The objective of this research is to determine the cellular, physiological, and biophysical basis for gigantothermy in the leatherback sea turtle. The following hypotheses will be tested: 1. The tissue metabolic rate of leatherback muscle is elevated above that of green turtles and intermediate between that of green turtles and mammals. 2. Aerobic metabolism is the primary source of energy for activity of nesting, and other exercise. 3. Leatherbacks maintain constant elevated body temperatures while active and at rest in both warm (tropical) and cold (north temperate) waters. 4. Blood flow to the skin and periphery is increased when on land, and while exercising in warm (tropical) waters, and reduced when in cold (north temperate) water. These hypotheses will be tested by completing the following experiments: 1. Measure the tissue metabolic rate of the pectoral muscles of leatherbacks and green turtles at temperatures from 5 to 35oC using a Gilson respirometer. 2. Measure the aerobic and anaerobic metabolic rates of adult leatherbacks while they are resting and active on land in the tropics and north temperate region. 3. Use multichannel sonic transmitters to measure the body temperature of resting and active turtles in warm and cold waters. 4. Measure skin blood flow using the 133xenon washout technique. Finally these data will be used to test a mathematical model that predicts the effects of body size and metabolic rate on heat transfer and body temperatures of leatherbacks on land and in the water.//
