Multi-scale variability analysis of Arctic soil bacterial communities

Understanding distribution patterns at various spatial scales is a central issue in microbial ecology. Beyond the lone identification of biogeographical patterns, understanding the environmental drivers behind community diversity and structure is key. While many studies identify pH as a major parameter structuring microbial communities at large spatial scales, many other variables impact distribution patterns on smaller scales. Here, we investigated the biogeographical patterns of Arctic soil microbial communities from 1 m to 500 m, within Adventdalen, Svalbard, using 16S sequencing, gravimetric measurements and X-ray fluorescence. Multivariate analyses identified key environmental variables shaping microbial communities and revealed the importance of soil moisture, organic carbon and elements such as aluminum, calcium and potassium in structuring distribution patterns. The indicator species analyses identified key associations between environmental variables and OTUs. Using geostatistical kriging, we mapped the biodiversity and distribution of key OTUs across the landscape. Overall, our results highlight the spatial heterogeneity in Arctic soils and identifies the sampling scale needed to characterize microbial communities within an area of interest with seemingly homogeneous landscapes.