Large‐scale evidence for microbial response and associated carbon release after permafrost thaw. (21st January 2021) - Chen, Yongliang
Abstract: Permafrost thaw could trigger the release of greenhouse gases through microbial decomposition of the large quantities of carbon (C) stored within frozen soils. However, accurate evaluation of soil C emissions from thawing permafrost is still a big challenge, partly due to our inadequate understanding about the response of microbial communities and their linkage with soil C release upon permafrost thaw. Based on a large‐scale permafrost sampling across 24 sites on the Tibetan Plateau, we employed meta‐genomic technologies (GeoChip and Illumina MiSeq sequencing) to explore the impacts of permafrost thaw (permafrost samples were incubated for 11 days at 5°C) on microbial taxonomic and functional communities, and then conducted a laboratory incubation to investigate the linkage of microbial taxonomic and functional diversity with soil C release after permafrost thaw. We found that bacterial and fungal α diversity decreased, but functional gene diversity and the normalized relative abundance of C degradation genes increased after permafrost thaw, reflecting the rapid microbial response to permafrost thaw. Moreover, both the microbial taxonomic and functional community structures differed between the thawed permafrost and formerly frozen soils. Furthermore, soil C release rate over five month incubation was associated with microbial functional diversity and C degradation gene abundances. By contrast, neither microbial taxonomic diversity nor community structure exhibited any significant effects on soil C release over the incubation period. These findings demonstrate that permafrost thaw could accelerate C emissions by altering the function potentials of microbial communities rather than taxonomic diversity, highlighting the crucial role of microbial functional genes in mediating the responses of permafrost C cycle to climate warming. Abstract : Based on soil samples collected along a 1000 km permafrost transect across the Tibetan Plateau, this study employed GeoChip and Illumina MiSeq sequencing to explore the impacts of permafrost thaw on microbial communities and their associations with permafrost carbon release. Our results showed that permafrost thaw shifted microbial taxonomic and functional diversity, and permafrost carbon release was associated with the changes in microbial functional diversity and carbon degradation gene abundances, but had no linkage with the microbial taxonomic diversity. These results demonstrate the important role of microbial functional genes in mediating permafrost carbon release in response to climate warming.