Of pH and Eh on release of nitrogen and phosphorus from sediments of West Lake.

The effects of pH and Eh on release of nitrogen and phosphorus from sediments of West Lake under different conditions were investigated by simulation test. Results showed that the net flux of NH4(+) -N release from sediments increased with pH, but NO3(-) -N showed negative-going release at all tested pH levels. The net flux of NH4(+) -N release from sediments was higher under anaerobic or aerobic condition of the overlying water, but only under aerobic condition would net release of NO3(-) -N occur. It was also shown that phosphorus released was mainly in its inorganic form, higher pH and anaerobic conditions of overlying water greatly stimulated release of phosphorus. In situ measurement at several West Lake locations indicated that sediment resuspension induced by boat propeller stimulated nutrients release from sediment into overlying water.