Figure 3.

Relative contribution of sand grain core community OTU_0.97 to total community based on sequencing of 16S rRNA gene fragments. The core community that was present on all 17 individual sand grains in June 2016, comprised 394 OTU_0.97. The taxonomic classification of core community OTU_0.97 is given on family level. Thus, each depicted family can comprise several OTU_0.97. Core community families and uncultivated clades contributing on average <0.5% to total 16S rRNA gene sequences are summarized as 'other core community OTU_0.97'. Depicted core community composition is based on subsampled data sets (n=44 901 sequences). For some families, that is, Woeseiaceae/JTB255, Flavobacteriaceae and Ectothiorhodospiraceae, a higher taxonomic resolution is given. *Sequences classified as Planctomycetaceae and Phycisphaeraceae rather represent several unclassified families within the class Planctomycetia and Phycisphaerae, respectively.