Fig. 1

Microbial community analysis of 7-day-old biofilms grown on LDPE, W-LDPE and wood, as well as the riverine planktonic community of the surrounding water. A Principal Component Analysis (PCoA) showing samples grouped by Robust Aitchison’s distance (i.e. Euclidean distance of robust Centered-Log Ratio transformed counts). The variation accounted for by each principal component is indicated in parentheses on the axes. Ellipses show the mean of three sample replicates for each treatment plus the standard deviation. ANOSIM and PERMANOVA tests between the treatments are shown in the box. B Chao1 richness and Simpson’s diversity index in the three replicates for each treatment. The results of ANOVA tests for differences between treatments are shown in boxes within the axes, while p-values for post-hoc Tukey’s honestly significant difference (HSD) between treatments are shown underneath (highlighted in red are significant values; p ≤ 0.05). Both (A) and (B) show results for reads classified to the species level. C Forty most abundant bacterial genera detected amongst all metagenomes (i.e. those above 0.5% relative abundance). Bacterial genera are grouped by phylogenetic similarity. Colour shading indicates the class each genus belongs to. The relative abundance of each genus (in %) is shown in the central heatmap, normalised per column. The top dendrogram shows samples grouped by Robust Aitchison’s distance. The heatmap on the right shows whether taxa were significantly differentially abundant between conditions. We used three tools to determine whether taxa were differentially abundant, ANCOM-II, ALDEx2 and MaAsLin2 (Table S2). White represents that no tool found the genus to be differentially abundant between conditions, while dark green shows that all three tools found a difference. Shapes within cells denote which of the three tools found a significant difference