Deep-Sea Primary Production at the Galápagos Hydrothermal Vents

Dense animal populations surrounding recently discovered hydrothermal vents at the Galápagos Rift sea-floor spreading center, 2550 meters deep, are probably sustained by microbial primary production. Energy in the form of geothermically reduced sulfur compounds emitted from the vents is liberated during oxidation and used for the reduction of carbon dioxide to organic matter by chemosynthetic bacteria.