Sentry dives to a biological oasis

WHOI operators deploy the autonomous underwater vehicle (AUV) Sentry during an expedition led by the University of Washington at a site called “Pythias Oasis.” The area, named after a Greek biologist, resides on the Cascadia Margin off the coast of Oregon. Scientists used Sentry to map and characterize “seeps” at the site–warm, mineral-rich water flowing from the seafloor 1,000 meters (~3,300 feet) below the surface. The area teems with life, including rockfish, eelpout fish, hagfish, anemones, “sea pig” sea cucumbers, crabs, snails, soft corals, and clam beds. Ongoing investigation of the submarine fluids may unearth new clues about seismic activity deep within the Cascadia Margin. (Photo by Michael Sessa, © Woods Hole Oceanographic Institution)