Microbial community structure represents a critical parameter for soil biogeochemical cycling as soil nutrient cycling is primarily driven by soil microbes. It is well known that various microbial groups play different roles in nutrient cycling; for example, bacteria and fungi vary in regulating litter decomposition due to different physiology. Therefore, how various microbial groups shift is critically important for global nutrient biogeochemistry. We took advantage of the recently launched National Ecological Observatory Network (NEON) project by compiling all soil microbial data from NEON dataset. Based on the phospholipid fatty acid content, we analyzed the relative abundance of a number of microbial functional groups: bacteria, fungi, actinomycetes, Gram-negative bacteria, arbuscular mycorrhizal fungi, cyanobacteria, diatoms + Gram-negative bacteria, type I methanotrophs, sulphate-reducing bacteria, cyanobacteria, and diatoms + Gram-negative bacteria.
Results/Conclusions
There are large spatial heterogeneities in microbial community structure and individual microbial functional group. Spatial biogeographic patterns are detected for bacteria, fungi, and total microbial group, but no clear spatial patterns for cyanobacteria and arbuscular mycorrhizal fungi. The biogeographic patterns show lower abundance and microbial diversity in the middle-latitude and relatively higher in low and high latitude; further analysis with mixed generalized linear regression and structural equation model show that edaphic factors, rather than meteorological factors, are the predominant control. A simulation with the CLM-Microbe model shows consistency with bacterial and fungal biomass along the latitude. The biogeographic patterns of microbial groups and microbial community shifts are vital information for better understanding the microbial roles in global climate change at a large scale.