Details

Autor(en) / Beteiligte

• Freeman, Simon E.
• Rohwer, Forest L.
• Gregg, Allison
• Coleman, Laura
• Buckingham, Michael J.

Titel

On the origins of ambient biological sounds in shallow water tropical ecosystems

Ist Teil von

• The Journal of the Acoustical Society of America, 2013-05, Vol.133 (5_Supplement), p.3396-3396

Erscheinungsjahr

2013

Quelle

American Institute of Physics (AIP) Journals

Beschreibungen/Notizen

• Although discovered more than 60 years ago, the origins of much ambient underwater biological noise remain unclear. Snapping shrimp sounds dominate some environments but elsewhere the shallow-water biological sound field is often heterogeneous. Here we show that dominant components of underwater ambient noise recorded on coral reefs around five islands in the central Pacific may be caused by the interaction of hard-shelled benthic macro-organisms with the substrate. Recordings show a consistent, nightly 4.7 to 6.9 dB increase in estimated pressure spectral density level in the 11 to 17 kHz band with a spectral peak centered between 14 to 15 kHz. Underwater time-lapse photography reveals a marked night-time increase in benthic invertebrate activity at most locations, temporally consistent with the increase in pressure spectral density level. Intensity-filtered recordings of an example species, the hermit crab Clibanarius diugeti, in quiet aquarium conditions reveal that transient sounds produced by interaction between the crustacean’s carapace, shell, and coral substrate are spectrally consistent with the central Pacific recordings. Passive acoustic monitoring of such ambient noise may be useful as a complementary ecological survey technique to SCUBA-based visual observations, which are typically poor in estimating the abundance and diversity of cryptobenthic organisms.