Polychaete - Ecology

Ecology

Polychaetes are extremely variable in both form and lifestyle and include a few taxa that swim among the plankton or above the abyssal plain. Most burrow or build tubes in the sediment, and some live as commensals. A few are parasitic. The mobile forms (Errantia) tend to have well-developed sense organs and jaws, while the stationary forms (Sedentaria) lack them but may have specialized gills or tentacles used for respiration and deposit or filter feeding, e.g., fanworms.

A few groups have evolved to live in terrestrial environments, like Namanereidinae with many terrestrial species, but are restricted to humid areas. Some have even evolved cutaneous invaginations for aerial gas exchange.

Notable polychaetes

• One notable polychaete, the Pompeii worm (Alvinella pompejana) is endemic to the hydrothermal vents of the Pacific Ocean. Pompeii worms are among the most heat-tolerant complex animals known.
• A recently discovered genus, Osedax, includes a species nicknamed the "bone-eating snot flower".
• Another remarkable polychaete is Hesiocaeca methanicola, which lives on methane clathrate deposits.
• Lamellibrachia luymesi is a cold seep tube worm that reaches lengths of over 3 metres and may be the most long-lived animal at over 250 years old.
• A still unclassified multi-legged predatory polychaete worm was identified only by observation from the underwater vehicle Nareus at the bottom of the Challenger Deep, the greatest depth in the oceans, near 10,902 m (35,768 ft) depth. It was about an inch long visually, but the probe failed to capture it, so it could not be studied in detail.