In 1977, a geology-focused American expedition aboard the R/V Knorr to the Galápagos Rift uncovered a thriving deep-sea ecosystem that relies on chemosynthesis instead of photosynthesis, featuring giant tube worms, clams, mussels, crabs, and microbial life.

Hydrothermal vent fluids were rich in hydrogen sulfide, powering chemosynthetic bacteria that convert inorganic carbon and water into organic matter, forming the base of the vent ecosystem’s food web.

Initial observations from ANGUS imagery showed dense white clams and other life at a hydrothermal vent site roughly 2,500 meters deep, prompting Alvin crewed dives that confirmed active vents and abundant organisms around them.

By 2024, more than 500 active vent fields have been identified globally with over 600 vent-endemic species, highlighting the Galápagos Rift discovery’s ecological significance and implications for astrobiology, including potential life on icy moons like Europa and Enceladus.

The vent ecosystem operates without sunlight, relying on chemical energy from Earth's interior, a finding that reshaped understanding of life’s energy sources and informed theories about life in similar environments elsewhere.

Colleen Cavanaugh’s 1981 work revealed that tube worms host symbiotic chemosynthetic bacteria in their trophosomes, effectively farming bacteria for nutrients, a discovery that extended to clams and mussels by the mid-1980s.

The discovery reframed the history of biology by showing that life can persist in darkness through microbial chemosynthesis and symbiotic relationships, a paradigm-shifting insight from a mission originally aimed at geology and heat flow.