Phosphorus Bioavailability in a Phosphorus-Abundant System under Repeated Sediment Resuspension Conditions

Variation of bioavailable phosphorus(BAP) concentrations,i.e.,the sum of dissolved total phosphorus(DTP) and bioavailable particulate phosphorus(BAPP),was investigated in a phosphorus(P)-abundant system as influenced by repeated sediment resuspension.The overlying water and sediments in the studied system collected from a city canal,with the initial BAP concentration about 0.679 mg·L-1 in the overlying water.The sediments were disturbed with rotating blade once every day for 30 days in the experimental system.Concentrations of dissolved inorganic phosphorus(DIP),DTP,and total phosphorus(TP) in overlying water and algal available phosphorus(AAP),total phosphorus(Tot-P) in suspended particles were determined in diminishing frequency.It was found that the BAP decreased rapidly in the beginning few days in the sediment resuspension system,and then kept decreasing gradually at a low level,compared with the static conditions.This was mainly attributed to the sharp decrease of DIP.It is suggested that repeated sediment resuspension plays a significant role in phosphorus migration and converting it to more stable forms.