Influence of an infaunal bivalve on the erosion of an intertidal cohesive sediment: A flume and modeling study
Limnol. Oceanogr., 43(6), 1998, 1332-1343 | DOI: 10.4319/lo.1922.214.171.1242
ABSTRACT: A model was developed to describe the erosion of a cohesive sediment within an annular flume. The model relates the rate of resuspension of sediment per unit area to the difference between the amount of sediment available for resuspension from the bed and the amount already resuspended into the water column. The rate of erosion also depends on the excess free-stream near-bed current velocity above a critical threshold velocity. The basic five parameter model describes 96% of the variation in suspended sediment concentration within the flume, where natural sediment is exposed to increments in current velocity (up to 43 cm s-l, equivalent to a shear stress of 1.5 Pa) in the absence of macrofauna. The addition of a small clam, Macoma balthica, to the experimental system led to increased levels of resuspension at all velocities. This effect increased asymptotically with Macoma population density and could be modeled using two additional parameters. Complete analysis of the resulting seven-parameter model showed that the effect of the fauna was confined solely to the amount of sediment available for resuspension.