An understanding of hydrostatic pressure as an ecological and evolutionary factor in the seas is being sought through the study of deep-sea barophilic bacteria. Pressure adapted bacteria have been found in cold deep oceans and in warmer deep seas such as the Mediterranean, Sulu and Celebes Seas. Laboratory studies on bacteria from various habitat depths implicate pressure as a far greater influence in the ecology and evolution of deep-sea life than has been recognized. Furthermore, deep-sea bacteria may be integral parts of the food web since they make polyunsaturated fatty acids that are required dietary lipids for animals. The objectives of proposed laboratory work are: to determine the role of deep-sea bacterial polyunsaturated fatty acids in the deep-sea food web; to evaluate the extent of the genetic and biochemical basis for barophily; and to determine if the barophilic response is invariant with respect to the type of energy yielding reaction used by an organism.
