Fig. 2.

Relative abundance and comparison profiles of archaeal 16S rRNA OTUs identified in anaerobic digesters containing either waste water sludge with no additional organic substrate (inoculum, IC), IC plus wheat straw (IC + WS), or IC plus seaweed (IC + SW). a, b The relative abundance of archaeal lineages at a phylum-level and OTU-level, respectively. OTU abundance shifts between WS and SW digesters c were measured as either fold-change increases (+) or decreases (−) against IC measurements. Colour coding in b and c are as follows: blue indicates IC, red indicates IC + WS and green indicates IC + SW. Lineage information for selected OTUs and OTU affiliation to previously described, highly prevalent core phylotypes (Rivière et al. 2009) is provided. OTUs numbers in the x-axis correspond to ARC_nor-terminology referred to in the text. Total methane yields are included in a for IC + WS and IC + SW, which are provided in the original publication on methane production (Vivekanand et al. 2012) and normalized for production in IC. VS* volatile solids