Giant Tubeworm

• GeneralIt has neither mouth nor gut: it lives off internal bacteria that work on sulphide.
• fisiologíaIt lives beside hydrothermal vents thousands of metres down and takes its energy from symbiotic bacteria that oxidise sulphur compounds, rather than from sunlight.
• Its haemoglobin, which gives the plume its red colour, carries oxygen and sulphide at the same time without the latter poisoning it, something exceptional in animal biochemistry.
• Its discovery in 1977 off the Galápagos showed that whole ecosystems exist that do not depend on sunlight, and changed what was thought possible about life on Earth and on other planets.
• The adult has no mouth, no gut and no anus. All its nourishment comes from the billions of chemosynthetic bacteria it houses in an internal organ called the trophosome.
• Those bacteria use the energy in the vent's hydrogen sulphide to fix carbon, just as plants use light. It is an entire ecosystem that does not depend on the sun.
• The larva is born with a mouth and a gut: that is how the bacteria get in, and afterwards the digestive system turns into the trophosome.
• Its red plume is haemoglobin, and an extraordinary haemoglobin at that: it carries oxygen and sulphide at the same time without the latter poisoning it, something that would kill almost any other animal.
• It grows faster than any other marine invertebrate known: it can colonise a new vent, reach sexual maturity and measure a metre and a half in under two years.
• It was discovered in 1977, at the Galápagos hydrothermal vents, and the find changed what was believed about the limits of life.

Skeleton type

Invertebrate - no rigid skeleton (annelid)

Habitat and environment

Hydrothermal vents at 2,500 m

Sources consulted: Jones (1981) · Cavanaugh et al. (1981), Science · Lutz et al. (1994), Nature · Animal Diversity Web · ScienceDirect (Hughes 1989) · Science Advances, How colonial animals evolve · Wikipedia, Zooid