, Volume 39, Issue 1, pp 59–69 | Cite as

A North Sea and Baltic Sea Model Ensemble Eutrophication Assessment

  • Elin Almroth
  • Morten D. Skogen
Review Paper


A method to combine observations and an ensemble of ecological models is suggested to produce a eutrophication assessment. Using threshold values and methodology from the Oslo and Paris Commissions (OSPAR) and the Helsinki Commission (HELCOM), four models are combined to assess eutrophication for the Baltic and North Seas for the year 2006. The assessment indicates that the entire southeastern part of the North Sea, the Kattegat, the Danish Straits, the Gulf of Finland, and the Gulf of Riga as well as parts of the Arkona Basin, the Bornholm Basin, and the Baltic proper may be classified as problem areas. The Bothnian Bay and parts of the Baltic proper, the Bornholm Basin, and the Arkona Basin are classified as potential problem areas. This method is a useful tool for the classification of eutrophication; however, the results depend on the threshold values, and further work is needed within both OSPAR and HELCOM to harmonize these values.


Eutrophication OSPAR CP Assessment Modelling North Sea Baltic Sea 



The authors wish to thank Tapani Stipa (FIMR) and Ian Sehested Hansen (DHI) for providing the BalEco and MIKE III model results, and Kari Eilola (SMHI) for good ideas, discussions, and support in the development of the method used in this study. This study was supported by the Nordic Councils Air and Sea group through the BANSAI project.


