THERMAL-DEPENDENCE OF TISSUE METABOLISM IN THE GREEN TURTLE, CHELONIA-MYDAS

To better understand how tissue specific metabolic rates might contrib ute to the maintenance of elevated body temperatures in green turtles (Chelonia mydas), we determined the effect of temperature on oxygen co nsumption of green fat, small intestine, nonswimming skeletal muscle, pectoralis muscle, liver, heart, and kidney tissues from 5-35 degrees C. We found a direct relationship between tissue metabolic rate (micro liters of O-2/g wet mass per hour) and temperature in all tissues meas ured except for green fat. The Q(10) values ranged from 0.65 to 3.38. There were significant differences in metabolic rate among tissues as well as in how temperature influenced tissue metabolic rates. Tissue m etabolic rates were highest in kidney and heart tissues. Green fat and small intestine had the lowest and most temperature-insensitive value s. Muscle tissue had a high oxygen consumption relative to other repti les, and this elevated metabolism may provide a functional advantage f or long distance swimming and heat production.