Hydrothermal Vents
Magma chambers that lie near the earth's surface at mid-ocean ridges like the East Pacific Rise drive hydrothermal systems. These magma chambers spew lava to generate new seafloor, but even when seemingly quiescent, they crack the seafloor and allow seawater under the crust. Contact with the hot rocks warms the water and drives oxygen off as the water leaches other chemicals from the rocks. Hot, chemically distinct water emerges from beneath the earth's surface at hydrothermal vents. The hot water rises and emerges through vents on the seafloor. Although the water temperature is often over 100°C (212° F), the high seafloor pressure keeps it from boiling. The unusual chemicals the hot water carries include those that bacteria can use as energy sources.
Where bacteria proliferate animals that eat bacteria congregate, as do animals that live not by eating bacteria or anything else, but by taking energy from bacteria that grow inside their bodies. Although most animals cannot survive in the harsh vent habitat, a distinct group of animals are unique to EPR vents. Some of the larger vent animals include the conspicuous Giant Tube Worms, Giant Clams, and mussels. The tinier denizens of the vents include limpets, copepods, and amphipods.
