Biodiversity in Oxygen Minimum Zones of Seabed

Some regions of the deep ocean floor support abundant populations of organisms, despite being overlain by water that contains very little oxygen, according to an international study led by scientists at the United Kingdom's National Oceanography Centre, Southampton. But global warming is likely to exacerbate oxygen depletion and thereby reduce biodiversity in these regions, they warn.

The sunlit surface waters tend to be well oxygenated as a result of their connection with the atmosphere. Here, tiny marine algae called phytoplankton thrive. When they die and sink, they are degraded by bacteria, using oxygen from the water column.
In regions of high plant growth, this can result in the natural development of mid-water oxygen minimum zones (OMZs), especially where oxygen is not replenished by mixing of the water column. Where they touch the continental slope, OMZs create strong seafloor oxygen gradients at depths between 100 and 1000 m.
In addition to low oxygen, sediments within OMZs often contain large amounts of organic matter. As a result, species of animals and protozoans (foraminifera) that can tolerate low oxygen may flourish, despite the stressful conditions. However, if oxygen depletion is very severe, many types of animals disappear. Where animals are present, OMZs provide a variety of habitats created by steep gradients in oxygen and sulphide concentrations, different seafloor types, and variations in acidity and nutrient availability.
In this new synthesis, based on a survey of published and unpublished data, the team of researchers analysed the habitats and biodiversity of well-developed OMZs in the Arabian Sea, eastern Pacific and Bay of Bengal.
"Oxygen seems to be the overriding factor controlling biological diversity and seabed community composition within OMZ core regions," said Professor Andrew Gooday of NOCS: "Where oxygen levels increase, the strong seafloor gradients create variety that exerts an increasingly important influence, with different habitat types supporting different kinds of organisms. In particular, the lower boundaries of OMZs, where oxygen levels begin to rise and food is plentiful, often teem with large organisms, among them brittle stars and spider crabs."
On some continental margins, exposed rocks support encrusting animals, while muddy regions with organic-rich sediments support tube-living organisms and bacterial mats. Movements of the upper boundaries of OMZs, caused by seasonal or longer-term climatic changes, may cause sudden shifts in community composition.
The activities and bodies of some organisms also create opportunities for others. Even the dead play their role.
"The skeletons and carcasses of marine animals provide discrete habitats where other creatures can thrive," said NOCS' Dr Brian Bett: "For example, scavengers such as shrimp-like crustaceans exploit accumulations of dead jellyfish, fish and crabs, while other species live off whale bones."
Although the upper boundaries of OMZs can move up and down in response to climatic changes, the core regions of OMZs are typically very stable, persisting over geological timescales.
"OMZs may be a cradle of biological diversity, promoting speciation by creating strong gradients in the environmental conditions that are important for species as well as barriers to population exchange," explained Gooday, while acknowledging that this needs to be fully investigated using molecular techniques.
Although diversity is strongly depressed locally, particularly in OMZ cores, the researchers conclude that, on balance, OMZs probably enhance regional diversity because they tend to increase environmental variety. In addition, low oxygen concentrations promote adaptations, such as small body size and enlarged body surfaces, which enhance oxygen uptake.
However, global climate change presents a major threat -
"Increased ocean temperature is expected to reduce vertical water mixing and decrease oxygen solubility in seawater," said Bett: "If this results in larger, more intense OMZs, the impact on biodiversity is likely to be negative."
The researchers are Andrew Gooday and Brian Bett (NOCS), Elva Escobar (Universidad Nacional Auto´ noma de Mexico), Baban Ingole (National Institute of Oceanography, India) , Lisa Levin and Carlos Neira (Scripps Institution of Oceanography, La Jolla), Akkur Raman (Andhra University, India), and Javier Sellanes (Universidad Cato´ lica del Norte, Coquimbo, Chile).
The research was the product of a workshop organised by Prof. Lisa Levin (Scripps Institution of Oceanography) within the framework of COMARGE, a project of the Census of Marine Life. NOCS researchers were also supported by the HERMIONE project funded by the European Commission's Seventh Framework Programme under the priority 'Deep-Sea Ecosystems', and the Natural Environment Research Council, UK, project Oceans 2025.

Andrew J. Gooday, Brian J. Bett, Elva Escobar, Baban Ingole, Lisa A. Levin, Carlos Neira, Akkur V. Raman, Javier Sellanes. Habitat heterogeneity and its influence on benthic biodiversity in oxygen minimum zones. Marine Ecology, 2010; 31 (1): 125 DOI: 10.1111/j.1439-0485.2009.00348.x

Hawaiian Submarine Canyons Are Hotspots of Biodiversity and Biomass for Seafloor Animal Communities

Underwater canyons have long been considered important habitats for marine life, but until recently, only canyons on continental margins had been intensively studied. Researchers from Hawaii Pacific University (HPU) and the Universtiy of Hawaii at Manoa (UHM) have now conducted the first extensive study of canyons in the oceanic Hawaiian Archipelago and found that these submarine canyons support especially abundant and unique communities of megafauna (large animals such as fish, shrimp, crabs, sea cucumbers, and sea urchins) including 41 species not observed in other habitats in the Hawaiian Islands.

