Ocean Planet: Recently Revealed
Far from sunlight, sulfur supports strange life forms
"We were dancing off the walls . . . it was a discovery cruise . . . like Columbus."
said
John Edmond, geochemist, on the cruise that first found hydrothermal vents
In 1977 geologists exploring fractures in the ocean
floor found more than they had anticipated. Large, odd-looking
animals were surviving on the sunless, otherwise barren sea floor
by what turned out to be an entirely unknown mode of life.
Vent worm food depends on sulfur, not sunlight. Bacteria convert
chemicals from the sulfur-rich fluid spewed out of vents to
energy, in a process called chemosynthesis.
Vent worms have no mouth or digestive tract. Instead,
chemosynthetic bacteria living in their tissues provide
nourishment. Other animals eat bacteria, harbor bacteria in their bodies, or eat bacteria-eaters.
Hemoglobin (which transports hydrogen sulfide to
the bacteria) makes the vent worms red.
Black smokers, the hottest submarine hot springs, can reach 518-716 F (270-380 C).
The super-hot water laced with hydrogen
sulfide and other minerals spews out of cracks in the earth's
crust.
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