Fig. 3

Carbon flow in the STACK shale play. From left to right, complex polymers may be degraded by inferred fermentative microorganisms and converted to organic acids, which could be utilized by sulfate- and thiosulfate-reducing microorganisms. Color of each MAG oval corresponds to taxonomic classification, and the size of each circle within each MAG indicates max. % relative abundance for the STACK 16, 17, & 14 wells, respectively. Completeness estimates for each MAG are listed after the MAG taxonomy in the key. All graphs depicting organic acid concentrations are in μM measurements. Solid lines between inferred fermenters (far left) and organic acids indicate genomic potential and statistical prediction to that metabolite via sPLS (VIP>2), while dashed lines only indicate genomic potential. All other solid lines between MAGs and complex polymers, and between organic acids and sulfate reducers, indicate genomic potential for degradation or uptake, respectively.