Ambient noise levels with depth from an underwater glider survey across shipping lanes in the Gulf of St. Lawrence, Canada

Romina A S Gehrmann; David R Barclay; Hansen Johnson; Najeem Shajahan; Veronique Nolet; Kimberley T A Davies

doi:10.1121/10.0020908

Ambient noise levels with depth from an underwater glider survey across shipping lanes in the Gulf of St. Lawrence, Canada

J Acoust Soc Am. 2023 Sep 1;154(3):1735-1745. doi: 10.1121/10.0020908.

Authors

Romina A S Gehrmann¹, David R Barclay¹, Hansen Johnson¹, Najeem Shajahan², Veronique Nolet³, Kimberley T A Davies⁴

Affiliations

¹ Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada.
² School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, V8W2Y2, Canada.
³ Transport Canada Innovation Centre, Ottawa, K1A 0N8, Canada.
⁴ University of New Brunswick, Saint John, New Brunswick, E2K 5E2, Canada.

PMID: 37712751
DOI: 10.1121/10.0020908

Abstract

A two-month-long glider deployment in the Gulf of St. Lawrence, Canada, measured the ambient sound level variability with depth and lateral position across a narrow channel that serves as an active commercial shipping corridor. The Honguedo Strait between the Gaspé Peninsula and Anticosti Island has a characteristic sound channel during the Summer and Fall due to temperature variation with depth. The experiment comprised continuous acoustic measurements in the band 1-1000 Hz and oceanographic (temperature and salinity) measurements from a profiling electric glider down to 210 m water depth. The mean observed ambient sound depth-profile was modeled by placing a uniform distribution of sources near the surface to represent a homogeneous wind-generated ocean wave field and computing the acoustic field using normal modes. The measurements and predictions match within the observed error bars and indicate a minimum in the sound channel at 70 m depth and a relative increase by ∼1 dB down to 180 m depth for frequencies >100 Hz. The impact of detector depth, the distance to a busy shipping corridor, wind noise, flow noise, and self-noise are discussed in the context of passive acoustic monitoring and marine mammal detection.