marine diving adaptations

When marine mammals dive into deep, high pressurized waters, they experience an increase in dissolved nitrogen gas in their bloodstreams. The dissolved gas poses a threat because if the divers ascend too fast, they experience a phenomenon known as the “bends,” whereby gas bubbles form inside the body and increase the risk of contracting decompression sickness. Fortunately, marine mammals have a special lung architecture that creates two different pulmonary regions to combat high-pressure depths. They have a compressible chest that limits the amount of nitrogen gas that can be absorbed. The authors of the review article suggest that the physiology of diving mammals is poorly understood, and that there are other cardiorespiratory mechanisms that provide a better explanation for their ability to dive deeply. The results of the paper showed that many marine mammals can withstand high levels of nitrogen gas that would normally cause decompression sickness 50% of the time. The authors also hypothesized that parasympathetic stimulation helps limit lung perfusion, which is a necessary for diving to great depths. They propose that high amounts of stress can interfere with this process and might explain the failure of a normal dive response. Overall, these findings are significant because they offer a new perspective on the physiological and respiratory adaptations that enable cetaceans to dive at great depths.