"Long before it's in the papers"
January 27, 2015


Scientists to explore deep ocean trench

April 11, 2014
Courtesy of the National Science Foundation
and World Science staff

What lives in the deep­est part of the ocean? Sci­en­tists plan to use the world’s only full-o­cean-depth un­der­wa­ter ro­bot and oth­er tech­nol­o­gy to find out, ex­plor­ing the Ker­madec Trench at the bot­tom of the Pa­cif­ic Ocean.

The 40-day proj­ect, to start April 12, kicks off a three-year col­la­bo­ra­tive ef­fort. The proj­ect, known as the Ha­dal Ec­o­sys­tem Stud­ies Proj­ect or HA­DES, is to con­duct the first sys­tem­at­ic study of life in ocean trench­es, com­par­ing it to the neigh­bor­ing abyss­al plain­s—flat seafloor ar­eas usu­ally found at depths be­tween 9,843 and 19,685 feet (3,000 and 6,000 me­ters).

Snail­fish from 7000 me­ters in the north­ern Ker­ma­dec Trench (Cre­dit: Alan Jamie­son, Ocean­lab, U. of Aber­deen)

“We will shine a light in­to the dark­ness of Earth’s deep-o­cean trench­es,” said Da­vid Gar­ri­son, pro­gram di­rec­tor at the U.S. Na­t­ional Sci­ence Founda­t­ion Di­vi­sion of Ocean Sci­ences, which funds HA­DES.

The trench, off New Zea­land, is the world’s fifth deep­est un­der­wa­ter trench, at 32,963 feet or 6.24 miles (10,047 me­ters). It’s al­so one of the cold­est, due to the in­flow of deep wa­ters from Ant­arc­ti­ca.

Ocean trench­es re­main among the plan­et’s least-explored en­vi­ron­ments thanks to the ex­treme pres­sures at such depths and the tech­ni­cal dif­fi­cul­ties of reach­ing them. “We know rel­a­tively lit­tle about life in ocean trench­es—the deep­est ma­rine habi­tats on Earth,” said Tim Shank, a bi­ol­o­gist at the Woods Hole Oceanographic In­sti­tu­tion in Woods Hole, Mass., one of the par­ti­ci­pat­ing or­gan­iz­a­tions.

“We did­n’t have the tech­nol­o­gy to do these kinds of de­tailed stud­ies be­fore. This will be a first-order look at com­mun­ity struc­ture, adapta­t­ion and ev­o­lu­tion: how life ex­ists in the trench­es.” 

Sci­en­tists plan to let the pub­lic share in the dis­cov­er­ies through live-streaming Web events from the seafloor in­clud­ing narra­t­ion from the sci­en­tists. The work will al­so be chron­i­cled in vid­e­o, pho­tos and blog up­dates on the ex­pe­di­tion web­site.

What ma­rine an­i­mals live in the Ker­madec Trench, and how do they sur­vive the crush­ing pres­sures found at that depth? These are among the ques­tions the sci­en­tists will try to an­swer. They plan to con­duct re­search at 15 sta­t­ions, in­clud­ing sites in shal­low wa­ter for test­ing pur­poses, sites along the trench ax­is and sites in the abyss­al plain.

At each one, they plan to de­ploy free-falling, baited im­ag­ing lan­ders called Ha­dal-Landers and “el­e­va­tors” out­fit­ted with expe­ri­men­tal equipment. The un­der­wa­ter ro­bot, Ne­re­us, will be used col­lect sam­ples and to stream im­age­ry from its vi­deo­cam­era to a re­search ship via a fiber-optic fil­a­ment about the width of hu­man hair.

The ex­pe­di­tion is to build on ear­li­er stud­ies of the Ker­madec Trench by Jamieson and col­leagues at the Na­t­ional In­sti­tute of Wa­ter and At­mos­pher­ic Re­search and the Uni­vers­ity of To­kyo. Us­ing the Ha­dal-Lander, they doc­u­mented new spe­cies of an­i­mals in the Ker­madec and oth­er trench­es in the Pa­cif­ic.

Once thought de­void of life, trench­es may be home to many un­ique spe­cies, bi­ol­o­gists say. There is grow­ing ev­i­dence that food is plen­ti­ful there. While it is still un­clear why, or­ganic ma­te­ri­al in the ocean may be car­ried by cur­rents and de­posited in­to the trench­es.

How an­i­mals in the trench­es evolved to with­stand high pres­sures is un­known, but Shank plans to com­pare the genomes of trench an­i­mals to piece to­geth­er how they can sur­vive there. “The chal­lenge is to de­ter­mine wheth­er life in the trench­es holds nov­el ev­o­lu­tion­ary path­ways that are dis­tinct from oth­ers in the oceans,” he said.

