Fig. 4

The phylogenetic positions of high-abundance OTUs classified as SRP by epicPCR. Fonts in bold indicate reference sequences, those in blue indicate the core OTUs (high abundance in at least one sample from any lake), in red indicate non-specific OTUs (high abundance in samples collected from at least two lakes), and in black indicate lake-specific OTUs (high abundance in samples from a single lake). Red arc lines indicate OTUs affiliated with the 11 phyla previously unreported to be involved in dissimilatory sulfate reduction. The size of blue circles on branches represent the bootstrap values of 50–100. The bars around the tree indicate the relative abundance of OTUs in the lake where they were most abundant. The outer ring of strips is the taxonomic affiliation of OTUs at the phylum level. The legend on the bottom indicates the colors used for phyla in the outer strip