Impacts of lake water environmental condition on bioavailable-phosphorus of surface sediments in Lixia River basin, China

Bioavailable-phosphorus (BAP) fractions of the lake surface sediments (the upper 0-5cm depth) and environmental indicators of the related lake water column were investigated in five lakes in Lixia River basin during three seasons in order to evaluate the impacts of environmental indicators of the water column on the BAP fractions of surface sediments. The concentration of BAP varied significantly in different seasons. Factor analysis was used to identify the factors which influence sedimentary BAP significantly in the different seasons. The results showed that AAP and Olsen-P were significantly affected by the chemical oxygen demand through the bacterial activity in summer. The high intensity of bacterial activity and density of algae, and low concentrations of NO3-N and dissolved oxygen under high temperature enhanced the BAP released from anaerobic sediment and significantly contributed to the eutrophication of the lake, especially in summer. In addition, macrophyte roots were beneficial to absorption of AAP and Olsen-P.