In 1994, conservationists raised a big ruckus about the danger of a sound experiment called ATOC, which is now underway. Munk and his colleagues planned to install a low-pitched rumbling sound source on the ocean floor off California, and measure how quickly its sound moved across the Pacific Ocean.
Sound travels faster in warmer water.
So, after a few years measurement, if ATOC sounds were traveling faster, the researchers could conclude that the ocean, and presumably the rest of the earth, was getting warmer. ATOC scientists responded by designing a preliminary experiment to examine how ATOC sounds might affect marine mammals. The ATOC research group at the University of California, Santa Cruz, lead by biology professor Dan Costa, has ventured out in boats and planes, looking for behavior changes in marine life near the sound source. So far, the researchers report almost no effect. Most oceanographers and biologists now agree that what we stand to learn from the ATOC marine mammals justifies whatever harm the experiment might cause.