Abstract:
Biological activity in marine sediment creates a time-varying, randomly fluctuating medium. A bio-diffusive sediment model is proposed for density and sound-speed fluctuations within the sediment. Using perturbation theory to model sediment volume scattering, the decorrelation of the scattered field due to biological activity can be predicted. This decorrelation can be estimated from field data by comparing seafloor backscatter from the same location at different times. By fitting the model to such data, sediment bio-diffusion constants can be estimated. Such acoustically inferred values of sediment bio-diffusion are compared with directly measured values. [Work supported by ONR.]