Gigantic carpet of deep-sea tubeworms found

A large tubeworm \'bush\' containing more than 14,000 animals Gigantic meadows of tubeworms have been found living 5,900-feet below the ocean surface off the coast of Costa Rica.Researchers from the Scripps Institution of Oceanography in California dived down in a submersible and were not only staggered by the size of the tubeworm clusters – but the conditions they were living in.
The marine ecosystem not only contained hydrothermal vents, where hot water surges from the seafloor, but also cold areas containing cracks that seeped large quantities of methane into the water.
Until now, it wasn’t thought that the two systems could live happily side by side.
The researchers coined a new term to describe the ecosystem - a ‘hydrothermal seep’.
The site, called Jaco Scar, lies at a tectonic plate margin off Costa Rica.
The animals range from those that inhabit hot vents or cold seeps, to species that exist in both settings.
However, the most interesting for the researchers were the tubeworms.
Lamellibrachia barhami: A tubeworm that lives at hydrothermal vents and methane seeps
The amazing marine ecosystem was found off the coast of Costa Rica
Sea-ing is believing: Lamellibrachia barhami, left, is a tubeworm that lives at hydrothermal vents and methane seeps off the coast of Costa Rica, right
Researcher Lisa Levin told LiveScience that ‘in some places they went on as far as you could see, just a huge meadow’.
They also assembled together in clusters numbering over 14,000 individuals and in water containing high levels of methane.
‘The discovery shows that we still have much to learn about hydrothermal vents and methane seeps and about the vast depths of the oceans,’ said David Garrison, director of the National Science Foundation\'s Biological Oceanography Program, which funded the research.
‘We need to re-think the boundary,’ he said, ‘of where a vent begins or a seep ends.’
In addition to tube worms, the team documented deep-sea fish, mussels, clam beds and high densities of crabs.
Because so little is known about the deep ocean, the researchers say it\'s likely that other hybrid or ‘mosaic’ ecosystems remain undiscovered, possibly with marine life specialised to live in such environments.
‘Plenty of surprises are left in the deep sea,’ said Levin. ‘There are new species, and almost certainly new ecosystems, hidden in the oceans.’
The human presence in Alvin, a submersible, deep-diving research craft was key to the findings.
‘The site had been visited by other researchers using remotely-operated vehicles,’ said Levin, ‘but it wasn\'t until human eyes saw shimmering water flowing under a tubeworm \'bush\' that we really understood how special Jaco Scar is.’
Results of the study appeared this week in the journal Proceedings of the Royal Society B: Biological Sciences.