Expedition to Mid-Cayman Rise Identifies Unusual Variety of Deep Sea Vents

The first expedition to search for deep-sea hydrothermal vents along the Mid-Cayman Rise has turned up three distinct types of hydrothermal venting, reports an interdisciplinary team led by Woods Hole Oceanographic Institution (WHOI) in this week's Proceedings of the National Academy of Sciences. The work was conducted as part of a NASA-funded effort to search extreme environments for geologic, biologic, and chemical clues to the origins and evolution of life.Hydrothermal activity occurs on spreading centers all around the world. However, the diversity of the newly discovered vent types, their geologic settings and their relative geographic isolation make the Mid-Cayman Rise a unique environment in the world's ocean."This was probably the highest risk expedition I have ever undertaken," said chief scientist Chris German, a WHOI geochemist who has pioneered the use of autonomous underwater vehicles (AUVs) to search for hydrothermal vent sites. "We know hydrothermal vents appear along ridges approximately every 100 km. But this ridge crest is only 100 km long, so we should only have expected to find evidence for one site at most. So finding evidence for three sites was quite unexpected -- but then finding out that our data indicated that each site represents a different style of venting -- one of every kind known, all in pretty much the same place -- was extraordinarily cool."The Mid-Cayman Rise (MCR) is an ultraslow spreading ridge located in the Cayman Trough -- the deepest point in the Caribbean Sea and a part of the tectonic boundary between the North American Plate and the Caribbean Plate. At the boundary where the plates are being pulled apart, new material wells up from Earth's interior to form new crust on the seafloor.The team identified the deepest known hydrothermal vent site and two additional distinct types of vents, one of which is believed to be a shallow, low temperature vent of a kind that has been reported only once previously -- at the "Lost City" site in the mid-Atlantic ocean."Being the deepest, these hydrothermal vents support communities of organisms that are the furthest from the ocean surface and sources of energy like sunlight," said co-author Max Coleman of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Most life on Earth is sustained by food chains that begin with sunlight as their energy source. That's not an option for possible life deep in the ocean of Jupiter's icy moon Europa, prioritized by NASA for future exploration. However, organisms around the deep vents get energy from the chemicals in hydrothermal fluid, a scenario we think is similar to the seafloor of Europa, and this work will help us understand what we might find when we search for life there."While vent sites occupy small areas on the sea floor, the plumes formed when hot acidic vent fluids mix with cold deep-ocean seawater can rise hundreds of meters until they reach neutral buoyancy. Because these plumes contain dissolved chemicals, particulate minerals and microbes, they can then be detected for kilometers or more away from their source as they disperse horizontally in the ocean. The chemical signatures of these plumes vary according to the type of vent site from which they originated.The three known types of vent sites are distinguished by the kinds of rock that host the sites. The first type of vents occur throughout the world's mid-ocean ridges and are hosted by rocks that are rich in magnesium and iron --called mafic rocks. The second and third types of vent sites are hosted in rocks called ultramafic that form deep below the seafloor and are composed of material similar to the much hotter lavas that erupted on Earth's very earliest seafloor, thousands of millions of years ago.The discovery of ultramafic-hosted vent sites such as those on the Mid-Cayman Rise could provide insight into the very earliest life on our planet and the potential for similar life to become established elsewhere," said German.For this mission, German and his colleagues used the plumes in the search for hydrothermal vents, employing sensors mounted on equipment and robotic vehicles to track the chemicals back to their source. This expedition used a CTD (conductivity, temperature, and depth) array augmented with sensors to detect suspended particles and anomalous chemical compositions (the latter sensor courtesy of Ko-ichi Nakamura from AIST in Tsukuba, Japan) mounted on both a water sampling rosette and the hybrid vehicle Nereus, a deep-diving robot that can operate in both in tethered and free-swimming modes.Using the CTDs and Nereus in "autonomous" or free-swimming mode, the team sniffed out deep-sea plumes originating from the seafloor hydrothermal vents. Using a combination of shipboard and shore-based analyses of water samples for both their chemical and microbial contents, the team was then able to track the plumes toward their sources as well as to determine the likely nature of the venting present at each site. The ultimate goal was to switch Nereus into tethered or "remotely operated" (ROV) mode during the latter stages of the cruise and dive on each vent site to collect samples using Nereus' robotic manipulator arm."Part of the excitement of this NASA-funded project was the success of deploying a full-ocean-capable tethered vehicle to search for vents at 5000 m from the R/V Cape Hatteras, which, at 41 meters in length, is one of the smallest ocean-going ships in the national fleet. This is a first," said Cindy Lee Van Dover, co-author on the study and director of the Duke University Marine Laboratory.The first two sites the team identified are extremely deep and were named Piccard and Walsh in honor of the only two humans to dive to the Challenger Deep -- the deepest part of the world's ocean. The plume detected at the Piccard site -- 800 meters deeper than the previously known deepest vent -- was comparable to plumes from the "Type 1" vent sites, first found in the Pacific Ocean in 1977."We were particularly excited to find compelling evidence for high-temperature venting at almost 5000m depth. We have absolutely zero microbial data from high-temperature vents at this depth," said Julie Huber, a scientist in the Josephine Bay Paul Center at the Marine Biological Laboratory (MBL) in Woods Hole. Huber and MBL postdoctoral scientist Julie Smith participated in this cruise to collect samples, and all of the microbiology work for this paper was carried out in Huber's laboratory. "With the combination of extreme pressure, temperature, and chemistry, we are sure to discover novel microbes in this environment," Huber added. "We look forward to returning to the Cayman and sampling these vents in the near future. We are sure to expand the known growth parameters and limits for life on our planet by exploring these new sites."The Walsh plume also exhibited signals characteristic of a high temperature site, but with a chemical composition (notably the high methane-to-manganese ratio) typically found at a high temperature, ultramafic hosted "Type 2" vent site. The third site- which the team have named Europa, after the moon of Jupiter -- most closely resembles the "Lost City" vent site in the mid-Atlantic ocean -- to date the only confirmed low-temperature "Type 3" site.Half way through the six-day leg in which Nereus was converted into ROV mode, tropical storm Ida intervened and stopped the team from viewing or sampling the vent site. Though they had come within 250m of the vents at the seafloor, they had to ride out the storm for the last three days of the cruise and return to port frustrated. Happily, however, all was not lost the research team shared their findings with an international team led by Jon Copley of the National Oceanography Centre in Southampton, UK, who returned to the MCR in Spring 2010 and imaged active vents at both the Piccard and Europa locations using a deep-towed camera called Hybis."Given the range and diversity of systems present, and now that we have established exactly where the sites are and what they look like, we really can't wait to get back and collect first samples with our ROV Jason," said German. "This region has the potential to develop into an exciting natural laboratory with plenty of potential for repeat visits and long-term experiments over the decade ahead."By exploring this extreme and previously uninvestigated section of the Earth's deep seafloor, the researchers seek to extend our understanding of the limits to which life can exist on Earth and to help prepare for future efforts to explore for life on other planets.

