利用DGT技术研究湖泊缺氧区沉积物亚磷酸盐的分布规律与产生机制

摘要：亚磷酸盐(H2PO3-和HPO32-, +3)易于在缺氧性沉积物中形成和富集，在好氧性水体可转化为磷酸盐，被认为是水体磷循环研究中不可缺少的关键物质，但其产生机制和环境行为目前还不清楚。本项目拟采用被动采样技术-氧化锆薄膜扩散梯度（Zr-oxide DGT）与二维毛细管离子色谱痕量分析技术（2D-CIC），构建沉积物亚磷酸盐垂向分布信息的原位、高分辨（mm级）获取方法，重点分析太湖典型缺氧区沉积物中亚磷酸盐的垂向分布及季节性变化特征，深入研究磷酸盐-亚磷酸盐转化特征及其控制因子，揭示亚磷酸盐的时空分布规律和产生机制，为系统构建湖泊磷循环过程以及湖泊富营养化治理提供理论依据。

Phosphite (primarily H2PO3- and HPO32-, where the oxidation state of phosphorus is +3) could be easily produced and enriched in anoxic sediments, while it could be transformed to phosphate in oxic water. However, knowledge on the formation and environmental behavior of phosphite in lake is still limited although it has been assumed as an essential component in phosphorus cycle. By the diffusive gradients in thin films technique with the Zr-oxide binding phase (Zr-oxide DGT), coupled with the two-dimensional capillary ion chromatography (2D-CIC), the vertical distribution of phosphite in sediments at a high-resolution (mm level) is in-situ obtained. The established method is applied to analyze emphatically the vertical and seasonal variation characteristics of phosphite in anoxic sediments from Lake Taihu; and to study the transformation of phosphate-phosphite and its main factors. The results will reveal the temporal-spatial distribution and formation mechanism of phosphite in lake ecosystem, which will provide helpful information for the fully understanding of the phosphorus cycle and for the control of lake eutrophication.