Interesting Daily News

This unique preference for extreme temperatures may be the undersea worms' meal ticket, since they are apparently the only animals able to access - and feast on - lush mats of bacteria that thrive around deep-sea vents.

Authors Peter R. Girguis of Harvard University and Raymond W. Lee of Washington State University studied Paralvinella sulfincola, a member of the Alvinellidae family of worms dwelling at ocean depths of some 2,200 meters off the Pacific coast of Washington.

When the researchers placed them within a special high-pressure seawater aquarium with a sharp temperature gradient, these worms chose to remain at roughly 50 degrees Celsius for the duration of a seven-hour experiment.

For seven hours the worms chose to remain at around 50 degrees Celsius, performing their normal behaviors. Other inhabitants of equally inhospitable environments are known to die fairly quickly under such conditions; in one previous study of desert fire ants, all died within one minute of exposure to a temperature of 55 degrees Celsius. Such ants will survive brief forays into similarly hot areas to obtain food, but do not choose to remain in superheated environs as Alvinellids do.

"We speculate that these worms have evolved to prefer and tolerate these temperatures because it allows them to graze on bacterial lawns that no other organism can access", Girguis says. "Bacteria can survive much higher temperatures than animals, and often grow in lush mats, or lawns, in areas too hot to support animal life."