D5 Euthrophication

Human-induced eutrophication is minimised, especially adverse effects thereof, such as losses in biodiversity, ecosystem degradation, harmful algae blooms and oxygen deficiency in bottom waters.

Descriptor 5 is defined in Annex I of the MSFD as "Human-induced eutrophication is minimised, especially adverse effects thereof, such as losses in biodiversity, ecosystem degradation, harmful algal blooms and oxygen deficiency in bottom waters". Following the definition given by a dedicated MSFD Task Group Report on Descriptor 5, eutrophication is "a process driven by enrichment of water by nutrients, especially compounds of nitrogen and/or phosphorus, leading to: increased growth, primary production and biomass of algae; changes in the balance of organisms; and water quality degradation. The consequences of eutrophication are undesirable if they appreciably degrade the ecosystem health and/or the sustainable provision of goods and services."
© Fotolia, Author: Veronika Synenko


As stated in the COM DEC [2010/477/EU pdf] "The assessment of eutrophication in marine waters needs to take into account the assessment for coastal and transitional waters under Directive 2000/60/EC (Annex V, 1.2.3 and 1.2.4) and related guidance (Guidance Document on the Eutrophication Assessment in the Context of European Water Policies, Document No 23. European Commission (2009) ) in a way which ensures comparability, taking also into consideration the information and knowledge gathered and approaches developed in the framework of regional sea conventions".

The criteria and indicators for D5 assessment (listed below) should be synergistically considered. WFD assessments for the transitional water should be also used for the MSFD D5 assessment, where the WFD's Good Ecological Status should be linked with the MSFD's Good Environmental Status.
D5 Commission Decision (EU) 2017/848 of 17 May 2017
Human-induced eutrophication is minimized, especially adverse effects thereof, such as losses in biodiversity, ecosystem degradation, harmful algae blooms and oxygen deficiency in bottom waters.
Criteria
D5C1 – Primary: Nutrient concentrations are not at levels that indicate adverse eutrophication effects. The threshold values are as follows: 
(a) in coastal waters, the values set in accordance with Directive 2000/60/EC; 
(b) beyond coastal waters, values consistent with those for coastal waters under Directive 2000/60/EC. Member States shall establish those values through regional or subregional cooperation

D5C2 – Primary: Chlorophyll a concentrations are not at levels that indicate adverse effects of nutrient enrichment. The threshold values are as follows: 
(a) in coastal waters, the values set in accordance with Directive 2000/60/EC; 
(b) beyond coastal waters, values consistent with those for coastal waters under Directive 2000/60/EC. Member States shall establish those values through regional or subregional cooperation. 

D5C3 – Secondary: The number, spatial extent and duration of harmful algal bloom events are not at levels that indicate adverse effects of nutrient enrichment. Member States shall establish threshold values for these levels through regional or subregional cooperation.

D5C4 – Secondary: The photic limit (transparency) of the water column is not reduced, due to increases in suspended algae, to a level that indicates adverse effects of nutrient enrichment. The threshold values are as follows: 
(a) in coastal waters, the values set in accordance with Directive 2000/60/EC; 
(b) beyond coastal waters, values consistent with those for coastal waters under Directive 2000/60/EC. Member States shall establish those values through regional or subregional cooperation. 

D5C5 – Primary (may be substituted by D5C8): The concentration of dissolved oxygen is not reduced, due to nutrient enrichment, to levels that indicate adverse effects on benthic habitats (including on associated biota and mobile species) or other eutrophication effects. The threshold values are as follows: 
(a) in coastal waters, the values set in accordance with Directive 2000/60/EC; 
(b) beyond coastal waters, values consistent with those for coastal waters under Directive 2000/60/EC. Member States shall establish those values through regional or subregional cooperation. 

D5C6 – Secondary: The abundance of opportunistic macroalgae is not at levels that indicate adverse effects of nutrient enrichment. The threshold values are as follows: 
(a) in coastal waters, the values set in accordance with Directive 2000/60/EC; 
(b) should this criterion be relevant for waters beyond coastal waters, values consistent with those for coastal waters under Directive 2000/60/EC. Member States shall establish those values through regional or subregional cooperation.

D5C7 – Secondary: The species composition and relative abundance or depth distribution of macrophyte communities achieve values that indicate there is no adverse effect due to nutrient enrichment including via a decrease in water transparency, as follows: 
(a) in coastal waters, the values set in accordance with Directive 2000/60/EC; 
(b) should this criterion be relevant for waters beyond coastal waters, values consistent with those for coastal waters under Directive 2000/60/EC. Member States shall establish those values through regional or subregional cooperation. 

D5C8 – Secondary (except when used as a substitute for D5C5): The species composition and relative abundance of macrofaunal communities, achieve values that indicate that there is no adverse effect due to nutrient and organic enrichment, as follows: 
(a) in coastal waters, the values for benthic biological quality elements set in accordance with Directive 2000/60/EC; 
(b) beyond coastal waters, values consistent with those for coastal waters under Directive 2000/60/EC. Member States shall establish those values through regional or subregional cooperation.