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A new report finds noise pollution can be just as harmful to the ocean environment as other kinds of pollution, but the damage can be reversed Underwater Noise Pollution Is Disrupting Ocean Life ...
Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms.
Between 1950 and 1975, ambient noise at one location in the Pacific Ocean increased by about ten decibels (that is a tenfold increase in intensity). [120] Underwater noise pollution is unevenly distributed across marine environments, with the highest con-centrations occurring in shipping lanes, port areas, and densely trafficked ocean routes.
Noise exposure in the workplace can also contribute to noise-induced hearing loss and other health issues. Occupational hearing loss is one of the most common work-related illnesses in the U.S. and worldwide. [39] It is less clear how humans adapt to noise subjectively. Tolerance for noise is frequently independent of decibel levels.
Noise-induced hearing loss is a permanent shift in pure-tone thresholds, resulting in sensorineural hearing loss. The severity of a threshold shift is dependent on duration and severity of noise exposure. Noise-induced threshold shifts are seen as a notch on an audiogram from 3000 to 6000 Hz, but most often at 4000 Hz. [16]
Output of a computer model of underwater acoustic propagation in a simplified ocean environment. A seafloor map produced by multibeam sonar. Underwater acoustics (also known as hydroacoustics) is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water, its contents and its boundaries.
Upsweep is an unidentified sound detected on the American NOAA's equatorial autonomous hydrophone arrays. This sound was present when the Pacific Marine Environmental Laboratory began recording its sound surveillance system, SOSUS, in August 1991. It consists of a long train of narrow-band upsweeping sounds of several seconds in duration each.
Sound from an underwater source can propagate relatively freely through body tissues where there is contact with the water as the acoustic properties are similar. When the head is exposed to the water, a significant part of sound reaches the cochlea independently of the middle ear and eardrum, but some is transmitted by the middle ear. [99]