In this study,we investigated the presence of denitrifying anaerobic methane oxidizing microorganisms in high temperature,high pressure and high salt shale gas flowback water for the first time,along with their correlation with key environmental factors.The results indicated that DAMO archaea and bacteria were detected in all the seven shale gas flowback water,and the archaea exhibiting significantly higher abundance compared to bacteria with 16S rRNA gene copy ranging from 4.32×104∼5.83×105copies/L and 1.16×103～6.00×103 copies/L,respectively.Additionally,the functional genes mcrA and pomA of DAMO archaea and bacteria were also detected in all the samples.Four representative OTUs of DAMO bacteria and one representative OTU of DAMO archaea were identified in the shale gas flowback water.Despite the high salinity,the DAMO bacteria and archaea detected in flowback water shared a closer genetic relationship to those reported in freshwater environments.RDA correlation analysis revealed that the influence of physicochemical factors in flowback water on DAMO microorganisms was more evident in microbial function rather than microbial abundance.The abundance of pmoA gene was positively and significantly correlated with TOC content,while the abundance of mcrA gene was positively correlated with the concentrations of NO3-,NH4-,PO43-,and Cl-,with Cl-having the greatest impact.These results of the study expanded the understanding of the environmental distribution of DAMO microorganisms,providing a theoretical foundation for controlling greenhouse effect caused by methane emissions in flowback water,and contributing to a deeper comprehension of microbial processes in deep shale formations.
关键词
反硝化厌氧甲烷氧化/页岩气返排水/高盐/环境因子/群落结构
Key words
denitrifying anaerobic methane oxidation/shale gas flowback water/high salinity/environmental factors/community structure
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