Riftia

Riftia is a monotypic genus of polychaete annelid worms in the Siboglinidae family, which contains the sole species Riftia pachyptila, commonly known as the giant tubeworm or giant beardworm. R. pachyptila is found in association with geologically active regions of the deep sea. Riftia worms are sessile and are found clustered together in large colonies around deep-sea hydrothermal vents in the East Pacific Rise and the Galapagos Rift. The size of a patch of tube worms surrounding a vent can span tens of metres, and individuals can reach a length of 3 m (9 ft 10 in). R. pachyptila has the fastest growth rate of any known marine invertebrate, and have been known to colonize a new site, grow to sexual maturity, and increase in length to 4.9 ft (1.5 m) in less than two years. Adult Riftia worms lack a digestive system and rely on their symbiotic relationship with chemotrophic sulfur-oxidising bacteria to provide them with energy. The hydrothermal vent habitat in which Riftia lives provides a natural ambient temperature ranging from 2–30 degrees Celsius (36–86 °F) and emits large amounts of chemicals such as hydrogen sulfide that are utilised by the tube worm for bacterial chemosynthesis.