A
hydrothermal vent is a
fissure in a planet's surface from which
geothermally heated
water issues. Hydrothermal vents are commonly found near
volcanically active places, areas where
tectonic plates are moving apart, ocean basins, and
hotspots. Hydrothermal vents exist because the earth is both geologically active and has large amounts of water on its surface and within its crust. Common land types include
hot springs,
fumaroles and
geysers. Under the sea, hydrothermal vents may form features called
black smokers. Relative to the majority of the deep sea, the areas around submarine hydrothermal vents are biologically more productive, often hosting complex communities fueled by the chemicals dissolved in the vent fluids.
Chemosynthetic bacteria and
archaea form the base of the food chain, supporting diverse organisms, including
giant tube worms,
clams,
limpets and
shrimp. Active hydrothermal vents are believed to exist on
Jupiter's moon
Europa, and
Saturn's moon
Enceladus, and ancient hydrothermal vents have been speculated to exist on
Mars.