Researchers have been surveying volcanic underwater vents - sometimes
called black smokers - in the South West Indian Ridge in the Indian
Ocean.
The UK team found an array of creatures living in the
super-heated waters, including yeti crabs, scaly-foot snails and sea
cucumbers.
They believe some of the species may be new to science.
Hydrothermal vents were first discovered in 1977. These
fissures in the ocean floor spew out fiercely hot, mineral-rich water,
yet somehow, diverse ecosystems are able to thrive in these hostile
conditions.
Species such as this sea cucumber are not found in neighbouring ridge systems
The team, from the University of Southampton, was particularly
interested in the vents on the South West Indian Ridge because this
range is linked to the Mid Atlantic Ridge and the Central Indian Ridge,
where vent life has been well documented.
This area is also unusual because it is an "ultra-slow
spreading" ridge, which means it is less volcanically active than other
ridges, with fewer vents that are further apart.
Dr Jon Copley, chief scientist of the Indian Ocean vents
project, said: "This place is a real crossroads in terms of the vent
species around the world."
Using a remote-operated, underwater robot called Kiel 6000,
from the Leibniz Institute of Marine Sciences (IFM Geomar), in Germany,
the team was able to train their cameras on the vents.
In the hottest habitat around the black smokers, they found
snails and shrimp, as well as mussels, sea cucumbers and crabs. They
then compared these with the animals found at vents on the neighbouring
ridges.
Dr Copley said: "I was expecting there to be some
similarities to what we know from the Atlantic, and some similarities to
what we know from the Indian Ocean vents, and that was true, but we
also found types of animals here which are not known from either of
those neighbouring areas, and that was a big surprise.
"One was a type of yeti crab. There are two currently
described species of yeti crab known from the Pacific, and it isn't like
those, but it is the same type of animal, with long, hairy arms.
The team used an underwater robot to find creatures, such as this scaly-foot snail, around the vents in the Indian Ocean
"Also some sea cucumbers - not known from the Atlantic or Central Indian vents, but known from the Pacific."
He added: "We've got links to lots of different parts of the world here, which is very exciting."
The team was also surprised at the diversity of life they
found during this expedition, which was funded by the Natural
Environment Research Council (Nerc).
Dr Copley said: "In a lot of other vent fields I've been to,
in this hot zone where you get the animals there is often just one type
of animal living there: in the deep Mid Atlantic Ridge, it's the shrimp.
But here, we have seen three to four all in the same zone."
There was a diverse mix of creatures, including this stalked barnacle, around the vents
The findings should help researchers to learn more about how
life moves from vent to vent: vents are short lived, and without the
ability to hop from one system to the next, life there would go extinct.
"That is why vents are a great place to understand how
species disperse and evolve in the deep oceans, because they are like
little islands," Dr Copley added.
Despite these findings, the researchers are worried about the future of this underwater terrain.
China has been granted an exploratory licence by the
International Seabed Authority to explore the potential of mining the
vents in this area for their rich minerals.
Dr Copley said: "This vent field is the size of a few
football pitches, and it seems possible that it is the only known range
of some of these species.
"It would be very premature to start disrupting it before we really know the true extent of what lives in it."
Shrimp like this one may be under threat from deep-sea mining.
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