for National Geographic News
Looks alone suggest that deep-sea vents called black smokers emit a low rumble as they spew scalding, metal-rich fluids from the bowels of the Earth.
And in fact they do, according to the first-ever recordings of the phenomena.
The finding breaks a silence, so to speak, that began 15 years ago when researchers last tried to record the vents and heard nothing. The research also suggests that fish and other creatures may use the sounds to navigate the dark depths of the seas.
"Just by looking at them, it is really surprising they wouldn't be making noise," said Timothy Crone, a doctoral student in oceanography at the University of Washington in Seattle.
"They're violent little features."
Water shoots out of the fastest and largest black smokers at about 300 gallons (1,135 liters) a minute—twice the flow from a typical fire hose and enough to fill a bathtub in a few seconds.
Crone and his colleagues reported the findings last month in the Public Library of Sciences' online journal PLoS ONE.
The discovery of the sounds may help scientists study how vent flows respond to tides, earthquakes, and volcanic eruptions.
(Read related story: "Deep Sea Volcano Erupts on Film—A First" [May 24, 2006].)
Such information, Crone said, is key to understanding the cycling of chemicals from the Earth's crust into the ocean.
Most instruments used to measure flow, however, are short-lived when inserted in the scalding hot, acidic, and mineral-rich fluid.
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