Dolphins, like all mammals, have lungs and breathe air. Metabolic rate, an indication of the energy used by an organism, can be described from counting how many molecules of oxygen are consumed over a given period of time. We recently developed a device that can be used to estimate the metabolic rate in dolphins in the field (such as from a boat). The device consists of a flow-meter that measures the amount of air they inhale and exhale, and also measures the concentration of oxygen when they exhale. Together, the flow and gas concentration are used to determine the metabolic rate. In addition to metabolic rate, these measurements can be used to look at other things, like lung health. Human doctors use similar equipment and measurements, in a process called pulmonary function testing, to look at lung health in people. Respiratory disease is very serious for dolphins and can be life threatening. If an unusually large number of dolphins have respiratory disease, this may indicate that there is an infectious disease spreading (this was recently the case with morbillivirus on the east coast of the U.S.) or that there is a problem in the ecosystem. By comparing respiratory health in different populations of dolphins, we can learn more about the health of those populations, and the marine environment in which they live.
We are also using this equipment to study how dolphins and whales dive to extreme depths and hold their breath for such a long time. For example, the dolphins in Sarasota Bay generally dive to depths up to a maximum of 6 meters, while members of the same species of dolphins in Bermuda dive to depths over 900 meters. Working with the SDRP and Dolphin Quest has allowed us to collect respiratory data from free-ranging dolphins in order to learn more about their incredible physiology and diving ability, their health, and the ecosystem we all share with these amazing animals.
This article appeared on page 16 in the December 2015 issue of Nicks n Notches.