Hydrogen sulfide as an energy source for chemoautotrophic bacteria in the deep sea.

The autotrophs upon which these submarine oases depend are chemosynthetic bacteria. Some of the most common are sulfur oxidizers, bacteria that use CO2 as a source of carbon and get their energy by oxidizing elemental sulfur, hydrogen sulfide, or thiosulfite. The submarine volcanic vents with which these organisms are associated discharge large quantities of sulfide-rich warm water. The sulfur-oxidizing bacteria that exploit this resource around the vents are of two types: free-living forms and those that live within the tissues of a variety of invertebrate animals, including the giant tube worms.