Application of a biological tracer in transporting water volumes during eutrophication of Mondsee

The oligotrophic alpine lake Mondsee belonging to the system of eight lakes in the Salzkammergut region in Austria represented during our investigatio n the plankton distribution model in those parts of water areas that are si tuated in front of the estuaries of intensely eutrophicated mountain inflow torrents, such as Wangauer Ache and Fuschler Ache. Simultaneously with wat er sampling, measurements by drift floats were made to detect the water inf low direction and speed at several depths down to the bottom. The results h ave shown that horizontal as well as vertical plankton movement is an effic ient biotracer for water flow parameters. Samples were collected in a "ches sboard" way and also vertically at 5 m distances. Zoo-, phyto- and bacterio plankton were evaluated.