Undersea Superhighway: Long-Distance Larvae Speed to New Undersea Vent Homes

Working in a rare, "natural seafloor laboratory" of hydrothermal vents that had just been rocked by a volcanic eruption, scientists from the Woods Hole Oceanographic Institution (WHOI) and other institutions have discovered what they believe is an undersea superhighway carrying tiny life forms unprecedented distances to inhabit the post-eruption site.

One such "pioneer species," Ctenopelta porifera, appears to have traveled over 300 kilometers to settle at the site on the underwater mountain range known as the East Pacific Rise. "Ctenopelta had never been observed before at the…study site, and the nearest known population is 350 km to the north," said Lauren S. Mullineaux, a senior scientist in WHOI's biology department.
The discovery -- in collaboration with the Lamont-Doherty Earth Observatory (LDEO) and the NOAA Pacific Marine Environmental Laboratory (PMEL) -- clashes with the widely accepted assumption that when local adult life is wiped out in a hydrothermal eruption, it is replaced by a pool of tiny creatures from nearby vents. In this case, however, the larvae that re-settled the post-eruption vent area are noticeably different from the species that were destroyed and appeared to have traveled great distances to do so.
"This raises the question of how they can possibly disperse so far," says Mullineaux. The findings have implications, she says, for the wider distribution of undersea life. "If these new pioneers persist and cause a regime shift, that will expand their range and increase the regional diversity," Mullineaux says.
A report on the research by Mullineaux and her colleagues is published in the current (April 12) issue of the Proceedings of the National Academy of Sciences.
The discovery of hydrothermal vents on the bottom of the Pacific Ocean in 1977 revolutionized ideas about where and how life could exist. The seafloor vents gushing warm, mineral-rich fluids and teeming with life raised new question that researchers have been studying ever since, including: How can so much life thrive at the sunless seafloor? What is the nature of organisms at hydrothermal vents? How do animals migrate to other vent sites?
It was this last question that motivated Mullineaux and her team as they began their study of a vent area on the East Pacific Rise "to gather observations of currents, larvae and juvenile colonists…in order to understand what physical processes might facilitate dispersal," Mullineaux says. One of the group's primary challenges was to determine where the organisms around the vent came from.
As the scientists set out on their mission in 2006, "we got a surprise," said Mullineaux. "A seafloor eruption was detected at our study site…resulting in changes in topography and enormous disturbance to ecological communities.
"The eruption was, in essence, a natural experiment."
By the time the researchers arrived at the site, they found a scene quite unlike that usually observed at a hydrothermal vent. Normally, such fissures are teeming with life, supported by the hot chemicals that spew from the vents and provide food through microbial chemosynthesis, a deep-sea version of photosynthesis.
But at this spot on the East Pacific Rise, near 9 degrees North, there was no life. The eruption had wiped it out.
"Although the vents survived, the animals did not, and virtually all of the detectable invertebrate communities were paved over," said Mullineaux. "For us, this was an exciting event. In essence it was a natural clearance experiment that allowed us to explore how this elimination of local source populations affected the supply of larvae and re-colonization."
What they found went against the accepted assumption that most of the organisms to re-populate the area would come from relatively nearby. But instead, the new larval inhabitants came from considerable distance.
"These results show clearly that the species arriving after the eruption are different than those before," says Mullineaux, "with two new pioneer species, Ctenopelta porifera and Lepetodrilus tevnianus, prominent."
To the biologist, the most important finding is that "the processes of the larval stage -- as opposed to those of adult organisms--seem to control colonization," Mullineaux says. "We found that a pioneer colonization event by Ctenopelta radically changed the community structure."
But the question remained, how were these weak-swimming larvae propelled such vast distances to the decimated vent area? The answer may lie in a recently developed model by Mullineaux's colleagues Dennis McGillicuddy and Jim Ledwell of WHOI, Bill Lavelle of PMEL and Andreas Thurnherr of LDEO, all part of the LADDER team--LArval Dispersal on the Deep East Pacific Rise.
Seemingly the only way the emigrating larvae could get to their new home from so far away, Mullineaux says, would be to ride ocean-bottom "jets" traveling up to 10 centimeters a second, such as those identified in the work of McGillicuddy and Thurnherr.
Theoretically, however, even these ridge-crest jets might not quite be able to transport the larvae from 350 km within the time frame of their 30-day lifespan, she said. "Either the larvae are using some other transport or they are living longer than we thought," said Mullineaux.
She speculates that large eddies, or whirlpools of water, several hundred kilometers in diameter, may be propelling the migrating larvae even faster -- delivering them to their new home while they are still alive. Or perhaps, she says, the larvae are able to somehow reduce their metabolism and extend their life.
In any case, the findings present an array of fascinating scientific scenarios, Mullineaux says, that warrant further exploration.
They also may open up new ways of looking at the impacts of human activities on the seafloor, such as seafloor mineral mining, which could alter a vent site in a similar way to an eruption. Depending on the site, such activity could conceivably foster a greater diversity of species at a vent that has just been mined, or it could cause extinction, she said. But such scenarios are still highly speculative, she emphasizes.
Mullineaux's WHOI co-authors on the study were Diane K. Adams, currently at the National Institutes of Health, Susan W. Mills and Stace E. Beaulieu.
The project was funded by the National Science Foundation, along with supplemental support from WHOI's Deep Ocean Exploration Institute. Woods Hole Oceanographic Institution (2010, April 13). Undersea superhighway: Long-distance larvae speed to new undersea vent

