'The Hoff' crab is new ocean find

UK scientists have found an array of new species living around volcanic vents on the Southern Ocean floor south-east of South Georgia.

The haul includes a new type of yeti crab that researchers dubbed "The Hoff" crab when they first saw it, in honour of the famous American actor David Hasselhoff. The crab has long hairs - setae - on its ventral surface, or abdomen.

Great piles of the crabs were seen to come together. The creature has still to be formally classified. It is, however, a type of yeti crab, said Professor Alex Rogers who led the research cruise that found the animal, and it will be given a formal scientific name in due course.

Yeti crabs were first identified in the southern Pacific and are recognised for their hairs, or setae, along their claws and limbs that they use to cultivate the bacteria which they then eat.

              Isis has the capability to dive to more than 6km below the ocean surface

But the new species found around the vents that populate the East Scotia Ridge are slightly different in that they exhibit long setae on their ventral surface - on their undersides.

The crab occurs in staggering densities. It is just incredible to see these animals literally lying in heaps around the diffuse flow of these vents. At some places, they reached as many as 600 individuals per square metre.

The Hoff crab is just one of a number of species new to science to come out of the cruise, which also included researchers from the University of Southampton, the National Oceanography Centre and the British Antarctic Survey.

The cruise employed the UK deep-diving robotic submersible, Isis, to investigate the slowly spreading ridge near Antarctica.

It is dotted with hydrothermal vents - cracks in the volcanic rock where mineral-rich, hot waters gush from below the seabed to sustain an extraordinary array of organisms.

What surprised the team was not so much what they found, but rather what was absent. Vent systems in other parts of the world are dominated by animals such as tubeworms, mussels, other types of crab, and shrimps. These were all missing from the East Scotia Ridge.

This is fascinating because the cruise was originally initiated to investigate the hypothesis that the Southern Ocean acted as a gateway between the other major oceans of the world, allowing for the dispersal of vent organisms over geological timescales.

It was thought that the Southern Ocean's strong currents might help drive species from one ocean basin to another, and finding a very diverse group of animal types also at East Scotia Ridge would have been a powerful statement in support of this dispersal hypothesis.