RESPONSE OF INTERNAL PHOSPHORUS TRANSFORMATION IN LAKE SEDIMENTS TO DIFFERENT SULFATE CONCENTRATIONS

A five week experiment was carried out to test the influence of different sulfate concentrations (CK and addition of 500 mg/L and 1000 mg/L) using sediments and overlying water collected from Lake Nanhu in Wuhan, China. The results showed that, in sediments, pH increased and Eh decreased significantly (p < 0.01) in the first three weeks. The variation of sulfate reduction bacteria (SRB) amount increased initially and then fell, and had direct relation with sulfate concentration in the pore water. High sulfate concentrations led to a significant increase in total phosphorus (TP) and soluble reactive phosphorus (SRP) (p < 0.01) of the overlying water and pore water except for TP concentration of the pore water. TP and labile organic phosphorus (LOP) in sediments decreased significantly compared with the control (P < 0.05) though no significant difference was found in the other forms of phosphorus.