  1. Anonymous. 1993. North Sea quality status report. London: Oslo and Paris Commissions, 132 pp.Google Scholar
  2. Anonymous. 1998. Report of the ASMO modeling workshop on eutrophication issues 5–8 November 1996, The Hague, The Netherlands. Assessment and Monitoring Group of the OSPAR Commission, 86 pp.Google Scholar
  3. Cloern, J.E. 2001. Our evolving conceptual model of the coastal eutrophication problem. Marine Ecology Progress Series 210: 223–253.CrossRefGoogle Scholar
  4. Danmarks Miljøundersøgelser (
  5. DHI. 2001. Environmental hydraulics. DHI software user guide, documentation and reference manual. Horsholm, Denmark: DHI Water and Environment.Google Scholar
  6. Eilola, K., H.E.M. Meier, and E. Almroth. 2009. On the dynamics of oxygen, phosphorus and cyanobacteria in the Baltic Sea; a model study. Journal of Marine Systems 75: 163–184.CrossRefGoogle Scholar
  7. HELCOM. 2006. Development of tools for assessment of eutrophication in the Baltic Sea. BSEP 104, HELCOM, Helsinki, 64 pp.
  8. HELCOM. 2007. HELCOM Baltic Sea Action Plan.
  9. Intercessional Correspondence Group on Eutrophication Modelling (
  10. Lenhart, H.-J. 2001. Effects of river nutrient load reduction on the eutrophication of the North Sea, simulated with the ecosystem model ERSEM. Senckenbergiana Maritima 31: 299–312.CrossRefGoogle Scholar
  11. Marmefelt, E., B. Arheimer, and J. Langner. 1999. An integrated biochemical model system for the Baltic Sea. Hydrobiologia 393: 45–56.CrossRefGoogle Scholar
  12. Meier, H.E.M., R. Döscher, and T. Faxén. 2003. A multiprocessor coupled ice-ocean model for the Baltic Sea: Application to the salt inflow. Journal of Geophysical Research 108 (C8), article number 3273.Google Scholar
  13. Moll, A., and G. Radach. 2003. Review of three-dimensional ecological modelling related to the North Sea shelf system. Part 1: Models and their results. Progress in Oceanography 57: 175–217.CrossRefGoogle Scholar
  14. Neumann, T., W. Fennel, and C. Kremp. 2002. Experimental simulations with an ecosystem model of the Baltic Sea: A nutrient load reduction experiment. Global Biogeochemical Cycles 16: 1033. doi: 10.1029/2001GB001450.CrossRefGoogle Scholar
  15. Neumann, T., and G. Schernewski. 2005. An ecological model evaluation of two nutrient abatement strategies for the Baltic Sea. Journal of Marine Systems 56: 195–206.CrossRefGoogle Scholar
  16. OSPAR. 1988. PARCOM recommendation 88/2: On the reduction in nutrients to the Paris convention area. Publication 88/2, Paris Commission, London.
  17. OSPAR. 2003. OSPAR integrated report 2003 on the eutrophication status of the OSPAR maritime areas based upon the first application of the comprehensive procedure. OSPAR Commission, 59 pp.Google Scholar
  18. OSPAR. 2005a. Common procedure for the identification of the eutrophication status of the OSPAR maritime area. OSPAR, Reference number: 2005–3, London, 36 pp.
  19. OSPAR. 2005b. Ecological quality objectives for the greater North Sea with regard to nutrients and eutrophication effects. OSPAR Eutrophication Series: 229/2005, London, 33 pp.
  20. OSPAR. 2008. Revised draft assessment of the predicted environmental consequences for problem areas following nutrient reductions. Report on the 2nd OSPAR ICG-EMO workshop. OSPAR EUC08/5/2-E(L), 51 pp.Google Scholar
  21. Pitkänen, H., M. Kiirikki, O.P. Savchuk, A. Raike, P. Korpinen, and F. Wulff. 2007. Searching efficient protection strategies for the eutrophied Gulf of Finland: The combined use of 1D and 3D modeling in assessing long-term state scenarios with high spatial resolution. AMBIO 36: 272–279.CrossRefGoogle Scholar
  22. Radach, G., and A. Moll. 2006. Review of three-dimensional ecological modeling related to the North Sea shelf system—Part 2: Model validation and data needs. Oceanography and Marine Biology 44: 1–60.Google Scholar
  23. Radach, G., and J. Pätsch. 1997. Climatological annual cycles of nutrients and chlorophyll in the North Sea. Journal of Sea Research 38: 231–248.CrossRefGoogle Scholar
  24. Savchuk, P.O., and F. Wulff. 1999. Modeling regional and large-scale response of Baltic Sea ecosystems to nutrient load reductions. Hydrobiologia 393: 35–43.CrossRefGoogle Scholar
  25. Savchuk, P.O., and F. Wulff. 2007. Modeling the Baltic Sea eutrophication in a decision support system. AMBIO 36: 141–148.CrossRefGoogle Scholar
  26. Skogen, M.D. and H. Søiland. 1998. A user’s guide to NORWECOM v2.0. Tech. Rept. Fisken og Havet 18/98. Institute of Marine Research, Norway, 42 pp.Google Scholar
  27. Skogen, M.D., and L.R. Mathisen. 2009. Long term effects of reduced nutrient inputs to the North Sea. Estuarine, Coastal and Shelf Science 82: 433–442.CrossRefGoogle Scholar
  28. Skogen, M., H. Søiland, and E. Svendsen. 2004. Effects of changing nutrient loads to the North Sea. Journal of Marine Systems 46: 23–38.CrossRefGoogle Scholar
  29. Stipa, T., M.D. Skogen, I.S. Hansen, A. Eriksen, I. Hense, A. Kiiltomaki, H. Søiland, and A. Westerlund. 2003. Short term effects of nutrient reductions in the North Sea and the Baltic Sea as seen by an ensemble of numerical models. MERI, Report Series of the Finnish Institute of Marine Research 49, 43–70.Google Scholar
  30. Weigel, A.P., M.A. Liniger, and C. Appenzeller. 2008. Can multi-model combination really enhance the prediction skill of probabilistic ensemble forecasts? Quarterly Journal of the Royal Meteorological Society 134: 241–260.CrossRefGoogle Scholar
  31. Wirtz, K., and K. Wiltshire. 2005. Long-term shifts in marine ecosystem functioning detected by inverse modeling of the Helgoland roads time-series. Journal of Marine Systems 56: 262–282.CrossRefGoogle Scholar

Copyright information

© Royal Swedish Academy of Sciences 2010

Authors and Affiliations

  1. 1.Swedish Meteorological and Hydrological Institute, Oceanografiska enhetenVästra FrölundaSweden
  2. 2.Institute of Marine ResearchBergenNorway

Personalised recommendations