ScienceDaily— A section of the Arctic Ocean seafloor that holds vast stores of frozen methane is showing signs of instability and widespread venting of the powerful greenhouse gas, according to the findings of an international research team led by University of Alaska Fairbanks scientists Natalia Shakhova and Igor Semiletov.

The research results, published in the March 5 edition of the journal Science, show that the permafrost under the East Siberian Arctic Shelf, long thought to be an impermeable barrier sealing in methane, is perforated and is leaking large amounts of methane into the atmosphere. Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.

"The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world's oceans," said Shakhova, a researcher at UAF's International Arctic Research Center. "Subsea permafrost is losing its ability to be an impermeable cap."

Methane is a greenhouse gas more than 30 times more potent than carbon dioxide. It is released from previously frozen soils in two ways. When the organic material -- which contains carbon -- stored in permafrost thaws, it begins to decompose and, under oxygen-free conditions, gradually release methane. Methane can also be stored in the seabed as methane gas or methane hydrates and then released as subsea permafrost thaws. These releases can be larger and more abrupt than those that result from decomposition.

The East Siberian Arctic Shelf is a methane-rich area that encompasses more than 2 million square kilometers of seafloor in the Arctic Ocean. It is more than three times as large as the nearby Siberian wetlands, which have been considered the primary Northern Hemisphere source of atmospheric methane. Shakhova's research results show that the East Siberian Arctic Shelf is already a significant methane source: 7 teragrams yearly, which is equal to the amount of methane emitted from the rest of the ocean. A teragram is equal to about 1.1 million tons.

"Our concern is that the subsea permafrost has been showing signs of destabilization already," she said. "If it further destabilizes, the methane emissions may not be teragrams, it would be significantly larger."

Shakhova notes that Earth's geological record indicates that atmospheric methane concentrations have varied between about .3 to .4 parts per million during cold periods to .6 to .7 parts per million during warm periods. Current average methane concentrations in the Arctic average about 1.85 parts per million, the highest in 400,000 years, she said. Concentrations above the East Siberian Arctic Shelf are even higher.

The East Siberian Arctic Shelf is a relative frontier in methane studies. The shelf is shallow, 50 meters or less in depth, which means it has been alternately submerged or terrestrial, depending on sea levels throughout Earth's history. During Earth's coldest periods, it is a frozen arctic coastal plain, and does not release methane. As the planet warms and sea levels rise, it is inundated with seawater, which is 12-15 degrees warmer than the average air temperature.

"It was thought that seawater kept the East Siberian Arctic Shelf permafrost frozen," Shakhova said. "Nobody considered this huge area."

Earlier studies in Siberia focused on methane escaping from thawing terrestrial permafrost. Semiletov's work during the 1990s showed, among other things, that the amount of methane being emitted from terrestrial sources decreased at higher latitudes. But those studies stopped at the coast. Starting in the fall of 2003, Shakhova, Semiletov and the rest of their team took the studies offshore. From 2003 through 2008, they took annual research cruises throughout the shelf and sampled seawater at various depths and the air 10 meters above the ocean. In September 2006, they flew a helicopter over the same area, taking air samples at up to 2,000 meters in the atmosphere. In April 2007, they conducted a winter expedition on the sea ice.

They found that more than 80 percent of the deep water and greater than half of surface water had methane levels more than eight times that of normal seawater. In some areas, the saturation levels reached at least 250 times that of background levels in the summer and 1,400 times higher in the winter.

They found corresponding results in the air directly above the ocean surface. Methane levels were elevated overall and the seascape was dotted with more than 100 hotspots. This, combined with winter expedition results that found methane gas trapped under and in the sea ice, showed the team that the methane was not only being dissolved in the water, it was bubbling out into the atmosphere.

These findings were further confirmed when Shakhova and her colleagues sampled methane levels at higher elevations. Methane levels throughout the Arctic are usually 8 to 10 percent higher than the global baseline. When they flew over the shelf, they found methane at levels another 5 to 10 percent higher than the already elevated arctic levels.

