Optimizing nutrient reduction strategies in the marine environment - a simplified example from the north sea

Abstract

A coupled three dimensional physical, biological model (NORWECOM) has been used to study the effect of different reduction scenarios of nutrient inputs to the North Sea. Six different simulations where the nutrient loads from the Rhine and the German rivers have been varied, are perfonned. Outside the Belgian and Dutch coast there is a linear relationship between the decreased inputs from the Rhine and primary production with little effects of reduced inputs in the German rivers. In the German BightIDanish west coast effects are almost similar for reductions either in the Rhine or the German rivers. In the German Bight a summer oxygen minimum is also influence by a reduced input of nutnents, but the effects are relatively independent of which reduction scenario that have been chosen.