Which hydrothermal vent field in the Pacific was the first discovered, in 1977?

The Galápagos Rift was the first hydrothermal vent field discovered in 1977. The discovery occurred along an active spreading center in the eastern Pacific, roughly 400 miles west of Ecuador and northeast of the Galápagos Islands.

Scientists first detected unusual warm-water signals during earlier surveys, then investigated the area with the research vessel Knorr, the ANGUS deep-towed camera system, and the submersible Alvin. The expedition revealed hot springs on the seafloor surrounded by giant clams, tubeworms, mussels, crabs, and other animals unknown to science.

This discovery overturned the assumption that ecosystems ultimately depend on sunlight. At these vents, microbes use chemosynthesis, extracting energy from chemicals in the vent fluids. Those microbes form the base of a food web that supports dense communities in permanent darkness.

A common mix-up is confusing the Galápagos Rift discovery with the later discovery of black smokers. The first Galápagos vents were relatively low-temperature systems; the first actively growing high-temperature sulfide chimneys were found later, at the East Pacific Rise in 1979. The famous Rose Garden is one specific vent site within the broader Galápagos Rift field.