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Ocean soundscapes and trends from 2003 to 2021: 10-100 Hz
Michael A Ainslie1, Stephen P Robinson2, Peter M Harris2
1JASCO Applied Sciences (Europe) GmbH, Schwentinental 24223, Germany.
The Journal of the Acoustical Society of America
|June 17, 2025
Summary
Ocean ambient sound levels significantly decreased between 2003 and 2021, according to hydrophone data. This global trend in underwater sound may be linked to economic, environmental, and seismic events.
Area of Science:
- Oceanography
- Acoustics
- Environmental Science
Background:
- The Comprehensive Nuclear-Test-Ban Treaty Organization operates a global network of hydrophones.
- Analyzing ocean ambient sound provides insights into natural and anthropogenic activities.
Purpose of the Study:
- To analyze long-term trends in ocean ambient sound pressure levels.
- To identify dominant sound sources and their contribution to overall soundscape.
- To investigate potential causes for observed trends in underwater sound.
Main Methods:
- Processed acoustic data from nine hydrophones across six hydroacoustic stations in five oceans (2003-2021).
- Identified dominant natural and anthropogenic sound sources.
- Applied 20 statistical tests to analyze long-term trends in sound pressure level.
Main Results:
- Fifteen out of 20 statistical tests revealed a significant downward trend in sound pressure level.
- Observed long-term trends at four of the six hydroacoustic stations.
- Identified potential contributing factors including global recession, COVID-19 pandemic, seismic activity, and increasing sea surface temperature.
Conclusions:
- Ocean ambient sound levels have shown a significant decreasing trend globally.
- Environmental factors such as increasing sea surface temperature may influence sound propagation and near-surface source contributions.
- Further research is needed to fully understand the complex interplay of factors affecting ocean soundscapes.
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