New Species Found at Hot Vents Below the Icy Southern Ocean

OXFORD, UK, January 6, 2012 (ENS) – New species of yeti crab, starfish, barnacles, and sea anemones, and an octopus, also probably new to science, have been discovered on the seafloor near Antarctica, living in the hot, dark environment surrounding hydrothermal vents.

The discoveries were made by teams led by the University of Oxford, University of Southampton and its partner, the National Oceanography Centre, and the British Antarctic Survey. Their findings are published in the current issue of the journal “PLoS Biology.”

Since 2009, a remotely operated vehicle, ROV, has enabled the researchers to make the first two explorations of the East Scotia Ridge beneath the Southern Ocean. There, hydrothermal vents, including “black smokers” reaching temperatures of up to 382 degrees Celsius, create a unique environment lacking sunlight but rich in certain chemicals.

Colonies of a new species of yeti crab found at vent chimneys (Photo courtesy Oxford University)

“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 Professor Alex Rogers of Oxford University’s Department of Zoology, who led the research.

“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,” Rogers said.

The ROV dives brought back images showing huge colonies of the new species of yeti crab, thought to dominate the Antarctic vent ecosystem, clustered around vent chimneys.

Elsewhere, the ROV spotted numbers of a previously undescribed predatory seastar with seven arms crawling across fields of stalked barnacles.

The ROV’s camera documented an unidentified pale octopus on the seafloor nearly 2,400 meters (1.5 miles) beneath the surface.

“What we didn’t find is almost as surprising as what we did,” said Rogers. “Many animals such as tubeworms, vent mussels, vent crabs, and vent shrimps, found in hydrothermal vents in the Pacific, Atlantic, and Indian Oceans, simply weren’t there.”

A previously unidentified octopus near a vent on the Southern Ocean floor (Photo courtesy Oxford University)

Deep-sea hydrothermal vents are associated with seafloor spreading at mid-ocean ridges and in basins near volcanic island arcs, the authors write. “Hydrothermal vents and their communities of organisms have become important models for understanding the origins and limits of life as well as evolution of island-like communities in the deep ocean,” they write.

The team believes that the differences between the creatures found around the Antarctic vents and those found around vents elsewhere suggest that the Southern Ocean may act as a barrier to some vent animals.

“The East Scotia Ridge communities form a new biogeographic province with a unique species composition and structure,” the authors explain.

The unique species of the East Scotia Ridge also suggest that, globally, vent ecosystems may be much more diverse, and their interactions more complex, than previously thought.

In April 2011, Rogers was part of an international panel of marine scientists who gathered at Somerville College, Oxford to consider the latest research on the world’s oceans. A preliminary report from the panel in June warned that oceans are at risk of entering a phase of extinction of marine species unprecedented in human history.

“These findings are yet more evidence of the precious diversity to be found throughout the world’s oceans,” said Professor 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.”

ROV dives were conducted with the help of the crews of RRS James Cook and RRS James Clark Ross. The discoveries were made as part of a consortium project with partners from the University of Oxford, University of Southampton, University of Bristol, Newcastle University, British Antarctic Survey, National Oceanography Centre, and Woods Hole Oceanographic Institution supported by the UK Natural Environment Research Council and the U.S. National Science Foundation.

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