World's Deepest Known Undersea Volcanic Vents Discovered

A British scientific expedition has discovered the world's deepest undersea volcanic vents, known as 'black smokers', 3.1 miles (5000 metres) deep in the Cayman Trough in the Caribbean. Using a deep-diving vehicle remotely controlled from the Royal Research Ship James Cook, the scientists found slender spires made of copper and iron ores on the seafloor, erupting water hot enough to melt lead, nearly half a mile deeper than anyone has seen before.

Deep-sea vents are undersea springs where superheated water erupts from the ocean floor. They were first seen in the Pacific three decades ago, but most are found between one and two miles deep. Scientists are fascinated by deep-sea vents because the scalding water that gushes from them nourishes lush colonies of deep-sea creatures, which has forced scientists to rewrite the rules of biology. Studying the life-forms that thrive in such unlikely havens is providing insights into patterns of marine life around the world, the possibility of life on other planets, and even how life on Earth began.
The expedition to the Cayman Trough is being run by Drs Doug Connelly, Jon Copley, Bramley Murton, Kate Stansfield and Professor Paul Tyler, all from Southampton, UK. They used a robot submarine called Autosub6000, developed by engineers at the National Oceanography Centre (NOC) in Southampton, to survey the seafloor of the Cayman Trough in unprecedented detail. The team then launched another deep-sea vehicle called HyBIS, developed by team member Murton and Berkshire-based engineering company Hydro-Lek Ltd, to film the world's deepest vents for the first time.
"Seeing the world's deepest black-smoker vents looming out of the darkness was awe-inspiring," says Copley, a marine biologist at the University of Southampton's School of Ocean and Earth Science (SOES) based at the NOC and leader of the overall research programme. "Superheated water was gushing out of their two-storey high mineral spires, more than three miles deep beneath the waves." He added: "We are proud to show what British underwater technology can achieve in exploring this frontier -- the UK subsea technology sector is worth £4 billion per year and employs 40 000 people, which puts it on a par with our space industry."
The Cayman Trough is the world's deepest undersea volcanic rift, running across the seafloor of the Caribbean. The pressure three miles deep at the bottom of the Trough -- 500 times normal atmospheric pressure -- is equivalent to the weight of a large family car pushing down on every square inch of the creatures that live there, and on the undersea vehicles that the scientists used to reveal this extreme environment. The researchers will now compare the marine life in the abyss of the Cayman Trough with that known from other deep-sea vents, to understand the web of life throughout the deep ocean. The team will also study the chemistry of the hot water gushing from the vents, and the geology of the undersea volcanoes where these vents are found, to understand the fundamental geological and geochemical processes that shape our world.
"We hope our discovery will yield new insights into biogeochemically important elements in one of the most extreme naturally occurring environments on our planet," says geochemist Doug Connelly of the NOC, who is the Principal Scientist of the expedition.
"It was like wandering across the surface of another world," says geologist Bramley Murton of the NOC, who piloted the HyBIS underwater vehicle around the world's deepest volcanic vents for the first time. "The rainbow hues of the mineral spires and the fluorescent blues of the microbial mats covering them were like nothing I had ever seen before."
The expedition will continue to explore the depths of the Cayman Trough until 20th April.
In addition to the scientists from Southampton, the team aboard the ship includes researchers from the University of Durham in the UK, the University of North Carolina Wilmington and the University of Texas in the US, and the University of Bergen in Norway. The expedition members are also working with colleagues ashore at Woods Hole Oceanographic Institution and Duke University in the US to analyse the deep-sea vents.
The expedition is part of a research project funded by the UK Natural Environment Research Council to study the world's deepest undersea volcanoes. The research team will return to the Cayman Trough for a second expedition using the UK's deep-diving remotely-operated vehicle Isis, once a research ship is scheduled for the next phase of their project.
Additional information
(1) The expedition aboard the RRS James Cook began in Port of Spain, Trinidad on 21st March and ends in Montego Bay, Jamaica on 21st April. It is part of a £462k research project funded by the UK Natural Environment Research Council.
(2) The RRS James Cook is the UK's newest ocean-going research ship, operated by the Natural Environment Research Council. The current expedition is the 44th voyage of the ship.

National Oceanography Centre, Southampton (UK) (2010, April 12). World's deepest known undersea volcanic vents discovered. ScienceDaily. Retrieved April 16, 2010, from http://www.sciencedaily.com­ /releases/2010/04/100411214117.htm

Methane Gas Likely Spewing Into The Oceans Through Vents In Sea Floor

Scientists worry that rising global temperatures accompanied by melting permafrost in arctic regions will initiate the release of underground methane into the atmosphere. Once released, that methane gas would speed up global warming by trapping the Earth’s heat radiation about 20 times more efficiently than does the better-known greenhouse gas, carbon dioxide.