The research is published in the the March issue of the journal Marine Ecology.
The researchers used both visual and video surveys from 36 submersible dives (using UHM's Hawaii Undersea Research Laboratory submersibles Pisces IV and Pisces V) to characterize slope and canyon communities of animals at depths of 350-1500 meters along the margins of four islands of the Hawaiian Archipelago. The coastlines of Oahu and Molokai were selected as examples of high, mountainous islands with large supplies of terrestrial and marine organic matter which can be exported down slopes and canyons to provide food to deep-sea communities. Nihoa Island and Maro Reef were chosen to represent low islands and atolls that are likely to export less organic matter to feed the deep-sea fauna.
Eric Vetter, the lead author of this paper and a Professor of Marine Biology from HPU, had previously studied four canyon systems off the coast of California and found that the productive waters along southern California had resulted in the delivery and accumulation of substantial amounts of organic material. "Craig Smith (Professor of Oceanography at UHM and co-author of this study) and I wondered if the same dramatic contrast in benthic food resources between canyon and non-canyon settings seen in continental margins would also occur on tropical oceanic islands," says Vetter. "We reasoned that the low productivity in tropical regions would result in reduced source material for organic enrichment in canyons and that steep bathymetry combined with curving coastlines would limit the area over which material could be transported to individual canyons. On the other hand we thought that any amount of organic enrichment might have a measureable effect given the very low background productivity."
Canyon systems can enhance abundance and diversity of marine life by providing more varied and complex physical habitats, and by concentrating organic detritus moving along shore and downslope. On most continental margins, the continental shelf and slope are dominated by soft, low-relief sediments; in contrast, canyons crossing these margins often have steep slopes, rocky outcrops, and faster currents that can support fauna with diverse habitat requirements. The margins of oceanic islands generally are steeper than continental margins, making the physical contrast between canyon and non-canyon habitats potentially less dramatic than along continents. "We wanted to learn, given all of these differences, if tropical oceanic islands would be regions of special biological significance, particularly in terms of productivity and biodiversity," says Vetter.
To conduct the research off Oahu, Molokai, and Maro Reef, Vetter, Smith and UHM Doctoral student Fabio De Leo took turns in the submersibles counting marine life on the ocean bottom using visual transects and recording results into a voice recorder. The survey off of Nihoa Island was conducted using a video recorder attached to the submersible. The results of the 36 surveys showed that the highly mobile megafauna (like fish, sharks, shrimp and squid) were much more abundant in the canyons than on the open slopes at all depths studied. This suggests that canyons provide an especially good habitat for mobile species that are able to feed on accumulated organic matter but can escape the physical disturbances in canyons resulting from high currents and mobile sediments (e.g., migrating sand ripples).
"Perhaps the biggest surprise of this study was the large number of species, 41, that we found only in canyon habitats," says Smith. "This suggests that canyons support a substantial specialized fauna that would not exist in the Hawaiian archipelago in the absence of canyons. Thus, submarine canyons are contributing uniquely to biodiversity in the islands and merit careful attention for environmental protection and management."
The elevated abundance and biodiversity of megafauna (especially highly mobile species of fish and crustaceans) in canyons suggests that those environments experience greater food availability, and may provide critical habitat for commercially important bottom fish and invertebrate stocks. "From a conservation standpoint, these regions would be ideal candidates to become Marine Protected Areas (MPAs), especially due to the higher turnover of species diversity when compared to regular slopes," says De Leo. "If we prove that the animals are using the canyons as a feeding ground because the organic debris accumulates there and nowhere else outside the canyons, that's another argument for an MPA." Adds Smith, "if we allow the Hawaiian canyons to be overexploited or impacted by human activities such as dredge-spoil dumping, there is likely to be a significant drop in biodiversity in the deep waters of Hawaii. Clearly, canyon habitats merit special attention for inclusion in Hawaiian MPAs."
Future studies by the team of the Hawaiian canyon fauna include analyses of the stable carbon and nitrogen isotopes in shrimp, urchins and other bottom feeders to identify their main food sources. Because different potential food sources, such as land plants, seafloor algae and phytoplankton, often have different stable isotope "signatures," these analyses will help the researchers to understand what exactly is fueling the rich animal assemblages in the canyons. "We need biochemical proof that the canyons are really channeling this type of material," says DeLeo. "Carbon and nitrogen isotopic signatures could tell the difference between the detrital plant material and the phytoplankton material pools, so you can see if the animal in the canyon is eating phytoplankton cells coming from pelagic production or macroalgae coming from the coast."
Vetter says that their current research is also formulating conceptual models that will allow the researchers to predict which features associated with different canyon systems act to influence biological patterns including animal abundance and diversity. "DeLeo's PhD research will include data on megafauna and macrofauna (smaller animals living in the sediments) patterns in canyons along the U.S. West Coast, Hawaii, and New Zealand, which should make important strides here."
This research was supported by the National Oceanic and Atmospheric Administration (NOAA) Ocean Exploration Office, by the Hawaii Undersea Research Laboratory in the School of Ocean and Earth Science and Technology at UHM, and by the Census of Diversity of Abyssal Marine Life (CeDAMar). We also thank Capes-Fulbright for a fellowship for DeLeo.

Vetter et al. Hawaiian hotspots: enhanced megafaunal abundance and diversity in submarine canyons on the oceanic islands of Hawaii. Marine Ecology, 2010; 31 (1): 183 DOI: 10.1111/j.1439-0485.2009.00351.x

Seamount Scientists Offer New Comprehensive View of Deep-Sea Mountains

Lying beneath the ocean is spectacular terrain ranging from endless chains of mountains and isolated peaks to fiery volcanoes and black smokers exploding with magma and other minerals from below Earth's surface. This mountainous landscape, some of which surpasses Mt. Everest heights and the marine life it supports, is the spotlight of a special edition of the research journal Oceanography.

These massive underwater mountains, or seamounts, are scattered across every ocean and collectively comprise an area the size of Europe. These deep and dark environments often host a world teeming with bizarre life forms found nowhere else on Earth. More than 99 percent of all seamounts remain unexplored by scientists, yet their inhabitants, such as the long-lived deepwater fish orange roughy, show signs of habitat destruction and over exploitation from intense international fishing efforts.

Scientists from Scripps Institution of Oceanography at UC San Diego and colleagues from the National Oceanic Atmospheric Administration, Oregon State University, University of British Columbia and Woods Hole Oceanographic Institution were among those who contributed their expertise in seamount chemistry, physics, geology, hydrology, oceanography, biology and fisheries conservation to this special interdisciplinary effort to delve into the extremely broad research supported by seamounts and to communicate the science and threats facing them to the public.

"One of the key goals of this special issue was to bring together the extremely diverse seamount research community that ranges from fisheries science and conservation all the way to mantle geochemistry," said Hubert Staudigel a research geologist at Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics at Scripps and the lead guest editor of the special issue. "In my eyes, this volume of Oceanographygoes beyond that by presenting amazing new research in a way that the public can understand and get excited about."

"This issue of Oceanography offers a broad perspective on seamount research of all major disciplines to raise awareness of the diversity of seamount research and to promote collaboration among seamount scientists," wrote the editors of the issue, which represents the most comprehensive volume of peer-reviewed research on the subject to date.

"I was pleased to see how many of the contributions in this special issue deal with very practical and societally important issues of seamounts," said U.S. Geological Survey Director Marcia McNutt.

This Oceanography issue is the result of the work of a National Science Foundation-funded biogeoscience research coordination network organized by Staudigel and the co-editors of the volume. This comprehensive synthesis will establish new collaborations between scientists while at the same time offer a unique educational opportunity for the public to learn about an important feature on Earth that remains vastly unexplored.

The online edition is free and available athttp://www.tos.org/oceanography/index.html and the print edition will be available on March 10.

The special volume was edited by Staudigel; Anthony A.P. Koppers, Oregon State University; J. William Lavelle, National Oceanic and Atmospheric Administration; Tony J. Pitcher, University of British Columbia and Timothy M. Shank, Woods Hole Oceanographic Institution.

Deepest Explosive Eruption on Sea Floor: Underwater Remotely Operated Vehicle Jason Images Discovery

Oceanographers using the remotely operated vehicle (ROV) Jason discovered and recorded the first video and still images of a deep-sea volcano actively erupting molten lava on the seafloor.

Jason, designed and operated by the Woods Hole Oceanographic Institution for the National Deep Submergence Facility, utilized a prototype, high-definition still and video camera to capture the powerful event nearly 4,000 feet below the surface of the Pacific Ocean, in an area bounded by Fiji, Tonga and Samoa.

"I felt immense satisfaction at being able to bring [the science team] the virtual presence that Jason provides," says Jason expedition leader Albert Collasius, who remotely piloted the ROV over the seafloor. "There were fifteen exuberant scientists in the control van who all felt like they hit a home run. "

Collasius led a team that operated the unmanned, tethered vehicle from a control van on the research vessel and used a joystick to "fly" Jason over the seafloor to within 10 feet of the erupting volcano. Its two robotic arms collected samples of rocks, hot spring waters, microbes, and macro biological specimens.

