Driftia

Driftia is a genus of marine polychaete worms in the family Siboglinidae, a group commonly known as beard worms. Members of Driftia are found in the deep sea, particularly around hydrothermal vents, cold seeps, and other reducing environments on continental margins and mid-ocean ridges. They live inside protective chitinous tubes that they secrete and attach to substrate on the seafloor.

Anatomy and nutrition: Adult Driftia lack a functional digestive system. Instead, they rely on endosymbiotic bacteria housed in a specialized tissue region called the trophosome. The bacteria are chemosynthetic and oxidize sulfide or methane from vent or seep fluids to produce organic compounds that feed the worm. Gas exchange and waste removal occur through the body surface and the tube opening. The worm’s body typically comprises a short anterior region (vestimentum) and a longer trunk; in some species a crown of feathery appendages is present and used for gas exchange.

Life cycle: Reproduction is sexual, with release of eggs and sperm into the water column, followed by planktonic larval stages that disperse and later settle to form new individuals. Nutritional symbionts are generally acquired from the environment after settlement rather than inherited directly by offspring (horizontal transmission).

Ecology and relationships: Driftia is related to other siboglinids such as Riftia and Lamellibrachia and is part of vent- and seep-associated communities. Its presence signals reducing conditions in the seafloor ecosystem and contributes to the microbial loop that supports diverse deep-sea faunal assemblages.