An MIT paper appearing in the Journal of Geophysical Research online Aug. 29 elucidates how this underground methane in frozen regions would escape and also concludes that methane trapped under the ocean may already be escaping through vents in the sea floor at a much faster rate than previously believed. Some scientists have associated the release, both gradual and fast, of subsurface ocean methane with climate change of the past and future.
“The sediment conditions under which this mechanism for gas migration dominates, such as when you have a very fine-grained mud, are pervasive in much of the ocean as well as in some permafrost regions,” said lead author Ruben Juanes, the ARCO Assistant Professor in Energy Studies in the Department of Civil and Environmental Engineering.
“This indicates that we may be greatly underestimating the methane fluxes presently occurring in the ocean and from underground into Earth’s atmosphere,” said Juanes. “This could have implications for our understanding of the Earth’s carbon cycle and global warming.”
Juanes explains that some of the naturally occurring underground methane exists not as gas but as methane hydrate. In the hydrate phase, a methane gas molecule is locked inside a crystalline cage of frozen water molecules. These hydrates exist in a layer of underground rock or oceanic sediments called the hydrate stability zone or HSZ. Methane hydrates will remain stable as long as the external pressure remains high and the temperature low. Beneath the hydrate stability zone, where the temperatures are higher, methane is found primarily in the gas phase mixed with water and sediment.
But the stability of the hydrate stability zone is climate-dependent.
If atmospheric temperatures rise, the hydrate stability zone will shift upward, leaving in its stead a layer of methane gas that has been freed from the hydrate cages. Pressure in that new layer of free gas would build, forcing the gas to shoot up through the HSZ to the surface through existing veins and new fractures in the sediment. A grain-scale computational model developed by Juanes and recent MIT graduate Antone Jain indicates that the gas would tend to open up cornflake-shaped fractures in the sediment, and would flow quickly enough that it could not be trapped into icy hydrate cages en route.
“Previous studies did not take into account the strong interaction between the gas-water surface tension and the sediment mechanics. Our model explains recent experiments of sediment fracturing during gas flow, and predicts that large amounts of free methane gas can bypass the HSZ,” said Juanes.
Using their model, as well as seismic data and core samples from a hydrate-bearing area of ocean floor (Hydrate Ridge, off the coast of Oregon), Juanes and Jain found that methane gas is very likely spewing out of vents in the sea floor at flow rates up to 1 million times faster than if it were migrating as a dissolved substance in water making its way through the oceanic sediment — a process previously thought to dominate methane transport.
“Our model provides a physical explanation for the recent striking discovery by the National Oceanic and Atmospheric Administration of a plume 1,400 meters high at the seafloor off the Northern California Margin,” said Juanes. This plume, which was recorded for five minutes before disappearing, is believed not to be hydrothermal vent, but a plume of methane gas bubbles coated with methane hydrate.
The Jain and Juanes paper in the Journal of Geophysical Research also explains the short-term consequences of injecting carbon dioxide into the ocean’s subsurface, a method proposed by some researchers for reducing atmospheric greenhouse gas. Juanes found that while some of the CO2 would remain trapped as a hydrate, much would likely spew up through fractures just as methane does.
“It is important to keep both methane and carbon dioxide either in the pipeline or underground, because the consequences of escape can be quite dangerous over time,” said Juanes.
This research was funded by the U.S. Department of Energy.
Adapted from materials provided by Massachusetts Institute of Technology, Department of Civil and Environmental Engineering.

Mussels Have Adapted To Extremely Acidic Waters Near Underwater Volcanoes

Understanding How Mussels Have Adapted To Extremely Acidic Waters Near Underwater VolcanoesA student at Dalhousie University in Halifax, Nova Scotia is bringing understanding to the troubling problem of ocean acidification due to increasing atmospheric carbon dioxide.As an undergraduate, Kim Davies worked with Dr. Verena Tunnicliffe, biology professor at the University Victoria, examining how mussels have adapted to extremely acidic waters near underwater volcanoes. The paper she co-authored will be published in the May issue of the journal Nature Geoscience.Carbon dioxide (CO2) emitted to the atmosphere by human activities is being absorbed by the oceans, making them more acidic. Evidence indicates that emissions of carbon dioxide from human activities over the past two centuries have already led to a reduction in the average pH of surface seawater. Because acidification affects the process of calcification, the impact is severe on marine animals like corals, plankton and mollusks which have shells or plates.So what happens to these animals over time? That's what the researchers wanted to find out by examining vent mussels (Bathymodiolus brevior) living on the side of submarine volcanoes. The mussels, which have a calcium carbonate skeleton, are under constant stress, bathed by carbon dioxide bubbling out of the ground and from hydro-thermal vents deep beneath the surface.And yet some of the mussels, gathered by remotely operated vehicles along the Mariano volcanic arc near Japan, were determined to be more than 40 years old and had physiologically adapted to living in their extreme environment.The researchers discovered the mussels grew much slower than mussels in other areas and their shells were very thin. As well, the mussels' shells were completely covered with protective protein coverings; any breach of that outer layer would quickly destroy the mussel by dissolving the underlying calcium carbonate."Their shells—you could see right through them," says Ms. Davies, who did the lab analysis of samples gathered some 1,500 metres below the surface. "And yet, this species of mussels was able to adapt and build up a tolerance living close to these hydro-thermal vents as long as their protective covering was intact."She surmised mussels in other areas would be more vulnerable to ocean acidification because of crabs that scurry over them and wear away at their protective covering. Those predators were absent in the mussel beds near the hydro-thermal vents."It's such a euphoric feeling to see that something I did as an undergrad is regarded as important science," says Ms. Davies, a PhD student at Dalhousie whose research is now focused on the feeding ecology of the North Atlantic right whale. "Wow, it's so great just to see your name in a high-level journal."Dalhousie University

