Word: sounds
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Dates: during 2000-2009
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...young. Dr. Sandra Levey of New York City's Lehman College says 13% of teenagers aged 16 to 19 already show signs of noise-induced hearing loss. The inner ear contains small hair cells that vibrate against an inner membrane, generating an electrical signal that the brain interprets as sound, Levey explains. When bombarded by loud volumes over an extended period of time, these hair cells die off. The result is hearing loss, and potentially an array of other nasty consequences. A study conducted by Levey and Dr. Brian Fligor of Harvard University, which is nearing completion, suggests teens with...
...silent, and some "have high frequency vocalizations, which can only be detected when a PAM system is quite close." In other words, it would be too late to avoid airgun harm. Lee-Ann Ford, president and founder of Hong Kong-based Linking Individuals for Nature Conservation (LINC), says the sound of airgun explosions is 265 decibels at the source, and 110 decibels almost five miles away. The approximate hearing threshold for humans and marine mammals is 180 decibels, so "at [five miles] they're still being harmed," Ford says. (Read TIME's review of eco-documentary The Cove...
...formations for almost four months around Taiwan this spring, during which the crew popped its 36 airguns in the water every 20 or 60 seconds, depending on the instruments used to record the acoustic waves. Airguns, which are towed underwater at the back of the ship, cause loud, explosive sounds at a low frequency made when their pressurized air gets released into the water. The sound waves they generate are used to help build a picture of the rock structure beneath the seafloor, delineating fault lines, cracks or underwater volcanoes...
...environmental operations at the NSF. "The risk to people for not pursuing this type of research is simply not part of the story," Lang says. In the past, explosives like dynamite were used to create seismic waves. Improvement of recording devices and computer analysis has further decreased the airgun sound intensity required for geological research. Airguns are "the best existing technology to produce the desired type of sound," he says. Lincoln Hollister, professor of geosciences at Princeton University, also rejects claims that airgun use is correlated with damage to marine life, like lesions to the ears and brains or mass...
...about the environment - so they should do everything above board and by the book, without any reluctance," Rose of HSI says. "It is highly likely that there is better technology out there." With so many suggestions coming from both sides, common scientific goals - creating lower-intensity devices that create sound waves, understanding geologic processes and preserving marine mammals' safety - may be getting drowned...