What is a geothermal vent?
Geothermal vents only exist on the ocean floor, typically located near oceanic ridge spreading centers. They are also called smokers because they resemble chimneys that spew dark mineral rich water heated by hot newly-formed oceanic crust and the volcanic activity associated with ocean spreading centers. They support an entire diverse ecosystem in an area where few scientists expected to find thriving life forms. The basis of the ecosystem is a hydrogen-sulphide-digesting bacteria, that in turn provides food for larger organisms. Since this part of the sea floor is well below the depth that light can penetrate, the primary energy source is from these chemosynthetic bacteria that utilize chemical energy. Large clams exist in these areas that feed on the chemosynthetic organisms. Here is the USGS link that has deep sea photos of smokers: http://pubs.usgs.
