Fig. 4
The NMDS plot analyses of the bacterial communities (phylum level). The results were based on the pyrosequencing data of the 16S ribosomal RNA genes. The data points are numbered according to specific sampling days. The blue arrows indicate the highly significant (p < 0.05) bacterial phyla, whereas the black arrows represent the highly significant (p < 0.05) reactor parameters as correlation vectors of the bacterial community succession. The arrow length shows the correlation with the ordination axis, while the arrow direction corresponds to the community structures