Alvinella pompejana, (also known as the Pompeii worm), is a species of deep-sea polychaete worm (commonly referred to as "bristle worms"). It is an extremophile found only at hydrothermal vents in the Pacific Ocean, discovered in the early 1980s off the Galápagos Islands by French marine biologists.
In 1980 the French researchers Daniel Desbruyères and Lucien Laubier, just few years after the discovery of the first hydrothermal vent system, identified one of the most heat-tolerant animals on Earth - Alvinella pompejana, the Pompeii worm. It was described as a deep-sea polychaete that resides in tubes near hydrothermal vents, along the seafloor. In 1997 marine biologist Craig Cary and colleagues found the same worms in a new section of Pacific Ocean, near Costa Rica, also attached to hydrothermal vents. The new discovery and subsequent researches led to important progress in the scientific knowledge of these very special worms.
They can reach up to 5 inches in length and are pale gray with red tentacle-like gills on their heads. Perhaps most fascinating, is that their tail end is often resting in temperatures as high as 176 °F (80 °C), while their feather-like head sticks out of the tubes into water that is a much cooler 72 °F (22 °C). Scientists are attempting to understand how Pompeii worms can withstand such extreme temperatures by studying the bacteria that form a "fleece-like" covering on their backs. Living in a symbiotic relationship, the worms secrete mucus from tiny glands on their backs to feed the bacteria, and in return they are protected by some degree of insulation. The bacteria have also been discovered to be chemolithotrophic, contributing to the ecology of the vent community. Recent researches suggest that the bacteria might play an important role in the feeding of the worms.
Attaching themselves to black smokers, the worms have been found to thrive at temperatures of up to 80 °C (176 °F), making the Pompeii worm the most heat-tolerant complex animal known to science after the tardigrades (or water bears), which are able to survive temperatures over 150 °C.