Through its fiber optic tether, ROV Jason transmitted-high definition video of the eruption as it was occurring. The unique camera system, developed and operated by the Advanced Imaging and Visualization Lab at WHOI, was installed on Jason for the expedition to acquire high quality imagery of the seafloor. The AIVL designs, develops, and operates high resolution imaging systems for scientific monitoring, survey, and entertainment purposes. AIVL imagery has been used in several IMAX films and hundreds of television programs and documentaries.

The video from the research expedition, which departed Western Samoa aboard the RV Thomas Thompson on May 5, 2009, was shown for the first time at the American Geophysical Union fall meeting in San Francisco.

"Less than 24 hours after leaving port, we located the ongoing eruption and observed, for the first time, molten lava flowing across the deep-ocean seafloor, glowing bubbles three feet across, and explosions of volcanic rock," reported Joe Resing, a chemical oceanographer at the University of Washington and NOAA, and chief scientist on the NOAA- and National Science Foundation-funded expedition.

For more than a decade, monitoring systems have allowed scientists to listen for seafloor eruptions but there has always been a time lag between hearing an eruption and assembling a team and a research vessel to see it. This has meant that scientists have always observed eruptions after the fact.

"We saw a lot of interesting phenomena, but we never saw an eruption because it happens so quickly," said Robert Embley, a NOAA PMEL marine geologist and co-chief scientist on the expedition. "As geologists, you want to see the process in action. You learn a lot more about it watching the process."

The scientists involved in the expedition had praise for the people and the technology that helped bring that dream to fruition.

"I don't think there are too many systems in the world that could do what Jason does," said Embley. "It takes a good vehicle, but a great group of experienced people to get close [to an eruption], hold station, and have the wisdom to understand what they can and cannot do."

The Jason team maneuvered the vehicle to give scientists an up-close view of the glowing red vents explosively ejecting lava into the sea- often not more than a few feet away from the exploding lava -- and the ability to take samples.

Enhancing the experience was the ability to view the eruption in high-definition video. Designed to operate at depths of up to 7,000 meters, the unique still and video camera system acquired 30-60 still images per second, at the same time generating motion, high def video at 30 frames per second. The system uses a high-definition zoom lens -- nearly twice the focal length of Jason's present standard definition camera -- that enables researchers to see up-close details of underwater areas of interest that they otherwise could not see.

"We were lucky to have those cameras on the vehicle. They are important to the science," said Tim Shank, a WHOI macro-biologist on the expedition. "We use the high def cameras to try to identify species. They allow us to look at the morphology of the animals -- some smaller than 3 or 4 inches long."

"In terms of understanding how the volcano is erupting, the high frame rate lets you stop the motion and look to see what is happening," said Resing. "You can see the processes better."

The National Science Foundation funded the installation of the camera system for this expedition. The system is being tested in advance of a permanent upgrade in 2010 to the cameras on Jason as well as the manned submersible Alvin. Maryann Keith, of WHOI's AIVL, Shank, and other scientists operated the camera system with the assistance of the Jason team during the expedition.

In addition to the benefits to science, the cameras will serve the added purpose of giving the public more access to seafloor discoveries.

"Seeing an eruption in high definition video for the first time really brings it home for all of us, when we can see for ourselves the very exciting things happening on our planet, that we know so little about," Embley said.

World's Oldest Submerged Town Dates Back 5,000 Years

Archaeologists surveying the world’s oldest submerged town have found ceramics dating back to the Final Neolithic. Their discovery suggests that Pavlopetri, off the southern Laconia coast of Greece, was occupied some 5,000 years ago — at least 1,200 years earlier than originally thought.

These remarkable findings have been made public by the Greek government after the start of a five year collaborative project involving the Ephorate of Underwater Antiquities of the Hellenic Ministry of Culture and The University of Nottingham.

As a Mycenaean town the site offers potential new insights into the workings of Mycenaean society. Pavlopetri has added importance as it was a maritime settlement from which the inhabitants coordinated local and long distance trade.

The Pavlopetri Underwater Archaeology Project aims to establish exactly when the site was occupied, what it was used for and through a systematic study of the geomorphology of the area, how the town became submerged.

This summer the team carried out a detailed digital underwater survey and study of the structural remains, which until this year were thought to belong to the Mycenaean period — around 1600 to 1000 BC. The survey surpassed all their expectations. Their investigations revealed another 150 square metres of new buildings as well as ceramics that suggest the site was occupied throughout the Bronze Age — from at least 2800 BC to 1100 BC.

The work is being carried out by a multidisciplinary team led by Mr Elias Spondylis, Ephorate of Underwater Antiquities of the Hellenic Ministry of Culture in Greece and Dr Jon Henderson, an underwater archaeologist from the Department of Archaeology at The University of Nottingham.

Dr Jon Henderson said: “This site is unique in that we have almost the complete town plan, the main streets and domestic buildings, courtyards, rock-cut tombs and what appear to be religious buildings, clearly visible on the seabed. Equally as a harbour settlement, the study of the archaeological material we have recovered will be extremely important in terms of revealing how maritime trade was conducted and managed in the Bronze Age.”

Possibly one of the most important discoveries has been the identification of what could be a megaron — a large rectangular great hall — from the Early Bronze Age period. They have also found over 150 metres of new buildings including what could be the first example of a pillar crypt ever discovered on the Greek mainland. Two new stone built cist graves were also discovered alongside what appears to be a Middle Bronze Age pithos burial.

Mr Spondylis said: “It is a rare find and it is significant because as a submerged site it was never re-occupied and therefore represents a frozen moment of the past.”

The Archaeological Co-ordinator Dr Chrysanthi Gallou a postdoctoral research fellow at The University of Nottingham is an expert in Aegean Prehistory and the archaeology of Laconia.

Dr Gallou said: “The new ceramic finds form a complete and exceptional corpus of pottery covering all sub-phases from the Final Neolithic period (mid 4th millennium BC) to the end of the Late Bronze Age (1100 BC). In addition, the interest from the local community in Laconia has been fantastic. The investigation at Pavlopetri offers a great opportunity for them to be actively involved in the preservation and management of the site, and subsequently for the cultural and touristic development of the wider region.”

The team was joined by Dr Nicholas Flemming, a marine geo-archaeologist from the Institute of Oceanography at the University of Southampton, who discovered the site in 1967 and returned the following year with a team from Cambridge University to carry out the first ever survey of the submerged town. Using just snorkels and tape measures they produced a detail plan of the prehistoric town which consisted of at least 15 separate buildings, courtyards, streets, two chamber tombs and at least 37 cist graves. Despite the potential international importance of Pavlopetri no further work was carried out at the site until this year.

This year, through a British School of Archaeology in Athens permit, The Pavlopetri Underwater Archaeology Project began its five year study of the site with the aim of defining the history and development of Pavlopetri.

