Spatiotemporal Variations in Water Quality and Bacterial Communities in the Jiaoxi River After Reservoir Impoundment and Their Driving Factors

DOI: https://doi.org/10.62517/jlsa.202607307

Author(s)

Peng Zhang, Hao Gong, Xiuyu Zong

Affiliation(s)

Shaanxi Modern Architectural Design and Research Institute Co, Ltd, Xi'an, Shaanxi, China

Abstract

Reservoir impoundment alters the hydrodynamic conditions and nutrient distribution in rivers, thereby affecting bacterial community composition and ecosystem function. Investigating the spatiotemporal response patterns of river water quality and bacterial communities following reservoir impoundment is crucial for assessing the ecological impacts of water conservancy projects. To evaluate the water quality status and bacterial community response characteristics of the Jiaoxi River upstream of the Sanhekou Reservoir following its impoundment as part Within the framework of the Han-Wei Water Diversion Project, we collected water samples at various cross-sections, measured physicochemical parameters, and conducted a comprehensive Assessing Water Quality Using the Single-Factor Method, principal component analysis, and the cloud model. Additionally, 16S rDNA amplicons were sequenced to examine bacterial community composition and diversity, The RDA and Pearson correlation tests, meanwhile, helped identify the primary environmental factors. Our findings indicate that the water quality of the Jiaxi River is generally very good. However, the commercial service area is a weak link in the aquatic environment of the study section of the river; at this location, total nitrogen (TN) met Class III standards, while key indicators at the remaining sampling sections all met Class II or higher standards; In the aquatic bacterial community, a total of 45 phyla, 121 classes, 326 orders, 576 families, and 1,375 genera were identified, with the dominant phyla being Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria; Community composition exhibited distinct spatiotemporal variations and was jointly influenced by seasonal changes and local hydrodynamic conditions; RDA and correlation analyses indicated that WT, COD, and NH₄⁺-N were generally negatively correlated with changes in community structure, while DO and pH were positively correlated with multiple dominant phyla. This study can serve as a reference for ecological conservation and pollution risk identification at the water source areas of the Han-Wei River Water Diversion Project.

Keywords

Jiaoxi River; Reservoir Impoundment; Water Quality Assessment; Bacterial Community; Spatiotemporal Variation; Environmental Drivers.

References

[1]Zhang, R. N., Liu, Z., Zhang, S. H., et al. Effects of watershed land use types on river water quality: A case study of the Nanpan River in the Pearl River Basin (in Chinese). Journal of Hydroecology, pp. 1–13. [2]Yang, H. Y. Causes of urban water supply quality deterioration and preventive measures (in Chinese). Urban Water Supply, 2021, (2): 31–34. [3]Wu W, Chen H, Xu S, et al. Water environment characteristics and water quality assessment of water source of diversion system of project from Hanjiang to Weihe River. International Journal of Environmental Research and Public Health, 2023, 20(4): 2890. [4]Nong X, Luo K, Lin M, et al. Relationships between water quality of a long-distance inter-basin water diversion project and air pollution emissions along the canal: Distributions, lag effects, and nonlinear responses. Environmental Pollution, 2024, 361: 124813. [5]Cheng B, Zhang Y, Xia R, et al. Backwater makes the tributaries of large river becoming phosphorus “sink”. Water Research, 2024, 261: 122012. [6]Zhang L, Fang W, Li X, et al. Strong linkages between dissolved organic matter and the aquatic bacterial community in an urban river. Water Research, 2020, 184: 116089. [7]Wang X, Li H, Zhang R, et al. Bacterial community and dissolved organic matter networks in urban river: The role of human influence. Environmental Research, 2024, 263: 120021. [8]Shi K, Zhang J, Zhao Y, et al. Distinct co-succession of dissolved organic matter and bacterial generalists and specialists in inflow rivers of Baiyangdian Lake. Environmental Research, 2025: 121378. [9]Guo, N. N., Qi, Y. K., Meng, S. L., et al. Research progress in restoration technologies for eutrophic lakes (in Chinese). Chinese Agricultural Science Bulletin, 2019, 35(36), 72–79. [10]Ding F, Hao S, Zhang W, et al. Using multiple machine learning algorithms to optimize the water quality index model and their applicability. Ecological Indicators, 2025, 172: 113299. [11]Fan, Y. L., Hu, G. L., Bai, Y. R., et al. Water quality assessment and prediction of the Shiyang River Basin based on a secondary game cloud model (in Chinese). Water Purification Technology, 2025, 44(5), 44–56. [12]Zhu A, Liang Z, Gao L, et al. Dispersal limitation determines the ecological processes that regulate the seasonal assembly of bacterial communities in a subtropical river. Frontiers in Microbiology, 2024, 15: 1430073. [13]Yi, H. M. Research and application of a cloud model-based safety evaluation method for reservoir dams (in Chinese). Hongshui River, 2022, 41(6), 1–6. [14]Xiang R, Wang L, Li H, et al. Water quality variation in tributaries of the Three Gorges Reservoir from 2000 to 2015. Water Research, 2021, 195: 116993. [15]Liu X, Huang W, Qi Z, et al. Seasonal water storage of large reservoirs exacerbates eutrophication risk in the fluctuating backwater zone: A case study of Three Gorges Reservoir, China. Ecological Indicators, 2025, 171: 113100. [16]Lenart-Boroń A, Boroń P, Kulik K, et al. Anthropogenic pollution gradient along a mountain river affects bacterial community composition and genera with potential pathogenic species. Scientific Reports, 2022, 12: 18140. [17]Shi K, Zhang J, Zhao Y, et al. Spatiotemporal distribution, assembly processes, and key drivers of bacterial communities in a multi-terrain river basin of northern China. Journal of Environmental Chemical Engineering, 2025: 116756. [18]Xiao P, Wu Y, Zuo J, et al. Differential microbiome features in lake–river systems of Taihu basin in response to water flow disturbance. Frontiers in Microbiology, 2024, 15: 1479158. [19]Tan, Q. Y., Lü, J. Y., Bai, X. Y., et al. Vertical distribution and source tracking of bacterial community composition and nitrogen cycling functions in a typical urban inland river (in Chinese). Environmental Science, 2023, 44(3), 1497–1507