小流域地下水流微生物空间差异分析

针对目前水文过程中微生物研究基本空白的现状,选择了珠海市近海小流域地下水作采样分析,运用不依赖培养(cultured-independent)的分子生物学分析技术,构建16S rRNA基因文库,研究小流域尺度下微生物的空间分布.实验数据表明,近海小流域地下水上、中、下3组井的微生物优势类群及其丰度既有相似的地方又有差别.相似的是3组井均以变形菌、Candidate divisionOPx、古菌(含泉古菌和广生古菌)、放线菌为优势类群,而且变形菌均占了很大比例,在R、M、D组井中分别为23.21%、36.21%、28.84%;不同的是R组井微生物优势类群还有拟杆菌和硝化螺旋菌;M组井另有真杆菌和酸杆菌,D组井中则以拟杆菌为优势类群.从原核微生物16SrRNA基因系统发育树可以看出,3组井的微生物主要类群大同而小异,各自的微生物多样性比较丰富,3组井的微生物优势类群变化佐证了微生物对地下水环境的生态系统功能有一定的指示作用.

Spatial Characteristics of Microbial Groups Associated with the Groundwater Flow in a Small Watershed

Few reports of microbial groups associated with the groundwater flow system are available in China. 16S rRNA gene library was constructed by the cultured-independent approach to investigate gene sequences of microorganism in groundwater samples from the recharge (R), intermediate (M) and discharge (D) zones of an experimental watershed at Zhuhai campus of Sun Yat-sen University. Proteobacterium, Candidate division OPx, uncultured archaeon (uncultured Crenarchaeote and Euryarchaeote) and Actinobacterium are found predominant in all these three zones with the Proteobacterium accounting for 23.21%, 36.21%, and 28.84% in R, M, D zone respectively. The other predominant microbial groups were identified for varied zones, e. g. Eubacterium and Nitrospira in the R wells, Eubacterium and Acidobacterium in the M wells, and Bacteroidetes bacterium in the D wells. Linkages and potential evolution of microbial groups among three zones were examined by using the genetic neighbor-joining tree. Environmental adaptation along the groundwater flow contributes to the similarity and discrepancy of microorganism in term of the genetic tree, and the ecological functions of the microbial groups need further assessment.