On trends in nutrient concentration in the northern Wadden Sea of Sylt

Abstract

The mean values on hydrographical parameters in the Wadden Sea of Sylt taken weekly over a period of seven years (1975, 1976 and 1984 to 1988) were compared in order to detect trends in concentrations of nutrients or plankton. An increase in NO2, NO3, PO4 and Si could be found in summer. NH4 showed a negative trend. Corresponding with the rising nutrient-level, Chlorophyll-a and pH show a positive trend. Salinity decreased significantly. Changes in NH4 and NO2 were correlated with rainfall. © 1989 Biologische Anstalt Helgoland.