PERMANOVA main tests of bacterial community composition based on Bray-Curtis dissimilarities of OTUs (16S ribosomal amplicon pyrosequencing; ‘initial dilution’ summer).

1Significant results (p (perm)<0.05) are highlighted in bold. Displayed are the test for the factor ‘pH’ and the partitioning of multivariate variation for the ‘initial dilution’ (only summer experiment). p-values were obtained using type III sums of squares and 999 permutations under the full model. d.f.: degrees of freedom, SS: sums of squares, Sq. root: square root of the component of variation attributable to that factor in the model, in units of Bray-Curtis dissimilarities.