Four more fieldwork seasons are planned before their research is published in full in 2014.

To see the expedition for yourself, watch the video podcast on YouTube — http://www.youtube.com/watch?v=kepaQu4uerg

And on the University's Podcast website — http://communications.nottingham.ac.uk/podcasts.html.

New Robot Travels Across The Seafloor To Monitor The Impact Of Climate Change On Deep-sea Ecosystems

Like the robotic rovers Spirit and Opportunity, which wheeled tirelessly across the dusty surface of Mars, a new robot spent most of July traveling across the muddy ocean bottom, about 40 kilometers (25 miles) off the California coast. This robot, the Benthic Rover, has been providing scientists with an entirely new view of life on the deep seafloor. It will also give scientists a way to document the effects of climate change on the deep sea. The Rover is the result of four years of hard work by a team of engineers and scientists led by MBARI project engineer Alana Sherman and marine biologist Ken Smith.

About the size and weight of a small compact car, the Benthic Rover moves very slowly across the seafloor, taking photographs of the animals and sediment in its path. Every three to five meters (10 to 16 feet) the Rover stops and makes a series of measurements on the community of organisms living in the seafloor sediment. These measurements will help scientists understand one of the ongoing mysteries of the ocean—how animals on the deep seafloor find enough food to survive.

Most life in the deep sea feeds on particles of organic debris, known as marine snow, which drift slowly down from the sunlit surface layers of the ocean. But even after decades of research, marine biologists have not been able to figure out how the small amount of nutrition in marine snow can support the large numbers of organisms that live on and in seafloor sediment.

The Benthic Rover carries two experimental chambers called "benthic respirometers" that are inserted a few centimeters into the seafloor to measure how much oxygen is being consumed by the community of organisms within the sediment. This, in turn, allows scientists to calculate how much food the organisms are consuming. At the same time, optical sensors on the Rover scan the seafloor to measure how much food has arrived recently from the surface waters.

MBARI researchers have been working on the Benthic Rover since 2005, overcoming many challenges along the way. The most obvious challenge was designing the Rover to survive at depths where the pressure of seawater is about 420 kilograms per square meter (6,000 pounds per square inch). To withstand this pressure, the engineers had to shield the Rover's electronics and batteries inside custom-made titanium pressure spheres.

To keep the Rover from sinking into the soft seafloor mud, the engineers outfitted the vehicle with large yellow blocks of buoyant foam that will not collapse under extreme pressure. This foam gives the Rover, which weighs about 1,400 kilograms (3,000 pounds) in air, a weight of only about 45 kilograms (100 pounds) in seawater.

Other engineering challenges required less high-tech solutions. In constructing the Rover's tractor-like treads, the design team used a decidedly low-tech material—commercial conveyor belts. After watching the Benthic Rover on the seafloor using MBARI's remotely operated vehicles (ROVs), however, the researchers discovered that the belts were picking up mud and depositing it in front of the vehicle, where it was contaminating the scientific measurements. In response, the team came up with a low-tech but effective solution: they removed the heads from two push brooms and bolted them onto the vehicle so that the stiff bristles would clean off the treads as they rotated.

The team also discovered that whenever the Rover moved, it stirred up a cloud of sediment like the cloud of dust that follows the character "Pig-Pen" in the Charlie Brown comic strip. This mud could have affected the Rover's measurements. To reduce this risk, the engineers programmed the Rover to move very, very slowly—about one meter (3 feet) a minute. The Rover is also programmed to sense the direction of the prevailing current, and only move in an up-current direction, so that any stirred-up mud will be carried away from the front of the vehicle.

In its basic configuration, the Benthic Rover is designed to operate on batteries, without any human input. However, during its month-long journey this summer, the Rover was connected by a long extension cord to a newly-completed underwater observatory. This observatory, known as the Monterey Accelerated Research System (MARS), provided power for the robot, as well as a high-speed data link back to shore.

According to Sherman, "Hooking up the Rover to the observatory opened up a whole new world of interactivity. Usually when we deploy the Rover, we have little or no communication with the vehicle. We drop it overboard, cross our fingers, and hope that it works." In this case, however, the observatory connection allowed MBARI researchers to fine tune the Rover's performance and view its data, videos, and still images in real time. Sherman recalls, "One weekend I was at home, with my laptop on the kitchen table, controlling the vehicle and watching the live video from 900 meters below the surface of Monterey Bay. It was amazing!"

Later this fall, the Rover will be sent back down to the undersea observatory site in Monterey Bay for a two-month deployment. Next year the team hopes to take the Rover out to a site about 220 km (140 miles) offshore of Central California. They will let the Rover sink 4,000 meters down to the seafloor, where it will make measurements on its own for six months. The team would also like to take the Rover to Antarctica, to study the unique seafloor ecosystems there. The Rover may also be hooked up to a proposed deep-water observatory several hundred miles off the coast of Washington state.

In addition to answering some key questions of oceanography, the Benthic Rover will help researchers study the effects of climate change in the ocean. As the Earth's atmosphere and oceans become warmer, even life in the deep sea will be affected. The Benthic Rover, and its possible successors, will help researchers understand how deep-sea communities are changing over time.

Just as the rovers Spirit and Opportunity gave us dramatic new perspectives on the planet Mars, so the Benthic Rover is giving researchers new perspectives of a dark world that is in some ways more mysterious than the surface of the distant red planet.

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Adapted from materials provided by Monterey Bay Aquarium Research Institute.

