垂向环流作用下湖泊沉积物磷迁移行为

以巢湖十五里河入湖河口原位底泥为研究对象，通过室内模型实验，模拟了垂向环流的动水条件下，溶解态无机磷（DIP）在泥水界面的释放-吸附过程，探讨了不同强度环流对河口底泥DIP迁移的影响行为.结果表明：垂向环流扰动会引起上覆水中溶解氧（DO）和悬浮颗粒物（SPM）含量明显上升，且其平衡浓度与扰动强度均呈正相关，但悬浮物中值粒径（D₅₀）则随扰动强度的增大而降低；垂向环流作用下沉积物DIP的释放量随时间呈“Λ”型分布，显著区别于其他动水扰动情形，释放峰值与环流强度成显著正相关（P=0.047<0.05），但平衡值则与之呈显著负相关（P=0.034<0.05）；环流扰动的增强促进了DIP在沉积物上的吸附，并构建了耦合天然水动力效应的沉积物DIP Freundlich等温吸附经验公式：lgQ_e=2.7074e^1.3487τ+0.9463e^-1.4830τlgC_e.

Migration of phosphorus in lake sediments under vertical circulations

The release-adsorption dynamic characteristics of dissolved inorganic phosphorus (DIP) regulated by the vertical circulations at the sediment-water interface were examined through laboratory experiments with sediment samples collected from Shiwuli River estuary in Chaohu Lake. Potential effects of circulation intensity on the migration behavior of DIP from the sediments were discussed. Results showed that: the vertical circulation leaded to the increases of dissolved oxygen (DO) and suspended particulate matter (SPM) in the overlying water, with elevated disturbance intensities causing high equilibrium concentrations, however, the values of median diameter (D₅₀) were noted with a decreasing trend; the quantity of DIP released from sediment showed a clear Λ-type trend in terms of time under the disturbance of vertical circulations, of which the peak values were found positively correlated with the disturbance intensities (P=0.047<0.05), and the equilibrium concentrations were negatively correlated (P=0.034<0.05); increase of circulatory disturbance would enhance the adsorption of DIP by sediment, based on which, a modified Freundlich equation covering the hydrodynamic effect was constructed: lgQ_e=2.7074e^1.3487τ+0.9463e^-1.4830τlgC_e.