| 引用本文: | 秦宇,杨博逍,李哲,赫斌,杜海龙.夏季金沙江下游水-气界面CO2、CH4通量特征初探.湖泊科学,2017,29(4):991-999. DOI:10.18307/2017.0423 |
| QIN Yu,YANG Boxiao,LI Zhe,HE Bin,DU Hailong.CO2 and CH4 flux across water-air interface in summer in the downstream of Jinsha River, Southwest China. J. Lake Sci.2017,29(4):991-999. DOI:10.18307/2017.0423 |
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| 夏季金沙江下游水-气界面CO2、CH4通量特征初探 |
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秦宇1, 杨博逍1, 李哲2, 赫斌3, 杜海龙2
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1.重庆交通大学水利水运工程教育部重点实验室, 重庆 400074;2.中国科学院重庆绿色智能技术研究院, 中国科学院水库水环境重点实验室, 重庆 400714;3.重庆大学城市建设与环境工程学院, 重庆 400045
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| 摘要: |
| 河流是连接大陆和海洋两大碳库的桥梁，在全球碳循环中的作用举足轻重. 金沙江作为长江的上游段，对区域碳循环及区域化学风化的影响非常重要. 于2015年8月8-18日对金沙江下游水-气界面CO2与CH4通量特征进行监测与分析. 采用顶空平衡法结合薄边界层模型估算法计算表层水体CO2与CH4的分压以及水-气界面的交换通量，并分析环境变量与其之间的相关性. 研究发现，金沙江下游表层水体p（CO2）平均值为2724.84±477.18 μatm，表层水体p（CH4）平均值为59.96±6.74 μatm；水-气界面CO2通量平均值为2.24±0.50 mmol/（m2·h），CH4通量平均值为0.000163±0.00009 mmol/（m2·h），通量与分压趋势基本保持一致. 表层水体p（CO2）与溶解性无机碳浓度、碱度均呈显著正相关，而p（CH4）与水温、叶绿素a浓度均呈显著正相关，CO2通量与p（CO2）、溶解性无机碳浓度、碱度均呈正相关，CH4通量与p（CH4）、风速均呈正相关，其他环境因素对通量的影响不明显，仍需进一步研究. 金沙江下游水-气界面CH4扩散通量较低，而CO2扩散通量在世界主要河流中属于中等水平. |
| 关键词: 金沙江 CO2 CH4 水-气界面通量 顶空平衡法 薄边界层模型估算法 影响因素 |
| DOI：10.18307/2017.0423 |
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| 基金项目:国家自然科学基金项目（51679226，51609026）和重庆市教委科学技术研究项目（KJ1500506）联合资助. |
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| CO2 and CH4 flux across water-air interface in summer in the downstream of Jinsha River, Southwest China |
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QIN Yu1, YANG Boxiao1, LI Zhe2, HE Bin3, DU Hailong2
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1.Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University 400074, P.R.China;2.CAS Key Lab of Reservoir Environment, Chongqing Institute of Green and Intelligence Technology, Chinese Academy of Sciences, Chongqing 400714, P.R.China;3.College of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, P.R.China
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| Abstract: |
| Rivers connect continent and ocean, the two major carbon pools, which play an important role in global carbon cycling. Jinsha River is the upstream of Yangtze River and significantly influences carbon cycle and chemical weathering in the watershed. Water-air CO2 and CH4 fluxes were measured from August 8 to 18, 2015 in the downstream of Jinsha River. The study used the headspace equilibrium method and thin boundary layer method to estimate p(CO2) and p(CH4) in surface water and exchange fluxes between water and air. Results showed that in summer p(CO2) and CO2 fluxes were 2724.84±477.18 μatm and 2.24±0.50 mmol/(m2·h), respectively, the p(CH4) and CH4 fluxes were 59.96±6.74 μatm and 0.000163±0.00009 mmol/(m2·h), and the trend of differential pressure was consistent with flux. p(CO2) has significant positive correlation with dissolved inorganic carbon and total alkalinity. p(CH4) has significant positive correlation with water temperature and chlorophyll-a. Air-water CO2 fluxes was mainly impacted by p(CO2), dissolved inorganic carbon and total alkalinity. CH4 fluxes was significantly impacted by p(CH4) and wind speed. Impacts from other environmental factors such as nutrients were not obvious, and more studies shall be conducted to elucidate the variance of flux and its controlling factors. The air-water CH4 fluxes of Jinsha River was low, and the air-water CO2 fluxes was in medium level, comparing to other major rivers in the world. |
| Key words: Jinsha River CO2 CH4 water-air flux headspace equilibrium method thin boundary layer method environmental factors |
