Monitoring bubble growth in supersaturated blood and tissue ex vivo and the relevance to marine mammal bioeffects

There have been several recent reports that active sonar systems can lead to serious bioeffects in marine mammals, particularly beaked whales, resulting in strandings, and in some cases, to their deaths. We have devised a series of experiments to determine the potential role of low-frequency acoustic sources as a means to induce bubble nucleation and growth in supersaturated ex vivo bovine liver and kidney tissues, and blood. Bubble detection was achieved with a diagnostic ultrasound scanner. Under the conditions of this experiment, supersaturated tissues and blood led to extensive bubble production when exposed to short pulses of low frequency sound.