2023_programme: Underwater noise pollution and risk assessment in an Artic fjord : on the importance of three-dimensional propagation modeling

• Session: 01. Acoustics in polar environments
  Organiser(s): Jaroslaw Tegowski, Philippe Blondel and Hanne Sagen
• Lecture: Underwater noise pollution and risk assessment in an Artic fjord : on the importance of three-dimensional propagation modeling [invited]
  Paper ID: 1860
  Author(s): Richard Gaetan, Mathias Delphine, Collin Jeremy, Chauvaud Laurent, Bonnel Julien
  Presenter: Bonnel Julien
  Abstract: Anthropogenic underwater noise has been a growing issue in Arctic waters. Indeed, because of climate change, sea ice covering is decreasing, and Arctic waters are opening to human activities (marine traffic, resource exploration and exploitation, military exercises). This increasing activity introduces underwater noise pollution in what used to be virtually pristine acoustic environments.\nAs a pollutant, noise can affect marine life by modifying natural behaviors and/or inducing physiological damage. Among nonlethal effects of noise pollution, auditory masking is the most pervasive since it inhibits an animal from perceiving important acoustic signals, needed for reproduction, predator avoidance, foraging, communication as well as orientation and navigation. Assessing masking effects has thus become a common tool to monitor underwater noise pollution, but it requires good acoustic propagation modeling to predict sound exposure levels.\nUnderwater noise modeling for acoustic risk assessments are mainly carried out using simplistic propagation models, which approximate a 3D propagation in several planes (Nx2D), instead of using full 3D propagation models. Nevertheless, Nx2D propagation models are impractical for winding geography and steep bathymetry as found in Arctic fjords. The purpose of this study is to compare disturbance and masking effects on some Arctic animal species from shipping noises, modeled through a traditional Nx2D ray model (BELLHOP) and a full 3D ray model (BELLHOP3D). \nResults showed clear differences of predicted underwater shipping noise footprint in an Arctic fjord between using a traditional Nx2D model and a full 3D model. Indeed, the disturbance and masking risks for some Arctic species were higher when using a full 3D model than a Nx2D model. Full 3D acoustic propagation model is therefore essential to predict the growing anthropogenic noise pollution in Arctic coastal and estuarine environments.
• Corresponding author: Dr Julien Bonnel
  Affiliation: Woods Hole Oceanographic Institution
  Country: United States
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