亚热带流域植硅体碳与硅循环耦合机制及其迁移转化过程

In watershed ecosystem, the Si cycle mainly impacts on C cycle by two pathways, in which one pathway is that phytolith can seal some organic carbon to form a stable phytolith-occluded organic carbon and then store in soil, and the other is that silicate mineral in soil consume atmospheric CO2 by chemical weather process and release dissolved Si to river ecosystem. The typical subtropical watershed in China is selected as study area in the project. The aims of this study are to analyze the Si stability and transformation process in subtropical watershed, discuss the regulation mechanism of Si cycle on C, further understand the “dissolution-stability” trajectory of Si-C in hydrological pathway, quantify the effect of Si cycle on C transformation, disclose the mechanism of Si-C couple cycle in ecosystem, and provide scientific basis for deeply research on C cycle process and mitigating CO2 emission under global change.

流域生态系统硅循环主要通过两种途径影响生态系统碳循环，一是通过植硅体封存碳形成植硅体碳，能长期稳定的储存在土壤中，二是通过土壤中硅酸盐矿物的化学风化过程消耗大气中的CO2，释放出溶解态的Si到河流生态系统。本项目以亚热带典型流域为研究区域，分析亚热带流域Si稳定性和迁移转化过程，探讨环境变化下Si循环过程中对C的调控机制，进一步了解亚热带流域Si-C在水文路径中的“溶解-稳定”轨迹，定量评估亚热带流域Si循环过程对碳的迁移转化的影响，深入揭示流域系统Si-C耦合循环机理，为深入研究全球变化下C循环过程以及减缓大气CO2排放提供科学依据。

本项目以亚热带典型流域为研究区域，分析亚热带流域Si稳定性和迁移转化过程，探讨环境变化下Si循环过程中对C的调控机制, 取得如下三个方面研究成果：1.亚热带流域Si、C沉降动态变化；2.亚热带流域不同植被类型和土壤Si-C稳定性研究；3.解析流域Si-C输出水文驱动机制。本项目取得如下研究成果：共发表论文28篇，SCI论文23篇，CSCD论文4篇；其中第一标注的SCI论文4篇，CSCD论文2篇；其余SCI论文均为第二、三标注。第一标注发表的SCI论文包括Ecological Indicators, Ecohydrology和Journal of Cleaner Production等；在研究生培养方面，指导4名学生先后共计14人次获得国家研究生奖学金及各类专业奖学金。