A small hydrothermal vent chimney is home to thermo-tolerant worms, seen here at the base of the chimney with their star-shaped gills protruding from their tubes. The white patches at the base of the chimney are microbial mats. This photograph was taken at the Cleft hydrothermal field, located off the coast of Oregon 2200 meters below sea level. Credit:W. Chadwick, National Undersea Research Program and Monterey Bay Aquarium Research Institute