Increased CH4 and CO2 production and diffusive flux in rivers with high urbanization
编号:1486 访问权限:仅限参会人 更新:2024-12-31 21:34:49 浏览:214次 拓展类型1

报告开始:2025年01月16日 13:30(Asia/Shanghai)

报告时间:15min

所在会场:[S18] Session 18-The River-Estuary-Bay Continuum: Unveiling the Carbon and Nitrogen Cycles Under Global Change [S18-2] The River-Estuary-Bay Continuum: Unveiling the Carbon and Nitrogen Cycles Under Global Change

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摘要
Rapid urbanization considerably influences carbon biogeochemical cycle of river systems. Our knowledge is, however, limited on the magnitude and extent of urbanization effects on CH4 and CO2 fluxes from inland waters (river, lakes and reservoir). Field samplings and measurements were conducted in 27 river segments of two 4th-order and three 3rd-order tributary rivers in China’s mountainous Three Gorges Reservoir (TGR) area to underscore the impacts of urbanization intensity on riverine dissolved gas concentrations and gases diffusive fluxes. pCO2 level was significantly higher in the river segments with increased proportion of urban land. Both pCO2 level and CO2 flux rate of the higher urban intensity River Taohua showing the highest urban land coverage (3872 μatm and 574 mmol m-2 d-1) were significantly higher than those of the Nan River (1737 μatm and 218 mmol m-2 d-1) and Puli River (1218 μatm and 130 mmol m-2 d-1) that drain less urbanized land areas. We found that pCO2 was positively correlated with the concentrations of chlorophyll-a (Chl-a), nutrients (i.e., TDN and TDP), dissolved organic carbon (DOC) and colony-forming units (CFU), and was negatively correlated with pH and dissolved oxygen (DO). pH and DOC loading were the better parameters for predicting pCO2 in the river draining more urbanized land area, and pH and Chl-a were the better parameters for predicting pCO2 in the river draining less urbanized area. dCH4 concentration (3546 ± 6770 nmol L-1) in the river segments draining higher urban area (20% ≤ urban land proportion ≤ 46%) was 5-6 times higher than those (615 ± 627 nmol L-1 and 764 ± 708 nmol L-1) in the river segments draining less urban area (0.1% ≤ urban land proportion < 2% and 2 ≤ urban land proportion < 20%). Total nitrogen (TN) showed the most powerful prediction capacity when compared to other water parameters. Nutrient elements could predict dCH4 well in rivers draining higher urban areas (urban ≥ 2%), which also reflected the lateral input of pollutants (e.g., TN, ammonia nitrogen, total phosphorus and dissolved oxygen). River bottom sediment fraction contributed to trapping organic matter and nutrients as well as to oxic and anoxic conditions, thereby determining reach-scale spatial patterns of dCH4 concentration. A meta-analysis of urbanization effects on C emission across China was also revealed. Being rapid urbanization a common feature, we suggest that riverine GHGs emissions will increase into the future under urban development.

 
关键词
urban rivers, human activities, greenhouse gases, gas fluxes, climate change
报告人
Siyue Li
Professor Wuhan Institute of Technology

稿件作者
Siyue Li Wuhan Institute of Technology
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重要日期
  • 会议日期

    01月13日

    2025

    01月17日

    2025

  • 09月27日 2024

    初稿截稿日期

  • 01月17日 2025

    注册截止日期

主办单位
State Key Laboratory of Marine Environmental Science, Xiamen University
承办单位
State Key Laboratory of Marine Environmental Science, Xiamen University
Department of Earth Sciences, National Natural Science Foundation of China
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