Diving dolphins are exhalation champions
Every air-breathing marine mammal faces a multitude of challenges as it dives beneath the waves: carbon dioxide and nitrogen accumulation in the blood can cause intoxication and decompression sickness, while low internal pressures in rigid lungs can force blood into the delicate airways. Yet, whales, dolphins and seals rarely seem to suffer these ill effects. Andreas Fahlman from Texas A&M University - Corpus Christi, USA, says, 'It had been assumed that the respiratory systems of all marine mammals are similar with a stiff upper airway and collapsible lungs'. However, there was little evidence to support the assumption and Fahlman was repeatedly told that the measurements couldn't be made because of the incredibly high flow rates generated by exhaling dolphins.