Internal phosphorus loading in selected lakes of the Cybina River valley

The aim of this study was to assess the ability of bottom sediments to release or accumulate phosphorus. Ex situ experiments with the use of undisturbed sediment cores were done in 11 lakes situated in the Cybina River valley (Wielkopolska, Poland). Phosphorus release was observed both in aerobic and anaerobic conditions, however greater values were noted in the latter ones. Maximum values reached 41.4 mg m-2 d-1 P and 12.2 mg m-2 d-1 P in anaerobic and aerobic conditions, respectively.