The status of phytoplankton, measured by chlorophyll a

Key message 

The status of phytoplankton is poor or bad in the north eastern sub-areas where the concentrations of chlorophyll-a are high.

The status of phytoplankton is moderate in the south western sub-areas where the concentrations of chlorophyll-a are slightly elevated.

The amount of phytoplankton in the water has decreased during the last decade in the Gulf of Riga, the Western Gotland Basin, the Arkona Sea and the Kattegat

Figure:   Ecological status for summer time phytoplankton concentration, measured as chlorophyll a, during the period 2003-2007. The interpolated map has been produced in three steps: 1) the status of coastal assessment units has been interpolated along the shores, 2) the status of open sea basins have been interpolated and 3) the coastal and open interpolations have been combined using a smoothing function. The larger circles indicate the status of open sea assessment units and the smaller circles that of the coastal assessment units.

Policy relevance

Phytoplankton concentration in the summer is a direct proxy of eutrophication, and to a great extent a result of increased loading.

Author(s) and institutions

Vivi Fleming-Lehtinen, Pirkko Kauppila, Hermanni Kaartokallio - Finnish Environment Institute (SYKE), Finland

References

Andersen, J.H., P. Axe, H. Backer, J. Carstensen, U. Claussen, V. Fleming-Lehtinen, M. Järvinen, H. Kaartokallio, S. Knuuttila, S. Korpinen, M. Laamanen, E. Lysiak-Pastuszak, G. Martin, F. Møhlenberg, C. Murray, G. Nausch, A. Norkko, & A. Villnäs. 2010. Getting the measure of eutrophication in the Baltic Sea: towards improved assessment principles and methods. Biogeochemistry. DOI: 10.1007/s10533-010-9508-4.

HELCOM 2009a. Eutrophication in the Baltic Sea. An integrated thematic assessment of the effects of nutrient enrichment in the Baltic Sea region. Baltic Sea Environment Proceedings No. 115B.

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Last updated 4 May 2010