Ventilation, gas exchange and metabolic scaling of a sea turtle.

Ventilation of green turtles (Chelonia mydas) was affected by the position in which the animal was placed: supine animals breathed slowly 0.07 breaths/min) and deeply (8.0 L/breath); prone animals breathed more rapidly (0.43 breaths/min) and more shallowly (3.5 L/breath). From the respiratory exchange ratio and other indicators it appears that green turtles hyperventilate during exercise and hypoventilate during recovery. O2 consumption of the resting sea turtle (0.024 L-kg-1-h-1) is similar to that of other large turtles. Maximal O2 consumption (0.25L-kg-1-h-1) is greater than that of other large turtles. Minimal O2 consumption scaled in proportion to the -0.17 power of the body mass of green turtles over the range of 0.030 to 141.5 kg. The maximal O2 consumption scaled in proportion to the -0.06 power of body mass for the same range of body masses.