基于复合DGT技术研究亚深水型湖泊沉积物-水界面Fe-P-S耦合循环

Sediment phosphorus release was primarily controlled by the coupling cycle of the iron(Fe), phosphorus(P), and sulfur(S) at the water-sediment interface in lakes. Due to lacking effective synchronous in-situ monitoring techniques, currently researches on the processes, mechanisms and influencing factors of the Fe-P-S coupling cycle in the water-sediment interface are scarce. In this study, advanced composite Diffusive Gradients in thin-films Technique (DGT) is employed to monitor the in situ high-resolution and two-dimensional concentration distributions of Fe, P, and S in the water-sediment interface in the Hongfeng Lake, a typical sub-deep lake located in the southwestern China, while in situ simultaneous observations of environmental conditions are achieved using Microelectrode Measurement System (MMS). In this study, methodology of the in-situ, synchronous, high-resolution observations of the water-sediment interface will be established by joint applications of the composite DGT and MMS. In addition, systematical field monitoring and laboratory simulations of the Fe-P-S coupling cycle in the water-sediment interface in the sub-deep lake are first carried out. The results of this present study will characterize the spatiotemporal distribution and variation of the Fe-P-S in the water-sediment interface under different environmental conditions, elaborate the processes, mechanisms and influencing factors of the sediment Fe-P-S coupling cycle in the sub-deep lake, reveal the primary controlling factor and environmental process restricting in the P release from the sediments, and scientifically assess the ecological risk and environment effects of the sediment P release in the sub-deep lake. Furthermore, the results may provide important theoretical basis for the development of the scientific prevention and treatment programs for lake eutrophication.

湖泊沉积物内源磷释放受沉积物-水界面Fe-P-S耦合循环控制，但由于缺乏有效的同步原位监测技术，目前对沉积物-水界面Fe-P-S耦合循环过程、机制与控制因素缺乏深入系统的研究。本项目拟选取我国西南地区典型的亚深水型湖泊红枫湖为研究对象，应用复合DGT技术原位高分辨率获取沉积物-水界面Fe、P、S的二维浓度分布信息，结合微电极测量系统对环境条件的原位同步监测，探索建立沉积物-水界面原位、同步、高分辨率观测的方法体系。通过野外观测和室内模拟研究，率先系统开展亚深水型湖泊沉积物-水界面Fe-P-S耦合循环过程研究，揭示不同环境条件下沉积物-水界面Fe-P-S时空分布特征及变化规律，阐明亚深水型湖泊沉积物-水界面Fe-P-S耦合循环过程、机制与控制因素，揭示控制亚深水型湖泊沉积物磷释放的关键因子和环境过程，科学评估亚深水型湖泊沉积物磷释放风险及生态效应，为科学制定湖泊富营养化防治方案提供理论依据。

由于缺乏有效的原位、同步、高分辨率分析测试技术，目前对湖泊沉积物-水界面Fe-P-S耦合循环过程、机制与控制因素缺乏深入系统的研究。本项目选取典型亚深水型湖泊红枫湖为研究对象，联合应用复合DGT技术和微电极测量技术，建立了湖泊沉积物-水界面O2-pH-H2S/Fe-P-S原位、同步、高分辨率观测分析方法；基于该方法率先开展了湖泊沉积物-水界面Fe-P-S耦合循环过程与机制研究，精确获取了红枫湖代表性湖区沉积物-水界面Fe-P-S的二维分布信息，定量估算了红枫湖沉积物内源磷的释放通量，阐明了季节性缺氧是红枫湖沉积物内源磷释放的主要驱动机制，揭示了湖泊沉积物-水界面“Fe-P-S”耦合循环的微观过程与机理，并提出了Fe/P和Fe/S比值作为湖泊沉积物内源磷释放潜力的新有效评价指标。研究成果为科学制定湖泊富营养化防治方案提供了重要理论依据。