Eutrophisation (EO5)

OE 5 Définition:

L’eutrophisation d’origine anthropique est évitée, en particulier pour ce qui est de ses effets néfastes, tels que l’appauvrissement de la biodiversité, la dégradation des écosystèmes, la prolifération d’algues toxiques et la désoxygénation des eaux de fond.


Messages clés:

  • The available data show that assessment is possible. Key nutrient concentrations are within characteristic ranges for coastal areas and in line with the main processes undergoing in concerned interested area. The Eastern Mediterranean Sea (EMS) is still the most oligotrophic area of the whole Mediterranean basin, and the largest phosphorus-limited body of water in the global ocean. The main coastal areas in the Mediterranean which are historically known to be influenced by natural and/or anthropogenic inputs of nutrients are the Alboran Sea, the Gulf of Lions, the Gulf of Gabès, the Adriatic, Northern Aegean and the SE Mediterranean (Nile–Levantine).
  • A more comprehensive set of data is required at coastal hotspots in order to assess accurately trends for nutrients. Significant trends need to be detected from long time series that are able to capture nutrient concentrations changes in coastal waters as the analysis of short time series can erroneously lead to interpret some spatial patterns produced by random processes nutrients concentration trends.
  • Whilst data is available through the MEDPOL database, and relevant data is also available through EEA, EMODnet-Chemistry and other information sources, priority should be given to ensure Mediterranean countries regularly report quality assured nutrient monitoring data in line with IMAP.
  • The IMAP assessment criteria for eutrophication based on Common Indicator 14 (Chlorophyll a concentration in the water column) are applicable and confirm the main status of eutrophication in the coastal area. It is recommended for reference condition and thresholds/boundary values for key nutrients in the water column have to be built and harmonised through the Mediterranean region, using national data submitted to MEDPOL and other existing available databases, as appropriate.

Regular reporting for all Ecological Objectives should be established/strengthened.