Another volcanic vent story has hit the news after British scientists revealed details of the world's most extreme deep-sea vent – 5km down in a rift in the Caribbean sea floor.
The undersea hot springs known as ‘black smoker’ vents are 0.8km deeper than any seen before and shoot jets of mineral-laden water over a kilometre up into the ocean at temperatures which may exceed 450°C.
What comes as the biggest surprise is that despite these extreme conditions, the vents are teeming with thousands of a new species of shrimp.
The team from the National Oceanography Centre and University in Southampton revealed that their expedition in April 2010 to the trench south of the Cayman Islands found up to 2000 shrimp per m2 of a new species of pale shrimp around the 6m tall mineral spires of the vents.
Instead of conventional eyes, the shrimp instead have a light-sensing organ on their backs, which may help them to navigate in the faint glow of deep-sea vents. The researchers have named the shrimp Rimicaris hybisae, after the deep-sea vehicle that they used to collect them.
The Cayman shrimp is related to a species called Rimicaris exoculata, found at other deep-sea vents 4,000km away on the Mid-Atlantic Ridge. Elsewhere at the Beebe Vent Field, the team saw hundreds of white-tentacled anemones lining cracks where warm water seeps from the sea bed.
"Studying the creatures at these vents, and comparing them with species at other vents around the world will help us to understand how animals disperse and evolve in the deep ocean," says one of the marine biologists Dr Jon Copley.
The team also unexpectedly found other black smoker vents nearby on the slopes of the underwater mountain Mount Dent suggesting that these vents may be more widespread than previously thought. The vents on Mount Dent also thronged with the new species of shrimp along with snake-like fish, and previously unseen species of snail and a flea-like crustacean called an amphipod.
"One of the big mysteries of deep-sea vents is how animals are able to disperse from vent field to vent field, crossing the apparently large distances between them," says Copley. "But maybe there are more 'stepping stones' like these out there than we realised."
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