河流生态健康评价的底质微生物生物完整性指数方法研究

With the rapid development of social and economic, amounts of pollutants are discharged into rivers， and the river ecosystem is damaged seriously. The concept of sustainable development has led people to pay more attention on river ecological health assessment. To data, the biological indicators for river ecological health assessment have been primarily focused on aquatic animals and plants, but poor knowledge of the microbial indicator has been known for us. Therefore, the aim of this research is to develop sediment microbe index of biotic integrity (SM-IBI) for river ecological health assessment. The microbial community diversity in the sediment of typical rivers around the Tai lake will be first detected by high throughput sequencing. All potential metrics of microbial communities in river sediments will be calculated and listed together. Subsequently, the correlation between environmental variables and sediment microbial community will be first discussed for the recognition of typical environmental variables which could remarkably affect microbial community structure. Field tests and model experiments in laboratory will be used to study the response mechanisms of critical and potential microbial metrics to the typical environmental variables. Thus, metric system of sediment microbial communities will be selected through kinds of comparison among potential microbial metrics. The relationship of microbial metrics will be clarified for the weight assignment of each microbial metric. At last, the standards of river ecological health assessment will be suggested based on the SM-IBI values among reference points and damaged points in the targeted rivers. This study will be valuable for the assessment, restoration and management of river ecological health.

随着人类活动加剧，河流生态系统遭受了不同程度的破坏，修复河流生态系统的前提是科学评价河流生态健康状况。目前河流生态健康评价指标体系主要关注水生动植物，但作为生态系统重要组成部分的微生物并未得到充分研究。本研究立足河流生态健康的内涵，拟以太湖流域典型河流为研究对象，结合野外观测和室内模拟试验，采用高通量测序及指标赋权法等，首先研究河流底质微生物总群落和功能菌群的时空分布规律，建立候选底质微生物特征指标库；其次探讨河流底质微生物与环境因子的相关性，阐明关键底质微生物特征对主导环境因子的响应机制；在此基础上，筛选得到底质微生物指标体系，阐明指标的权重关系，构建底质微生物完整性指数（SM-IBI）计算模型，提出河流生态健康评价标准，建立河流生态健康评价的SM-IBI方法。研究拟从微生物角度发展完善河流生态健康综合评价体系，为河流生态系统健康的管理和修复提供科学依据。

随着人类活动加剧，河流生态系统遭受了不同程度的破坏，修复河流生态系统的前提是科学评价河流生态健康状况。目前河流生态健康评价指标体系主要关注水生动植物，但作为生态系统重要组成部分的微生物并未得到充分研究。针对以上问题，本课题以太湖流域典型河流、城市内河秦淮河、长江下游的干流、长江三峡库区和长江源头河网为研究对象，首先采用高通量测序和荧光定量PCR等方法检测细菌结构和功能多样性，分别建立了包含群落多样性、结构、敏感性群体和功能属性的候选底质微生物特征指标库；其次通过随机森林、路径分析、网络分析等方法，分析了不同环境因子压力下微生物群落的稳定性和抵抗力，解析了微生物群落的演变规律，阐明关键底质微生物特征对主导环境因子的响应机制；在此基础上，通过变异性、敏感性、冗余性等一系列分析，分别筛选得到包含4-5个核心底质微生物指标的核心指标体系，通过贡献度分析，构建底质微生物完整性指数计算模型，最终提出河流生态健康评价标准，建立河流生态健康评价的底质微生物完整性指数计算方法。研究从微生物角度发展完善河流生态健康综合评价体系，为河流生态系统健康的管理和修复提供科学依据。本项目工作主要是针对湖泊河网、城市内河、大江大河、大型库区和高原河网这五种类型的水体，分别构建河流生态系统健康评价的底质微生物生物完整性指数评价方法，应用于河流生态健康评价和管理。