基于微生物生物完整性指数的地下水生态系统健康评价:以包钢稀土尾矿库周边地下水生态系统为例

生物完整性指数是水体生态系统健康评价的重要指标,已被广泛应用于湖泊河流等的生态系统健康评价中.但利用水体中分解者微生物群落构建IBI评价标准的报道很少,针对地下水生态系统的研究更是鲜见.本研究针对包钢稀土尾矿库周边地下水生态系统健康开展评价工作,基于地下水环境中微生物群落Illumina高通量测序信息,筛选关键环境因子,甄别敏感或耐受微生物分类属,确定候选生物参数,探索针对地下水的微生物完整性指数(microbiome index of biotic integrity,M-IBI)评价流程与标准构建方法.结果表明,总计12个地下水样点中,4个样点属于健康等级(Ⅰ级),占总样点的33.3%;2个样点属于亚健康等级(Ⅱ级),占总样点的16.7%;5个样点属于一般等级(Ⅲ级),占41.7%;1个样点属于较差等级(Ⅳ级),占8.3%;总体来看,靠近尾矿库的样点健康等级较低,而远离尾矿库参照点受到的干扰较小,健康等级较高,这可能与人类活动干扰影响程度密切相关.参照该地区地下水理化参数基础上的水质情况分析结果,发现应用M-IBI指数可较合理地评估包头稀土尾矿区周边地下水生态系统健康状况.结合生态系统健康内涵,本研究初步提出针对地下水生态系统健康的M-IBI指数评价体系构建流程.

Assessment of Ecosystem Health of Baogang Tailings Groundwater Based on Microbiome Index of Biotic Integrity (M-IBI)

Index of Biological Integrity (IBI) is a scientific tool used to evaluate health of aquatic ecosystems. IBI associates anthropogenic influences with biological activity in the water body, and is formulated using data developed from biosurveys. Compared with other biotic assemblage indicators of water quality, little attention has been paid to the application of microbial community in ecosystem health assessment for groundwater bodies so far. An approach based on microbiome index of biotic integrity was developed to assess groundwater ecosystem health in this study. The method based on Illumina high-throughput DNA sequencing was applied to achieve the information of microbial community. The key environmental factors were selected based on CCA analysis and the optimized values were calculated for defining the taxonomic genera sensitive and resistant to these factors. The resulting candidate biotic factors were used to construct microbiome index of biotic integrity (M-IBI) evaluating system. The results showed among the studied sample sites from groundwater of Baogang rare earth tailings, 33.3% of samples were at "Great" level, 16.7% at "Good" level, most of samples (41.7%) at "moderate" level and 8.3% at "Bad" level. The ecosystem healthy status of the sample sites near the tailings was affected by human disturbances, while the samples far away the tailings were at healthy level. The results of the groundwater ecosystem healthy assessment based on M-IBI system had a good match with the groundwater quality standard based on chemical properties. It indicated that M-IBI could be a potential index to evaluate the health of groundwater ecosystem.