OSPAR eutrophication assessment

Introduction

Coastal eutrophication is a growing marine environmental problem in Europe and the need for more effective monitoring and control measures is increasing. In 1997 the OSPAR Commission adopted the Common Procedure for the identification of the Eutrophication Status of the maritime area. OSPAR committed all members to reduce phosphorus and nitrogen inputs into the maritime areas and to combat eutrophication to achieve a healthy environment where eutrophication does not occur. The Common Procedure includes the main parameters involved in eutrophication processes which are differentiated in four categories of qualitative assessment criteria for application in the Comprehensive Procedure:

• Category I: Nutrient enrichment
• Category II: Direct effects of nutrient enrichment
• Category III: Indirect effects of nutrient enrichment
• Category IV: Other effects of nutrient enrichment

These assessment criteria can be different for the three maritime areas with regard to eutrophication (non-problem areas, potential problem areas and problem areas).

Ecological Quality Objectives (EcoQOs)

Ecological Quality Objectives are a tool to support the application of the ecosystem approach to the management of human activities affecting the marine environment and provide a means to define the desired quality of the marine environment. The specific EcoQOs correspond to a selection of assessment parameters and their assessment levels as applied under the Common Procedure. The specific EcoQOs for eutrophication agreed at the 5th North Sea Conference by Ministers and OSPAR 2002 are:

1. Winter DIN and/or DIP should remain below elevated levels, defined as concentration > 50% above salinity related and / or region-specific natural background concentrations.
2. Maximum and mean region-specific chlorophyll a concentrations during the growing season should remain below region-specific elevated levels, defined as concentrations > 50% above the spatial (offshore) and/or historical background concentration.
3. Region/area-specific phytoplankton eutrophication indicator species should remain below respective nuisance and/or toxic elevated levels (and increased duration).
4. Oxygen concentration, decreased as an indirect effect of nutrient enrichment, should remain above region-specific oxygen deficiency levels, ranging from 4-6 mg oxygen per liter.
5. There should be no kills in benthic animal species as a result of oxygen deficiency and/or nuisance/toxic phytoplankton indicator species for eutrophication.

Category I: Nutrient enrichment

Introduction

The major causes of nutrient enrichment in coastal areas are associated with the need to satisfy human nutrition and diet by the use of fertilizers. Nutrients such as nitrates and phosphates are the most common single factor causing eutrophication. These nutrient are necessary for the growth of plants and biomass production of microalgae (phytoplankton) and macroalgae.

References

1. OSPAR Commission, Background Document: Ecological Quality Objectives for the Greater North Sea with Regard to Nutrients and Eutrophication Effects [1]