Comparative temporary threshold shifts in a harbor porpoise and harbor seal, and severe shift in a seal (L)
Comparative temporary threshold shifts in a harbor porpoise and harbor seal, and severe shift in a seal (L)
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DOI：
10.1121/1.4808078
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发表时间：
2013-07-01
影响因子：
2.4
通讯作者：
Hoek, Lean
中科院分区：
文献类型：
--
作者：
Kastelein, Ronald A.;Gransier, Robin;Hoek, Lean
人为噪声可能会导致海洋哺乳动物的暂时性听阈偏移（TTS）。用相同的方法进行的测试表明，虽然它们对该频率的未掩蔽（基本）听力阈值相似，但港湾鼠海豚对以4 kHz为中心的倍频程白色噪声（OBN）引起的TTS比港湾海豹更敏感。一个港口密封暴露1小时的OBN具有非常高的声压级（SPL），22-30分贝以上的水平，导致TTS发作。这引起44 dB TTS;听力在4天内恢复。因此，对于该信号和该单次暴露，永久性阈值偏移需要比TTS起始水平高至少22 dB的水平。密封中的严重TTS表明，暴露于以4 kHz为中心的OBN 60 min的临界水平（高于该临界水平，TTS随着SPL的增加而迅速增加）在150和160 dB re 1 μ Pa之间。在许多国家的政策制定者制定的海洋哺乳动物TTS指南中，TTS假设遵循等能量假设，因此，当疲劳声音的声音暴露水平相等时，预计会诱发相同的TTS。然而，与以往的研究一样，本研究对这一模型提出了质疑。(C)2013年美国声学学会。
Anthropogenic noise may cause temporary hearing threshold shifts (TTSs) in marine mammals. Tests with identical methods show that harbor porpoises are more susceptible to TTS induced by octave-band white noise (OBN) centered around 4 kHz than harbor seals, although their unmasked (basic) hearing thresholds for that frequency are similar. A harbor seal was exposed for 1 h to an OBN with a very high sound pressure level (SPL), 22-30 dB above levels causing TTS onset. This elicited 44 dB TTS; hearing recovered within 4 days. Thus, for this signal and this single exposure, permanent threshold shift requires levels at least 22 dB above TTS onset levels. The severe TTS in the seal suggests that the critical level (above which TTS increases rapidly with increasing SPL) is between 150 and 160 dB re 1 mu Pa for a 60 min exposure to OBN centered at 4 kHz. In guidelines on TTS in marine mammals produced by policy makers in many countries, TTS is assumed to follow the equal energy hypothesis, so that when the sound exposure levels of fatiguing sounds are equal, the same TTS is predicted to be induced. However, like previous studies, the present study calls this model into question. (C) 2013 Acoustical Society of America.