Comparison of the underwater ambient noise measured in three large exhibits at the Monterey Bay Aquarium and in the inner Monterey Bay
By: Daniel Matthew O'Neal
Publisher: Naval Postgraduate School; Available from National Technical Information Service
Published: 1998
Place of publication: Monterey, Calif; Springfield, Va
Language: eng
Number of pages: 55
Description: Ambient underwater acoustic-noise recordings were made in three large exhibits at the Monterey Bay      Aquarium and the inner Monterey Bay, with the results reported here. Observed broadband (0-6.4 kHz)      acoustic noise levels ranged from 112-125 dB re 1 microPa for the aquarium exhibits under normal operating      conditions. Broadband acoustic noise levels of 113 dB and 116 dB re 1 microPa were observed for the      nearshore and offshore bay locations, respectively. A comparison of the noise spectrum in the aquarium's      largest exhibit to that of the environment which it attempts to simulate, the offshore bay, revealed a higher noise      level of approximately 15-25 dB in the exhibit for frequencies between 20 Hz and 6.4 kHz. A similar      comparison of the noise spectra of the two smaller exhibits and the nearshore bay location revealed a difference      of approximately 5-10 dB across the entire frequency range of 0-6.4 kHz. Aquarium measurements with      various mechanical equipment (motors, fans, pumps, sprinklers, wave machine) turned on and off highlighted      some of the prominent ambient noise contributors. It was concluded that the pump machinery is the greatest      contributor to ambient noise, with the strength directly related to the exhibits' proximity to the machinery room.
Notes: Thesis advisor(s): Steven R. Baker.

"June 1998."

Thesis (M.S. in Applied Physics) Naval Postgraduate School, June 1998.

Includes bibliographical references (p. 53)

Approved for public release; distribution unlimited.

Also available online.

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US Navy (USN) author.

dk/dk cc:9116 9/28/98