Elevated carbon dioxide accelerates the spatial turnover of soil microbial communities

Although elevated CO 2 ( eCO 2 ) significantly affects the α ‐diversity, composition, function, interaction and dynamics of soil microbial communities at the local scale, little is known about eCO 2 impacts on the geographic distribution of micro‐organisms regionally or globally. Here, we examined the β ‐diversity of 110 soil microbial communities across six free air CO 2 enrichment ( FACE ) experimental sites using a high‐throughput functional gene array. The β ‐diversity of soil microbial communities was significantly ( P  < 0.05) correlated with geographic distance under both CO 2 conditions, but declined significantly ( P  < 0.05) faster at eCO 2 with a slope of −0.0250 than at ambient CO 2 ( aCO 2 ) with a slope of −0.0231 although it varied within each individual site, indicating that the spatial turnover rate of soil microbial communities was accelerated under eCO 2 at a larger geographic scale (e.g. regionally). Both distance and soil properties significantly ( P  < 0.05) contributed to the observed microbial β ‐diversity. This study provides new hypotheses for further understanding their assembly mechanisms that may be especially important as global CO 2 continues to increase.