Die Auswirkungen der Naehrstoffe (Stickstoff und Phosphor) auf die Gewaesserbeschaffenheit der Stromelbe unter sich veraendernden Belastungsbedingungen Abschlussbericht

Abstract

There is a research deficit on the effects of nutrients on the biological water quality in rivers, specially in regards to the relationship between the input of nutrients in river basins and the measured load in the rivers. Considerable differences exist in the nutrient budgets due to loss and retention of the nutrients during their transport from basin to river outlet. The objective of the project was to investigate processes which influence the eutrophication in the Elbe in order to determine new water quality targets needed to decrese the algae growth. Sampling was carried out during varios times of the year via boat cruises along the Elbe from Schmilka to Neu Darchau (532 km). The chlorophyll content increased 3 to 6 fold accompanied by a reduction in concentrations of soluble phosphorus and silicate. Up to 20% of the nitrogen was eliminated by denitrification. 10-12% of the total annual load of phosphorus was transported out of the river by dredging and high flooding events. An effective suppression of the eutrophication is not yet possible, because the SPR concentr. are still above the threshold values 1-15 #mu#g/P/1. (orig.)SIGLEAvailable from TIB Hannover: F00B473 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman