New species discovered around Antarctic hydrothermal vents

Huge colony of yeti crabs

Huge colony of a new species of yeti crab

4 January 2012 by Tamera Jones

Scientists have discovered huge numbers of new marine species clustered in the hot, dark environment surrounding hydrothermal vents on the deep sea floor near Antarctica.

The findings include a new species of yeti crab, an unidentified octopus, an undescribed seven-armed sea-star, starfish, barnacles, limpets and sea anemones.

Yeti crabs are so called because they look unusually hairy. They use these hairs, or setae, on their claws and limbs, as a breeding ground for bacteria which they feed on. But the yeti crabs the researchers found around Antarctica are a completely new species, with hairs on their undersides.

The UK-led team made its discovery after exploring the East Scotia Ridge on the sea floor off the coast of South Georgia in the Southern Ocean, using a remotely-operated vehicle (ROV) called Isis.

The ridge, around 2500 metres deep, is dotted with hydrothermal vents where geothermally-heated water forces its way to the surface through cracks or fissures in the sea floor.

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

- Professor Alex Rogers, Oxford University

The temperature of the sea water around these hydrothermal vents reaches 382 degrees Celsius. Added to their depth, this makes exploring them without an ROV virtually impossible.

"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 sulfide," says Professor Alex Rogers from Oxford University, 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," he adds.

Unidentified pale octopus

An unidentified pale octopus was seen nearly 2,400m down

Highlights from the research trip include images showing huge colonies of the new species of yeti crab clustered around vent chimneys.

But Rogers and his team were just as surprised at what they didn't find as well as what they did.

"Many animals such as tubeworms, vent mussels, vent crabs, and vent shrimps found around hydrothermal vents in the Pacific, Atlantic and Indian Oceans, simply weren't there," he explained.

This was a surprise for the team, because some researchers have suggested the Southern Ocean vents could act as a gateway connecting other vents in other oceans, allowing creatures to slowly disperse across the oceans over thousands or millions of years.

But the new discovery suggests the extreme conditions of the Southern Ocean could instead act as a barrier to dispersal.

"What controls which creatures live at different hydrothermal vents is more complex than we previously thought," says Rogers.

"These findings are yet more evidence of the precious diversity to be found throughout the world's oceans," he adds. "Everywhere we look, whether it's 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."

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.

The study is published in PLoS Biology.

The Discovery of New Deep-Sea Hydrothermal Vent Communities in the Southern Ocean and Implications for Biogeography, PLoS Biology - Alex D Rogers, Paul A Tyler, Douglas P Connelly, Jon T Copley, Rachael James, Robert D Larter, Katrin Linse, Rachel A Mills, Alfredo Naveira Garabato, Richard D Pancost, David A Pearce, Nicholas V C Polunin, Christopher R German, Timothy Shank, Philipp H Boersch-Supan, Belinda J Alker, Alfred Aquilina, Sarah A Bennett, Andrew Clarke, Robert JJ Dinley, Alastair GC Graham, Darryl RH Green, Jeffrey A Hawkes, Laura Hepburn, Ana Hilario, Veerle AI Huvenne, Leigh Marsh, Eva Ramirez-Llodra, William DK Reid, Christopher N Roterman, Christopher J Sweeting, Sven Thatje, Katrin Zwirglmaier, doi:10.1371/journal.pbio.1001234