Confidence rating of marine eutrophication assessments

image of Confidence rating of marine eutrophication assessments

This report presents the development of a methodology for assessing confidence in eutrophication status classifications. The method can be considered as a secondary assessment, supporting the primary assessment of eutrophication status. The confidence assessment is based on a transparent scoring of the 'value' of the indicators on which the primary assessment is made. Such secondary assessment of confidence represents a first step towards linking status classification with information regarding their accuracy and precision and ultimately a tool for improving or targeting actions to improve the health of the marine environment.



Finnish case study

This case study presents an eutrophication assessment confidence rating work carried out in conjunction with the first HELCOM thematic eutrophication assessment of the Baltic Sea (HELCOM 2009a) at the Finnish Institute of Marine Research (presently Finnish Environment Institute – Marine Research Centre). The study includes a HEAT assessment with three quality elements for four Northern sub-basins as well as with two quality elements (QE) for three eastern-southern sub-basins. For northern sub-basins some quality elements include multiple indicators, otherwise there is only one indicator per quality element, reflecting the current availability of open-sea eutrophication indicators in the Baltic Sea. Indicators for category I, II and III eutrophication effects were included in the study. For the QE “plankton”, the summer surface chlorophyll a indicator reflects the biomass of planktonic primary producers. For the QE “invertebrate benthic fauna”, a gammadiversity indicator based on the average number of taxa was employed. The QE “physico-chemical features” included Secchi depth and winter dissolved nutrients (NO2+NO3, PO4) in the surface waters. Our aim was to employ concrete, robust and transparent criteria in the confidence assessment of the indicators selected for the current study.


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