Subsurface Microbial Invasion Affects the Microbial Community of Coal Seams

摘要

Coal seam microorganisms have attracted much attention for their special functions that are closely related to secondary biogenic gas formation, but the influence of subsurface microbial invasion on coal microorganisms remains poorly understood. In this study, subsurface microorganisms from soils at different depths were used to infect coal samples, and the abundance and composition of the microbial community were analyzed by quantitative polymerase chain reaction (PCR) and high-throughput sequencing. The results showed that methane production from the coal samples treated with soil extractions did not increase significantly nor did the abundance and transcriptional activity of archaeal 16S rRNA and mcrA genes. In contrast, two soil extractions significantly improved the abundance and transcriptional activity of the coal bacteria. There was no significant difference in the effects of different soil extractions on bacterial abundance and transcriptional activity, but differences in the effects on alpha- and beta-bacterial diversity between the coal samples treated by different soil extractions were found. Soil extraction from the shallow layer soil far away from the coal mine increased the bacterial alpha-diversity of the coal samples and changed the bacterial community composition. In addition, this soil extraction increased various bacterial groups in the coal sample and changed the predictive metagenome functional contents of the coal samples from the bacterial sequence data. In summary, this study provides basic microbial information for subsurface microbial invasion of coal seams and helps increase understanding of the source of microorganisms in in situ coal seams and the changes in the microbial community during subsurface microbial migration.