An intercomparison of nutrient concentrations in surface water in agricultural and natural reserve peatlands in the Netherlands and pristine Scandinavian peatlands.

Abstract

Eutrophication due to high nitrogen (N) and phosphorus (P) concentrations is associated with the poor ecological status in ecosystems, including peatlands. The EU Water Framework Directive (WFD) therefore requires adequate nutrient concentrations to achieve “good ecological status” in surface water bodies. Proper application of the WFD requires knowledge of the background loading of nutrients in surface water. Currently a systemic insight lacks in the variability of nutrient concentrations in natural reserve peatland and agriculturally used peatland in the Netherlands, and between Dutch natural reserve peatlands and international pristine peatlands. This insight in the variability of nutrient concentrations is indispensable in determining the nutrient background loading. This study compares nutrient concentrations in natural reserve peatlands with agricultural peatlands in the Netherlands and with pristine peatlands in Scandinavia between 1998 and 2018. Nitrogen concentrations were found to be lower in Dutch peatland surface water with a long history of natural conservation, and higher in agricultural peatland and natural reserve peatland with a more recent natural reserve designation. Phosphorus concentrations were found to be high in peatland with a recent natural reserve designation and rather similar in agricultural peatland and older natural reserve peatland. Nutrient concentrations in pristine Nordic peatland were generally lower than Dutch peatland. Suggested controls for nutrient concentration variability are historical land use, including fertilization; water level management, including inlet water and lowered groundwater tables; geochemistry of peat soils, including peat mineralisation; and atmospheric deposition of N.