Hydrothermal Vents

In 1975, an expedition called FAMOUS (French-American Mid-Ocean Undersea Study) sent a submarine to explore the hydrothermal vents in the Mid- Atlantic Ridge, which is located in the center of the Atlantic Ocean, between the African and European continents. No hydrothermal vents were found. In 1976, unmanned crafts (“diving saucers”) went into the Galapagos Rift. A rift is a boundary between tectonic plates. The samples of water that were that were brought back had strange mineral content. In 1977 scientists used the Alvin, a 25-foot long submarine designed for deep-ocean use, in an expedition led by scientist Robert Ballard. Alvin dove down 2,500 feet in the Galapagos Rift and discovered hot springs: the hydrothermal vents.

            Hydrothermal vents are created when there is a gap in the ocean floor and there is volcanic activity nearby. When the water touches the magma in this gap, it overheats and shoots back up at 212-570 degrees Fahrenheit, but the water doesn’t boil over because of the water pressure from above. After it shoots out, the water cools to about 73 degrees Fahrenheit and is cloudy with minerals. Some of these minerals were the strange minerals that were found during the 1976 expedition.

             One type of hydrothermal vent is called a “black smoker”. “Black smokers” are a kind of deep-ocean hydrothermal vent that spews out black sulfides, which might taste like black soot, and superheated water, which is about 662 degrees Fahrenheit. They are made out of mineral piles with holes in them, so that they look like chimneys. These “chimneys” can be as tall as 200 feet.

  Many life forms live near these hydrothermal vents, such as giant mussels, giant clams, white crabs, and tube worms. Giant mussels have yellow shells and live on bacteria they filter out of the seawater. Giant clams, however, have white shells, have red flesh rich in oxygen and measure about one foot across. White crabs eat the giant mussels, the giant clams and the tube worms. The tube worm has white stalks waving from the ground, and red plumes at the top, which are filled with blood. They have no mouths or digestive tracts, but live on the energy produced by the bacteria that live in them. They can grow as long as 8 feet. Scientists John Corliss and John Edmond wrote in Ocean: an Illustrated Atlas, “Shimmering water streams up past giant tube worms never before seen by man. A crab scuttles over lava encrusted with limpets while a pink fish basks in the warmth.”

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