水库底泥缺氧状态下的磷释放规律研究

Affinity relationship between phosphorus and sediment determines the deposition of phosphorus in the reservoir. Considering the accelerating release of particulate phosphorus under anoxic condition, the effect of reservoir on rivers phosphorus cycle is obvious significant. Phosphorus is the main limit nutrition for ecological, it is very important to recognized the migration and transformation of phosphorus under the action of reservoir as it’s an important part for understanding the role of reservoir on ecological. Previous studies about the cycle of phosphorus in the natural were concentrated in the lake. This project intends to adopt a cycling testing device to simulate the reservoir condition, experiment scale and condition for this device is close to the prototype. Laboratory experiments with different environment factors such as dissolved oxygen will be carry out to systematic study the rule of phosphorus transformation and migration. Based on the experiment data, the internal response mechanism of phosphorus to different environmental factors would be discussed. Moreover, a general physical model for explain phosphorus transformation under reservoir sedimentation will be established. The vertical distribution data of dissolved oxygen (DO) would provide support for established an oxygen diffusion model, which can be used to analysis DO condition in the reservoir deposited. Results of this study will further enrich the theory condition of reservoir on phosphorus cycle process, and provide technological support to the prevention of reservoir eutrophication and downstream ecological system repair.

磷与泥沙的亲和关系决定了磷在水库中大量淤积，考虑到颗粒态磷在水库底泥缺氧环境中的加速释放，水库作用对河流磷循环的影响非常明显。磷是河流的主要生物限制营养，水库作用下磷的迁移转化规律是认识水库生态作用的重要环节。以往关于磷在自然水体中循环规律研究主要集中在湖泊中，对水库这种深水、淤积环境下的规律缺乏系统研究。本项目拟采用一种接近原型尺度和条件的循环装置模拟水库深水淤积底泥环境，对不同环境影响因子下水库沉积物中磷的迁移转化规律进行系统研究，探讨底泥磷释放对不同影响因子的内在响应机制，建立磷在水库淤积环境中的迁移转化模式；构建深水扰动环境下溶解氧扩散模型，深入剖析水库底泥溶解氧状态。研究结果将丰富水库磷循环动力学的理论基础，为水库富营养预防管理及下游生态系统修复提供技术参考。

磷是河流的主要生物限制营养，磷与泥沙的亲和关系决定了磷在水库中大量淤积。考虑到颗粒态磷在水库底泥缺氧环境中的加速释放，水库作用对河流磷循环的影响非常明显。因此，水库作用下磷的迁移转化规律是认识水库对河流生态作用的重要环节。项目根据实测资料、理论和模型系统分析了长江磷自然循环属性、水库作用及可能的环境影响。流域水库改变泥沙、磷及循环规律是当前长江干流环境条件的实质性改变，是长江保护生态面临的主要问题和修复重点之一，建议在大型水库持续挖泥用以功能性修复河流物质通量和消除上游潜在污染内源。本项目进一步对扰动强度、温度、PH值等不同环境影响因子下三峡水库沉积物中磷的迁移转化规律进行系统研究，探讨底泥磷释放对不同影响因子的内在响应机制，采用不同的动力学模型模拟磷的释放过程，研究结果将丰富水库磷循环动力学的理论基础，为水库富营养预防管理及下游生态系统修复提供技术参考。