Effectiveness of ocean gliders in monitoring ocean acoustics and anthropogenic noise from ships: A systematic review

Abstract

Underwater noise emissions from marine vehicles contribute to increasing ocean ambient noise levels, which is a threat to marine ecosystems. Passive acoustic monitoring, normally performed using moored-anchored systems, is commonly used to assess ocean soundscapes, vessel noise, and the presence of marine species. A systematic literature review was conducted to explore the use of autonomous underwater gliders (AUG) as an alternative to traditional moored systems for monitoring and assessing ship noise levels. We conducted thorough searches in Scopus and Web of Science, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We considered 13 articles on ocean glider applications for passive surveys and 8 articles on challenges in assessing underwater ship noise levels. Our findings were supplemented with international standards and guidelines from classification societies. Gliders are effective platforms for ship noise signature assessment due to their low noise signature and extended autonomy. In addition, AUGs can perform a 3D scan of the water column salinity, temperature, and density, which are needed to estimate sound propagation loss accurately. Further research is required to assess the potential of AUGs for accurately estimating ship noise levels by integrating oceanographic and acoustic data.