Denitrification-associated taxa increase in relative abundance following methanol and triclosan exposure. Shown are relative abundance trends for selected OTUs related to organisms known to be methylotrophic denitrifiers. Boxplots of relative abundance include interquartile range, with median plotted as horizontal line and mean plotted as asterisk. For all boxes, n = 8 samples except for day 14, low where n = 7 samples. Note differing y-axis scales. Significant pairwise comparisons are highlighted in Additional file 11: Table S4.