中文关键词CO₂释放水-气界面日变化季节变化环境因子 英文关键词CO₂ emissionwater-air interfacedaily changeseasonal changeenvironmental factors

作者	单位	E-mail
罗佳宸	中国科学院重庆绿色智能技术研究院, 重庆 400074 中国科学院大学, 北京 100049	18696798071@163.com
李思悦	中国科学院重庆绿色智能技术研究院, 重庆 400074	syli2006@163.com

中文摘要 为研究河流水-气界面CO₂通量的季节和日变化特征；于2016年7月15~17日以及2017年11月4~6日对三峡库区嘉陵江支流竹溪河进行定点定时采集表层水样，并同步监测关键环境因子，采用亨利定律结合薄边界层模型计算其水-气界面CO₂通量F（CO₂）.结果表明，竹溪河表层水CO₂分压p（CO₂）及界面CO₂脱气通量呈现出显著的日间和季节变化，以及明显的日内变化特征：在上午09：00前后达到释放高峰，随后波动下降；水-气界面CO₂通量日间均值分别为（100.9±31.6）、（78.6±12.1）、（83.9±29.7）、（137.5±42.1）、（147.6±34.0）、（132.4±21.7）mmol·（m²·d）^-1；并表现出夏季表层水体CO₂释放通量明显低于秋季，其均值分别为（87.8±27.5）mmol·（m²·d）^-1和（139.2±34.0）mmol·（m²·d）^-1；总体表现出大气CO₂源的特征.竹溪河p（CO₂）和F（CO₂）受到诸多环境因子的影响，相关分析表明，pH、碱度、水温和气温是主要环境影响因子，CO₂释放通量可以用pH和碱度预测. 英文摘要 Diurnal and seasonal characterization of CO₂ partial pressure p(CO₂) and CO₂ areal flux F(CO₂) at the water-air interface in an anthropogenic river in the Three Gorges Reservoir area was studied. A tributary of the Jialing River in Chongqing Municipality was chosen, and daily and seasonal samples were taken in summer and autumn, focusing on riverine p(CO₂), F(CO₂), and their associated controls. Henry's law combined with the thin boundary layer model was adopted to estimate the CO₂ flux via the water-air interface. The results indicated that F(CO₂) was not high on average, namely (87.8±27.5) mmol·(m²·d)^-1 and (139.2±34.0) mmol·(m²·d)^-1 in summer and autumn, respectively. The water-air interface F(CO₂) showed significant hourly, daily, and seasonal variations. CO₂ release peaked around 09:00 and then slightly decreased. We also found that pH, alkalinity, water, and temperature were significantly related to p(CO₂) and F(CO₂), whereas pH and alkalinity were the best predictors of F(CO₂). This study aids understanding of the impacts of urbanization on CO₂ emissions in the rivers and helps to re-evaluate local riverine CO₂ budgets.

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