New Discovery: World’s Deepest Known Undersea Volcanic Vents

First photograph of the world's deepest known 'black smoker' vent, erupting water hot enough to melt lead, 3.1 miles deep on the ocean floor. Credit: NOC

Scientists have discovered the deepest underwater hydrothermal vents ever known off the Cayman Islands in the Caribbean. Some 3.1 miles below the surface, the slender spires are made of copper and iron ores and erupt water hot enough to melt lead. The “black smoker" vent is a half-mile deeper than those found previously.

"Seeing the world's deepest black-smoker vents looming out of the darkness was awe-inspiring," says Jon Copley, a marine biologist at the University of Southampton's School of Ocean and Earth Science (SOES) based at the NOC and leader of the overall research program, in a press release. "Superheated water was gushing out of their two-storey high mineral spires, more than three miles deep beneath the waves".

In the dark, barren waters of the deep sea, such hydrothermal vents support an array of unique creatures—including giant tube worms, clams, and crabs—that aren’t found anywhere else on the planet.

"It was like wandering across the surface of another world," says geologist Bramley Murton of the NOC, who piloted the HyBIS underwater vehicle around the world's deepest volcanic vents for the first time. "The rainbow hues of the mineral spires and the fluorescent blues of the microbial mats covering them were like nothing I had ever seen before."

As the BBC reports, it’s likely researchers won’t be the only ones to visit these remarkable environments:

Gold, silver, copper and zinc are all present in the mineral-rich emissions of the vent systems and recent advances in deep-sea oil exploration are giving miners the chance to exploit these areas for the first time. Nautilus Minerals, a small Canadian company backed by the giant mining company Anglo-American, has just received an environmental permit from the government of Papua New Guinea to conduct the world's first deep-sea mining in the vent fields of the Bismarck Sea. Giant undersea excavators will be built this year, and ore could be rising from depths of 1,600m by 2012.

A possible undersea “gold rush” worries environmentalists and some researchers. A 2007 report from the Environmental Defense Fund said that even though mining efforts will likely focus on dormant vents, the sensitive ecosystems could still be at risk:

While it seems clear that miners would avoid active vents (due to hazardous conditions), direct impacts on biological communities peripheral to vents and indirect impacts on vent communities themselves remain possibilities. Significant biological communities occur near cool or cold vents, as well as at hot vents. Crabs and other vent organisms have been observed quite far from actual vents, and may use large ranges for feeding. The Marine Minerals Service of the US Department of Interior concluded that a major fraction of the benthic life around vents would be destroyed by mining nearby.

You can follow the researchers on their expedition through April 20 on their blog.