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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