Seafloor Mud Volcanoes And Brine Pools Reveal New Information On Their Microbial Processes

Everyone knows of volcanoes and their ability to do anything from burying cities to changing the climate. Less-well-known are mud volcanoes, vents bubbling gases and a slurries of fine solids suspended in liquids. The most familiar of the latter are the gurgling and flapping vents in places such as Yellowstone National Park.Even less known are undersea mud volcanoes, but a new study by a biogeochemist at the University of Georgia and her colleagues has shown for the first time distinct and unexpected patterns of microbial metabolism where fluids emanating from seafloor mud volcanoes and their cousins called brine pools mix with overlying seawater."Very few results describing rates of microbial activity in seafloor brines have been published, and none show the detailed stratification of microbial processes with the brine fluids documented here," said Samantha Joye, a faculty member in the department of marine sciences in UGA's Franklin College of Arts and Sciences.The research has implications for life processes on everything from early Earth to moons in our Solar System—such as Jupiter's Europa and Mars—where brine fluids could support microbiological life. The study was published today in the journal Nature Geosciences. Other authors of the paper include Vladimir Samarkin, Beth Orcutt and Christof Meile also of the University of Georgia; Ian McDonald of Texas A&M University; Kai-Uwe Hinrichs and Marcus Elvert of the University of Bremen; Andreas Teske, Karen Lloyd and Mark Lever of the University of North Carolina at Chapel Hill; and Joseph Montoya of the Georgia Institute of Technology. The team studied two kinds of emission areas at depths of about 600 meters beneath the Gulf of Mexico: mud volcanoes and seafloor brine pools. Undersea mud volcanoes can be quite active, with plumes of gas, mainly methane, extending hundreds of meters from the seafloor. These features can cover large areas, and gas bubbles are a consistent feature. Brine pools form in depressions in the largely flat ocean bottom and are less active but can be quite expansive, too."Almost nothing is known about deep-sea mud volcanoes," said Joye. "And seafloor brine pools represent dynamic and challenging habitats where microorganisms endure variations in fluid composition, temperature and flow regimes."Hypersaline brine pools are a unique and understudied seafloor habitat in the Gulf of Mexico. Brine pools form when warm, salty fluids migrate up through the sediments through fissures in the sediment. So, at places where seepage is active, brine fluids with four or five times as much salt as seawater will also escape. The brine is much denser than seawater, so it pools on the surface after cooling to ambient temperature.One of the reasons so little is known about undersea mud volcanoes and brine pools is their sheer inaccessibility. Joye used the Johnson Sea Link, a deep-sea scientific research submersible built by the Harbor Branch Oceanographic Institution, to study the features on the ocean floor.For the first time, the team studied "slices" of water above a mud volcano and a seafloor brine, with an eye to understanding how microbial processes change in their water columns. While both areas were anoxic (depleted of dissolved oxygen) and hypersaline and thus inhospitable for most life, microorganisms thrive there. The Joye team's study documented differences in the depth distribution and magnitude of key microbial processes.Joye and colleagues discovered that rate of sulphate reduction and acetate production were greater in the brine pool, while the mud volcano supported higher rates of methane production. "We believe the composition of the microbial communities and their metabolism are linked to differences in geochemical and flow differences between the sites," said Joye. Another surprise was that microbial activity was measureable at the deepest samples collected, so it is feasible that active microbes extend deep into the subsurface of the mud volcano systems in the Gulf of Mexico, linking the deep biosphere with ocean-bottom habitats."This work integrates so many aspects of science so well, that it has the potential to tell us many things about processes on the ocean floor," said Joye. "From this work, for example, we now know that flow regimes in deep sea brines dictate dominant patterns of microbial activity. Also, when you think of hypersaline systems, we documented methane production from acetate at salinity levels twice the accepted levels."The work was supported by grants from the National Science Foundation, the National Oceanic and Atmospheric Administration, the Department of Energy, the American Chemical Society, the Environmental Protection Agency and NASA.

Underwatertimes.com News ServiceApril 6, 2009 19:39 EST

Genetic Adaptations Key To Extreme Microbe's Survival In Challenging Environment

The genome of a marine bacterium living 2,500 meters below the ocean's surface is providing clues to how life adapts in extreme thermal and chemical gradients, according to an article published Feb. 6 in the journal PLoS Genetics.

