What If Gone

Species → Giant Tube Worm

Giant Tube Worm

Riftia pachyptila

No population figure exists — the species lives exclusively around…
Extinction risk Not Evaluated
Foundation speciesMarine environmentObligate mutualism
Giant Tube Worm (Riftia pachyptila)
Photo: Ifremer, Wikimedia Commons (CC BY 4.0)

What if it disappeared?

Impact High
At discovery

Lacking a mouth, gut, or anus as an adult, the giant tube worm draws its entire energy supply from symbiotic bacteria housed in an internal organ, the trophosome, which can make up as much as half the worm's total body mass.

Documented
Detail

Cavanaugh, C.M., Gardiner, S.L., Jones, M.L., Jannasch, H.W. et Waterbury, J.B. (1981). Prokaryotic Cells in the Hydrothermal Vent Tube Worm Riftia pachyptila Jones: Possible Chemoautotrophic Symbionts. Science, 213(4505), 340–342.

This discovery provided the first evidence of chemoautotrophic symbiosis in an animal: trophosome bacteria oxidize the toxic hydrogen sulfide emitted by the hydrothermal vent to produce the energy and organic compounds the worm needs, in exchange for shelter and a constant supply of inorganic compounds the worm draws from the surrounding water.

Over 2 years, East Pacific Rise

Following the 1991 submarine volcanic eruption at 9°50'N on the East Pacific Rise, giant tube worms colonized the new site, reached sexual maturity, and grew to 1.5 m in length in under two years — making it the fastest-growing marine invertebrate ever measured.

Documented
Detail

Lutz, R.A., Shank, T.M., Fornari, D.J., Haymon, R.M., Lilley, M.D., Von Damm, K.L. et Desbruyères, D. (1994). Rapid growth at deep-sea vents. Nature, 371, 663–664.

This extreme growth rate reflects the inherent instability of the ecosystem the tube worm founds: a hydrothermal site can appear or die out within just a few years depending on local volcanic activity, forcing colonies to rapidly colonize new vents in order for the species to persist along the ridge as a whole.

Not measured to date

Considered a foundation species of the hydrothermal vent ecosystem — its dense biomass provides shelter and food for shrimp, crabs, and other invertebrates specific to these vents — but no study measures what the giant tube worm's disappearance from a given site would change for the rest of that community.

Insufficient

Documentation

Last verified: August 14, 2026