When was the first deep-sea hydrothermal vent community found?

The first deep-sea hydrothermal vent community was found in 1977 during an expedition to the Galápagos Rift. Researchers discovered dense clusters of unusual organisms living around vent openings on the ocean floor. The ecosystem depended on bacteria that used chemical compounds such as hydrogen sulfide instead of sunlight. This was one of the most important biological discoveries of the 20th century and opened up a new understanding of deep-ocean habitats.