BEDLOAD AND NEARBED DETRITUS TRANSPORT IN A TIDAL SALT-MARSH CREEK

Bedload and nearbed transport of coarse (>1 mm) detritus particles wer e investigated in a tidal creek of a salt marsh in the Westerschelde e stuary (south-west Netherlands). Using a fyke net positioned on the cr eek bottom, hourly transport through the creek was measured during 14 flood-ebb cycles in 1990 and 1991. Transport was bidirectional with fl ood imports varying between 32 and 2601 g dry weight (DW), and ebb exp orts 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 an nual loss of coarse organic matter by bedload plus nearbed transport t hrough the creek was estimated to be less than 0.2% of the estimated a nnual above-ground plant biomass production in the drainage area of th e creek. Therefore, it is concluded that this type of detritus transpo rt is probably insignificant for the carbon balance of the salt marsh. (C) 1996 Academic Press Limited