Black Smoker

A black smoker is a high-temperature hydrothermal vent that discharges acidic, metal-rich fluid up to about 400 degrees C, which mixes with cold seawater and precipitates a black cloud of fine iron and copper sulfide particles. The minerals build chimneys of pyrite, chalcopyrite, and anhydrite that can grow several meters tall. Black smokers were first seen in 1979 on the East Pacific Rise at 21 degrees North. They sit on spreading ridges where seawater circulates through hot young crust, leaches metals, and returns to the seafloor. Chemosynthetic communities of tube worms and clams live on the vent chemistry, independent of sunlight.