SS4.13 Water Quality of Lakes, Rivers and Coastal Zones
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
De GalanSM, Vrije Universiteit Brusssel, Analytical and Environmental Chemistry, Brussels, Belgium, sdegalan@vub.ac.be
Baeyens, W, , Vrije Universiteit Brusssel, Analytical and Environmental Chemistry, Brussels, Belgium, wbaeyens@vub.ac.be
Brion, N, N, Vrije Universiteit Brusssel, Analytical and Environmental Chemistry, Brussels, Belgium, nnbrion@vub.ac.be
 
SPATIAL AND SEASONAL TRENDS IN NUTRIENT CONCENTRATIONS IN THE SOUTHERN BIGHT OF THE NORTH SEA FOR THE PAST DECADE.
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Statistical analysis of nutrient data obtained during 7 years of monitoring indicated strong seasonal and spatial variability, with highest concentrations in winter and significantly higher concentrations in the coastal area compared to the offshore ones. In the North Sea ammonium concentrations significantly decreased from 1995 on, while for nitrate a weak but not significant decrease was observed. Despite a drastic reduction in the riverine inputs of phosphorus to the North Sea during the last decade, phosphate concentrations only slightly decreased somewhat similar to what happened with nitrate. Phosphate concentrations are generally low (maximum concentration of 2.5 ÁM) compared to the other dissolved nutrients. Average nitrate concentrations are 18 ÁM but extreme concentrations up to 140 ÁM are observed. As a consequence, nutrient ratios strongly deviating from the Redfield ratio are often observed.