Download4 Eutrophication

Eutrophication is still a problem in Regions II, III and IV and the objective of no eutrophication will only be partly achieved by 2010. Reductions in phosphorus discharges exceed the OSPAR target of 50% compared to 1985, but nitrogen discharges are still the main problem, especially those from agriculture. Concern about atmospheric nitrogen inputs is increasing. It can take decades for reduction measures to have positive effects in the sea because nutrients are released from soils and sediments.

OSPAR Contracting Parties should cooperate

  • to implement with urgency OSPAR and EU measures to reduce nutrient inputs to eutrophication problem areas and take additional action if needed to eliminate eutrophication problems;
  • to set within OSPAR appropriate reduction targets for nutrient inputs to individual problem areas;
  • to promote consideration of marine eutrophication when implementing the EU Nitrates Directive and in the revision of international nitrogen air emission targets and standards, for example, those set by the EU, UNECE and IMO;
  • to refine OSPAR’s assessment methodologies, including modelling of nutrient transports;
  • to improve OSPAR’s monitoring framework through coordinated use of novel observation tools and coordination of data collection on sources, inputs and environmental status.

Nutrients, especially nitrogen and phosphorus, are essential for the growth of aquatic plants which form the basis of marine food webs. Natural processes regulate the balance between nutrient availability and the growth of marine plants and animals in ecosystems. Excess nutrients introduced into the sea by human activities can disturb this balance and may result in accelerated algal growth, leading to adverse effects on water quality and marine ecology. This process is known as eutrophication. OSPAR works under its Eutrophication Strategy to combat eutrophication and to achieve a healthy marine environment.

OSPAR Strategy objectives for eutrophication

  • Combat eutrophication in the OSPAR maritime area in order to achieve and maintain, by 2010, a healthy marine environment where eutrophication does not occur.
  • Reduce inputs of nitrogen and phosphorus to areas affected by or likely to be affected by eutrophication in the order of 50% compared to 1985.

OSPAR Regions