R&D highlights edition 2019

PROJECTS Ecosystems and environmental quality 20 Threshold values for chlorophyll. Left panel: advised by JMP- EUNOSAT project. Right panel: currently used by OSPAR. T he JMP-EUNOSAT project has developed a new way of monitoring and assessing pollution with nutrients (eutrophication). Excess nutrients stimulate algal growth, depriving water plants and animals of oxygen and light. EU Member States are required to report every six years on the water quality of their seas for the Marine Strategy Framework Directive (MSFD). Until now, the picture of water quality that has emerged from these reports has been incoherent due to the different threshold values and monitoring methods used by different countries. The threshold value in place is 50% above the natural background concentration for all countries around the North Sea. However, countries have used different approaches to estimate background concentrations and the threshold values therefore lack coherency (Figure 1). The European Commission has asked countries to make improvements so that assessment reports in the future will provide a clear picture of the level of eutrophication in the North Sea. The JMP-EUNOSAT project (Joint Monitoring Programme of the Eutrophi­ cation of the North Sea with Satellite data) has developed a new shared approach for the monitoring and assessment of eutrophication in the North Sea: • Threshold values for nutrient and algae concentrations are derived by Deltares using the samemethod for all countries; • Deltares has subdivided the North Sea into areas with similar ecological functioning for the purposes of assessment; • Quality-controlled satellite data are provided by RBINS as an additional common source of information on algae concentrations; • Countries collaborate to improve the coherence and cost efficiency of their data management and reporting (contribution fromAarhus University). Rijkswaterstaat was responsible for project coordination and communications. Throughout the project, progress and plans have been regularly communicated with representatives from all countries involved under the OSPAR umbrella. At the end of the project, the participants agreed to test the new approach in their upcoming eutrophication assessment reports and compare it with the present method. To this end, the assessment areas and threshold values, including the underlying models, will be further refined and discussed by the countries. The project proposed using the year 1900 for the definition of natural background concentrations. Nutrient inputs from rivers to the North Sea in 1900 have been estimated by SMHI (Sweden) with their hydrological model of Europe. Deltares then used these results to produce model estimates of the corresponding nutrient and algae concentrations throughout the North Sea. Field observations of nutrients and algae are available for recent years and we therefore also ran the models for those years to check whether the models can reproduce recent field observations. New threshold values were derived that were 50% above the model-estimated concentrations for 1900. This project was financially supported by contract nr. 11.0661/2017/750678/ SUBIENV.C2 of DG-Environment part of the “European Maritime and Fisheries Fund” 3rd call: “Implementation of the Until now, eutrophication assess­ ments for the North Sea have lacked coherency due to the use of different monitoring methods and threshold values by different countries. We have developed a new monitoring and assessment strategy using coherent moni­ toring data (including satellite data), coherent threshold values and coherent assessment areas. COHERENT EUTROPHICATION ASSESSMENTS FOR THE NORTH SEA WITH SATELLITE DATA second cycle of the MSFD”. Contact: Anouk blauw, Anouk.Blauw@deltares.nl , t +31 (0)88 335 8389 Theo Prins ,Theo.Prins@deltares.nl, t +31 (0)88 335 8584 Further reading : https://www.informatiehuismarien.nl/ projecten/algaeevaluated/

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