Acoustic scattering by benthic and planktonic shelled animals

Area of Science:

• Acoustics
• Marine Biology
• Sonar Technology

Background:

• Benthic and planktonic shelled animals with spiral shells, such as Littorina littorea, are significant acoustic scatterers in the ocean.
• Understanding their acoustic properties is crucial for sonar performance and ecological monitoring.

Purpose of the Study:

• To conduct acoustic backscattering measurements and develop scattering models for spiral-shelled animals.
• To analyze the physics of acoustic scattering by these complex biological structures.

Main Methods:

• Measurements of acoustic backscattering were performed on Littorina littorea over a frequency range of 24 kHz to 1 MHz.
• Data were analyzed in both frequency and time domains, with scattering models approximating the shell as a deformed sphere.

Main Results:

• Scattering resonance structure was found to be strongly dependent on the angle of orientation.
• Two models, a modal-series-based solution and a ray-based formula, provided reasonably accurate predictions for backscattering.

Conclusions:

• The developed models enhance predictions for sonar performance and the remote detection and classification of shelled organisms.
• This research provides insights into the acoustic scattering mechanisms of complex biological targets in marine environments.