Long-term trends in nutrient budgets of the western Dutch Wadden Sea (1976–2012)

A.S. Jung*, A.G. Brinkman, E.O. Folmer, Peter M.J. Herman, Henk W. van der Veer, C.J.M. Philippart

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

7 Citations (Scopus)


Long-term field observations of nitrogen [N] and phosphorus [P] concentrations were used to construct nutriënt budgets for the western Dutch Wadden Sea between 1976 and 2012. Nutrients come into the western Dutch Wadden Sea via river runoff, through exchange with the coastal zone of the North Sea, neighbouring tidal basins and through atmospheric deposition (for N). The highest concentrations in phosphorus and nitrogen were observed
in themid-1980s. Improved phosphorus removal atwaste water treatment plants, management of fertilization in agriculture and removal of phosphates from detergents led to reduced riverine nutrient inputs and, consequently, reduced nutrient concentrations in theWadden Sea. The budgets suggest that the period of the initial net import of phosphorus and nitrogen switched to a net export in 1981 for nitrogen and in 1992 for phosphorus. Such different behaviour in nutrient budgets during the rise and fall of external nutriënt concentrations may be the result of different sediment-water exchange dynamics for P and N. It is hypothesized that during the period of increasing eutrophication (1976–1981) P, and to a lesser degree N, were stored in sediments as organic and inorganic nutrients. In the following period (1981–1992) external nutrient concentrations
(especially in the North Sea) decreased, but P concentrations in the Wadden Sea remained high due to prolonged sediment release, whilst denitrification removed substantial amounts of N. From1992 onwards, P andN budgetswere closed by net loss,most probably because P stores were then depleted and denitrification continued. Under the present conditions (lower rates of sediment import and depleted P stores), nutrient concentrations in this area are expected to be more strongly influenced by wind-driven exchange with the North Sea and precipitation-driven discharge from Lake IJssel. This implies that the consequences of climate change will be more important, than during the 1970s and 1980s.
Original languageEnglish
Pages (from-to)82-94
JournalJournal of Sea Research
Publication statusPublished - 2017


  • Wadden Sea
  • Coastal North Sea
  • Nutrient exchange
  • Nitrogen
  • Phosphorus
  • Eutrophication
  • Nutrient budgets

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