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ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Microbiological Chemistry and Geomicrobiology
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1563578
This article is part of the Research Topic Microbial Involvement in Biogeochemical Cycling and Contaminant Transformations at Land-Water Ecotones - Volume 2 View all articles
Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected system
Provisionally accepted- 1 Hebei University of Science and Technology, Shijiazhuang, China
- 2 Research Center for Eco-environmental Sciences, Chinese Academy of Sciences (CAS), Beijing, Beijing Municipality, China
Abstract: Nitrogen pollution poses a severe threat to freshwater ecosystems, particularly under intensified agricultural and urbanization activities. This study focused on Baiyangdian Lake (BYD) and its main inflowing rivers Fu River (FH), Baigou River (BGY), and Xiaoyi River (XY) to systematically investigate the spatio-temporal distribution, primary sources of nitrogen pollution, and its impact on sediment microbial community structure. The study revealed significant seasonal variations in nitrogen pollution load and sources, with nitrogen levels in rivers increasing substantially from May to August. Atmospheric deposition was the dominant nitrogen source in May (43.9%), while agricultural fertilizers and sewage became the major sources in August (23.3% and 26.4%, respectively). The microbial communities also exhibited temporal and spatial variations, with microbial diversity and species richness being significantly higher in the wet season. Notably, microbial composition shifted, showing a decrease in Proteobacteria and an increase in Firmicutes and Actinobacteriota. River-lake connectivity was another key factor, with the connectivity index of Fu River being significantly higher in August compared to Baigou and Xiaoyi rivers. In the structural equation modeling (SEM) analysis, river-lake connectivity was significantly positively correlated with nitrogen pollution, while nitrogen pollution showed a significant negative correlation with microbial α-diversity. This suggests that high connectivity facilitates nitrogen transfer and accumulation, but also leads to a reduction in local microbial diversity. Furthermore, the analysis revealed that river-lake connectivity directly influenced nitrogen concentrations, which in turn indirectly regulated microbial diversity.
Keywords: nitrogen pollution, microbial community structure, Spatio-temporal distribution, River-lake connectivity, River-lake systems
Received: 20 Jan 2025; Accepted: 10 Mar 2025.
Copyright: © 2025 Chen, Zhang, Zheng, Gao and Zhao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Lulu Zhang, Hebei University of Science and Technology, Shijiazhuang, China
Yu Zhao, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences (CAS), Beijing, 100085, Beijing Municipality, China
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