National Oceanic and
Atmospheric Administration
United States Department of Commerce


FY 2014

Sources of long-term ambient ocean sound near the Antarctic Peninsula

Dziak, R.P., H. Matsumoto, D.R. Bohnenstiehl, K.M. Stafford, M. Park, W.S. Lee, H. Klinck, M.J. Fowler, T.-K. Lau, J.H. Haxel, and D.K. Mellinger

In Proceedings of the 2nd International Conference and Exhibition on Underwater Acoustics (UA2014), Island of Rhodes, Greece, 22–27 June 2014, 157–165 (2014)

Hydrophone arrays (250–1000 Hz) were deployed within the Bransfield Strait and Scotia Sea (Antarctic Peninsula region) from 2005 to 2009 to study sources of ambient ocean sound. Icequakes, which are broadband, short duration signals derived from fracturing of large free-floating icebergs, are a prominent feature of the ocean soundscape. Icequake activity peaks during austral summer and is minimum during winter, likely following freezethaw cycles. Iceberg grounding and rapid disintegration also releases significant acoustic energy, equivalent to large-scale geophysical events. Overall ambient sound levels can be as much as ~10–20 dB higher in the open, deep ocean of the Scotia Sea compared to the relatively shallow Bransfield Strait. Noise levels become lowest during the low annual temperatures of the austral winter, likely due to freezing of regional sea ice of all scales. Ambient noise levels are highest during austral spring and summer, presumably due to melting and cracking icebergs. Vocalizations of blue (Balaenoptera musculus) and fin (B. physalus) whales also dominate the long-term spectra records in the 15–28 and 85 Hz bands. Blue whale call energy is a maximum during austral summer-fall in the Drake Passage and Bransfield Strait when ambient noise levels are a maximum and sea-ice cover is a minimum. Fin whale vocalizations were also most common during austral summer-early fall months in both the Bransfield Strait and Scotia Sea. The hydrophone data overall do not appear to show sustained anthropogenic sources (e.g. ships), likely due to low coastal populations and the difficult marine conditions of the Southern Ocean.

Feature Publications | Outstanding Scientific Publications

Contact Sandra Bigley |