Hydrothermal Vent
D2. Hydrography, tides, waves, bathymetry and marine geologyDefinition
Seafloor opening discharging geothermally heated water.
A hydrothermal vent is a seafloor opening, mostly along mid-ocean ridges and back-arc basins, where seawater that has circulated through hot young crust discharges as mineral-rich fluid up to about 400 degrees Celsius. The hottest, sulfide-laden ‘black smokers’ precipitate chimneys and metal-sulfide deposits. Discovered in 1977 at the Galapagos Rift, vents host chemosynthetic ecosystems built on microbial oxidation of hydrogen sulfide rather than sunlight.