Wa­ter pres­sure, which at depths found in ocean trench­es can be up to 1,100 times that at the sur­face, is known to in­hib­it the ac­ti­vity of cer­tain pro­teins. Yan­cey ex­pects to in­ves­t­i­gate the role that piezolytes—small mo­le­cules that pro­tect pro­teins from pres­sure—play in the adapta­t­ion of trench an­i­mals.

Ev­i­dence al­so sug­gests that trench­es act as car­bon sinks, mak­ing the re­search rel­e­vant to cli­mate change stud­ies. “The bulk of our knowl­edge of trench­es is only from snap­shot vis­its us­ing mostly trawls and cam­era lan­ders,” Shank said. “Only de­tailed sys­tem­at­ic stud­ies will re­veal the role trench­es may play as the fi­nal loca­t­ion of where most of the car­bon and oth­er chem­i­cals are se­ques­tered in the oceans.”

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What lives in the deepest part of the ocean? Scientists plan to use the world’s only full-ocean-depth underwater robot and other technology to find out, exploring the Kermadec Trench at the bottom of the Pacific Ocean. The 40-day project, to start April 12, kicks off a three-year collaborative effort. The project, known as the Hadal Ecosystem Studies Project or HADES, is to conduct the first systematic study of life in ocean trenches, comparing it to the neighboring abyssal plains—flat seafloor areas usually found at depths between 9,843 and 19,685 feet (3,000 and 6,000 meters). “We will shine a light into the darkness of Earth’s deep-ocean trenches,” said David Garrison, program director at the U.S. National Science Foundation Division of Ocean Sciences, which funds HADES. The trench off New Zealand is the world’s fifth deepest underwater trench, at 32,963 feet or 6.24 miles (10,047 meters). It’s also one of the coldest, due to the inflow of deep waters from Antarctica. Ocean trenches remain among the planet’s least-explored environments thanks to the extreme pressures at such depths and the technical difficulties of reaching them. “We know relatively little about life in ocean trenches--the deepest marine habitats on Earth,” said Tim Shank, a biologist at the Woods Hole Oceanographic Institution in Woods Hole, Mass., one of the participating organizations. “We didn’t have the technology to do these kinds of detailed studies before. This will be a first-order look at community structure, adaptation and evolution: how life exists in the trenches.” Scientists plan to let the public share in the discoveries through live-streaming Web events from the seafloor including narration from the scientists. The work will also be chronicled in video, photos and blog updates on the expedition website. What marine animals live in the Kermadec Trench, and how do they survive the crushing pressures found at that depth--some 15,000 pounds per square inch? These are among the questions the scientists will try to answer. They plan to conduct research at 15 stations, including sites in shallow water for testing purposes, sites along the trench axis and sites in the abyssal plain. At each one, they will deploy free-falling, baited imaging landers called Hadal-Landers and “elevators” outfitted with experimental equipment--including respirometers to see how animal metabolism functions, plus water-sampling bottles to investigate microbial activity. The underwater robot, Nereus, will be used collect samples and to stream imagery from its video camera to a research ship via a fiber-optic filament about the width of human hair. The expedition is to build on earlier studies of the Kermadec Trench by Jamieson and colleagues at the National Institute of Water and Atmospheric Research and the University of Tokyo. Using the Hadal-Lander, they documented new species of animals in the Kermadec and other trenches in the Pacific. Once thought devoid of life, trenches may be home to many unique species, biologists say. There is growing evidence that food is plentiful there. While it is still unclear why, organic material in the ocean may be carried by currents and deposited into the trenches. In addition to looking at how food supply varies by depth, the researchers plan to investigate the role energy demand and metabolic rates of trench organisms play in animal community structure. “The energy requirements of hadal animals have never been measured,” said Jeff Drazen of the University of Hawaii, who will lead efforts to study food distribution and the energy demands among trench creatures. How animals in the trenches evolved to withstand high pressures is unknown, but Shank plans to compare the genomes of trench animals to piece together how they can survive there. “The challenge is to determine whether life in the trenches holds novel evolutionary pathways that are distinct from others in the oceans,” he said. Water pressure, which at depths found in ocean trenches can be up to 1,100 times that at the surface, is known to inhibit the activity of certain proteins. Yancey expects to investigate the role that piezolytes--small molecules that protect proteins from pressure--play in the adaptation of trench animals. Piezolytes, which Yancey discovered, may explain previous findings that not all deep-sea proteins are able to withstand high pressures. “We’re trying to understand how life can function under massive pressures in the hadal zone,” said Yancey. “Pressure might be the primary factor determining which species are able to live in these extreme environments.” Evidence also suggests that trenches act as carbon sinks, making the research relevant to climate change studies. “The bulk of our knowledge of trenches is only from snapshot visits using mostly trawls and camera landers,” Shank said. “Only detailed systematic studies will reveal the role trenches may play as the final location of where most of the carbon and other chemicals are sequestered in the oceans.”