Measuring critical erosion shear stress of intertidal sediments with EROMES erosion device

摘要

EROMES erosion device was used to measure critical erosion shear stress of intertidal sediments in the German Wadden Sea. Various physical, sedimentological and biological parameters were determined for 4 stations at the study site during 3 field campaigns in April, May and June 2001 to assess which parameters controlloing sediment erodibility at the study site. These parameters included: wet bulk density, mud content, water content, organic content and chlorophyll-a concentration of the surficial sediment. The critical erosion shear stress varied between 0.10 to 2.05 N m-2 and these values fall above Shields predicted values. Modes of sediment erosion that observed in this study can be classified as type-I and Type-II erosion. Critical erosion shear stress correlated most significantly with Chlorophyll-a concentration suggesting that microphytobenthos biomass (measures by chlorophyll-a concentration) seem to be the main factors in controlling the erosion potential of the sediment surface at the study site.