Nutrient dynamics in temperate European catchments of different land use under changing climate

Abstract

Study region: Vltava River basin, South Bohemian Region of the Czech Republic, Central Europe Study focus: To understand the dynamics of nutrients (nitrogen, phosphorus, and organic carbon) in streams, we combined hydrometeorological, hydrochemical and isotopic data (stable water and nitrate isotopes) from three catchments with different predominant land-use effects (forest, agricultural and settlement). New hydrological insights for the study region: Our study underlines that current climate change and associated hydrological changes, such as decrease in flow, play an important role in the transport and dynamics of nutrients in the catchment. We have found that due to the different origins and pathways, individual nutrients had diverse behaviour patterns in streams and responded differently to changing climate. Hydrological patterns in streams became clear when systematic and continuous monitoring under a changing climate was applied, highlighting the need for such data to better understand the impact of hydrological drivers, particularly for long-term dynamics. In three studied catchments, streamflow showed a decreasing trend in line with rising air temperature, declining snow cover and increasing evapotranspiration. Time series analyses of nitrate concentrations revealed decreasing trends, whereas dissolved organic carbon increased in all catchments regardless of land use. Long-term trends of total phosphorus concentrations were positive in anthropogenically impacted streams. Stable nitrate isotopes indicated distinct nitrate sources and processes, but also their seasonality in relation to hydrological patterns and land use.

Keywords

• Isotope hydrology
• Water chemistry
• Forest
• Agriculture
• Central Europe