The giant tube worm has a number of remarkable adaptations to cope with the extreme environment in which it lives. The body is split into four distinct regions, each of which has a different role in gas-exchange, anchorage and support, and the acquisition of nutrients. The trunk of the worm is found inside the chitinous tube. It is equipped with a specialised organ, called the trophosome, which is lined on the inner surface with lots of special, symbiotic bacteria, which the giant tube worm relies on to obtain the energy and nutrients it requires for growth and development. The bacteria convert the chemicals in the water surrounding the hydrothermal vents, such as sulphide, into organic material that can be used by the tube worm for nourishment (2) (3) (3).
Because of the relative inaccessibility of the hydrothermal vents, scientists are only beginning to understand more about the ecology of the giant tube worm. As yet, very little is known about the reproductive biology of the species; however, it is thought that individuals spawn by releasing a cloud of eggs or sperm, which are dispersed upwards by a propulsion of water, caused by the worm rapidly withdrawing into its tube (6). How fertilisation occurs is not known, but the young of the giant tube worm are known to be free-living, non-feeding larvae, which later settle on the substrate surrounding a hydrothermal vent and become sessile for the remainder of their adult life (4) (5).