mark Shrop
A discussion with the filmmaker about the need for more sea voyages of discovery and the question of why when it comes to the deepest abysses in the oceans, there is nothing like diving there with your body and actually being there
Director James Cameron ("Avatar", "Titanic") is the only one who dived alone to the deepest place on earth: the Challenger Sink in the Mariana Trench, southwest of Guam, which is about 11,000 meters deep. A documentary that will be released soon commemorates the achievement. Cameron earned him respect among scientists because he tried hard to ensure that the dive, which took place on March 26, 2012, also served important scientific purposes. After the dive, he donated his submarine, DEEPSEA CHALLENGER, to the Woods Hole Oceanographic Institution (WHOI).
A Scientific American reporter spoke with Cameron during his visit to Woods Hole, where members of his private staff worked in collaboration with the institute's engineers. Here are excerpts we edited from the conversation.
How did you feel when you finally landed at the bottom of Challenger Hole?
There was a tremendous sense of achievement and pride among the crew, considering the problems each of them had overcome. I didn't feel in danger at all. I didn't even think about it. I trusted the engineering. I felt that I had a great privilege to see something that no one had seen yet. And yet I wonder if what I saw from the window was really a xenophyophore [a large single-celled organism]. My first impression was that the place was very lunar and desolate. It turns out that was a false impression. There were all kinds of little creatures there, but I saw only a few of them. We discovered the others when we examined the videos taken in the high definition. But there is a limit to what you can learn in one dive. If I had landed twenty meters to the right or left I might have made the discovery of the century. It leaves a taste for more and makes you want to keep going.
Why has the investment in manned research dives to great depths been relatively small in recent years?
Manned submarines still have a very important role, but by their very nature they are larger than remotely operated vehicle (ROV) or fully autonomous (AUV) robotic submarines, and they are more expensive to operate. Since the mentality regarding the funding of the exploration of the depths is, as we say, at the bottom, for many of the researchers the only possible access to great depth is only through robotic, independent submarines that are controlled remotely. But if you build only unmanned submarines, and then say that manned submarines will not produce a high enough scientific yield, you are essentially creating a self-fulfilling prophecy. That's why challenging ventures like DEEPSEA CHALLENGER are important. They shake up fossilized ways of thinking.
What do you think about the state of ocean research funded by governments?
This is a course of action that has not proven itself so far. And if the governments do not support discovery expeditions, we will have to finance them from private or commercial sources, which is the situation today.
What do you think is the most intriguing part of exploring the deep underwater chasms?
Discovery of evidence supporting the hypothesis that the first life may have been fueled by chemical reactions that occurred in geological subduction zones [the tectonic process that creates the chasms]. This can be a particularly fruitful field. We know that tectonic activity has been happening more or less since the earth was formed, and it is a good, stable and long-term source of energy. With this hypothesis in my mind I hit rock bottom and felt like I was looking at the cradle of life itself.
What's the next thing you want to do?
We haven't decided yet. I would like to see integrated, remotely controlled and independent systems built to scan the Hadean depths [deeper than 6,000 meters] and I would support such a project, if someone else were to lead it. But in the coming years I will not be able to run such a venture myself because I will be busy full-time with the "Avatar" sequels. But I'll get back to it. We only tasted the tip of the fork. We shot only a few arrows at the target.
More on the subject
Hadal Trenches: The Ecology of the Deepest Places on Earth. Alan J. Jamieson
et al. in Trends in Ecology & Evolution, Vol. 25, no. 3, pages 190–197; March 2010.
Nereus website
Report on the sinking of Nereus, by Larry Greenmeyer
Additional reporting
The article was published with the permission of Scientific American Israel
