'Lost world' of sea life thrives on Antarctic sea floor

AFP Yahoo News 5 Jan 11;

A seven-pronged starfish, a mysterious pale octopus and a new kind of yeti crab are among a teeming community of previously undiscovered life on the sea floor near Antarctica, British researchers said.

The species, described this week on the online journal PloS Biology, were first glimpsed in 2010 when researchers lowered a robotic vehicle to explore the East Scotia Ridge deep beneath the Southern Ocean, between Antarctica and the tip of South America.

The dark and remote area is home to hydrothermal vents, which are deep-sea springs that spew liquid at temperatures of up to 382 degrees Celsius (720 Fahrenheit), and have previously been found to host unusual life forms in other parts of the world.

"Hydrothermal vents are home to animals found nowhere else on the planet that get their energy not from the Sun but from breaking down chemicals, such as hydrogen sulphide," said lead researcher Alex Rogers of Oxford University.

"The first survey of these particular vents, in the Southern Ocean near Antarctica, has revealed a hot, dark, 'lost world' in which whole communities of previously unknown marine organisms thrive."

Hydrothermal vents were first discovered in 1977 off the Galapagos Islands.

The latest discoveries 2,400-2,600 meters deep include several new types of sea anemones, stalked barnacles and unidentified octopi, and a new kind of starfish that was observed feeding on the fauna around the vents.

A new type of blond, furry-legged yeti crab, a species formally known as Kiwa hirsuta which was first seen at hydrothermal vents in the South Pacific in 2005, was also found to have different DNA than those already known to man.

Fish were uncommon, and only seen on the peripheries of the hot zones.

Researchers were equally intrigued by what they did not find -- including many of the giant worms, vent mussels, crabs, clams and shrimp that have been found before at other deep sea vents in the Pacific, Atlantic and Indian Oceans.

The differences in species suggest that the geographic conditions of the area may make it a distinct province for certain forms of life, which have been unable to migrate to other parts of the globe's sea floor.

"These findings are yet more evidence of the precious diversity to be found throughout the world's oceans," said Rogers.

"Everywhere we look, whether it is in the sunlit coral reefs of tropical waters or these Antarctic vents shrouded in eternal darkness, we find unique ecosystems that we need to understand and protect."

Researchers on the project came from the University of Oxford, University of Southampton and the British Antarctic Survey. Their research appears online in the January 3 issue of PLoS Biology.