Hydrothermal vent communities and plate tectonics

Deep in the oceans, hydrothermal vents are home to an extraordinary array of fauna. These animals depend primarily not on sunlight, but on the chemical energy of the hot fluids issuing from the cracked volcanic rocks along the mid-ocean ridges. Of the 442 species so far discovered, only 9% are known to occur elsewhere. Regional similarities in the distribution of this fauna seem to be controlled by the distance between vents along the mid-ocean ridge system and by the history of the tectonic development of the ridges.