Bacteria And Algae Act As Biocatalysts For Deep-sea Raw Material Deposition

The sea floor is strewn with raw materials that could be very important in the future: Manganese and iron, but also rarer and more precious elements such as cobalt, copper, zinc and nickel, are present in great quantities in the form of deep-sea nodules and crusts. The depositions of such materials from seawater and sediment is the result of a process known as biomineralization.Microorganisms such as bacteria and algae contribute to this process of nodule and crust accretion and catalyze the accumulation of metals, as has been shown by new research at the Institute of Physiological Chemistry and Pathobiochemistry at Johannes Gutenberg University Mainz. The new findings could, the scientists believe, contribute to an environment-friendly and sustainable use of valuable marine natural resources.Competition for the resources on the seabed has already begun; the industrialized countries have already staked their claims and marked off regions with large re-serves of raw materials. "This is a potential source of international conflict," believes Professor Werner Müller of the University of Mainz. Once we understand exactly how the deep-sea nodules and crusts are created, we might perhaps in the not too distant future be in the position to develop strains of microorganisms that could very specifically "grow" important raw materials for us.Müller has been investigating the submarine world for over 30 years and is regarded as a pioneer of sponge research in Germany. But the interests of the qualified molecular biologist are not restricted to sponges, which he considers to offer a virtually inexhaustible source of raw materials, starting with bioactive substances for medical use to silicates for optic pathways. In his eyes, bacteria and algae are also genuine little magicians.Manganese nodules are formed on the sea floor at depths of 4,000 to 5,000 meters. In the last 10 million years or so, an estimated 300 billion tonnes of manganese has accumulated in the form of nodules. "This is quite astonishing when you consider that the concentration of manganese in seawater is vanishingly small," says Müller. Besides manganese, the nodules (which resemble potato tubers) also contain iron and non-ferrous heavy metals which accumulate in layers. Once a tiny bio-seed has formed, metal ions attach themselves continuously to the outer layer.Working in cooperation with Chinese scientists, mainly Professor Dr X. H. Wang, Müller has now discovered what triggers this process. According to their findings, the bio-seeds are bacteria that have an additional protein layer, known as the S-layer, on their outer membrane. "The outermost stratum of the S-layer is an ideal organic matrix that not only protects microorganisms against harmful environmental effects but also facilitates the deposition of minerals." Müller and his research partners have found complete chains of bacteria with S-layers in manganese nodules that provided the basis for the synthesis of the biomaterials. "Once the primary layer is present, autocatalysis takes over and the material completes the process itself."In the case of deep-sea crusts, a unicellular alga rather than a bacterium provides the bio-seed. The deep-sea crusts – also known as manganese or cobalt crusts – are found at depths of 800 to 2,400 meters and also contain significant quantities of valuable raw materials. They are created by coccolithophorides, a form of armoured algae that are completely encased in a protective shell of calcium carbonate. These algae live at a depth of around 100 metres. When they die, their protective shells fall to deeper levels where bonds with manganese ions are formed by means of chemi-cal transformation."Perhaps we can use nature as our model, so that in future we will also be able to exploit algae and bacteria to extract manganese and other metals from a seawater environment," explains Müller. This could help to defuse potential future conflict for resources and contribute to sustainable production, without damaging the deep-sea environment.Journal reference:Xiaohong Wang, Werner E.G. Müller. Marine biominerals: perspectives and challenges for polymetallic nodules and crusts. Trends in Biotechnology, 2009; 27 (6): 375 DOI: 10.1016/j.tibtech.2009.03.004Mainz, Universitaet.

Thermal Conductivity Of Seafloor

The first German offshore wind facility is expected be put into operation sometime in 2009. A total of 12 giant wind turbines out at the North Sea will turn near the isle of Borkum, each one generating 5 megawatts of power, the largest worldwide. The electrical current they will produce will be conveyed over a distance of 45 km past Norderney to the mainland, at a depth of two to three meters buried in the seafloor.

In addition to many other technical challenges making the whole project controversial, a measurement problem regarding the cable needed to be resolved: How could the thermal conductivity of the seafloor be determined accurately enough to be able to predict the later influences of temperature on the buried cable?
The seafloor contains great quantities of pebble gravels which create many inhomogeneities and, naturally water which additionally interferes with any measurement due to convection. After several renowned test institutes had given up in the face of these obstacles , the commissioned engineering company turned to the measurement experts of the Physikalisch-Technische Bundesanstalt (PTB). And they were able to help.
Using a method they had recently developed themselves, they successfully measured the thermal conductivity of several seafloor samples at the required accuracy. The instrument had already proven its worth in in-situ measurements of river sediments of the Spreewald situated near the German town of Lübben. The measuring instrument is all-purpose. A manufacturer will soon be bringing it on the market under licence. First it will be presented from 26 to 28 May 2009 at the Sensor&Test trade fair in Nuremberg at the PTB booth.
Adapted from materials provided by Physikalisch-Technische Bundesanstalt (PTB)

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

Oil In Ocean Shows Up On NASA Images: Half Of The Oil In The Ocean Bubbles Up Naturally From Seafloor

About half of the oil in the ocean bubbles up naturally from the seafloor, with Earth giving it up freely like it was of no value. Likewise, NASA satellites collect thousands of images and 1.5 terrabytes of data every year, but some of it gets passed over because no one thinks there is a use for it.

Scientists recently found black gold bubbling up from an otherwise undistinguished mass of ocean imagery. Chuanmin Hu, an optical oceanographer at the University of South Florida, St. Petersburg, and colleagues from the National Oceanic and Atmospheric Administration (NOAA) and the University of Massachusetts–Dartmouth (UMass), found that they could detect oil seeping naturally from the seafloor of the Gulf of Mexico by examining streaks amid the reflected sunlight on the ocean's surface.
Most researchers usually discard such "sun glint" data as if they were over-exposed photos from a camera. "Significant sun glint is sometimes thought of as trash, particularly when you are looking for biomass and chlorophyll," said Hu. "But in this case, we found treasure."
The new technique could provide a more timely and cost-effective means to survey the ocean for oil seeps, to monitor oil slicks, and to differentiate human-induced spills from seeps.
Oil decreases the roughness of the ocean surface. Depending on the angles of the camera and of the light reflection, oil creates contrasting swaths that can show up in airborne images as either lighter or darker than the surrounding waters.
The detection and monitoring of oil spills and seeps by satellite is not new. Visible, infrared, microwave, and radar sensors have all been used, with synthetic aperture radar (SAR) being the most popular and reliable method in recent years according to the study authors. SAR imagery can be very expensive, the authors note, and timely, repeat coverage is not always possible, particularly in tropical regions.
Using imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA's Terra and Aqua satellites, Hu and colleagues assert, is far cheaper because the data is collected daily and provided freely by NASA, without the need for special observation requests. And the polar orbits of Terra and Aqua allow images of oil slicks to be collected several times per week in tropical regions and perhaps several times a day at higher latitudes. The description of the new technique was published in January in Geophysical Research Letters.
Hu actually happened upon the oil imagery while looking for signs of harmful algal blooms—commonly referred to as "red tide"—in the western Gulf of Mexico. Examining MODIS images, he kept noticing streaks across the sun glint reflections. After conferring with study co-authors Xiaofeng Li and William Pichel of NOAA and Frank Muller-Karger of UMass, Hu became aware that the streaks could be oil from natural seeps on the seafloor.
Hu and colleagues then defined a geographic area of the western Gulf and obtained MODIS images for the month of May for nine consecutive years (2000 to 2008) from NASA's Goddard Space Flight Center, Greenbelt, Md. The team reviewed more than 200 images containing sun glint, and found more than 50 with extensive oil slicks.
Exactly how much oil naturally seeps out of the seafloor is unknown, and most estimates are very crude because there has never been a proper global survey made for the public record. Researchers identified the natural seepage rate as a critical unanswered question when the National Academy of Sciences compiled its third Oil in the Sea report in 2003.
"This capacity for detecting oil in the ocean has great potential, not just for oil seeps but for responding to oil spills," said Chris Reddy, a marine chemist at the Woods Hole Oceanographic Institution in Massachusetts. "Scientists might be able to use this to forensically study old spills, to watch how new ones evolve in real time, and to rule out a spill when there is none. Ultimately, this could lead to a better use of our public resources."
The technique could be useful for detecting and monitoring oil spills from ships and other platforms, though Hu emphasized that the spills must be large enough (at least hundreds of meters or feet) to be visible in the MODIS imagery. If there is suspicion of a large human-caused spill, for instance, researchers would be able to review ocean imagery to see if the slick was present before the alleged spill, indicating a natural seepage. On the other hand, MODIS satellite imagery collected on a regular basis could help coastal managers track and mitigate the effects of large accidental spills.
The new method is not perfect, as cloud cover or a lack of sun glint can limit its use. Hu and colleagues suggest it may be best used as a complement to SAR, which penetrates cloud cover and can be tilted to get the necessary imaging angle.
"If you can get an image on a two- to three-day time frame and anywhere on the globe, that's pretty spectacular," said Reddy. "The first few days are critical to tracking oil in the ocean, so it helps to be able to use technology in real time to make informed decisions about cleanup."
Adapted from materials provided by NASA/Goddard Space Flight Center.

