The dynamics of freshwater bacterial communities in aquatic environments are important as they provide valuable insights into the processes that drive ecosystem functioning and assess the overall health of these ecosystems. However, much remains unknown about the determinants of bacterial community dynamics in urban ponds, especially in the context of a warming climate. In this study, we conducted a whole-metagenomic shotgun sequencing analysis of bacterial communities in subtropical urban ponds located in Shenzhen, southern China, to understand the temporal dynamics and assembly mechanisms of bacterial communities in response to warm conditions (26.4–32.1 °C). Over a one-month period, 30 surface water samples collected from three adjacent ponds yielded a total of 381 bacterial species, corresponding to 21 phyla. Among these species, Proteobacteria were the most prevalent, with 40.42% of them classified as pathogenic bacteria affecting both humans and animals. The bacterial diversity and species relative abundance exhibited distinct patterns over a relatively short time interval of 2 to 3 days, underscoring the dynamic nature of bacterial communities and the unique characteristics of each pond as a potential habitat. The bacterial community tended to return to a community type resembling an earlier sampling period, demonstrating the potential for a seasonal cycle and ecological processes involving both random changes in population (stochastic processes) and non-random patterns of species (deterministic processes). Stochastic processes explained 72.1–77.5% of the community composition, representing a stronger influence of stochastic processes over deterministic processes in shaping the bacterial community. The results suggest that under warm conditions, the bacterial community is largely regulated by stochastic processes, with temperature playing a vital role in increasing species richness and species relative abundance, including those of human and animal pathogenic bacteria.

Geng, Z.. (2024). Dynamics and assembly mechanisms of microbial communities in subtropical urban ponds (Unpublished master's thesis). Shenzhen MSU-BIT University, Shenzhen, China.