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Shi K, Zhao Y, Wu C, Geng Y, Zhou S, Chai B. Revealing the distribution characteristics and key driving factors of dissolved organic matter in Baiyangdian Lake inflow rivers from different seasons and sources. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175768. [PMID: 39191325 DOI: 10.1016/j.scitotenv.2024.175768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2024] [Revised: 07/23/2024] [Accepted: 08/22/2024] [Indexed: 08/29/2024]
Abstract
The river course is a transitional area connecting the source and receiving water bodies. The dissolved organic matter (DOM) in the river course is an important factor affecting the aquatic environment and ecological health. However, there are shortcomings in studying the differences and quantitative contributions of river DOM in different seasons and sources. In this study, ultraviolet-visible (UV-vis) and three-dimensional fluorescence spectra were used to characterize the optical properties, analyze the spatiotemporal changes, and establish the quantitative relationship between environmental factors and DOM in the inflow rivers of Baiyangdian Lake. The results showed that the relative DOM concentrations in summer and autumn were significantly higher than those in the other seasons (P < 0.001) and that the DOM source (SR < 1) was mainly exogenous. The fluorescence abundance of protein-like substances (C1 + C2 + C3) was the highest in spring, whereas that of humus C4 was the highest in autumn. Moreover, the inflow rivers exhibited strong autogenetic characteristics (BIX > 1) throughout the year. Self-organizing maps (SOM) indicated that the main driving factors of water quality were NO3--N in spring, autumn, and winter and DO, pH, and chemical oxygen demand (COD) in summer. Random forest analysis showed that the fluorescent components (C1-C4) were closely related to the migration and transformation of nitrogen, and pH and nitrogen were the main predictors of each component. The Mantel test and structural equation model (SEM) showed that temperature and NO3--N significantly influenced the DOM concentration, components, and molecular properties in different seasons. Moreover, the river source also affected the distribution mechanism of DOM in the water body. Our study comprehensively analyzed the response of DOM in inflow rivers in different seasons and water sources, providing a basis for further understanding the driving mechanisms of water quality.
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Affiliation(s)
- Kun Shi
- School of Civil Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Yuting Zhao
- Hebei Key Laboratory of Pollution Prevention Biotechnology, College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Chenbin Wu
- Hebei Key Laboratory of Pollution Prevention Biotechnology, College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Yuting Geng
- Hebei Key Laboratory of Pollution Prevention Biotechnology, College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Shilei Zhou
- School of Civil Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China; Hebei Key Laboratory of Pollution Prevention Biotechnology, College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China.
| | - Beibei Chai
- Collaborative Innovation Center for Intelligent Regulation and Comprehensive Management of Water Resources, School of Water Conservancy and Hydroelectric, Hebei University of Engineering, Handan 056038, China
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Wang C, Xv Y, Wu Z, Li X, Li S. Denitrification regulates spatiotemporal pattern of N 2O emission in an interconnected urban river-lake network. WATER RESEARCH 2024; 251:121144. [PMID: 38277822 DOI: 10.1016/j.watres.2024.121144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 01/08/2024] [Accepted: 01/14/2024] [Indexed: 01/28/2024]
Abstract
Urban rivers are hotspots of N2O production and emission. Interconnected river-lake networks are constructed to improve the water quality and hydrodynamic conditions of urban rivers in many cities of China. However, the impact of the river-lake connectivity project on N2O production and emission remains unclear. This study investigated dissolved N2O and emission of the river-lake network in Wuhan City, China from March 2021 to December 2021. The results showed that river-lake connection greatly decreased riverine Nitrogen (N) concentration and increased dissolved oxygen (DO) concentration compare to traditional urban rivers. N2O emissions from the urban river interconnected with lakes (LUR: 67.3 ± 92.6 μmol/m2/d) were much lower than those from the traditional urban rivers (UR: 467.3 ± 1075.7 μmol/m2/d) and agricultural rivers (AR: 20.4 ± 15.3μmol/m2/d). Regression tree analysis suggested that the N2O concentrations were extremely high when hypoxia exists (DO < 1.6 mg/L), and TDN was the primary factor regulating N2O concentrations when hypoxia does not occur. Thus, we ascribe the low N2O emission in the LUR and AR to the lower N contents and higher DO concentrations. The microbial process of N2O production and consumption were quantitatively estimated by isotopic models. The mean proportion of denitrification derived N2O (fbD) was 63.5 %, 55.6 %, 42.3 % and 42.7 % in the UR, LUR, lakes and AR, suggested denitrification dominated N2O production in the urban rivers, but nitrification dominated N2O production in the lakes and AR. The positive correlation between logN2O and fbD suggested that denitrification is the key process to regulate the N2O production and emission. The abundance of denitrification genes (nirS and nirK) was much higher than that of nitrification genes (amoA and amoB), also evidenced that denitrification was the main N2O source. Therefore, river-lake interconnected projects changed the nutrients level and hypoxic condition, leading to the inhibition of denitrification and nitrification, and ultimately resulting in a decrease of N2O production and emission. These results advance the knowledge on the microbial processes that regulate N2O emissions in inland waters and illustrate the integrated management of water quality and N2O emission.
