Niche differentiation drives microbial community assembly and succession in full-scale activated sludge bioreactors

Network models and community phylogenetic analyses are applied to assess the composition, structure, and ecological assembly mechanisms of microbial communities. Here we combine both approaches to investigate the temporal dynamics of network properties in individual samples of two activated sludge systems at different adaptation stages. At initial assembly stages, we observed microbial communities adapting to activated sludge, with an increase in network modularity and co-exclusion proportion, and a decrease in network clustering, here interpreted as a consequence of niche specialization. The selective pressure of deterministic factors at wastewater treatment plants produces this trend and maintains the structure of highly functional and specialized communities responding to seasonal environmental changes.

Automated summary

Network models and community phylogenetic analyses were used to examine the temporal dynamics of network properties in microbial communities in activated sludge systems. The results showed that during the initial assembly stages, the microbial communities adapted to the activated sludge environment, leading to an increase in network modularity and co-exclusion proportion, and a decrease in network clustering. This suggests niche specialization as a result of the selective pressure of deterministic factors in wastewater treatment plants.