The dynamics of bacterioplankton communities in aquatic environments are of great importance as they provide valuable insights into the microbial diversity, ecological processes, and ecosystem functioning that are specific to these environments. However, there is still a lack of knowledge regarding the factors that determine variations in the bacterioplankton community in unique aquatic habitats such as endorheic ponds in urban environments. We conducted high-frequency sampling of bacterioplankton using high-throughput sequencing technology over a one-month period (August, 2022; n = 30) in an endorheic urban pond located in the subtropical monsoon climate zone of China. Our primary objective was to gain a comprehensive understanding of the factors that influence the dynamics of the bacterioplankton community in such a unique freshwater ecosystem. We classified the bacterioplankton community into different subcommunities: abundant taxa (AT), consisting of 117 operational taxonomic units (OTUs), conditionally rare taxa (CRT), consisting of 6,774 OTUs, and rare taxa (RT), consisting of 5,012 OTUs. The temporal dynamics of the bacterioplankton community exhibited substantial changes, largely driven by fluctuations in the dominant Actinobacteria and Proteobacteria phyla, as well as the Synechococcus genus, which is a group of cyanobacteria. The community compositions within subcommunities, particularly in CRT, exhibited significant differences. Water physicochemistry emerged as the most influential environmental condition, explaining pure variances of 0.8%, 0.01%, and 0.02% in AT, CRT, and RT subcommunities, respectively. Co-occurrence networks revealed significant species associations within the bacterioplankton community, emphasizing the key role of stochastic processes in shaping the community structure, especially within CRT and RT subcommunities, which accounted for 40% and 18.1% of the explained community variance, respectively. The results suggest that the environment plays a crucial role as a determinant in shaping the composition of the bacterioplankton community in a subtropical endorheic urban pond.

Cao, L. (2023). Determinants of bacterial community composition in a subtropical endorheic urban pond (Unpublished master's thesis). Shenzhen MSU-BIT University, Shenzhen, China.