Picture of the Week—Shrimp at an Undersea Volcano

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Last month, a group of oceanographers onboard the R/V Thompson visited the active underwater volcano NW Rota-1 near Guam. This volcano is special because it is the only submarine volcano that scientists have observed erupting (via the remotely operated vehicle Jason) and it is continuously active. The researchers discovered that since 2006, when the volcano was last visited, it had built a new cone 40 meters high and 300 meters wide—about as tall as a 12-story building and as wide as a city block. They also found plenty of unusual creatures, including crabs, limpets and shrimp:

The shrimp reveal intriguing adaptations to volcano living.

"The 'Loihi' shrimp has adapted to grazing the bacterial filaments with tiny claws like garden shears," said Tunnicliffe. "The second shrimp is a new species--they also graze as juveniles, but as they grow to adult stage, their front claws enlarge and they become predators."

The Loihi shrimp was previously known only from a small active volcano near Hawaii--a long distance away. It survives on the fast-growing bacteria and tries to avoid the hazards of the volcanic eruptions. Clouds of these shrimp were seen fleeing volcanic bursts.

The other species attacks the Loihi shrimp and preys on marine life that wanders too close to the volcanic plumes and dies. "We saw dying fish, squid, etc., raining down onto the seamount, where they were jumped on by the volcano shrimp--a lovely adaptation to exploiting the noxious effects of the volcano," Tunnicliffe said.