Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected system

Intensified agricultural and urban activities have exacerbated nitrogen pollution, posing a severe threat to freshwater ecosystems, particularly under intensified agricultural and urbanization activities. This study systematically examined Baiyangdian Lake (BYD) and its principal inflowing rivers, n...

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Main Authors: Haoda Chen, Lulu Zhang, Zishuai Zheng, Yuang Gao, Yu Zhao
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/articles/10.3389/fmicb.2025.1563578/full
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author Haoda Chen
Lulu Zhang
Lulu Zhang
Zishuai Zheng
Yuang Gao
Yu Zhao
author_facet Haoda Chen
Lulu Zhang
Lulu Zhang
Zishuai Zheng
Yuang Gao
Yu Zhao
author_sort Haoda Chen
collection DOAJ
description Intensified agricultural and urban activities have exacerbated nitrogen pollution, posing a severe threat to freshwater ecosystems, particularly under intensified agricultural and urbanization activities. This study systematically examined Baiyangdian Lake (BYD) and its principal inflowing rivers, namely Fu River (FH), Baigouyin River (BGY), and Xiaoyi River (XY) to characterize the spatio-temporal distribution, primary nitrogen sources, and the impact on sediment microbial community structure. Results indicated pronounced seasonal variations in both nitrogen pollution loads and sources, with riverine nitrogen levels rising markedly from dry season (May) to wet season (August). Atmospheric deposition accounted for 43.9% of the nitrogen input dry season, whereas in wet season, agricultural fertilizers and sewage contributed 23.3 and 26.4%, respectively. Additionally, microbial communities exhibited distinct temporal and spatial patterns, with significantly higher diversity and species richness being during the wet season. The, microbial composition shifted, as evidenced by a decline in Proteobacteria and increases in Firmicutes and Actinobacteriota. River-lake connectivity emerged as a critical factor, with FH displaying a notably higher connectivity index in wet season compared to BGY and XY rivers. Structural equation modeling (SEM) analysis further revealed that river-lake connectivity was significantly and positively correlated with nitrogen pollution, was significantly and negatively correlated with microbial α-diversity. These findings demonstrated that river-lake connectivity directly influenced nitrogen concentrations, which in turn indirectly modulated microbial diversity.
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publisher Frontiers Media S.A.
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spelling doaj-art-a251dcc9ac0a4802b6c139564d9edada2025-08-20T03:03:25ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2025-04-011610.3389/fmicb.2025.15635781563578Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected systemHaoda Chen0Lulu Zhang1Lulu Zhang2Zishuai Zheng3Yuang Gao4Yu Zhao5College of Environment Science and Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, ChinaCollege of Environment Science and Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, ChinaBiotechnology Laboratory for Pollution Control in Hebei, Shijiazhuang, ChinaCollege of Environment Science and Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, ChinaCollege of Environment Science and Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, ChinaState Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Science, Beijing, ChinaIntensified agricultural and urban activities have exacerbated nitrogen pollution, posing a severe threat to freshwater ecosystems, particularly under intensified agricultural and urbanization activities. This study systematically examined Baiyangdian Lake (BYD) and its principal inflowing rivers, namely Fu River (FH), Baigouyin River (BGY), and Xiaoyi River (XY) to characterize the spatio-temporal distribution, primary nitrogen sources, and the impact on sediment microbial community structure. Results indicated pronounced seasonal variations in both nitrogen pollution loads and sources, with riverine nitrogen levels rising markedly from dry season (May) to wet season (August). Atmospheric deposition accounted for 43.9% of the nitrogen input dry season, whereas in wet season, agricultural fertilizers and sewage contributed 23.3 and 26.4%, respectively. Additionally, microbial communities exhibited distinct temporal and spatial patterns, with significantly higher diversity and species richness being during the wet season. The, microbial composition shifted, as evidenced by a decline in Proteobacteria and increases in Firmicutes and Actinobacteriota. River-lake connectivity emerged as a critical factor, with FH displaying a notably higher connectivity index in wet season compared to BGY and XY rivers. Structural equation modeling (SEM) analysis further revealed that river-lake connectivity was significantly and positively correlated with nitrogen pollution, was significantly and negatively correlated with microbial α-diversity. These findings demonstrated that river-lake connectivity directly influenced nitrogen concentrations, which in turn indirectly modulated microbial diversity.https://www.frontiersin.org/articles/10.3389/fmicb.2025.1563578/fullnitrogen pollutionmicrobial community structurespatio-temporal distributionriver-lake connectivityriver-lake systems
spellingShingle Haoda Chen
Lulu Zhang
Lulu Zhang
Zishuai Zheng
Yuang Gao
Yu Zhao
Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected system
Frontiers in Microbiology
nitrogen pollution
microbial community structure
spatio-temporal distribution
river-lake connectivity
river-lake systems
title Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected system
title_full Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected system
title_fullStr Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected system
title_full_unstemmed Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected system
title_short Hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river-lake connected system
title_sort hydrological connectivity shape the nitrogen pollution sources and microbial community structure in a river lake connected system
topic nitrogen pollution
microbial community structure
spatio-temporal distribution
river-lake connectivity
river-lake systems
url https://www.frontiersin.org/articles/10.3389/fmicb.2025.1563578/full
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AT luluzhang hydrologicalconnectivityshapethenitrogenpollutionsourcesandmicrobialcommunitystructureinariverlakeconnectedsystem
AT zishuaizheng hydrologicalconnectivityshapethenitrogenpollutionsourcesandmicrobialcommunitystructureinariverlakeconnectedsystem
AT yuanggao hydrologicalconnectivityshapethenitrogenpollutionsourcesandmicrobialcommunitystructureinariverlakeconnectedsystem
AT yuzhao hydrologicalconnectivityshapethenitrogenpollutionsourcesandmicrobialcommunitystructureinariverlakeconnectedsystem