The research focused on the bacterium Nautilia profundicola, a microbe that survives near deep-sea hydrothermal vents. Microorganisms that thrive at these geysers on the sea floor must adapt to fluctuations in temperature and oxygen levels, ranging from the hot, sulfide- and heavy metal-laden plume at the vents' outlets to cold seawater in the surrounding region.
The study combined genome analysis with physiological and ecological observations to investigate the importance of one gene in N. profundicola. That gene, called rgy, allows the bacterium to manufacture a protein called reverse gyrase when it encounters extremely hot fluids from the Earth's interior.
Previous studies found the gene only in microorganisms growing in temperatures greater than 80°C, but N. profundicola thrives best at much lower temperatures.
"The gene's presence in N. profundicola suggests that it might play a role in the bacterium's ability to survive rapid and frequent temperature fluctuations in its environment," said Assistant Professor of Marine Biosciences Barbara Campbell, the study's lead scientist.
Additional University of Delaware contributors were Professor of Marine Biosciences Stephen Craig Cary, Assistant Professor of Marine Biosciences Thomas Hanson, and Julie Smith, marine biosciences doctoral student. Also collaborating on the project were researchers from the Davis and Riverside campuses of the University of California; the University of Louisville; the University of Waikato in Hamilton, New Zealand; and the J. Craig Venter Institute in Rockville, Md.
The researchers also uncovered further adaptations to the vent environment, including genes necessary for growth and sensing environmental conditions, and a new route for nitrate assimilation related to how other bacteria use ammonia as an energy source. Photosynthesis cannot occur in the hydrothermal vents' dark environment, where hot, toxic fluids oozing from below the seafloor combine with cold seawater at very high pressures.
These results help to explain how microbes survive near the vents, where conditions are thought to resemble those found on early Earth. Nautilia profundicola contains all the genes necessary for life in conditions widely believed to mimic those in our planet's early biosphere and could aid in understanding of how life evolved.
"It will be an important model system," Campbell said, "for understanding early microbial life on Earth."
Adapted from materials provided by University of Delaware, via EurekAlert!, a service of AAAS.

Three New Species Discovered On Deep-sea Voyage

Scientists from the California Institute of Technology (Caltech) and an international team of collaborators have returned from a month-long deep-sea voyage to a marine reserve near Tasmania, Australia, that not only netted coral-reef samples likely to provide insight into the impact of climate change on the world's oceans, but also brought to light at least three never-before-seen species of sea life.

"It was truly one of those transcendent moments," says Caltech's Jess Adkins of the descents made by the remotely operated submersible Jason. Adkins was the cruise's lead scientist and is an associate professor of geochemistry and global environmental science at Caltech. "We were flying--literally flying--over these deep-sea structures that look like English gardens, but are actually filled with all of these carnivorous, Seuss-like creatures that no one else has ever seen."
The voyage on the research vessel RV Thompson explored the Tasman Fracture Commonwealth Marine Reserve, southwest of Tasmania. The voyage was funded by the National Science Foundation and was the second of two cruises taken by the team, which included researchers from the United States--including scientists from Caltech and the Woods Hole Oceanographic Institution in Massachusetts, which owns and operates the submersible Jason--and Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO). The first of those voyages was taken in January 2008, with this most recent one spanning 33 days from mid-December 2008 through mid-January 2009.
Up until now, the area of the reef the scientists were exploring--called the Tasman Fracture Zone--had only been explored to a depth of 1,800 meters (more than 5,900 feet). Using Jason, the researchers on this trip were able to reach as far down as 4,000 meters (well over 13,000 feet).
"We set out to search for life deeper than any previous voyage in Australian waters," notes scientist Ron Thresher from CSIRO's Climate Adaptation and Wealth from Oceans Flagships.
The cruise had two main goals, says Adkins. One was to try to use deep-sea corals to reconstruct the paleoclimate--with an emphasis on the changes in climate over the last 100,000 years--and to understand the fluctuations in CO2 found in the ice-core records. Investigators also wanted to look at changes in the ocean over a much smaller slice of time--the past few hundred to one thousand or so years. "We want to see what's happened to the corals over the Industrial Revolution timescale," says Adkins. "And we want to see if we can document those changes."
The second goal? "Simply to document what's down there," says Adkins.
"In one sense, the deep ocean is less explored than Mars," he adds. "So every time you go to look down there you see new things, magical things."
Among the "magical things" seen on this trip were
a new species of carnivorous sea squirt that "looks and behaves like a Venus fly trap," says Adkins;
new species of barnacles (some of which Adkins says may even belong to an entirely new family); and
a new species of sea anemone that Adkins calls "the bane of our existence," because it looks just like the coral they were trying to collect.
The sea anemone was particularly vexing for the researchers, because they were hoping to find deep-sea (or abyssal) samples of the fossilized coral, but were unable to find the coral much below 2,400 meters (nearly 7,800 feet). The look-alike sea anemone, on the other hand, kept popping up all over the place on the deep-sea floor, raising--and then dashing--the scientists' hopes.
"Not being able to find the coral down deeper was our single biggest disappointment on the trip," says Adkins.
Still, the 10,000-plus samples collected will help the researchers begin their work of deciphering just what has been happening to the ocean throughout the centuries of climate change, and during and between glacial cycles. First up: dating the fossils collected on this trip in order to determine which slice of history they came from.
"The deep ocean is part and parcel of these rapid climate changes," says Adkins. "These corals will be our window into what their impact is on climate, and how they have that impact. The info is there; now we just have to unpack it."
Further funding for the research came from CSIRO, the Commonwealth Environmental Research Facilities' Marine Biodiversity Hub, and the Australian Department of the Environment, Water, Heritage and the Arts.
Adapted from materials provided by California Institute of Technology.

