Eutrophication and reoligotrophication represent major drivers for lake ecosystems around the globe. Lake Constance is a model sytem for studying both, eutrophication and reoligotrophication effects on lake ecosystems due to 1) the large disturbance amplitude caused by eutrophication during the 20th century, 2) the sucessful reoligotrophication, which resulted in a reduction of total phosphorous conentrations of more than one order of magnitude since the late 1970s. We study various aspects of the eutrophication and oligotrophication history of Lake Constance using time-series analyses (Maike Sabel), paleolimnological methods (Simone Wengrat) and resurrection ecology (Pelita Octorina).