The East Siberian Arctic Shelf, in addition to holding large stores of frozen methane, is more of a concern because it is so shallow. In deep water, methane gas oxidizes into carbon dioxide before it reaches the surface. In the shallows of the East Siberian Arctic Shelf, methane simply doesn't have enough time to oxidize, which means more of it escapes into the atmosphere. That, combined with the sheer amount of methane in the region, could add a previously uncalculated variable to climate models.

"The release to the atmosphere of only one percent of the methane assumed to be stored in shallow hydrate deposits might alter the current atmospheric burden of methane up to 3 to 4 times," Shakhova said. "The climatic consequences of this are hard to predict."

Shakhova, Semiletov and collaborators from 12 institutions in five countries plan to continue their studies in the region, tracking the source of the methane emissions and drilling into the seafloor in an effort to estimate how much methane is stored there.

Shakhova and Semiletov hold joint appointments with the Pacific Oceanological Institute, part of the Far Eastern Branch of the Russian Academy of Sciences. Their collaborators on this paper include Anatoly Salyuk, Vladimir Joussupov and Denis Kosmach, all of the Pacific Oceanological Institute, and Orjan Gustafsson of Stockholm University.

Source: http://www.sciencedaily.com/releases/2010/03/100304142240.htm

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

Join us on Facebook:
www.facebook.com/OceanicDefense
Visit our official website:
www.oceanicdefense.org
Follow us on Twitter:
www.twitter.com/OceanicDefense

New studies suggest that great white sharks may migrate so they can dine on giant squids.

In what could be the ultimate marine smack-down, great white sharks off the California coast may be migrating 1,600 miles west to do battle with creatures that rival their star power: giant squids.

A series of studies tracking this mysterious migration has scientists rethinking not just what the big shark does with its time but also what sort of creature it is.

Few sea denizens match great white sharks and giant squids in primitive mystique. Both are the subject of popular mania; both are inscrutable. That these two mythic sea monsters might convene for epic battles in the stark expanses of the Pacific is enough to make a documentarian salivate.

For more reserved scientists, the possible link between sharks and squid, suggested by marine ecologist Michael Domeier of the Marine Conservation Science Institute in Fallbrook, is just one part of emerging research that has altered their understanding of the great whites.

The shift began eight years ago with the surprising discovery that great white sharks migrate, somewhat as humpback whales do. That and subsequent studies have demolished the iconic image of great whites lurking in relative shallows, ready to snatch an errant swimmer, as popularized in the movie "Jaws."

Domeier said he believes the animals "are not a coastal shark that comes out to the middle of the ocean. They are an ocean shark that comes to the coast. It is a complete flip-flop."

Picture them not as a dorsal fin off the beach but rather as an unseen leviathan swimming through black depths where the oxygen thins and fish glow in the dark, and maybe pouncing on a 30-foot squid.

The squid part is controversial. But Domeier's work and that of other scientists increasingly suggests that great white sharks are not randomly roving eating machines.

Instead, they obey set migration patterns, have distinct populations and return to the same locales. They are not desperadoes but dutiful migrants: Nomads but not outlaws, they yearn for home.

But this new understanding raised a question: Why would an animal so large, that grows teeth as humans grow hair, bother to go so far when it can dine on just about anything in fin's reach? The migration is especially puzzling because it means sharks miss out on coastal food supplies, said the University of Hawaii's Kevin Weng, who also tracked sharks' migration.

Determined to find the reason, Domeier and his team spent three years catching 22 great whites off Mexico's Guadalupe Island, southwest of San Diego, and bolting high-tech tags to their fins. The area, like California's Farallon Islands, is a hot spot for shark visits.

The team used hooks that could cradle a volleyball. They wrestled the sharks onto platforms, lifted them aboard their vessel and put towels over their eyes. The 4,000-pound predator is only a minor threat out of water, Domeier said. But after being thwacked off his feet, he learned to tie up their tails.

Funded by Newport Beach's George T. Pfleger Foundation and others, Domeier arranged a voyage with a National Geographic Channel television crew to follow the sharks in a 126-foot boat. The crew used the tags to track the sharks to an area of the deep Pacific about 1,500 miles east of Kauai that scientists consider an ecological desert because it is so biologically unproductive.

