At deepest hydrothermal vent yet found, an 'awe-inspiring' view
Scientists have found a hydrothermal vent community three miles beneath the sea near the Cayman Islands. Other vents have led to the discovery of new and exotic creatures.
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Essentially these ultra-slow centers – which include the Arctic's Gakkel Ridge and the Southwest Indian Ridge in the southern Indian Ocean – were thought to be too cool to generate the hydrothermal vents. But during the past decade, expeditions to these locations have found otherwise.Skip to next paragraph
In Pictures Hydrothermal vents
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Scientists with the census realized "that we had to understand how the Cayman Trough fit into the biogeography and the chemistry of the global ocean," Tyler says.
The research by Tyler and his colleagues builds on an expedition last fall by the Woods Hole Oceanographic Institution (WHOI). It conducted an initial cruise to the trough as part of the Census of Marine Life's so-called ChESS project, which aims to catalogue marine organisms at undersea hydrothermal vents.
But the cruise ended with only the tantalyzing chemical fingerprints of hydrothermal activity in water samples brought up from the deep ocean, notes Chris German, a WHOI marine scientist who led that expedition. His team's data isolated the black smokers' location to within a radius of about 800 feet, he explained during a presentation at last fall's meeting of the American Geophysical Union in San Francisco.
Armed with that information, Tyler and his colleagues were able to focus their search on that area.
Understanding the deep-sea world
As scientists find more vent communities, broader questions are emerging, says Ronald D'Or, senior scientist for the census. While some creatures appear to be common among many of these deep-sea ecosystems, others appear to be unique to their locations, he says.
For the Cayman Trough, genetic comparisons between organisms there and those found on the East Pacific Rise might yield insights into organism migration, since roughly 30 million years ago, what is now the Caribbean Sea was a patch of ocean that connected the Atlantic and Pacific.
This week, scientists reported such vent-community migrations – on a much smaller scale. Researchers at WHOI and the Lamont-Doherty Earth Observatory at Palisades, N.Y., reported the discovery of sea snails at a hydrothermal site on the East Pacific Rise where the snails had never been seen before.
An volcanic eruption had wiped out the previous assembly of organisms at this site. And the nearest known snail population was some 215 miles north.
Modeling studies suggested the otherwise slow-swimming larvae were propelled to their new home by current "jets" along the crest of the ridge. That colonization "radically altered the community structure" at the post-eruption site, according to Lauren Millineaux, a senior scientist at WHOI.
The results appear in yesterday's issue of the Proceedings of the National Academy of Sciences.