Hydraulic and thermal performance trigger the deterministic assembly of water microbiomes: From biogeographical homogenization to machine learning model.

Water quality at the point of consumption has long been a health issue because of the potential for microbial ecology. However, research on water hydraulic performance remains in its infancy, and in particular, little is known about the effects of thermal performance during winter. This study explored the effects of stagnation and municipal heating on microbial communities in tap water, focusing on spatial and temporal variations in microbial community composition. The results revealed that stagnation significantly alters the microbial community, especially in heating areas, where the temperature exacerbates microbial growth. Furthermore, hydraulic and thermal performance drive deterministic assembly processes in microbial communities, as evidenced by the reductions in β-diversity, normalized stochasticity ratio (NST), and neutral community model (NCM) fit. Machine learning models revealed that stagnation time greater than 8 h results in increased community abundance because of longer exposure to organic matter and nutrients. The study finding illustrate the importance of environmental influences on microbial community dynamics, and provide valuable insights into the water microbial community, particularly in areas with prolonged stagnation.