水位调控下沉积物磷的迁移转化行为与规律研究

Artificial water level manipulation impacts on lake and reservoir sediment phosphorus transportation and circulation with different mechanisms and approaches when compared to natural water level fluctuation. Moreover, present separated simulation experiment conducted under static water level is inadequate to reveal the continuity and related effect of dynamic water level fluctuation on sediment phosphorus behavior. In this study, permanent submerged, intermittent submerged sediment as well as intelligent peristaltic pump is employed to conduct dynamic water level regulation experiments. Accompanied the sediment physical and chemical properties monitoring before and after manipulation, process and trend for sediment physical and chemical properties variation is discussed; characters and mechanisms for sediment phosphorus storage, bioavaibility and adsorption-desorption with water level manupulation is evaluated and finally，impacts degree and approach for phosphorus transfer and release between water and sediment interface is recognized. Initiation of this study will reveal the phosphorus substance flow mechanism of lake and reservoir sediment with overlying water level manipulation, and explore the impacts mechanism of water level manipulation on sediment phosphorus fundamentalenvironmental behavior within the activities of hydropower operation, regulation and water resource management.

自然水位变化与人为水位调控对湖库沉积物磷的输送循环影响机制与程度不同，现有静态水位条件下的淹水落干模拟研究也不足以反映水位动态调控对不同受淹类型沉积物磷环境行为影响的连续性和关联性。项目选择永久淹没和间歇淹没沉积物为研究对象，利用智能化蠕动泵模拟水位动态调控情景，基于水位调控下沉积物关键理化性质指标监测，探讨水位调控影响沉积物的物理化学性质变化过程与趋势的机制；分析水位调控下沉积物磷赋存形态转化、生物可利用性变化以及吸附-解吸行为的变化特征及规律；揭示水位调控影响磷在水体-沉积物间迁移释放行为的程度及途径。项目的开展有助于辨识湖库水位调控下不同受淹类型沉积物磷的物质输移规律，进而阐明水利水电调度运行及水资源管理活动中水位调控对沉积物磷基础环境行为的影响机制。

自然水位变化与人为水位调控对湖库沉积物磷的输送循环影响机制与程度不同，现有静态水位条件下的淹水落干模拟研究也不足以反映水位动态调控对不同受淹类型沉积物磷环境行为影响的连续性和关联性。.. 项目选择丹江口水库神定河口永久淹水和间歇淹水沉积物为研究对象，利用智能化蠕动泵模拟水位动态调控情景（三个水位调控循环，水位变化速率为0cm/d、3cm/d和6cm/d），基于水位调控下沉积物关键理化性质指标监测，探讨水位调控影响沉积物的物理化学性质变化过程与趋势的机制；分析水位调控下沉积物磷赋存形态转化、生物可利用性变化以及吸附-解吸行为的变化特征及规律；揭示水位调控影响磷在水体-沉积物间迁移释放行为的程度及途径。.. 研究结果表明：（1）单个水位调控循环内，上覆水磷浓度随水位上升而增加，随水位下降而减少，浓度曲线为“U”型分布；（2）慢速水位调控如3cm/d有利于磷释放，增加水位调控循环能够上覆水磷浓度；（3）水位调控导致沉积物有机质流失，水位调控速率越高，沉积物颗粒的中值粒径越大，比表面积（SSA）越小；（4）无论何种淹没沉积物，水位调控后粒径20μm以上和以下的颗粒含量分别增加和减少；磷吸附以物理吸附为主且颗粒扩散为主要限速步骤；（5）水位调控增加了沉积物无定形铁铝氧化物（Feox和Alox）含量，使磷最大吸附容量增加了2.03-390.75 mg/kg，但同时降低了25.81-50.00%的磷吸附缓冲容量；（6）水位调控导致Org-P和O-P转化为活性磷，应将Org-P和O-P视作广义B-P组分。.. 项目的开展有助于辨识湖库水位调控下不同受淹类型沉积物磷的物质输移规律，进而阐明水利水电调度运行及水资源管理活动中水位调控对沉积物磷基础环境行为的影响机制。