Mr. Splashy Pants and his friends evolved in an ocean without Navy sonar. Instead of submarines, most cetaceans evolved to worry about another predator, the Orca (Killer Whale). It turns out the frequency of sonar from the Navy is similar enough to that of the Orca that it may trigger certain cetaceans to perform a series of shallow dives.
The study in the current issue of Marine Mammal Science argues that this diving behavior, if extended an unnatural length of time could cause decompression sickness (the bends) in the cetaceans. After all, whales like Mr. Splashy Pants don't want to get eaten by a pod of Orca, so they continue to try and escape while the sonar is turned on.
Controversy has surrounded the use of sonar, and researchers have suspected a link between sonar testing and whale deaths for 20 years, but have been unable to identify the specific link between the two. The new model provides scientists a testable theory, and concludes that limiting the duration of sonar testing may prevent the Orca's prey from getting the bends. More details after the link.