Deep Sea Hydrothermal Vents

Deep-sea hydrothermal vents were discovered in 1977 when scientists diving in the submersible Alvin found lush communities of life clustered around cracks in the seafloor where superheated, mineral-rich water (up to 400°C) gushes from the Earth's interior. This was revolutionary: life here depends not on sunlight but on chemosynthesis — bacteria using hydrogen sulfide from the vents as an energy source. Vent ecosystems support giant tube worms up to 2 meters long, ghostly white crabs, eyeless shrimp, and bizarre fish, in complete darkness under crushing pressure. They suggest that life could exist on icy moons of Jupiter and Saturn (Europa, Enceladus) where liquid water and geothermal energy exist beneath ice sheets.