MODELING OF NUTRIENT RELEASE FROM THE SEDIMENT IN A TIDAL INLET, KERTINGE-NOR, FUNEN, DENMARK

The nutrient fluxes between sediment and water column in Kertinge Nor, a tidal inlet, during the period following a major reduction of nutri ent loading, were determined by means of the numerical, hydrodynamic m odel ''MIKE11''. The fluxes of the nutrients total-N and total-P were simulated over the two year period 1991 and 1992. The model results we re verified through direct measurements of total-P transport at the ou tlet and through total-P and total-N exchange experiments on sediment cores. The advantages of the presented numerical simulation of flux ra tes are: 1) that the fluxes represent the integrated effect of the ent ire sediment area, and 2) that extraordinary release events can be sim ulated with an adequate resolution in time (1-2 days), which is high c ompared to the simulation period of almost two years. Sediment fluxes determined from the model indicate that during the biologically import ant summer periods in 1991 and 1992 the sediment was the dominant sour ce for both total-N and total-P.