Measuring the Oxygen Consumption of Plethodon hubrichti and P. cinereus to Find the Metabolic Cause of Range Limitation of P. hubrichti: The Closed Respirometer and the Oxygen Probe

The Peaks of Otter area, a mountainous region of the central piedmont of Virginia, varies in elevation from 152 m to 1280 m. Plethodon cinereus is a salamander that is found at all elevations in this area. Plethodon hubrichti is a salamander that is found only at elevations above 600 m. It has been suggested that metabolism is the cause for the range limitation of P. hubrichti at lower elevations. The metabolism of salamanders can be determined by measuring oxygen consumption. Two apparati were evaluated to measure the oxygen consumption of these two salamander species at different temperatures to test that hypothesis. An oxygen probe designed for oxygen measurements in aqueous solutions was tested first, and the second apparatus tested was a closed respirometer. After many trials the oxygen probe was rejected due to technical problems. The closed respirometer apparatus was modified several times during repeated trials. The goal was to obtain a dependable apparatus that yielded consistent results. A metabolic difference between the two salamander species could not be determined although several trials were performed