Figure 2.

Relative abundance (%) of different phyla for SIP incubations showing results from heavy (density ca. 1.730 g ml⁻¹) fractions and light fractions (density ca. 1.700 g ml⁻¹) of samples incubated with ¹³CO or ¹³CO + ¹²CO₂ compared to the community detected in heavy fractions of un-incubated Control samples (i.e., no CO or CO₂ added). (A) DCmN11 showing significant increase in the proportion of Firmicutes in heavy fractions and (B) GR1 showing an increase in Firmicutes but also the large proportion of Crenarchaeota present in both the un-incubated environmental control sample and SIP fractions. 16S rRNA gene sequences were clustered at 97% similarity and classified using QIIME. “Other” includes phyla present at < 1%.