Marine waters affected by eutrophication (Indicator)

Key messages: 2,632 km² of the EU’s marine areas were classified as ‘eutrophic’ in 2023. From 2018 to 2023, the area affected by eutrophication in the EU did not change.

Marine waters affected by eutrophication in the EU, 2000-2023

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Urbanisation and agricultural changes starting in the 1950s have led to a form of pollution known as eutrophication, derived from excessive nutrients — mainly involving nitrogen and phosphorus compounds. Eutrophication changes the structure and functioning of the marine ecosystem and can lead to instability, followed by environmental problems (EEA, 2019).

The Copernicus Marine Service monitors all EU sea basins for both oxygen depletion and anomalies in chlorophyll-a levels that are indicative of eutrophication. The latter measurements reveal significant annual fluctuations in EU marine waters. Between 2000 and 2023, the size of the area affected by eutrophication was generally below 20,000km², representing less than 0.4% of the EU’s exclusive economic zone (EEZ). However, some years — including 2007, 2008, 2018 and 2022 — saw this area more than double, underscoring the pronounced annual variability in eutrophication.

In 2023, eutrophication impacted 2,632km² of EU marine waters. Analysis employing a smoothed 4-year moving average confirms a stable trend in eutrophication in the affected area from 2018 to 2023 — within EU waters.

Please consult the relevant indicators and signals below for a more comprehensive overview on the topic.

This indicator shows the extent of eutrophic marine waters in the EU's EEZ. An area is classified as eutrophic if chlorophyll-a concentrations, as a proxy, are above the 90th percentile of the 1998-2017 reference baseline for more than 25% of the observation days in a given year. The Copernicus Marine Service calculates the indicator from satellite imagery. More information on the data and methodology can be found on the Eurostat website.

References and footnotes

EEA, 2019, Nutrient enrichment and eutrophication in Europe's seas, EEA report No 14/2019, European Environment Agency (https://www.eea.europa.eu/publications/nutrient-enrichment-and-eutrophication-in) accessed 23 February 2023.
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EU, 2008, Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008 establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive) (OJ L 164, 25.6.2008, p. 19-40).
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Marine waters affected by eutrophication (Indicator)

Marine waters affected by eutrophication in the EU, 2000-2023

Zero Pollution Action Plan 2030 target or policy objectives

Other relevant indicators and signals

References and footnotes