Mike Castellini ~ Polar Visionary

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Physiology and Environment

Dr Michael Castellini was trained in the same lab at Scripps that invented the first dive recorders, a lab which also has deep connections to the University of Alaska Fairbanks. A paper on diving physiology in marine mammals published in 1933 by Lawrence Irving established the field – and Irving had ties to both Scripps and UAF. "This is where it all began," says Mike.

Mike's work in diving physiology research is based in comparative physiology and understanding how the animal adapts to its environment. Marine mammals have tremendous breath holding capacity. (To prove this point when visiting high school classrooms, Mike asks for volunteers to hold their breath – for an hour and a half.)

Marine mammals can withstand hundreds of atmospheres of pressure – the world record for a seal is 2000 meters. They have no sinuses and thus no sinus problems, and they don't get the "bends". They have a soft chest and they fully exhale before diving, so that they are carrying no air in their lungs, and below 100 meters their lungs are totally collapsed. They carry the oxygen they need in blood and muscle, so no nitrogen gets into their blood. They can make dozens of dives in a day.

"These animals are exquisite yoga masters when it comes to control of blood flow."
Marine mammals have incredible blood flow capacity, and can control both blood flow and heart rate willingly. Among other applications, medical researchers at the National Institutes of Health (NIH) working on research related to strokes, pulmonology and cardiology are very interested in research on marine mammals diving physiology.