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Affiliation(s)
- Chunlin Wang
- Institute of Changjiang Water Environment and Ecological Security, School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, 206 Guanggu 1st Road, Wuhan 430205, China
| | - Yuhan Xv
- Institute of Changjiang Water Environment and Ecological Security, School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, 206 Guanggu 1st Road, Wuhan 430205, China
| | - Zefeng Wu
- Institute of Changjiang Water Environment and Ecological Security, School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, 206 Guanggu 1st Road, Wuhan 430205, China
| | - Xing Li
- Institute of Changjiang Water Environment and Ecological Security, School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, 206 Guanggu 1st Road, Wuhan 430205, China.
| | - Siyue Li
- Institute of Changjiang Water Environment and Ecological Security, School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, 206 Guanggu 1st Road, Wuhan 430205, China.
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Li X, He Y, Wang X, Chen H, Liu T, Que Y, Yuan X, Wu S, Zhou T. Watershed urbanization dominated the spatiotemporal pattern of riverine methane emissions: Evidence from montanic streams that drain different landscapes in Southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 873:162343. [PMID: 36813197 DOI: 10.1016/j.scitotenv.2023.162343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Methane (CH4) emissions from streams are an important component of the global carbon budget of freshwater ecosystems, but these emissions are highly variable and uncertain at the temporal and spatial scales associated with watershed urbanization. In this study, we conducted investigations of dissolved CH4 concentrations and fluxes and related environmental parameters at high spatiotemporal resolution in three montanic streams that drain different landscapes in Southwest China. We found that the average CH4 concentrations and fluxes in the highly urbanized stream (2049 ± 2164 nmol L-1 and 11.95 ± 11.75 mmol·m-2·d-1) were much higher than those in the suburban stream (1021 ± 1183 nmol L-1 and 3.29 ± 3.66 mmol·m-2·d-1) and were approximately 12.3 and 27.8 times those in the rural stream, respectively. It provides powerful evidence that watershed urbanization strongly enhances riverine CH4 emission potential. Temporal patterns of CH4 concentrations and fluxes and their controls were not consistent among the three streams. Seasonal CH4 concentrations in the urbanized streams had negative exponential relationships with monthly precipitation and demonstrated greater sensitivity to rainfall dilution than to the temperature priming effect. Additionally, the CH4 concentrations in the urban and semiurban streams showed strong, but opposite, longitudinal patterns, which were closely related to urban distribution patterns and the HAILS (human activity intensity of the land surface) within the watersheds. High carbon and nitrogen loads from sewage discharge in urban areas and the spatial arrangement of the sewage drainage contributed to the different spatial patterns of the CH4 emissions in different urbanized streams. Moreover, CH4 concentrations in the rural stream were mainly controlled by pH and inorganic nitrogen (NH4+ and NO3-), while urban and semiurban streams were dominated by total organic carbon and nitrogen. We highlighted that rapid urban expansion in montanic small catchments will substantially enhance riverine CH4 concentrations and fluxes and dominate their spatiotemporal pattern and regulatory mechanisms. Future work should consider the spatiotemporal patterns of such urban-disturbed riverine CH4 emissions and focus on the relationship between urban activities with aquatic carbon emissions.
