Hydrothermal vents were first observed by scientists in 1977. Researchers using the deep-submergence vehicle Alvin discovered them on the Galápagos Rift in the eastern Pacific Ocean.
The vents form where seawater circulates through cracks in oceanic crust near volcanic activity. The water is heated underground, reacts with minerals, and rises back through the seafloor carrying dissolved chemicals. When it meets cold seawater, minerals precipitate and can build chimney-like structures.
The discovery transformed ideas about deep-ocean life. Vent communities thrive without sunlight because bacteria use chemosynthesis to obtain energy from chemicals such as hydrogen sulfide. These microbes support food webs that include giant tube worms, clams, mussels, and specialized shrimp.
Hydrothermal vents are not the same as ordinary hot springs on land, and their temperatures can exceed 300 degrees Celsius under pressure. Scientists still study them for clues about extremophile biology, ocean chemistry, and possible environments for life beyond Earth.