On a calm, clear day in February 1977, Jack Corliss and two fellow explorers wedged themselves into the tiny, cramped cabin of the research submarine Alvin, said good-bye to the two support ships at the surface, and began a long descent into darkness. About 90 minutes later Alvin was gliding along the seafloor a mile and a half below the surface of the Pacific, and Corliss, a burly Oregon State University marine geologist, was peering out the porthole, searching for a phenomenon that had been suspected but never seen: submarine hot springs.
Searchlights blazing, Alvin cruised through black water above the Galápagos Rift, an undersea volcanic ridge along the equator 200 miles west of Ecuador. It was in just such a place, Corliss and the others surmised, that these so-called hydrothermal vents would be found--if they existed. Suddenly, just ahead, they spotted a huge cluster of clams. Tha was odd. What should so many large clams, fully a foot long, be doing so far below their sources of food?
Alvin floated nearer and Corliss pressed closer to the porthole. I saw a veil of shimmering water, he recalls. It reminded me of the way air wavers above hot pavement. Alvin extended its mechanical arm, in its grip a thermometer; 44 degrees. Not particularly warm by terrestrial standards, but at the ocean floor, where the climate is ordinarily close to freezing, this was bathtub temperature. The crew of the sub broke out in a cheer. The glistening veil was actually a sheet of water rising from the rocky floor. Corliss and his team had found their submarine hydrothermal vent.
As it turned out, Corliss’s team found four more hot springs in the Galápagos Rift, and since that initial exploration numerous other vents have been detected elsewhere on the ocean bottom. In these vents, seawater percolates through a maze of mineral-lined fractures to encounter magma deep in Earth’s crust. Heated by the magma, the water rushes upward to escape in the kind of shimmering veil Corliss noticed or in turbulent black smokers. The team also encountered strange forms of life clustered around the vents--giant worms and blind white crabs scurrying over bulging pillows of lava rock. This vast submerged world had a bizarre, elemental quality to it, as though it were a holdover from primordial Earth.
It was totally amazing, Corliss says. I began to wonder what all this might mean, and this sort of naive idea came to me. Could hydrothermal vents be the site of the origin of life?
