Hydrothermal vents are located where the tectonic plates are moving apart and spreading. This allows water from the ocean to enter into the crust of the earth where it is heated by the magma. The increasing pressure and temperature forces the water back out of these openings, on the way out, the water accumulates dissolved minerals and chemicals from the rocks that it encounters. Vents can be characterized by temperature and chemical composition as diffuse vents which release clear relatively cool water usually below 30 °C, as white smokers which emit milky coloured water at warmer temperatures, about 200-330 °C, and as black smokers which emit water darkened by accumulated precipitates of sulfide at hot temperatures, about 300-400 °C.
