Nutrient concentrations meet the threshold values of the Water Framework Directive (Dutch coastal water bodies) and OSPAR (assessment areas of the International North Sea), so there are no adverse effects of eutrophication. Indicator(s): Water Framework Directive: Nutrient concentrations (winter DIN) in Dutch coastal water bodies (IndicatorCode: NL-D5C1-KRW-2023). OSPAR: Nutrient concentrations (winter DIN and DIP) beyond 1 nautical mile (IndicatorCode: winter-nutrient-concentrations-qsr23-ospar). Thresholds: Water Framework Directive: DIN 0.46 mg/l (33 µmol/l). OSPAR: Rhine plume: DIN 29.7 µmol/l, DIP 1.15 µmol/l; Meuse plume: DIN 40.7 µmol/l, DIP 1.35 µmol/l; Scheldt plume 1: DIN 25.9 µmol/l, DIP 1.31 µmol/l; Scheldt plume 2: DIN 33.3 µmol/l, DIP 1.02 µmol/l; Southern North Sea: DIN 13.0 µmol/l, DIP 0.70 µmol/l; Eastern North Sea: DIN 7.3 µmol/l, DIP 0.6 µmol/l; Northern North Sea: DIN 10.3 µmol/l, DIP 0.71 µmol/l; Dogger Bank: DIN 7.2 µmol/l, DIP 0.76 µmol/l.

Chlorophyll a concentrations meet the threshold values of the Water Framework Directive (Dutch coastal water bodies) and OSPAR (assessment areas of the International North Sea), so there are no adverse effects of eutrophication. Indicator(s): Water Framework Directive: Concentrations of chlorophyll a in Dutch coastal water bodies. (IndicatorCode: Concentraties chlorofyl-a in de Nederlandse kustwaterlichamen (KRW)). OSPAR: Chlorophyll a concentrations beyond 1 nautical mile. (IndicatorCode: chl-a-concentrations-qsr23-ospar). Thresholds: Water Framework Directive: Ems-Dollart Coast: 10.13 µg/l; Northern Delta Coast, Holland Coast: 16.88 µg/l; Zeeland Coast, Wadden Coast: 15 µg/l (90 percentile). OSPAR: Rhine plume: 6.8 µg/l; Meuse plume: 8.0 µg/l; Scheldt plume l: 5.0 µg/l, Scheldt plume 2: 8.9 µg/l; Southern North Sea: 3.8 µg/l; Eastern North Sea: 1.2 µg/l; Northern North Sea: 1.1 µg/l; Dogger Bank: 1.3 µg/l (mean).

Oxygen concentrations meet the threshold values of the Water Framework Directive (Dutch coastal water bodies) and OSPAR (assessment areas of the International North Sea), so there are no harmful effects of eutrophication. Indicator(s): Water Framework Directive: Oxygen saturation (growing season) in Dutch coastal water bodies (IndicatorCode: NL-D5C5-KRW-2023). OSPAR: Oxygen concentrations near the seabed (growing season) beyond 1 nautical mile (IndicatorCode:seafloor-dissolved-oxygen-qsr23-ospar ). Thresholds: Water Framework Directive: >60% Oxygen saturation. OSPAR: Rhine plume, Meuse plume, Scheldt plume 1, Scheldt plume 2, Southern North Sea, Eastern North Sea, Northern North Sea, Dogger Bank: >=6 mg/l.