Figure 2

Phylogenetic tree showing the top 10 OTUs from the WWTP (AD, RS) and freshwater lake (LW, LS) samples. Methanosarcina acetivorans was used as the out-group. The scale bar represented 5% divergence. The abundance of the top 10 OTUs in each sample was shown in the heatmap referred to the colour key. AD: anaerobic digestion sample, RS: return sludge sample, LW: lake water sample, LS: lake sediment sample.