Distribution of bioavailable phosphorus between overlying water and SPM under abrupt expansion condition

Experiments on Phosphorus (P) fraction characteristics in sediment resuspension were performed under adequate hydrodynamic conditions. It is found that the concentration of Suspended Particulate Matter (SPM) in the eddy current region exhibits the “Matthew effect”. Velocity is an impact factor of the Equilibrium Phosphate Concentration (EPC), which is related to other hydraulic conditions. Overall bioavailable dissolved P in the SPM causes migration to overlying water and sediment, eventually being converted into a chemical speciation of P. Conditions of resuspension promote Al-P of SPM that migrated to the sediment and water. Concentrations of Al-P in SPM are reduced. P is released from SPM to water bodies, mainly through conversion into particulate P and dissolved total P. Meanwhile, exchange between SPM and sediments occur mainly through Ca-P migration. Al-P and BD-P possess similar geochemical characteristics or source. Ca-P and Al-P exhibit a negative correlation between migration and conversion.