'Barren' Seafloor Teeming With Microbial Life

Once considered a barren plain with the odd hydrothermal vent, the seafloor appears to be teeming with microbial life, according to a paper being published May 29 in Nature.

"A 60,000 kilometer seam of basalt is exposed along the mid-ocean ridge spreading system, representing potentially the largest surface area for microbes to colonize on Earth," said USC geomicrobiologist Katrina Edwards, the study's corresponding author.
While seafloor microbes have been detected before, this is the first time they have been quantified. Using genetic analysis, Edwards and colleagues found thousands of times more bacteria on the seafloor than in the water above.
Surprised by the abundance, the scientists tested another Pacific site and arrived at consistent results. This makes it likely that rich microbial life extends across the ocean floor, Edwards said.
The scientists also found higher microbial diversity on the rocks compared with other vibrant systems, such as those found at hydrothermal vents.
Even compared with the microbial diversity of farm soil--viewed by many as the richest--diversity on the basalt is statistically equivalent.
"These scientists used modern molecular methods to quantify the diversity of microbes in remote deep-sea environments," said David L. Garrison, director of the National Science Foundation's biological oceanography program.
"As a result, we now know that there are many more such microbes than anyone had guessed," he added.
These findings raise the question of where these bacteria find their energy.
"We scratched our heads about what was supporting this high level of growth when the organic carbon content is pretty darn low," Edwards recalled.
With evidence that the oceanic crust supports more bacteria compared with overlying water, the scientists hypothesized that reactions with the rocks themselves might offer fuel for life.
Back in the lab, they calculated how much biomass could theoretically be supported by chemical reactions with the basalt. They then compared this figure to the actual biomass measured. "It was completely consistent," Edwards said.
This lends support to the idea that bacteria survive on energy from the crust, a process that could affect our knowledge about the deep-sea carbon cycle and even evolution.
For example, many scientists believe that shallow water, not deep water, cradled the planet's first life. They reason that the dark carbon-poor depths appear to offer little energy, and rich environments like hydrothermal vents are relatively sparse.
But the newfound abundance of seafloor microbes makes it theoretically possible that early life thrived--and maybe even began--on the seafloor.
"Some might even favor the deep ocean for the emergence of life since it was a bastion of stability compared with the surface, which was constantly being blasted by comets and other objects," Edwards suggested.
Still, current knowledge of the deep biosphere can fit on the head of a pin, Edwards said. Most seafloor bacteria uncovered in this study show little relation to those cultivated in labs, which makes experimentation difficult.
Rather than bringing bacteria to the lab, however, Edwards plans to bring the lab to bacteria--with a microbial observatory 15,000 feet below sea level.
Thanks to a $3.9-million grant awarded in March by the Gordon and Betty Moore Foundation, Edwards and over 30 colleagues will continue studying seafloor bacteria, but will also study their subseafloor cousins that cycle through the porous rock.
The first expedition of its kind, the drilling operation will penetrate 100 meters of sediments and 500 meters of bedrock.
Besides experiments aimed at learning how precisely these bacteria alter rock, the scientists will measure the diversity, abundance and relatedness of microbes at different depths.
This will shed light on whether the bacteria evolved from ancestors that floated down from above or from some as yet unknown source deep in the crust.
The Nature study provides a crucial base of comparison between the seafloor and subseafloor microbes, both completely unknown until just recently.
The decade-long undertaking will further bridge the earth and life sciences, a key goal in the emerging field of geobiology, described by Edwards as the co-evolution of Earth and life.
The deep biosphere is uniquely suited for a geobiological approach, Edwards said, since a proper understanding requires genomics, analysis of microbe-rock chemical interactions and a timescale in the millions of years.
Edwards joined USC two years ago as part of its cluster hire of scientists with multidisciplinary interests related to geobiology. With its concentration of faculty in the field, Southern California and USC in particular are regarded as hubs for the geobiology research community.
USC recently hosted the 5th Annual Geobiology Symposium, co-organized by USC post-doctoral student Beth Orcutt, the second author of the Nature paper.
In addition, the USC Wrigley Institute for Environmental Studies runs a summer geobiology course on Catalina Island that brings together top students and faculty.
Edwards believes that most people just don't realize how much life thrives in the watery depths.
"If we can really nail down what's going on, then there are significant implications," she said. "It is my hope that people turn their heads and notice that there's life down there."
In addition to Edwards and Orcutt, the paper's co-authors are: Cara Santelli of the Woods Hole Oceanographic Institution (WHOI) and the MIT/WHOI Joint Program in Oceanography and Ocean Engineering; Erin Banning of the MIT/WHOI Joint Program in Oceanography and Ocean Engineering; Wolfgang Bach of WHOI and Universität Bremen; Craig Moyer of Western Washington University; Mitchell Sogin of the Marine Biological Laboratory at Woods Hole; and Hubert Staudigel of the Scripps Institution of Oceanography.
The research was funded by the National Science Foundation's Ridge 2000 program, the NASA Astrobiology Institute and Western Washington University.
Journal reference:
Cara M. Santelli, Beth N. Orcutt, Erin Banning, Wolfgang Bach, Craig L. Moyer, Mitchell L. Sogin, Hubert Staudigel & Katrina J. Edwards. Abundance and diversity of microbial life in ocean crust. Nature, 453, 653-656 (29 May 2008) DOI: 10.1038/nature06899
Adapted from materials provided by University of Southern California.

