城市不同环境空间下PM_(2.5)及表层土壤细菌群落结构差异性研究

Comparison on PM_(2.5) and Surface Soil Bacterial Community Structure among Different Urban Environmental Spaces

为探究不同环境空间下空气微生物的组成特征和来源,在桂林城区与市郊选择8类典型的人类活动环境空间,分别采集大气细颗粒物(PM_(2.5))及表层土壤样本,利用高通量测序技术分析样本的细菌群落结构。结果表明:在不同环境空间下,PM_(2.5)样本间的细菌群落结构差异性较小,表层土壤则表现出较明显的城区与市郊差异性,同一采样点的PM_(2.5)与表层土壤也表现出较大的差异性。PM_(2.5)与表层土壤中的主要细菌门为变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidetes)及厚壁菌门(Firmicutes),其相对丰度总和超过80%。各个环境空间中的微生物群落差异均表明人类活动对微生物群落的影响较大。此外,不同环境空间中的优势菌属也有所不同,这与环境的特点、细菌的生态功能相关。PM_(2.5)中的优势菌属为异样根瘤菌属(Allorhizobium Neorhizobium Pararhizobium Rhizobium)、假双头斧形菌属(Pseudolabrys)、甲基杆菌属(Methylobacterium)和不动杆菌属(Acinetobacter),而表层土壤中的优势菌属为鞘氨醇单胞菌属(Sphingomonas)、异常球菌属(Deinococcus)、马赛菌属(Massilia)和酸杆菌门(Acidobacteria)下的Subgroup_6属。

To investigate the composition and sources of airborne microorganisms in different environmental spaces,this study collected atmospheric fine Particulate Matter(PM_(2.5))and topsoil samples from eight typical human activity environments in both urban and suburban areas of Guilin.High throughput sequencing was employed to analyze the bacterial community structure.The results revealed that the bacterial community structure of PM_(2.5) samples varied little among different environmental spaces,while significant differences were observed in topsoil samples between urban and suburban areas.In addition,there were considerable differences between PM_(2.5) and topsoil samples from the same sampling points.The predominant bacterial phyla in both PM_(2.5) and topsoil were Proteobacteria,Actinobacteria,Chloroflexi,Bacteroidetes and Firmicutes,with the total relative abundance exceeding 80%.The microbial community differences between environmental spaces indicated substantial effects of human activities on these communities.Additionally,the dominant bacterial genera varied in different environments,correlating with environment characteristics and bacterial ecological functions.The dominant genera in PM_(2.5) samples included Allorhizobium Neorhizobium Pararhizobium Rhizobium,Pseudolabrys,Methylobacterium and Acinetobacter,and those in topsoil samples comprised Sphingomonas,Deinococcus,Massilia and Subgroup_6 under Acidobacteria.