Why are hydrothermal vents home to such unusual animals?

Hydrothermal vents are cracks on the seafloor where superheated, mineral-rich water escapes from the Earth’s crust. Because no sunlight reaches these depths, the ecosystem depends on chemosynthesis rather than photosynthesis. Bacteria and archaea use chemicals such as hydrogen sulfide to make organic compounds, supporting larger animals like giant tube worms, vent crabs, and specialized clams. The first major vent communities were discovered in 1977 near the Galápagos Rift by researchers using the submersible Alvin. This discovery changed biology because it showed that life can flourish independent of sunlight.