Fig. 5

Co-occurrence networks of denitrifying and anammox bacteria and their stability comparison among different stages across the anammox enrichment with lake sediments in bioreactor systems. Co-occurrence networks of denitrifying and anammox bacteria constructed based on the sequenced functional genes of nirS/K and hzsB (a). The node size represents the degree of each OTU. The black and red links represent positive and negative correlations, respectively. A summary of node-link statistics was also given, and numbers represent the nodes or links. The positive and negative proportion of the network correlations (b). Community stability as depicted by the robustness (c) and vulnerability (d), respectively. Robustness is measured as the proportion of the remaining species in community after 50% of the nodes were randomly removed, and vulnerability is measured as the maximum vulnerability of nodes in each network