地学前缘 ›› 2026, Vol. 33 ›› Issue (1): 25-38.DOI: 10.13745/j.esf.sf.2025.10.10

• 地下水-关键带相互作用与修复 • 上一篇    下一篇

垂向潜流带CO2产量主控因素转变阈值研究

周诗雨1(), 杨轶群1, 戴君一1, 高迪1, 李燊琰1, 王礼春1,2,3,*()   

  1. 1.天津大学 地球系统科学学院, 天津 300072
    2.天津大学 天津环渤海滨海地球关键带国家野外科学观测研究站, 天津 300072
    3.天津市 “环渤海地球关键带科学与可持续发展” 重点实验室, 天津 300072
  • 收稿日期:2025-07-19 修回日期:2025-09-20 出版日期:2026-01-25 发布日期:2025-11-10
  • 通信作者: *王礼春(1985—),男,博士,教授,博士生导师,主要从事环境流体动力学及物质迁移过程研究。E-mail: wanglichun@tju.edu.cn
  • 作者简介:周诗雨(2001—),女,硕士研究生,主要从事潜流带生物地球化学反应研究。E-mail: 2023231039@tju.edu.cn
  • 基金资助:
    国家自然科学基金重大项目(42293262);天津市科技计划项目(科技创新基地建设);天津市科技计划项目(24ZYJDJC00350);国家自然基金面上项目(42477063);河北沧州平原区地下水与地面沉降国家野外科学观测研究站开放课题(CGLOS-2022-03)

Study on the critical thresholds of identifying the transitions of dominant controlling factors for CO2 production in vertical hyporheic zones

ZHOU Shiyu1(), YANG Yiqun1, DAI Junyi1, GAO Di1, LI Shenyan1, WANG Lichun1,2,3,*()   

  1. 1. School of Earth System Science, Tianjin University, Tianjin 300072, China
    2. Critical Zone Observatory of Bohai Coastal Region, Tianjin University, Tianjin 300072, China
    3. Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin 300072, China
  • Received:2025-07-19 Revised:2025-09-20 Online:2026-01-25 Published:2025-11-10

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摘要：

河流碳排放是全球碳循环的关键环节,潜流带作为其重要组成部分,对碳排放具有显著影响。潜流带CO2产生和排放过程受河流温度和溶解氧(dissolved oxygen,DO)等动态因素控制,然而,目前大多数模型仍基于稳态条件,难以准确捕捉CO2产量动态变化,导致碳排放估算存在较大不确定性。为此,本研究构建了典型沙丘形态的潜流带生物地球化学耦合模型,引入日周期性变化的河流温度和DO,将其作为潜流带边界条件,利用COMSOL Multiphysics对耦合模型进行数值求解,并通过达姆科勒数(Damköhler number,Da)和相关系数来分析河流温度和DO波动边界条件对垂向潜流带CO2产量的动态影响及调控机制。研究结果表明,温度和DO对CO2产生速率具有显著调控作用且存在竞争关系。在潜流带平均滞留时间小于15.7 h时,存在温度阈值,使CO2产生速率的主控因素随河流平均温度发生转换。具体表现为:在温度阈值以下,主控因素为温度波动;而在温度阈值以上,主控因素为DO波动。更为重要的是,当平均滞留时间大于15.7 h时,主控因素转换机制不存在。本研究揭示了河流温度和DO波动对潜流带中CO2产生速率的调控机制,为理解河流碳循环提供了新视角,有助于准确评估潜流带在全球碳循环中的作用,并为预测河流生态系统对气候变化的响应提供理论依据。

关键词: 潜流带, 有氧呼吸, 温度阈值, CO2, 生物地球化学过程, 耦合模型

Abstract:

Riverine carbon emissions play a crucial role in the global carbon cycle, where the hyporheic zone (HZ) serves as a key component that significantly influences CO2 emission. The production of CO2 within the HZ is strongly affected by dynamic factors such as river temperature (T) and dissolved oxygen (DO). However, most existing models assumed that T and DO were time-invariant, leading to an inaccurate capture of the temporal variability of these processes, which ultimately caused significant uncertainty in riverine carbon emission estimation. To address this problem, this study developed a coupled model integrating physical and biogeochemical processes by including the periodic variations of T and DO for a representative bedform-induced HZ. The model was numerically solved using COMSOL Multiphysics, and the dynamic impacts of river T and DO on CO2 production within the HZ were analyzed using the Damköhler number (Da) and correlation coefficients. Our results indicate that both T and DO competitively regulate CO2 production rate. Moreover, when the mean residence time of HZ is less than 15.7 h, a critical temperature threshold (Tc) exists, above or below which the dominant role in regulating CO2 production rate shifts between T and DO. Specifically, when the mean river temperature is below Tc, the CO2 production is primarily controlled by T fluctuations, whereas above Tc, it is dominated by DO fluctuations. Notably, this shift in dominant role disappears when the mean residence time exceeds 15.7 h. Our study reveals how T and DO fluctuations impact dynamics of CO2 production in the HZ, and could improve the assessment of the HZ’s contribution to the global carbon cycle, particularly for predicting how the river ecosystem responds to climate change.

Key words: hyporheic zone, aerobic respiration, temperature threshold, CO2, biogeochemical processes, coupled model

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