Survey of different physico-chemical core parameters (POC, PN, TALK, nutrients, S13 C in DIC, S18O H2O) in the Scheldt River. Interaction between river water and the intertidal deposition zones. Interactions between riverine vegetation and river zones (detritus imput). Decay of plant detritus. Ammonification. Organic and inorganic carbon and nitrogen (particulate and dissolved) concentrations, flows, transformations, sources and sinks are studied in the upper estuary, the river Scheldt and the intertidal zones. d 13C, d15N and d18O signatures are used to trace specific sources and processes. The former Institute for Nature Conservation was a partner in this project