Newly Discovered Active Fault Building New Dalmatian Islands Off Croatian Coast

A newly identified fault that runs under the Adriatic Sea is actively building more of the famously beautiful Dalmatian Islands and Dinaride Mountains of Croatia, according to a new research report।

Geologists had previously believed that the Dalmatian Islands and the Dinaride Mountains had stopped growing 20 to 30 million years ago.
From a region northwest of Dubrovnik, the new fault runs northwest at least 200 km (124 miles) under the sea floor. The Croatian coast and the 1,185 Dalmatian Islands are an increasing popular tourist destination. Dubrovnik, known as "the Pearl of the Adriatic," is a UNESCO-designated World Heritage site.
At the fault, the leading edge of the Eurasian plate is scraping and sliding its way over a former piece of the African plate called the South Adria microplate, said lead researcher Richard A. Bennett of The University of Arizona in Tucson.
"It's a collision zone," said Bennett, a UA assistant professor of geosciences. "Two continents are colliding and building mountains."
Bennett and his colleagues found that Italy's boot heel is moving toward the Croatian coast at the rate of about 4 mm (0.16 inches) per year. By contrast, movement along parts of California's San Andreas fault can be 10 times greater.
The region along the undersea fault has no evidence of large-magnitude earthquakes occurring in the last 2,000 years. However, if the fault is the type that could move abruptly and cause earthquakes, tsunami calculations for the region need to be redone, he said.
"It has implications for southern Italy, Croatia, Montenegro and Albania."
At its southern end, the newly identified fault connects to a seismically active fault zone further south that caused a large-magnitude earthquake in Dubrovnik in 1667 and a magnitude 7.1 earthquake in Montenegro in 1979.
Geologists have been trying to figure out how the collision between the African and Eurasian continents is being played out in the Mediterranean.
Bennett was studying the geology of Italy's Alps and Apennine Mountains and realized he needed to know more about the mountains on the other side of the Adriatic।

Bennett and his colleagues published their article, "Eocene to present subduction of southern Adria mantle lithosphere beneath the Dinarides," in the January issue of the journal Geology. His co-authors are UA geoscientists Sigrún Hreinsdóttir and Goran Buble; Tomislav Bašiæ of the University of Zagreb and the Croatian Geodetic Institute; Željko Baèiæ and Marijan Marjanoviæ of the Croatian State Geodetic Administration in Zagreb; Gabe Casale, Andrew Gendaszek and Darrel Cowan of the University of Washington in Seattle.
The research was funded by the Croatian Geodetic Administration and the U.S. National Science Foundation.
The Croatian mountains and coasts are relatively understudied, in part because of years of political turmoil in the region, he said. So he teamed up with Croatian geologists.
Bennett is an expert in a technique called geodesy that works much like the GPS in a car.
"We put GPS units on rocks and watch them move around," he said. "We leave an antennae fixed to a rock and record its movement all the time. We basically just watch it move."
Just as the GPS in a rental car uses global positioning satellites to tell where the car is relative to a desired destination, the geodesy network can tell where one antenna and its rock are relative to another antenna.
Recent improvements in the technology make it possible to see very small movements of the Earth. He said, "In Croatia we can resolve motions at the level of about one mm per year."
The researchers found that the motion between Italy's boot heel and Eurasia is absorbed at the Dinaride Mountains and Dalmatian Islands.
Combining geodetic data with other geological information revealed that the movement is accommodated by a previously unknown fault under the Adriatic.
Bennett likens movement of the Eurasian plate to a snowplow blade piling up snow in front of it. The snow represents the sea floor being pushed up to form the Dalmatian Islands and the Dinaride Mountains.
"You can see hints of new islands out there," he said.
But those islands may not provide seaside vacations forever. Bennett said the Adriatic Sea is closing up at the rate of 4.5 km (2.8 miles) per million years. If things continue as they are now, he calculates the eastern and western shores of the Adriatic Sea will meet in about 50 to 70 million years.
"This new finding is an important piece in the puzzle to understanding Mediterranean tectonics," he said.
He plans to set out more antennas to learn more about current movement of the region and to figure out what the fault has been doing for the past 40 million years.
The additional information will also help gauge the region's earthquake potential.
Bennett said, "We want to see if the fault is freely slipping or is accumulating strain and therefore may produce a large earthquake in the future."
Adapted from materials provided by University of Arizona.

Oceana approach adopted to protect bering sea from destructive

The North Pacific Fishery Management Council, which advises the federal government on fisheries policy in U.S. waters off Alaska, voted unanimously today to protect approximately 180,000 square miles of previously unexploited areas in the Bering Sea from destructive bottom trawling.The Council chose Alternative 2, advocated by Oceana and other organizations and local communities, that freezes the current area, or "footprint," where trawling already occurs and sets a northern boundary for bottom trawling to protect habitat in the northern Bering Sea. This limits bottom trawling to those areas where it is already occurring, and provides essential protections for fragile and important areas while having a less than 2% economic impact on fisheries."Today's unanimous decision is a great victory for the whales, walrus, seabirds and other animals in the Bering Sea, and we are glad the Council voted to provide essential protections our oceans need in this age of global climate change and an exploding world population," said Jim Ayers, Vice President of Oceana, an international organization dedicated to protecting the world's oceans. "The northern Bering Sea is one of the last of our storehouses of natural wonders, and today's decision will help give the animals and ecosystems of the region a better chance for survival in these challenging times."Blue, humpback, gray and bowhead whales travel through the Bering Sea each year. The northern Bering Sea shelf is critical habitat for endangered spectacled eiders, with the entire population of these small seabirds coming to the Bering Sea each winter to feed on the clams and invertebrates that live in and on the seafloor. Clams and seafloor invertebrates are also a significant source of food for Pacific walrus, an important subsistence food for many local communities, which rely on the Bering Sea for the subsistence way of life integral to their culture.More than twenty local communities and organizations from the Bering Sea region, including the Eskimo Walrus Commission, sent letters or resolutions to the Council in support of protecting ocean habitat in the northern Bering Sea. In addition, the Council received more than 10,000 public comments - including petition signatures as well as individual letters and faxes - urging the Council to freeze the footprint of bottom trawling.According to the National Academy of Sciences, fishing boats that trawl on the bottom destroy important seafloor habitat, decimating corals, sponges and other sensitive areas. Many of these seafloor animals and habitat areas can take centuries to recover, if they recover at all.ADVERTISEMENT"Bottom trawling has devastating impacts on important seafloor habitats and compromises the resilience of an ecosystem," said Jon Warrenchuk, Ocean Scientist with Oceana. "Today's decision protects the wildlife and important seafloor habitats of the northern Bering Sea from future damage from trawling."The Council also had the opportunity protect undersea canyons and skate nurseries, many of which have never been explored or documented, through their Habitat Areas of Particular Concern (HAPC) process, but pushed that back to a later date.The Bering Sea is home to 26 species of marine mammals, including the critically endangered northern right whale; millions of seabirds hailing from all seven continents; more than 450 species of fish; and some of the world's largest submarine canyons. It also provides more than half of the seafood harvested in United States waters. Much is still not know about the effects of bottom trawling on this incredibly vibrant area of the world, and the fishing industry is aggressively expanding each year.The Council's decision today comes almost two years after they voted to protect the exquisite coral gardens of the Aleutian Islands. Protection for the Bering Sea was identified at that time as the next step for protecting essential habitat, and today's decision spreads that blanket of protection for marine life over more of this vibrant and productive part of the world.

Fragmented Structure Of Seafloor Faults May Dampen Effects Of Earthquakes

Many earthquakes in the deep ocean are much smaller in magnitude than expected। Geophysicists from the Woods Hole Oceanographic Institution (WHOI) have found new evidence that the fragmented structure of seafloor faults, along with previously unrecognized volcanic activity, may be dampening the effects of these quakes.

Examining data from 19 locations in the Atlantic, Pacific, and Indian oceans, researchers led by graduate student Patricia Gregg have found that “transform” faults are not developing or behaving as theories of plate tectonics say they should. Rather than stretching as long, continuous fault lines across the seafloor, the faults are often segmented and show signs of recent or ongoing volcanism. Both phenomena appear to prevent earthquakes from spreading across the seafloor, thus reducing their magnitude and impact.

