Spatiotemporal variations, assembly processes, and co-occurrence patterns of particle-attached and free-living bacteria in a large drinking water reservoir in China

Bobing Yu; Guijuan Xie; Zhen Shen; Keqiang Shao; Xiangming Tang

doi:10.3389/fmicb.2022.1056147

Spatiotemporal variations, assembly processes, and co-occurrence patterns of particle-attached and free-living bacteria in a large drinking water reservoir in China

Front Microbiol. 2023 Jan 19:13:1056147. doi: 10.3389/fmicb.2022.1056147. eCollection 2022.

Authors

Bobing Yu^{1

2}, Guijuan Xie^{1

3}, Zhen Shen^{1

2}, Keqiang Shao^{1

2}, Xiangming Tang^{1

2}

Affiliations

¹ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
² College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.
³ College of Biology and Pharmaceutical Engineering, West Anhui University, Lu'an, China.

Abstract

Particle-attached (PA) and free-living (FL) bacterial communities are sensitive to pollutant concentrations and play an essential role in biogeochemical processes and water quality maintenance in aquatic ecosystems. However, the spatiotemporal variations, assembly processes, co-occurrence patterns, and environmental interactions of PA and FL bacteria in drinking water reservoirs remain as yet unexplored. To bridge this gap, we collected samples from 10 sites across four seasons in Lake Tianmu, a large drinking water reservoir in China. Analysis of 16S rRNA gene libraries demonstrated spatiotemporal variations in bacterial diversity and identified differences in bacterial community composition (BCC) between PA and FL lifestyles. Capacity for nitrogen respiration, nitrogen fixation, and nitrate denitrification was enriched in the PA lifestyle, while photosynthesis, methylotrophy, and methanol oxidation were enriched in the FL lifestyle. Deterministic processes, including interspecies interactions and environmental filtration, dominated the assembly of both PA and FL bacterial communities. The influence of environmental filtration on the FL community was stronger than that on the PA community, indicating that bacteria in the FL lifestyle were more sensitive to environmental variation. Co-occurrence patterns and keystone taxa differed between PA and FL lifestyles. The ecological functions of keystone taxa in the PA lifestyle were associated with the supply and recycling of nutrients, while those in FL were associated with the degradation of complex pollutants. PA communities were more stable than FL communities in the face of changing environmental conditions. Nutrients (e.g., TDN and NO₃ ^-) and abiotic and biotic factors (e.g., WT and Chl-a) exerted positive and negative effects, respectively, on the co-occurrence networks of both lifestyles. These results improve our understanding of assembly processes, co-occurrence patterns, and environmental interactions within PA and FL communities in a drinking water reservoir.

Keywords: Lake Tianmu; assembly process; co-occurrence pattern; free-living bacteria; particle-attached bacteria; spatiotemporal variations.

Grants and funding

This study was funded by the National Natural Science Foundation of China (41971062) and the Natural Science Foundation of Jiangsu Province, China (BK20220018).