摘要：

Hydrothermal vents, first discovered in 1977 at 2500m depth on the Galapagos Rift, provide an example of such an alternative ecosystem supported by chemosynthetic primary production (Jannasch and Mottl, 1985). Hydrothermal fluid pouring from the cracks, crevices, and chimneys in the sea floor supports large numbers and kinds of bacteria capable of deriving energy from reduced compounds, such as hydrogen sulfide. This life-supporting fluid is the result of sea water circulating deep within porous basalts and reacting at high temperatures with the rock from magma chambers along ridge axes, where new sea floor is being formed. Large clusters of red-plumed tube-worms emerging from 2- to 3-m-long, thick, white tubes give another-worldly appearance to the rich community of animals sustained by the bacteria. These oases contrast sharply with the surrounding relatively barren rock surfaces on the mid-ocean ridge. Hydrothermal vent populations are of particular interest since these dense populations of large, fast-growing animals flourish in the dark at high pressures and low temperatures, the usual environment of the deep sea.

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