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Affiliation(s)
- Xianxiang Li
- Chongqing Key Laboratory of Wetland Science Research of the Upper Reaches of the Yangtze River, Chongqing 401331, China; Chongqing Observation and Research Station of Earth Surface Ecological Processes in Three Gorges Reservoir Area, Chongqing 405400, China; School of Geography and Tourism, Chongqing Normal University, Chongqing 400047, China
| | - Yixin He
- Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization, Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China
| | - Xiaofeng Wang
- Chongqing Key Laboratory of Wetland Science Research of the Upper Reaches of the Yangtze River, Chongqing 401331, China; Chongqing Observation and Research Station of Earth Surface Ecological Processes in Three Gorges Reservoir Area, Chongqing 405400, China; School of Geography and Tourism, Chongqing Normal University, Chongqing 400047, China.
| | - Huai Chen
- Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization, Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan 624400, China
| | - Tingting Liu
- Chongqing Key Laboratory of Wetland Science Research of the Upper Reaches of the Yangtze River, Chongqing 401331, China; East China Normal University, Shanghai 200241, China
| | - Yizi Que
- Chongqing Key Laboratory of Wetland Science Research of the Upper Reaches of the Yangtze River, Chongqing 401331, China; Chongqing Observation and Research Station of Earth Surface Ecological Processes in Three Gorges Reservoir Area, Chongqing 405400, China; School of Geography and Tourism, Chongqing Normal University, Chongqing 400047, China
| | - Xingzhong Yuan
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China
| | - Shengnan Wu
- Chongqing Observation and Research Station of Earth Surface Ecological Processes in Three Gorges Reservoir Area, Chongqing 405400, China; East China Normal University, Shanghai 200241, China
| | - Ting Zhou
- Chongqing Key Laboratory of Wetland Science Research of the Upper Reaches of the Yangtze River, Chongqing 401331, China; Chongqing Observation and Research Station of Earth Surface Ecological Processes in Three Gorges Reservoir Area, Chongqing 405400, China; School of Geography and Tourism, Chongqing Normal University, Chongqing 400047, China
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Tang W, Xu YJ, Ni M, Li S. Land use and hydrological factors control concentrations and diffusive fluxes of riverine dissolved carbon dioxide and methane in low-order streams. WATER RESEARCH 2023; 231:119615. [PMID: 36682236 DOI: 10.1016/j.watres.2023.119615] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 12/03/2022] [Accepted: 01/13/2023] [Indexed: 06/17/2023]
Abstract
We analyzed the impacts of land use/land cover types on carbon dioxide (CO2) and methane (CH4) concentration and diffusion in 1st to 4th Strahler order tributaries of the Longchuan River to the upper Yangtze River in China by using headspace equilibration method and CO2SYS program. Field sampling and measurements were conducted during the dry and wet seasons from 2017 to 2019. The average of calculated CO2 partial pressure (pCO2, mean ± SD: 2389 ± 3220 μatm) by CO2SYS program was 1.9-fold higher than the value (mean ± SD: 1230 ± 1440 μatm) 10 years ago in the Longchuan River basin, where the urban land area increased by a factor of 7 times. Further analysis showed that corrected pCO2 by headspace method and dissolved CH4 (dCH4) decrease as the stream order and flow velocity increase. The pCO2 and dCH4 in the wet season was lower than that in the dry season. The explanatory ability of land use types on the variation of corrected pCO2 and dCH4 was stronger at the reach scale than at the riparian and catchment scales in two seasons. Urban land at reach scale further showed much higher explanation on corrected pCO2 and dCH4 than cropland, grassland and forest land in the wet season. The Longchuan River emits approximately 112.5 kt CO2-C and 1.0 kt CH4-C per year, being 1.7-fold of the total lateral export of dissolved inorganic and dissolved organic carbon (68.3 kt C y-1). The findings highlight the scale effects of land use on the observed seasonality in dissolved carbon gases in low-order streams.
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Affiliation(s)
- Wei Tang
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
| | - Y Jun Xu
- School of Renewable Natural Resources, Coastal Studies Institute, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Maofei Ni
- College of Eco-Environmental Engineering, The karst environmental geological hazard prevention laboratory of Guizhou Minzu University, Guizhou Minzu University, Guiyang 550025, China
| | - Siyue Li
- Institute of Changjiang Water Environment and Ecological Security, School of Environmental Ecology and Biological Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, Wuhan 430205, China.
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