Good Environmental Status in relation to descriptor 5 is achieved when the human-induced eutrophication is minimised, especially the adverse effect thereof, such as losses in biodiversity, ecosystem degradation, harmful algal blooms and oxygen deficiency in bottom waters. GES is assessed with Black Sea Eutrophication assessment Tool (BEAST)

Nutrient concentrations do not lead to an undesirable disturbance to the balance of organisms present in the water or to the quality of the water concerned resulting from accelerated growth of algae, and are below the threshold values

The direct effects of nutrient enrichment associated with phytoplankton growth do not constitute or contribute to an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned, by meeting the threshold values. Chlorophyll a concentrations are below the thresholds

The magnitude of harmful algal bloom events (Noctiluca scintillans biomass) are not at levels that indicate adverse effects of nutrient enrichment and below the threshold values.

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 and is higher than the threshold values.

The biomass of opportunistic macroalgae (ESGII =opportunistic/total biomass, %) is not at levels that indicate adverse effects of nutrient enrichment and below the threshold values. Biomass percentage of opportunistic macroalgae (expressed as ESGII) from total biomass does not exceed 40%.

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 and are above the threshold values.

The concentration of bottom dissolved oxygen is not reduced, in the warm season, due to nutrient enrichment, to levels that indicate adverse effects on benthic habitat, above the threshold values.