A close look at the structure of a glass sponge (class Hexactinellida) seen at a depth of 780 meters (2,560 feet) during the seventh dive of the Seascape Alaska 3 expedition. Sponges were abundant and diverse during the dive, with many large barrel sponges, amphitheater-type sponges, and numerous encrusting forms being observed.
Glass Sponge
Image courtesy of NOAA Ocean Exploration, Seascape Alaska. Download larger version (jpg, 767 KB).

A close look at the structure of a glass sponge (class Hexactinellida) seen at a depth of 780 meters (2,560 feet) during the seventh dive of the Seascape Alaska 3 expedition. Sponges were abundant and diverse during the dive, with many large barrel sponges, amphitheater-type sponges, and numerous encrusting forms being observed.