Remote sensing’s contribution to evaluating eutrophication in marine and coastal waters

The aim of this report is to examine whether estimates of the plant pigment chlorophyll-a from satellite data can support the evaluation of eutrophication in European marine and coastal waters. Satellite images are a good indicator of the occurrence of algal blooms in relation to eutrophication but overestimate true chlorophyll-a concentrations in open sea areas by 60-70% and even more in coastal waters. The report recommends using chlorophyll-a images from March to April/May as an indicator of eutrophication in the North Sea, Skagerrak and Kattegat since they reflect the magnitude of the spring bloom in these areas.