Bedload and Nearbed Detritus Transport in a Tidal Saltmarsh Creek

Bedload and nearbed transport of coarse (>1 mm) detritus particles were investigated in a tidal creek of a salt marsh in the Westerschelde estuary (south-west Netherlands). Using a fyke net positioned on the creek bottom, hourly transport through the creek was measured during 14 flood–ebb cycles in 1990 and 1991. Transport was bidirectional with flood imports varying between 32 and 2601 g dry weight (DW), and ebb exports varying between 0 and 4737 g DW. In nine of 14 tidal cycles, the creek was functioning as a net exporting system. The material that was exported with the ebb consisted mainly of macrophyte material. The annual loss of coarse organic matter by bedload plus nearbed transport through the creek was estimated to be less than 0·2% of the estimated annual above-ground plant biomass production in the drainage area of the creek. Therefore, it is concluded that this type of detritus transport is probably insignificant for the carbon balance of the salt marsh.