Fig. 1: Distribution within the Black Sea water column and phylogeny of Ca. Cloacimonetes.

a Percentage of 16S rRNA gene reads attributed to different Ca. Cloacimonetes groups during BS2013. b Estimated abundance of the four Ca. Cloacimonetes MAGs. c Maximum likelihood phylogenetic tree of the FCB group superphylum based on 43 concatenated core genes. Circles along branches indicate ultrafast bootstrap approximation support values, with only values for deepest nodes shown. d Zoom in on the Ca. Cloacimonetes phylogeny. Numbers along branches indicate ultrafast bootstrap approximation support values. Scale bars in c, d represent mean number of substitutions per site.