基于微生物生物完整性指数的北京市城市河道生态系统健康评价

生物完整性指数（IBI）是河道生态系统健康评价的重要且被广泛应用的指标，然而，基于水体中分解者微生物群落构建IBI评价标准的研究较少。针对北京市城市河道生态系统健康状况开展评价，探索微生物生物完整性指数(M-IBI)评价流程与标准构建方法。基于沉积物中微生物Illumina高通量测序信息，筛选出关键环境因子（水质指标TN、TP、NH₃-N、NO₃-N和NO₂-N）确定候选生物指标，根据判别能力分析结果，确定Shannon指数、拟杆菌门（Bacteroidota）相对丰度、绿弯菌门（Chloroflexi）相对丰度、蓝藻门（Cyanobacteria）相对丰度、COD_Cr耐受属相对丰度和NH₃-N清洁属相对丰度6个指标，提出了指标标准化公式和健康评价标准。结果表明，以自然水体为补水的永定河各采样点评价结果均为健康状态，其他3条以城镇再生水厂出水为补水的河道中，清河4个采样点为健康至亚健康状态，凉水河5个采样点为健康至一般状态，大龙河4个采样点为亚健康至一般状态。M-IBI可以有效区分不同程度的受损点位，较合理地评价城市河道生态系统健康状况。

Evaluation of urban river ecosystem health in Beijing based on the microbial index of biotic integrity

The index of biotic integrity (IBI) is an important and widely used indicator for the evaluation of river ecosystem health. However, there are few studies on the construction of IBI evaluation criteria based on the use of decomposer microbial communities in water. The evaluation of the ecosystem health of urban rivers in Beijing was carried out, and the evaluation process and criteria construction method of the microbial index of biotic integrity (M-IBI) were explored. Based on the high-throughput sequencing information of microbial Illumina in the sediments, the key environmental factors were screened (water quality indicators TN, TP, NH3-N, NO3-N and NO2-N), and candidate biological parameters were determined. According to the results of discriminant analysis, six indexes were determined, including Shannon index, relative abundance of Bacteroidota, relative abundance of Chloroflexi, relative abundance of Cyanobacteria, relative abundances of CODCr tolerance genus and relative abundances of ammonia nitrogen clean genus. The standardized formula of parameters and the health evaluation standards were put forward. The evaluation results showed that each sampling point of the Yongding River supplied by natural water was evaluated as healthy state. Among the other three rivers, supplied by the effluent of the urban reclaimed water plant, four sampling points of the Qinghe River were evaluated as healthy to sub-healthy state, five sampling points of the Liangshui River were evaluated as healthy to general state, and four sampling points of the Dalong River were evaluated as sub-health to general state. M-IBI could effectively distinguish the damaged points of different degrees and give a reasonable evaluation of the health status of the urban river ecosystem.