Microbial characteristics and CO2 diffuse emission in the Mt. Changbai volcanic field, northeast China

Volcanism is one of the principal geologic processes that drive the transferring of carbon between interior and surface reservoirs, playing a crucial role in climate change and global warming. Clarifying the relationship between the characteristics of microorganisms and geological degassing of dormant volcanoes is one of the most important and fundamental tasks. In this study, the microbial characteristics (including bacteria, archaea, and fungi) of cold and hot springs and soil in the Tianchi volcano (TCV), northeastern China were comprehensively studied. Results of this study indicated that the microbial diversities of water environments (hot and cold springs) exhibited distinct characteristics compared to that of the soil, inferring that the microbial-driven carbon cycle in wet and dry degassing systems in the TCV are different. The CO₂ diffuse emission flux from the soil through micro-seepage decreased from the crater to the peripheral area, which broadly coincided with the diversity and richness of the microbial community. A moderate but significant correlation was found between soil CO₂ flux and microbial diversity of bacteria, archaea and fungi, differing from that observed in extreme volcanic environments and non-volcanic fields. This study is the first to report the correlation between microbial community diversity and soil CO₂ flux in a non-extreme volcanic environment. The findings reveal the diversity of microorganisms involved in the carbon cycle, which may provide a foundation for further in-depth exploration of the intrinsic microbial mechanisms in the carbon cycle.