National Geographic : 1971 Jan
Deep-sea "city" pulses with life T HE OCEAN'S DEPTHS can be a navigator's nightmare, in which you rarely know exactly where you are or where you have just been. Once, cruising at 1,300 feet on the Coronado Escarpment off San Diego, we sighted some "trees" of the black coral Antipathes (right)-rarely reported in California waters until this discovery. On later dives, we were never able to find these partic ular trees again. In such vast and perpetually night-shrouded regions, you can easily ghost by things only 35 feet away and never see them. Where these coral growths take hold, myriad creatures set up house keeping in their branches. Spidery Chirostylid lobsters clamber about, seeking bits of food amid the coral polyps. Feather stars, some attached, some swimming, look from a dis tance like parts of the tree itself. The egg case of a filetail shark (Parmaturusxaniurus) clings to a branch at lower center. Sea anemones, sponges, starfish, mol lusks, and barnacles live on and around the coral. 1/4 LIFE SIZE; EKTACHROME© N.G.S .