Respiratory physiology in the dolphin and other whales
Bottlenose dolphins, like all mammals, depend on the respiratory system to bring oxygen into the body and remove the carbon dioxide produced by aerobic metabolism. In marine mammals, such as dolphins, that divide their time at the surface exchanging gases through the lungs and spending considerable time underwater holding their breath, the lungs have specialized adaptations. For example, the hydrostatic pressure of water increases with depth, causing compression of air-filled spaces resulting in lung compression and eventually alveolar collapse. This process affects the function of the respiratory system and gas exchange during diving. In addition, dolphins need to complete a respiratory cycle during the short period in the air when porpoising, which has resulted in fast and high respiratory flow rates. Thus, life in the ocean has resulted in several adaptations to obtain sufficient oxygen to perform dives.
