Evaluating underwater ambient noise levels across a changing Arctic environment

Abstract

As a result of climate change, the Arctic underwater acoustic environment is undergoing an unprecedented transformation of its ambient noise sources, including an expanded wind fetch over open water and an intensification of maritime transportation lanes across Northern routes. This comparative study synthesizes multi-annual passive acoustic monitoring (PAM) data collected at various Alaskan Arctic environments (Bering Strait, Chukchi Plateau, Chukchi, and Beaufort Seas) in order to evaluate the statistics of ambient noise across the changing region. Mean levels at significant frequency ranges are presented, as well as percentile PSD levels in 1-Hz frequency bins. Remote sensing sea ice data is utilized to separate each annual dataset into 3 different regimes: open water, covered, and transition (when ice is forming or breaking up). During each, the dominant large-scale noise sources are characterized and the relationship between noise and local wind speed is evaluated. Through manual inspection, ship transits and seismic surveys have been extracted, allowing ambient level associations on the scale of hours or days. Consistently across all years, the Chukchi Plateau site, which is the most distant from shore, presents the lowest overall ambient noise levels (20-40 dB lower than other locations), potentially indicating a new Arctic ambient noise baseline.