Arctic heathland soil Raw sequence reads. soil metagenome

Arctic heathlands represent a major carbon store and key component of the global carbon cycle. Arctic warming and the vulnerability of soil carbon to microbial decomposition could amplify the effects of climate change. The sensitivity of plot-scale experiments simulating climate change effects on soil microbial communities may be compromised by influences of spatial and seasonal controls, and experimental approaches studying plot scale interactions have been limited. We investigated the variation in Arctic heathland soil bacterial communities at two survey sites in Sweden between spring and summer 2013, at scales of 0-1m, 1-100m and between sites (>100m) using 16S rRNA gene T-RFLP and amplicon sequencing. Amplicon sequencing supported the evidence of seasonal shifts, from r- to K-selected taxon dominated communities influencing in silico predictions of functional potential. Network analyses revealed seasonal keystone taxa, with a spring betaproteobacterial sub44 network centred upon a Burkholderia OTU and a reconfiguration to a summer sub-network centred upon an alphaproteobacterial OTU. The importance of two season-specific keystone taxa suggests that the general stability of Arctic heathland soil bacterial communities could be disproportionally influenced by seasonal perturbations affecting individual taxa.