scholarly journals Temporary threshold shift in bottlenose dolphins (Tursiops truncatus) exposed to mid-frequency tones

2005 ◽  
Vol 118 (4) ◽  
pp. 2696-2705 ◽  
Author(s):  
James J. Finneran ◽  
Donald A. Carder ◽  
Carolyn E. Schlundt ◽  
Sam H. Ridgway
2010 ◽  
Vol 127 (5) ◽  
pp. 3267-3272 ◽  
Author(s):  
James J. Finneran ◽  
Donald A. Carder ◽  
Carolyn E. Schlundt ◽  
Randall L. Dear

2008 ◽  
Vol 123 (5) ◽  
pp. 3506-3506
Author(s):  
James J. Finneran ◽  
Carolyn E. Schlundt ◽  
Brian K. Branstetter ◽  
Randall L. Dear

2011 ◽  
Vol 92 (8) ◽  
pp. 1887-1892 ◽  
Author(s):  
Jonathan A. David

Coastal waters are being subjected to underwater noise generated by increasing numbers of leisure and tour boats. Such noise has the potential to impair the hearing of neighbouring bottlenose dolphins, particularly as the noise from several distributed boats could summate at the point of reception. This potential has been assessed by comparing small boat noise, recorded over a range of 8–532 m, with noise that is known to induce hearing impairment in the form of a temporary threshold shift (TTS) or permanent threshold shift (PTS). Extrapolation of broadband boat noise levels yielded a minimum source sound pressure level of 156 dB re 1μPa at 1 m. An equal-energy model for TTS-onset predicted that boat noise could induce a TTS after 1 hour's exposure at 1.3 m and after 8 hours' exposure at 2.3 m. These distances increased with additional adjacent boats. Leisure boats are unlikely to induce a PTS, even at close range.


2008 ◽  
Vol 123 (5) ◽  
pp. 3618-3618
Author(s):  
T Aran Mooney ◽  
Paul E. Nachtigall ◽  
Stephanie Vlachos

2010 ◽  
Vol 127 (5) ◽  
pp. 3256-3266 ◽  
Author(s):  
James J. Finneran ◽  
Donald A. Carder ◽  
Carolyn E. Schlundt ◽  
Randall L. Dear

1973 ◽  
Vol 16 (2) ◽  
pp. 267-270 ◽  
Author(s):  
John H. Mills ◽  
Seija A. Talo ◽  
Gloria S. Gordon

Groups of monaural chinchillas trained in behavioral audiometry were exposed in a diffuse sound field to an octave-band noise centered at 4.0 k Hz. The growth of temporary threshold shift (TTS) at 5.7 k Hz from zero to an asymptote (TTS ∞ ) required about 24 hours, and the growth of TTS at 5.7 k Hz from an asymptote to a higher asymptote, about 12–24 hours. TTS ∞ can be described by the equation TTS ∞ = 1.6(SPL-A) where A = 47. These results are consistent with those previously reported in this journal by Carder and Miller and Mills and Talo. Whereas the decay of TTS ∞ to zero required about three days, the decay of TTS ∞ to a lower TTS ∞ required about three to seven days. The decay of TTS ∞ in noise, therefore, appears to require slightly more time than the decay of TTS ∞ in the quiet. However, for a given level of noise, the magnitude of TTS ∞ is the same regardless of whether the TTS asymptote is approached from zero, from a lower asymptote, or from a higher asymptote.


1976 ◽  
Vol 19 (2) ◽  
pp. 216-224 ◽  
Author(s):  
James T. Yates ◽  
Jerry D. Ramsey ◽  
Jay W. Holland

The purpose of this study was to compare the damage risk of 85 and 90 dBA of white noise for equivalent full-day exposures. The damage risk of the two noise levels was determined by comparing the temporary threshold shift (TTS) of 12 subjects exposed to either 85 or 90 dBA of white noise for equivalent half- and full-day exposures. TTS was determined by comparing the pre- and postexposure binaural audiograms of each subject at 1, 2, 3, 4, 6, and 8 kHz. It was concluded that the potential damage risk, that is, hazardous effect, of 90 dBA is greater than 85 dBA of noise for equivalent full-day exposures. The statistical difference between the overall effects of equivalent exposures to 85 dBA as compared to 90 dBA of noise could not be traced to any one frequency. The damage risk of a full-day exposure to 85 dBA is equivalent to that of a half-day exposure to 90 dBA of noise. Within the limits of this study, TTS t was as effective as TTS 2 for estimating the damage risk of noise exposure.


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