This is a bit of a long lecture for the twitter age, but incredibly interesting and highly relevant.
Our oceans are getting noisier. A lot noisier… doubling in volume every decade from the 1960’s to 2004 in the Pacific alone. Water is a better conductor than air, and the louder noises can travel for thousands of miles. Marine mammals are among the first to show stress symptoms as their sound-based communication and echolocation abilities become compromised.
Naval sonar is possibly the worst offender, and is thought to be the cause behind a number of mass strandings, including the March 2000 Bermuda Whale Stranding. (http://www.bahamaswhales.org/resources/Stranding_Article.pdf. Warning: Very long & technical!)
For more information, also see: http://en.wikipedia.org/wiki/Beached_whale#Sonar