Nutrient mitigation pathways for sustainable lake ecosystems in Europe

Excessive nutrient loading into rivers, lakes, and estuaries has been a primary driver of aquatic ecosystem degradation worldwide, and European lakes are no exception. Nutrient inputs from agriculture, compounded by climate change, threaten the ecological integrity of these water bodies. Sustainable management strategies must prioritize reducing external nutrient and sediment inputs from catchments, focusing on source control measures such as maintaining nitrogen (N) and phosphorus (P) levels in agricultural soils at or below optimal agronomic conditions, while enhancing natural attenuation processes along water and solute transport pathways. This study evaluates the impacts of different land use management options on European lake ecosystems under current and future climate change and socio-economic drivers. Using the Soil and Water Assessment Tool (SWAT+), we simulate nutrient and sediment load transport from catchments to receiving lakes, while the GPLake-M model assesses lake ecological regime shifts to identify optimal management and restoration strategies. The methodology is applied to case studies of Lakes Vico, Dümmer, and Bisret, serving as demonstration sites to inform broader applications across Europe. Our findings highlight pathways for reducing nutrient loading and achieving sustainable lake management, aligning with freshwater and climate policy objectives in the context of a changing climate, degrading aquatic ecosystems, and rising demands on land and food systems.