Identifying sentinel indicators of acoustic propagation conditions using the soundscape codea)

Area of Science:

• Marine acoustics and ecology
• Habitat characterization
• Bioacoustics

Background:

• Seafloor substrate and biological communities significantly influence underwater sound transmission loss in shallow waters.
• The soundscape code (SSC) offers a quantitative method for assessing acoustic properties of marine environments.

Purpose of the Study:

• To evaluate if SSC metrics can serve as sentinel indicators for marine habitat composition and spatial distribution.
• To assess the acoustic distinctiveness of different coastal habitats in the Gulf of Maine.

Main Methods:

• Hydrophones were deployed across three habitat types (sand, macroalgae, eelgrass) in four coastal locations.
• Hourly SSC metrics (amplitude, impulsivity, uniformity, periodicity) were calculated across five frequency bands.
• Multivariate statistical analysis, including discriminant analysis, was used to compare soundscapes.

Main Results:

• Discriminant analysis accurately differentiated between habitats and geographic regions using SSC metrics.
• SSC metrics demonstrated high predictive power for identifying acoustic propagation conditions.

Conclusions:

• SSC metrics are effective sentinel indicators for characterizing coastal marine habitats and their acoustic properties.
• This approach provides a rapid, quantitative assessment of soundscape variations linked to habitat types in the Gulf of Maine.