There, the sharks abruptly ended their migration, and satellite tags showed them milling around and diving.

Despite hours of surveys and trolling during last spring's monthlong voyage, members found barely any fish or other prey that the sharks might be eating.

But there was an exception: squids. Purple and neon flying squids were easy to find. There also were leaping sperm whales, a marine mammal known to feed in spawning areas for large squids. To Domeier, it was clear: The sharks had found a squid-based ecosystem with big enough prey to attract sperm whales.

Finally, the crew found a whitish carcass of a giant squid that had been chewed on, perhaps by various predators. Because of the lack of alternative food sources, and the pinging tags that traced deep and frequent dives, Domeier said, he formed a speculative conclusion: The sharks go to the area for the same reason as sperm whales: to feed on large squids, including the giant ones in the area, and on various predators the squids attract.

The weather turned bad, and the investigation ended early. The trip back was boring enough for the crew to form a band, then break up.

Domeier said he believes the sharks return to the coast to breed. His tags showed that some females stayed out at sea full-time.

The idea has set off robust debate. Some scientists argue it remains possible that the sharks mate offshore, and all agree that more research is needed to determine exactly what, and when, they eat. And it's highly unlikely anyone will ever see a shark making an easy kill of giant squid.

But Oscar Sosa-Nishizaki, a fisheries biologist in Ensenada, said the tagging effort helps researchers count sharks and plan conservation efforts.

Shark scientists face a dilemma: There is intense popular interest in their work, but some fret that it may hinder conservation. Media interest in sharks tends to be "sparse on detail, high on testosterone," said marine biologist Weng. "It's as if aliens were to visit planet Earth, and the only thing they saw of human beings was ultimate fighting on TV."

Though wary of pop biology, Domeier made the most of it. He used his time on camera to lobby against eating bluefin tuna and Chilean sea bass.

If mythic predator-mania gave him the chance, so be it, he said. "We are at a state of real disaster of our oceans," he said. "Perhaps the scientific routine . . . doesn't work."

jill.leovy@latimes.com

Source: http://articles.latimes.com/2010/mar/07/local/la-me-shark7-2010mar07

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

Join us on Facebook:
www.facebook.com/OceanicDefense
Visit our official website:
www.oceanicdefense.org
Follow us on Twitter:
www.twitter.com/OceanicDefense

ScienceDaily — Between the grains of sand on the sea floor there is an unknown and unexplored world. Pierre De Wit at Gothenburg University knows this well, and has found new animal species on the Great Barrier Reef, in New Caledonia, and in the sea off the Gullmarsfjord in the Swedish county of Bohuslän.

The layer of sand on ocean floor is home to a large part of the vast diversity of marine species. Species representing almost all classes of marine animals live here. The genus Grania, which belongs to the class of annelid worms Clitellata, is one of them.

Grania the globetrotter
Grania is a worm around two centimetres in length and mostly white, which is encountered in marine sand throughout the world, from the tidal zone to deep down in the ocean. The researcher Pierre De Wit, at the Department of Zoology of the University of Gothenburg, is analysing exactly how many species of Grania there are and how they are related to other organisms.

Four new species
De Wit has conducted studies at the Great Barrier Reef in Australia, where he and his colleagues have found four entirely new species of the Grania worm. One of them is the beautifully green-coloured Grania colorata. "These worms are usually colourless or white, and we have not been able to work out why this particular species is green," says De Wit.

Separate history
De Wit has also found a previously unknown worm in Scandinavia, dubbed Grania occulta, which can only be distinguished from a previously known species by DNA. The worms' genetics show that the evolutionary history of the two species is in fact entirely separate, and that one of them is actually more closely related to a species that looks completely different.

Important knowledge
"Species that were previously regarded as the same may prove to have a completely different function in the ecosystem, and have different tolerance of environmental toxins, for example. It is obviously important to know this in order to be able to take the right action to protect our fauna," says de Wit.

Source: http://www.sciencedaily.com/releases/2010/03/100308095836.htm

About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

Join us on Facebook:
www.facebook.com/OceanicDefense
Visit our official website:
www.oceanicdefense.org
Follow us on Twitter:
www.twitter.com/OceanicDefense