Eutrophication is a major cause of wetland degradation worldwide. In recent decades, reductions in nutrient inputs have led to improvements in water quality in many rivers and lakes in central and northern Europe, but long-term trends are less clear in southern Europe. The Doñana Biological Station conducted the first comprehensive study of water quality in Doñana, one of the most important wetland complexes in Europe and the Mediterranean region.
The core area of Doñana is a large...

Nitrogen (N) loading from anthropogenic activities is contributing to the eutrophication and degradation of wetlands worldwide. Doñana (southwestern Spain), includes a dynamic marshland protected as a UNESCO World Heritage Site, which has a catchment area exposed to increasing N inputs from intensive agriculture and poorly treated urban wastewaters. Identifying the sources of N entering this iconic wetland complex is vital for its conservation.