Millions of tiny Seastars inhabit undersea volcano

Marine scientists surveying a large undersea mountain chain were amazed to find millions of tiny Seastars swirling their arms to capture food in the undersea current.An expedition by 19 scientists, including five from Australia, studied the geology and biology of eight Macquarie Ridge sea mounts. They are part of a string of underwater volcanoes — dormant for millions of years — that stretches 875 miles from south of New Zealand toward Antarctica.The scientists also investigated the world's biggest ocean current — the Antarctic Circumpolar Current — amid expectations they would find evidence of climate change in the Southern Ocean.While the expedition's cameras found a wide range of Corals, a high density of Cardinal fish and the huge coral, the vast collection of brittle stars was the highlight of the voyage."I've personally never seen anything like this — all these animals, the sheer volume — all waiting for food from the current," expedition member and marine biologist Dr. Mireille Consalvey said Monday. "It challenged what we as scientists thought we knew."Expedition leader and marine biologist Ashley Rowden said Seastars usually cover only slopes away from the top of the undersea mountains."It got us excited as soon as we saw it," Rowden said of the site, dubbed "Brittle Star City."The Seastars are about 0.4 inch across, with arms about 2 inches long.The expedition began March 26 and returned to port in New Zealand's capital Wellington on April 26.Melbourne-based marine biologist Tim O'Hara, a Brittle star specialist, said the vast collection of brittle stars, or ophiuroid ophiacantha, is "like a relic of ancient times.""Normally fish would prey on them and eat them ... so for whatever reason there's a lack of fish predation there and it's seen this particular animal flourish," he said.O'Hara, who was not part of the voyage, said the speed of the sea current in the area may partly explain why fish were not feeding on the tiny animals.The Circumpolar Current merges the waters of the Atlantic, Indian and Pacific oceans and carries up to 150 times the volume of water flowing in all the world's rivers, oceanographer Mike Williams said.Australian oceanographer Steve Rintoul, who was not involved in the expedition, said there have been few measurements of the Antarctic Circumpolar Current, which "strongly influences regional and global climate" by carrying vast amounts of water and heat across oceans.Fewer than 200 of the world's estimated 100,000 sea mounts that rise more than a half a mile above the sea floor have been studied in any detail.

Deep sea vents yield new microbes

Hot vents deep in the ocean harbor thousands of previously unknown microorganisms, scientists report. By examining the DNA of microbes taken from two hydrothermal vents off the coast of Oregon, researchers identified as many as 37,000 different kinds of bacteria and 3,000 archaea, a type of microorganism distinct from bacteria, according to researchers from the Marine Biological Laboratory at Woods Hole, Mass. and the University of Washington. Their findings are reported in Friday's edition of the journal Science."Most of these bacteria had never been reported before," lead author Julie Huber of the MBL said in a statement. "Clearly, additional sampling of these communities will be necessary to determine the true diversity."The researchers also reported that the populations living at the two vents differed because of different chemical environments.

Deep Ocean's most turbulent areas has big impact on Climate

More than a mile beneath the Atlantic's surface, roughly halfway between New York and Portugal, seawater rushing through the narrow gullies of an underwater mountain range much as winds gust between a city's tall buildings is generating one of the most turbulent areas ever observed in the deep ocean।

In fact, the turbulence packs an energy wallop equal to about five million watts -- comparable to output from a small nuclear reactor, according to a landmark study led by Florida State University researcher Louis St. Laurent and described in the August 9 edition of the journal Nature.
The study -- an international collaboration of scientists from the United States and France -- documents for the first time the turbulent conditions in an undersea mountain range known as the Mid-Atlantic Ridge. It provides never-before-seen evidence that deep water turbulence swirling in the small passageways of such mountains is generating much of the mixing of warm and cold waters in the Atlantic Ocean.
Better understanding of the mechanisms of mixing is crucial, says St। Laurent, an assistant professor of physical oceanography at FSU and the study's co-principal investigator, because mixing produces the overall balance of water temperatures that helps control the strength of the Gulf Stream -- the strong, warm ocean current that starts in the Gulf of Mexico, flows along the U.S. east coast to Canada and on to Europe, and plays a crucial climate role.

"Oceanographers are working hard to understand how processes in the ocean help to keep the Earth's climate stable," St. Laurent said. "We are aware that the climate is warming, but we don't yet fully understand how the changes will affect society. Our work will result in better models for predicting how the ocean will affect the climate in the future and a better understanding of sea-level rise, weather patterns such as El Nino, and the impact of these events on fisheries."
St. Laurent compared the flow of seawater through underwater gullies in the Mid-Atlantic Ridge to the wind, so familiar to hikers, that blows through mountain passages on land.
"That wind creates a condition known as turbulence, which can blow the hat from your head," St। Laurent said. "In the ocean, turbulence is produced when water flows quickly though oceanic passages. The turbulence stirs the almost freezing-water near the bottom with warmer water that is closer to the surface much as you would mix cream into coffee by stirring it with a spoon.

"We know that the mixing of warm surface water with very cold deep water is one of several factors that influence the Earth's climate," he said. "The mixing we observed and measured for our study allows the warmth at the surface of the ocean to 'diffuse' deep into the sea. The overall balance between warm and cold water in the Atlantic helps control the strength of the Gulf Stream, which moves heat away from the Earth's equator toward regions that receive much less heating from the sun's rays."
St. Laurent's co-principal investigator and co-author was Andreas M. Thurnherr, a former postdoctoral researcher in the FSU oceanography department and now a scientist at Columbia University. The field study took place in August 2006 during a three-week expedition aboard a French research vessel to a location close to the Azores, volcanic islands 2,000 miles east of the U.S. and west of Europe that comprise an above-sea portion of the mostly submerged Mid-Atlantic Ridge.
To measure the energy generated by the extraordinarily intense turbulence more than a mile below the ocean's surface, St. Laurent and crew used a custom-made instrument called the "turbulence profiler," outfitted with special sensors.
"The turbulence profiler measured the output using 'watts,' the same unit of measurement as printed on light bulbs," St. Laurent said. "In the undersea mountain passage where we intentionally looked, we found turbulence levels as large as one-10th watt per cubic meter of seawater. This is a huge amount of energy when you add all the seawater in the passage, equal to around five million watts, which is comparable to output from a nuclear reactor."
Article: "Overflow Mixing of Lower Thermocline Water on the Crest of the Mid-Atlantic Ridge"

Note: This story has been adapted from a news release issued by Florida State University.

