Novel analysis of in-situ acoustic and optical data collected in a shallow, wave- and current-driven environment enabled determination of: (1) particle characteristics that were most affected by near-bed physical forcing, and (2) characteristic shear stress, τchar, at which the rate of changes to particle characteristics were most pronounced. Results indicated that moderate τchar values of 0.125 Pa drove changes in particle composition during summer. In winter, particle concentration effects were most affected at τchar of 0.05 Pa, suggesting dominance of fluff layer resuspension. Changes to particle size were most relevant during a biologically productive springtime period, with initiation of particle disaggregation occurring most commonly at τchar of 0.25 Pa. The values of τchar determined from acoustic and optical data are consistent with laboratory-based measurements of critical shear stress for resuspension of site sediments, and with typical critical shear stress values for resuspension of cohesive sediments as reported in the literature.
