Sounding an alarm over deep sea noise
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In recent decades, humans have added raucous clatter to the primal chorus. Scientists note that the noise of a typical cargo vessel could rival that of a jet. Even louder, they say, are air guns fired near the surface from ships used in oil and gas exploration. Their waves radiate downward and penetrate deep into the seabed, helping oil companies locate hidden pockets of hydrocarbons.
Marine biologists have linked human noises to reductions in mammalian vocalisation, which suggests declines in foraging and breeding. Worse, the US Navy estimates that blasts from its sonars result in permanent hearing losses for hundreds of sea mammals every year and temporary losses for thousands.
The federal sound study examined all these noises but zeroed in on commercial shipping because it represented a continuous threat. Vessels for fishing and research, including new ships being built for NOAA, are already being quieted around the world. Other measures for quieting include adding layers of sound-absorbing tiles to the walls of noisy rooms as well as mounting engines, pumps, air compressors, and other types of reciprocating machinery on vibration isolators.