Organically bonded carbon which sediments during the period of vegetation in the Müggel lake — being one of the water supply sources for the capital of the GDR — amounts to 10% of the carbon quantity which is bonded by primary production during the same period of time. The sedimentation behaviour and the composition of sediments with regard to their contents of combined carbon, nitrogen and phosphorus and other substances are discussed. Moreover, conclusions are presented concerning the history of the Müggel lake for centuries and the possibilities to sanita