Effects of climate and land use on water balance and water quality in selected European lakes

Lakes, natural or artificial, are important sources of freshwater and are frequently managed to provide ecosystem services. Consequently, the water balance and water quality in lake ecosystems could be subject to different stressors associated to physical, chemical, or anthropogenic activities. Therefore, this study provides insights into the factors that influence the water balance of selected European lakes and their implications on water quality. An analysis of isotopic, chemical, and land use data using statistical and artificial intelligence models showed that climate, in particular air temperature and precipitation, played a key role in intensifying evaporation losses from lakes. Groundwater table depth and other catchment factors also had an impact on the water balance. The study also highlights that lakes at lower altitudes with shallow depths and catchments dominated by urban or crop cover were more sensitive to water balance changes. These lakes had higher evaporation-to-inflow ratios and increased levels of total nitrogen concentration in the water. However, lakes at higher elevations with deeper depths and a predominantly forested catchment area are less sensitive to changes in the water balance. These lakes, which are often of glacial origin, were characterized by lower evaporation losses and, thus, better water quality in terms of total nitrogen concentration. Overall, understanding the relationship between water balance and water quality is crucial for effective lake management and the preservation of freshwater ecosystems.