Monster Seminar Jam - Impacts of Anthropogenic
Dr. John Hildebrand, Scripps Institution of Oceanography, University of California, San Diego
Sources of anthropogenic sound are becoming both more pervasive and more powerful, increasing both oceanic background noise levels and peak sound intensity levels. Anthropogenic activities in the ocean have increased over the past 50 years, resulting in more low frequency (less than 1000 Hz) and mid-frequency (1¿20 kHz) noise. Contributors to anthropogenic noise are commercial shipping, defense-related activities, hydrocarbon exploration and development, research, and recreation.
There is growing concern that sound introduced into the sea by human activities has detrimental effects on marine mammals. Mounting evidence suggests that high-intensity anthropogenic sound from sonar and airguns leads to strandings and subsequent mortality of beaked whales. Although the mechanisms of injury in these events are unclear, the species affected and implicated sound levels follow a consistent pattern. A more pervasive, yet more subtle, problem may be the effects of increases in background noise levels from commercial shipping. Higher levels of background noise may interfere with marine mammals ability to detect sounds, whether these are calls of members of their own species, echoes from prey, or natural sounds that aid in navigation or foraging.
Date and Time:
March 10, 2005,
11:00 am - 12:30 pm