Gregg, a doctoral candidate in the MIT/WHOI Joint Program in Oceanography and Oceanographic Engineering, conducted the study with seismologist Jian Lin and geophysicists Mark Behn and Laurent Montesi, all from the WHOI Department of Geology and Geophysics। Their findings were published in the July 12 issue of the journal Nature.

Oceanic transform faults cut across the mid-ocean ridge system, the 40,000-mile-long mountainous seam in Earth’s crust that marks the edges of the planet’s tectonic plates. Along some plate boundaries, such as the Mid-Atlantic Ridge, new crust is formed. In other regions, such as the western Pacific, old crust is driven back down into the Earth.

If you imagine the mid-ocean ridge as the seams on a baseball, then transform faults are the red stitches, lying mostly perpendicular to the ridge। These faults help accommodate the motion and geometry of Earth’s tectonic plates, cracking at the edges as the different pieces of rocky crust slip past each other.

The largest earthquakes at mid-ocean ridges tend to occur at transform faults. Yet while studying seafloor faults along the fast-spreading East Pacific Rise, Gregg and colleagues found that earthquakes were not as large in magnitude or resonating as much energy as they ought to, given the length of these faults.

The researchers decided to examine gravity data collected over three decades by ships and satellites, along with bathymetry maps of the seafloor. Conventional wisdom has held that transform faults should contain rocks that are colder, denser, and heavier than the new crust being formed at the mid-ocean ridge. Such colder and more brittle rocks should have a “positive gravity anomaly”; that is, the faults should exert a stronger gravitational pull than surrounding seafloor region. By contrast, the mid-ocean ridge should have a lesser gravity field, because the crust (which is lighter than underlying mantle rocks) is thicker along the ridge and the newer, molten rock is less dense.

But when Gregg examined gravity measurements from the East Pacific Rise and other fast-slipping transform faults, she was surprised to find that the faults were not exerting extra gravitational pull। On the contrary, many seemed to have lighter rock within and beneath the faults.

“A lot of the classic characteristics of transform faults didn’t make sense in light of what we were seeing,” said Gregg. “What we found was the complete opposite of the predictions.”

The researchers believe that many of the transform fault lines on the ocean floor are not as continuous as they first appear from low-resolution maps. Instead these fault lines are fragmented into smaller pieces. Such fragmented structure makes the length of any given earthquake rupture on the seafloor shorter—giving the earthquake less distance to travel along the surface.

It is also possible that magma, or molten rock, from inside the earth is rising up beneath the faults. Earthquakes stem from the buildup of friction between brittle rock in Earth’s plates and faults. Hot rock is more ductile and malleable, dampening the strains and jolts as the crust rubs together and serving as a sort of geological lubricant.

“What we learn about these faults and earthquakes underwater could help us understand land-based faults such as the San Andreas in California or the Great Rift in eastern Africa,” said Lin, a WHOI senior scientist and expert on seafloor earthquakes। “In areas where you have strike-slip faults, you might have smaller earthquakes when there is more magma and warmer, softer rock under the fault area.”

The findings by Gregg, Lin, and colleagues may also have implications for understanding the theory of plate tectonics, which says that new crust is only formed at mid-ocean ridges. By traditional definitions, no crust can be created or destroyed at a transform fault. The new study raises the possibility that new crust may be forming along these faults and fractures at fast-spreading ridges such as the East Pacific Rise.

“Our understanding of how transform faults behave must be reevaluated,” said Gregg. “There is a discrepancy that needs to be addressed.”

Funding for this research was provided by the NSF Graduate Research Fellowship Program, the WHOI Deep Ocean Exploration Institute, the NSF Ocean Sciences Directorate, and the Andrew W. Mellon Foundation Awards for Innovative Research.

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the ocean's role in the changing global environment.

Note: This story has been adapted from a news release issued by Woods Hole Oceanographic Institution.

Marine Geophysicists Probe Sea Floor

A team from U of T’s marine geophysics group is participating in a joint project to create the world’s largest cable-linked sea floor observatory on the Pacific Ocean floor.

Located in the northeast Pacific off the coasts of British Columbia, Washington and Oregon, the active Juan de Fuca tectonic plate is one of the smallest of the dozen major plates that make up the Earth’s crust.
“The idea of this project is we can observe a whole array of different phenomena that are associated with plate tectonics and other processes in the ocean with this reasonably small -- by earth-scale standards -- sea floor laboratory,” said Eleanor Willoughby, a research associate in marine geophysics at U of T.
Known as the North-East Pacific Time-Series Undersea Networked Experiments, or NEPTUNE, the project will allow scientists to monitor biological, oceanographic and geological processes over a period that could stretch to more than two decades, depending on the long-term impacts on equipment from the immense water pressure and the corrosive effects of salt water.
NEPTUNE is a joint U.S.-Canada venture led by the University of Victoria in Canada and the University of Washington in the United States. In addition to the University of Toronto, 11 Canadian universities as well as other Canadian scientific institutions and governmental organizations are participating in the project.
“We know very little about three-quarters of the world’s surface -- what’s underneath the sea floor of the ocean,” said Reza Mir, a PhD candidate in exploration geophysics at U of T whose doctoral research will be largely devoted to NEPTUNE.
The first stage of NEPTUNE is scheduled to start in summer 2008. Six unmanned sea floor nodes, each roughly the size of a sport utility vehicle and each hosting an array of instruments, equipment and video cameras will be installed on the ocean floor in Canadian waters. These sea floor laboratories will then be connected to each other and to land via 800 kilometres of fibre optic cable, allowing scientists to conduct experiments and collect a wide range of data about this area of ocean.
U of T’s contribution includes designing and assembling the instrumentation required for two research projects at one of the nodes. One of these experiments involves designing an electromagnetic transmitter that will be used to study methane as it vents from the sea floor and where it exists in the form of gas hydrates (crystals containing methane found among sea floor sediments). The second experiment will use a gravity meter and a differential pressure gauge to measure the elastic properties of sea floor sediments and how the sea floor reacts relative to surface wave action.
Willoughby said methane deposits beneath the sea floor represent an untapped resource, a potential hazard and a source of greenhouse gas.
“Gas hydrates help hold the sea floor together and if they’re disassociated because of pressure or temperature changes there could be slump or a slide and these in turn can trigger tsunamis, so we need to know about their long-term stability,” Willoughby said. “And because hydrates store methane very compactly, it’s a potential energy source. It’s estimated there’s more than twice as much organic carbon trapped in gas hydrates than all other sources combined -- oil, gas, coal, anything else.”
Members of the NEPTUNE research team at U of T are Willoughby and Mir; Professor Nigel Edwards, project supervisor; Carsten Scholl, post-doctoral fellow, data modelling and interpretation; Andrei Swidinsky, PhD candidate, computer modelling.
Note: This story has been adapted from a news release issued by University Of Toronto.