Exploration of new avenues like cold water coral and under water research in Arctic Ocean

The research vessel, Polarstern leaves Bremerhaven for its 22nd Arctic expedition with a new shine, to begin its first work in the International polar year।

With a new coat of paint, thorough ship inspection, and sailing under the flag of the Helmholtz Association, Polarstern begins to make its way toward the north on May 29। The flagship of the Alfred Wegener Institute for Polar and Marine Research (AWI), is initially heading to Northern Norway and then on to Spitsbergen during its 22nd Arctic expedition.

One of the scientific priorities is the European project HERMES (Hotspot Ecosystem Research on the Margins Of European Seas), in which the ecological ecosystems of the deep sea will be investigated. The manned underwater craft, JAGO, belonging to the Leibniz Institute of Marine Sciences, IFM GEOMAR from Kiel and the remote-controlled underwater craft QUEST from the MARUM of the University of Bremen are all planning to be used.
130 scientists from 11 countries, divided into three groups will participate in the expedition. Professor Dr. Jörn Thiede, director of the Alfred Wegener Institute for Polar and Marine Research will take the scientific leadership of the first stage.
The focus of this research will be the coldwater corals off the coast of Norway। Coldwater corals develop in a similar way to their tropical reef counterparts. They form unique ecosystems, within which, one may be able to find more than 600 different animal species. With the help of the underwater craft, JAGO, the coral reef will be able to be examined, photographed and probed. A scientist will be able to accompany the crafts pilot down to about 400 meters below the sea. Read More about this story at science daily

First Seafloor Vents On Ultraslow-spreading Ridge

Scientists have found one of the largest fields of seafloor vents gushing super-hot, mineral-rich fluids on a mid-ocean ridge that, until now, remained elusive to the ten-year hunt to find them.

“The discovery of the first active vents ever found on an ultraslow-spreading ridge is a significant milestone event,” said Jian Lin, leader of a team of Woods Hole Oceanographic Institution (WHOI) scientists who participated in a Chinese expedition to the remote Southwest Indian Ridge in the Indian Ocean in February and March.
Since deep-sea hydrothermal vents were first discovered 30 years ago in the Pacific Ocean, scientists have studied them all along the Mid-Ocean Ridge, a 40,000-mile-long mountain range that zigzags through the middle of the world’s ocean basins like a giant zipper. The ridge marks the area where the Earth’s giant tectonic plates spreads apart and new ocean crust forms from hot lava rising from deep within Earth’s mantle.
Most studies of the chimney-like vent structures have taken place along ridges in the “fast-spreading” East Pacific Rise (100 to 200 millimeters per year) and the “slow-spreading” Mid-Atlantic Ridge (20 to 40 millimeters per year). Only in recent years have scientists explored “ultraslow-spreading ridges” (less than 20 millimeters per year) in the Arctic and Indian Oceans—remote areas tough to get to, and therefore the least studied.
Scientists initially thought ultraslow-spreading ridges would be too cold to host large hot vents. But in the past decade, some scientists began to hypothesize that the slower a ridge spreads, the fewer vents it would have—but the bigger the vent fields would be.
“This cruise confirmed that hypothesis,” said Lin, a marine geophysicist and U.S. Coordinator of the 20-day expedition aboard the Chinese research vessel Dayang 1. “People have been looking for active hot vents on ultraslow ridges for more than 10 years,” Lin said.
In 2005-06, as part of China’s first around-the-world oceanographic expedition, Lin had sailed as a US chief scientist on Dayang 1 to the Southwest Indian Ridge, where scientists found tantalizing evidence of active hydrothermal venting. They gathered critical data that led them back to the site this year.
During the February-March expedition, the team nailed the discovery with the aid of ABE, WHOI’s Autonomous Benthic Explorer, which has been instrumental in recent years in helping scientists find vents on the bottom of the ocean much quicker than ever before. ABE acts like a robotic deep-sea bloodhound: In a sequence of dives, its sensors “sniff out” clues indicating a plume of fluids emanating from a vent and collect data scientists use to home in on the vent.
ABE also uses sonar to create maps of vent fields and takes photographs about 5 meters above them. ABE snapped 5,000 images of the robust Southwest Indian Ridge vent site, which is among the largest known to date. It is larger than a football field (120 meters by 100 meters).
The discovery was a first for China. “This discovery reflects China’s increasing contribution to ocean science in general, and ridge science in particular,” Lin said.
The China Ocean Mineral Resources R&D Association (COMRA) in Beijing, China, funded the 2005-06 expedition and ABE’s participation in the current one. COMRA, which represents China in the International Seabed Authority, has been exploring the deep sea for mineral resources since the early 1990s.
China is increasing investments in ocean science, Lin said. COMRA’s primary interests lay in the large sulfide deposits created by hydrothermal vents, which are rich in copper, zinc, gold, and other minerals, he said.
“Our Chinese colleagues were the happiest people I’ve ever seen at sea when they brought the first samples aboard,” said Dana Yoerger, scientist in the WHOI Deep Submergence Laboratory and co-designer of ABE, who participated in the expedition. Once ABE pinpointed the site’s exact location, the Chinese team sent down its “TV grab”— a grappling device guided by a television camera—and retrieved a reddish chunk of a vent chimney, Yoerger said.
The researchers outran a tropical cyclone and collected the data they needed in just six days and three ABE dives. “It was the most ruthlessly efficient science we’ve ever done,” said Christopher German, chief scientist of the WHOI-operated National Deep Submergence Facility, who also participated in the expedition. “We had no margin for error.”
The Chinese science party was led by chief scientist Chunhui Tao, a geophysicist at the Second Institute of Oceanography in Hanzhou, China.
“The two international teams worked exceedingly well for this kind of complex operation,” Lin said
Note: This story has been adapted from a news release issued by Woods Hole Oceanographic Institution.