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

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. Presented at the VI International Wadden Sea Symposium (Biologische Anstalt Helgoland, Wattenmeerstation Sylt, D-2282 List, FRG, 1–4 November 1988)