Third Integrated Report on the Eutrophication Status of the OSPAR Maritime Area

Executive Summary

Data is available on ODIMS via: https://odims.ospar.org/layers/geonode:ospar_eut_status_2017_06_001
And the report was used for the Intermediate Assessment: https://oap.ospar.org/en/ospar-assessments/intermediate-assessment-2017/pressures-human-activities/eutrophication/third-comp-summary-eutrophication/

Eutrophication is still a problem

The overall objective of the OSPAR Eutrophication Strategy is to achieve a healthy marine environment where no eutrophication occurs. To determine progress towards the objective, the OSPAR Common Procedure was applied by nine Contracting Parties for a third time in 2017, using data from 2006 to 2014. This application indicates that the strategic objective has not yet been achieved. Eutrophication is still a problem in 7% of the North-East Atlantic, mainly affecting coastal areas. The Greater North Sea had the largest problem area (approximately 98,000km²) with respect to eutrophication, extending along the coast from Belgium to Danish and Swedish waters. Small problem areas (5 to 400 km²) were found along the coast of France, Norway and the United Kingdom. In the Celtic Seas many small inshore and coastal areas were classified as problem areas (approximately 500 km²). In the Bay of Biscay two problem areas (approximately 800 km²) were identified.

Eutrophication status in areas assessed under the third application of the Common Procedure (2006–2014) in terms of problem areas, potential problem areas and non-problem areas. Available via:  https://odims.ospar.org/layers/geonode:ospar_eut_status_2017_06_001

Positive trends observed

Between applications of the Common Procedure in 2008 and 2017 the spatial extent of problem areas has decreased in Denmark, France, Germany, Ireland, Norway and the United Kingdom. For Belgium and the Netherlands it remained constant. For Sweden there was a small increase in the extent of problem areas, as a greater area was assessed in 2017 compared to previous applications. The total spatial extent of problem areas has decreased from nearly 169,000km² in 2003 to 119,000km² in 2008 and 100,000 km² in 2017. The extent of potential problem areas has decreased from 2008 to 2017 and some of these are former problem areas that are showing improvements. Eutrophication status improved mainly in offshore and outer coastal waters of the Greater North Sea, in particular in Danish waters and in the Skagerrak, while there were a few improvements in inner coastal and inshore waters.

Significant nutrient input reductions

Improvements in eutrophication status are largely dependent on reducing anthropogenic inputs of nitrogen and phosphorus into problem areas. Contracting Parties have made great efforts to reduce nutrient inputs since the 1980s. OSPAR initiatives, together with actions under EU Directives and the Gothenburg Protocol of UNECE Convention on Long-range Transport of Air Pollution (CLRTAP), have resulted in substantial reductions of up to 50% in some areas. Inputs of phosphorus to the Greater North Sea, the Celtic Seas, the Bay of Biscay and the Iberian Shelf have all reduced since 1990. However, the rate of decrease in phosphorus inputs to the Greater North Sea has slowed since 2003. Nitrogen inputs have also reduced, by up to 25% in the case of the Greater North Sea. Of particular note is that atmospheric nitrogen inputs have reduced by 30% since 1990.

Although Contracting Parties have substantially decreased nutrient inputs, this has not yet resulted in an improvement of the overall eutrophication status. The main reason is that improvements in eutrophication effects parameters (chlorophyll concentrations, abundance of phytoplankton indicator species, oxygen depletion) happen slowly as a result of time lags in the marine system.

Further efforts are needed

Further effort is needed to reduce nutrient inputs in particular for nitrogen into the marine environment. Transboundary nutrient transport, both between Contracting Parties and from outside the OSPAR maritime area, remains a challenge, since nutrient reduction requirements are not only driven by the eutrophication status of Contracting Parties’ own waters but also need to consider nutrients exported to the waters of other Contracting Parties. OSPAR’s ecological modelling group ICG-EMO is working to improve quantification of transboundary nutrient fluxes. Some modelling studies estimate that nutrient input reductions beyond the current objective of the Eutrophication Strategy of a 50% reduction in anthropogenic loads in relation to input levels in 1985 will be needed to convert all problem areas into non-problem areas.

Experience gained in applying the Common Procedure

The Common Procedure has proved a good operational tool for the assessment of the eutrophication status and a useful instrument for addressing the requirements of the Marine Strategy Framework Directive (2008/56/EC).

A further application of the Common Procedure is necessary to follow up the effectiveness of reduction measures within OSPAR and under relevant EU regimes, for the eutrophication status of the North-East Atlantic. Contracting Parties have identified a number of issues concerning the Common Procedure that need to be addressed before its fourth application. Among them are: differences in assessment levels that result in contrasting classifications; the need to identify improvements in areas that have not yet achieved non-problem area status; remaining disparities between the Common Procedure and the Water Framework Directive; the need to make the fourth application less resource-intensive, and; technical issues relating to data analysis and emerging technologies such as automatic systems and remote sensing.