Fig. 6

Non-metric multidimensional scaling ordination diagrams of temporal variations in bacterial and archaeal community structures. The ordination is based on Bray–Curtis similarity matrices of the relative abundance data obtained from high-throughput amplicon sequencing (a and d) and T-RFLP (b and e) for the bacterial and archaeal community, respectively; c and f show the average pairwise Bray–Curtis distance for the four reactors at the different sampling periods based on the high-throughput amplicon sequencing and T-RFLP results for, respectively, the bacterial and archaeal community; the black ellipses group sampling period P0 (steady-state process) for each reactor