Freshwater nutrient retention in contemporary Europe

Nutrient retention in lakes and rivers is an essential regulating ecosystem service that protects downstream water bodies from nutrient excess, reducing anthropic impacts on aquatic habitats. This dataset reports the amount of retention of total nitrogen (TN) and total phosphorus (TP) in rivers and lakes (plus their sum, i.e. freshwater retention) estimated for contemporary Europe (2012-2021). Nutrient retention was assessed with the model GREEN, run in ensemble mode to provide its uncertainty. Retention is expressed in total load (kg per year) of nutrients retained in the river segment or lake in the spatial model unit to which it refers. The ensemble was used to assess median retention (q50), its 90% prediction intervals (q05 and q95), plus a robust coefficient of variation of the median (CVQ) quantifying the uncertainty. Please note: to facilitate the use of the dataset, retention is provided per hydrological Basins and per basic model unit (catchment). Given the uncertainty in input data and modelling structure, the use retention at the scale of catchment is discouraged. Instead, we recommend aggregating catchments' retention to larger spatial units of interest (e.g. districts or subbasins). To complement the dataset, annual nutrient loads and concentrations to seas (at the basin outlets) for 1990-2021 are provided. These annual estimates are obtained with the GREEN version presented in Vigiak et al. 2025, run with the best available regional parameter sets (GREEN V2A). It represents one single simulation extracted from the ensembles identified for freshwater retention estimation, thus annual values are provided without uncertainty. Data distribution provided as attribute table of CCM 2.1 elementary catchment polygons and basin polygons.