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Ambient noise dynamics in a heavy shipping area
G Bazile Kinda1, Florent Le Courtois1, Yann Stéphan1
1Shom, 13, rue du Chatellier, CS 92803, 29228 Brest cedex 2, France.
Marine Pollution Bulletin
|July 31, 2017
Summary
This study analyzed underwater noise in the Celtic Sea, finding levels often exceeded 100dB re 1μPa. Results emphasize designing oceanic moorings to reduce pseudo-noise and account for water column properties.
Area of Science:
- Marine acoustics
- Oceanography
- Environmental monitoring
Background:
- Underwater noise is a key component (Descriptor 11) of the EU Marine Strategy Framework Directive (MSFD).
- Continuous noise is monitored using one-third octave bands at 63Hz and 125Hz.
- The Celtic Sea is a high-traffic shipping zone with a seasonal thermal front.
Purpose of the Study:
- To analyze underwater noise levels in the Celtic Sea.
- To assess temporal and spatial noise variations.
- To investigate the influence of water column properties on noise levels.
Main Methods:
- Analysis of underwater noise across extended frequency bands (beyond MSFD recommendations).
- Assessment of temporal and spatial noise dynamics.
- Correlation of noise levels with water column physical properties.
Main Results:
- Underwater noise levels in the Celtic Sea exhibited a high dynamic range.
- Noise levels frequently surpassed 100dB re 1μPa.
- Water column properties significantly influence noise characteristics.
Conclusions:
- Oceanic mooring systems require careful design to minimize pseudo-noise.
- Physical properties of the water column are critical considerations for underwater noise management.
- Effective management of underwater noise is essential for marine ecosystems.
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