Pathways, chemical processes and long-term changes of nutrients in Lake Neusiedl

This paper deals with nutrient dynamics at Lake Neusiedl, an issue that is inseparable from the inputs and exchange processes of suspended matter. Older studies from the early 1980s are summarised, discussed and compared with new findings from an ongoing EU INTERREG project (REBEN). The article first deals with the suspended matter and nutrient loads in Lake Neusiedl via the largest tributary of the lake, the river Wulka. In a second section changes due to chemical processes during the passage of the river Wulka through the reed belt at Donnerskirchen are described. The long-term development of nutrients in the open lake are discussed in the third part of the paper, which closes with the description of the horizontal distribution of suspended matter and nutrients in the reed belt and conclusions about horizontal currents and exchange processes. The most important finding of the data analysis is the decline of the phosphorus load of the river Wulka in recent decades, a corresponding reaction of the trophic conditions in the lake itself and the importance of horizontal exchange processes between the open lake and the reed belt for the preservation of a good water quality in the open water zone and a good ecological status of Lake Neusiedl.