Tundra microbial community taxa and traits predict decomposition parameters of stable, old soil organic carbon

• Published in: The ISME Journal
• Main Authors: Hale, Lauren Univ. of Oklahoma, Norman, OK . Inst. for Environmental Genomics, US Dept. of Agriculture , Parlier, CA . San Joaquin Valley Agricultural Sciences Center, Feng, Wenting Univ. of Oklahoma, Norman, OK, Chinese Academy of Agricultural Sciences, Beijing . Inst. of Agricultural Resources and Regional Planning, Yin, Huaqun Univ. of Oklahoma, Norman, OK . Inst. for Environmental Genomics; Central South Univ., Changsha, Hunan, Guo, Xue Univ. of Oklahoma, Norman, OK . Inst. for Environmental Genomics; Tsinghua Univ., Beijing . State Key Joint Lab. of Environment Simulation and Pollution Control, Zhou, Xishu Univ. of Oklahoma, Norman, OK . Inst. for Environmental Genomics; Central South Univ., Changsha, Hunan, Bracho, Rosvel Univ. of Florida, Gainesville, FL, Pegoraro, Elaine Univ. of Florida, Gainesville, FL, Northern Arizona Univ., Flagstaff, AZ . Center for Ecosystem Science and Society, Penton, C. Ryan Arizona State Univ., Mesa, AZ, Arizona State Univ., Tempe, AZ . Center for Fundamental and Applied Microbiomics, Biodesign Inst., Wu, Liyou Univ. of Oklahoma, Norman, OK . Inst. for Environmental Genomics, Cole, James Michigan State Univ., East Lansing, MI . Center for Microbial Ecology, Konstantinidis, Konstantinos T. Georgia Inst. of Technology, Atlanta, GA . School of Civil and Environmental Engineering and School of Biology, Luo, Yiqi Univ. of Oklahoma, Norman, OK, Tiedje, James M. Michigan State Univ., East Lansing, MI . Center for Microbial Ecology, Schuur, Edward. A. G. Univ. of Florida, Gainesville, FL, Zhou, Jizhong Univ. of Oklahoma, Norman, OK . Inst. for Environmental Genomics; Tsinghua Univ., Beijing . State Key Joint Lab. of Environment Simulation and Pollution Control; Lawrence Berkeley National Lab. , Berkeley, CA
• Language: unknown
• Published: 2022
• Subjects: 59 BASIC BIOLOGICAL SCIENCES; permafrost; Tundra
• Online Access: http://www.osti.gov/servlets/purl/1580991; https://www.osti.gov/biblio/1580991; https://doi.org/10.1038/s41396-019-0485-x

The susceptibility of soil organic carbon (SOC) in tundra to microbial decomposition under warmer climate scenarios potentially threatens a massive positive feedback to climate change, but the underlying mechanisms of stable SOC decomposition remain elusive. Herein, Alaskan tundra soils from three depths (a fibric O horizon with litter and course roots, an O horizon with decomposing litter and roots, and a mineral-organic mix, laying just above the permafrost) were incubated. Resulting respiration data were assimilated into a 3-pool model to derive decomposition kinetic parameters for fast, slow, and passive SOC pools. Bacterial, archaeal, and fungal taxa and microbial functional genes were profiled throughout the 3-year incubation. Correlation analyses and a Random Forest approach revealed associations between model parameters and microbial community profiles, taxa, and traits. There were more associations between the microbial community data and the SOC decomposition parameters of slow and passive SOC pools than those of the fast SOC pool. Also, microbial community profiles were better predictors of model parameters in deeper soils, which had higher mineral contents and relatively greater quantities of old SOC than in surface soils. Overall, our analyses revealed the functional potential of microbial communities to decompose tundra SOC through a suite of specialized genes and taxa. In conclusion, these results portray divergent strategies by which microbial communities access SOC pools across varying depths, lending mechanistic insights into the vulnerability of what is considered stable SOC in tundra regions.