Marine waters affected by eutrophication

This indicator shows the extent of eutrophic marine waters in the EU's exclusive economic zone (EEZ). An area is classified as eutrophic if chlorophyll-a concentrations, as a proxy, are above the 90th percentile of the 1998–2017 reference base line for more than 25 % of the observation days in a given year. The Copernicus Marine Service calculates the indicator from satellite imagery.Eutrophication is the process by which an excess of nutrients — mainly phosphorus and nitrogen — leads to increased growth of plant material, particularly planktonic algae, in an aquatic body, resulting in a decrease in water quality. This can, in turn, cause death by hypoxia of aquatic organisms. Anthropogenic activities, such as farming, agriculture, aquaculture, industry and sewage, are the main source of nutrient input in problem areas.