三峡库区主要河流秋季pCO_2及其影响因素
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摘要
于2015年10月对三峡库区主要河流表层水体中的溶解性碳组成进行了测定,结合水文地质条件和水化学关键指标,对河流表层水体二氧化碳分压(p CO_2)的空间变化及影响因素进行了研究,并利用模型法分析了水-气界面CO_2通量特征.结果表明,三峡库区主要河流秋季pCO_2介于18.75~296.31 Pa之间,均值为(141.06±77.51)Pa;河流CO_2脱气通量平均值为(101.1±78.0)mmol·(m2·d)-1,其中86%的采样点位表现为大气CO_2源的特征.p CO_2与DO和pH显著负相关,与HCO-3显著正相关.由于山区河流流速快和水力停留时间短等特征,河流有机碳原位呼吸是导致p CO_2与DO和pH很强的负相关关系的主要原因.研究结果为准确估算三峡库区河流CO_2逸出量提供了重要的数据支撑.
An extensive investigation on the main tributaries of the Three Gorges Reservoir( TGR) region was conducted in autumn( Oct. 2015),with focuses on riverine CO_2 partial pressure( p CO_2) and its associated controls. Our results indicated that p CO_2 in the main rivers of the TGR region ranged from 18. 75 to 296. 31 Pa,with a mean value of( 141. 06 ± 77. 51) Pa in the autumn,which was much higher than the atmospheric CO_2 concentration. Therefore,the studied rivers acted as an atmospheric CO_2 source,and the mean CO_2 emission rate to the atmosphere was estimated at( 101. 1 ± 78. 0) mmol·( m~2·d)-1. The highest and lowest values were( 131. 9 ±101. 8) and( 70. 3 ± 54. 3) mmol·( m2·d)-1,respectively. p CO_2 in the main rivers of the TGR area was significantly related to DO,pH,and bicarbonate. Furthermore,the biogeochemical process of within-river respiration of organic carbon rather than photosynthesis resulted in negative relationships between p CO_2 and DO or pH because of the high velocities and short residence time in these mountainous rivers and streams. Our results will help to accurately develop the carbon budget for the rivers of the Three Gorges Region.
An extensive investigation on the main tributaries of the Three Gorges Reservoir( TGR) region was conducted in autumn( Oct. 2015),with focuses on riverine CO_2 partial pressure( p CO_2) and its associated controls. Our results indicated that p CO_2 in the main rivers of the TGR region ranged from 18. 75 to 296. 31 Pa,with a mean value of( 141. 06 ± 77. 51) Pa in the autumn,which was much higher than the atmospheric CO_2 concentration. Therefore,the studied rivers acted as an atmospheric CO_2 source,and the mean CO_2 emission rate to the atmosphere was estimated at( 101. 1 ± 78. 0) mmol·( m~2·d)-1. The highest and lowest values were( 131. 9 ±101. 8) and( 70. 3 ± 54. 3) mmol·( m2·d)-1,respectively. p CO_2 in the main rivers of the TGR area was significantly related to DO,pH,and bicarbonate. Furthermore,the biogeochemical process of within-river respiration of organic carbon rather than photosynthesis resulted in negative relationships between p CO_2 and DO or pH because of the high velocities and short residence time in these mountainous rivers and streams. Our results will help to accurately develop the carbon budget for the rivers of the Three Gorges Region.
引文
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[27]李丽,蒲俊兵,李建鸿,等.亚热带典型岩溶溪流水气界面CO2交换通量变化过程及其环境影响[J].环境科学,2016,37(7):2487-2495.Li L,Pu J B,Li J H,et al.Variations of CO2exchange fluxes across water-air interface and environmental meaning in a surface stream in subtropical karst area,SW China[J].Environmental Science,2016,37(7):2487-2495.
[28]蒋滔,郭劲松,李哲,等.三峡水库不同运行状态下支流澎溪河水-气界面温室气体通量特征初探[J].环境科学,2012,33(5):1463-1470.Jiang T,Guo J S,Li Z,et al.Air-water surface greenhouse gas flux in Pengxi river at different operational stages of the Three Gorges Reservoir[J].Environmental Science,2012,33(5):1463-1470.
[29]王亮,肖尚斌,刘德富,等.香溪河库湾夏季温室气体通量及影响因素分析[J].环境科学,2012,33(5):1471-1475.Wang L,Xiao S B,Liu F D,et al.Fluxes of greenhouse gases from Xiangxi river in summer and their influencing factors[J].Environmental Science,2012,33(5):1471-1475.
[30]李凌宇,于瑞宏,田明扬,等.黄河二氧化碳逸出时空变化及其影响因素——以头道拐水文站为例[J].生态学报,2017,37(22):7636-7646.Li L Y,Yu R H,Tian M Y,et al.Spatial-temporal variations and influencing factors of carbon dioxide evasion from the Yellow river:an example of the Toudaoguai Gauging Station[J].Acta Ecologica Sinica,2017,37(22):7636-7646.
[31]Dos Santos M A,Rosa L P,Sikar B,et al.Gross greenhouse gas fluxes from hydro-power reservoir compared to thermo-power plants[J].Energy Policy,2006,34(4):481-488.
[32]St Louis V L,Kelly C A,Ducheminé,et al.Reservoir surfaces as sources of greenhouse gases to the atmosphere:a global estimate:reservoirs are sources of greenhouse gases to the atmosphere,and their surface areas have increased to the point where they should be included in global inventories of anthropogenic emissions of greenhouse gases[J].Bio Science,2000,50(9):766-775.
[33]Richey J E,Melack J M,Aufdenkampe A K,et al.Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2[J].Nature,2002,416(6881):617-620.
[2]Meybeck M.Carbon,nitrogen,and phosphorus transport by world rivers[J].American Journal of Science,1982,282(4):401-450.
[3]Dyer K R.Biogeochemistry of major world river[J].Aquatic Conservation Marine&Freshwater Ecosystems,1991,1(2):189-190.
[4]Raymond P A,Hartmann J,Lauerwald R,et al.Global carbon dioxide emissions from inland waters[J].Nature,2013,503(7476):355-359.
[5]Huang W M,Bi Y H,Hu Z Y,et al.Spatio-temporal variations of GHG emissions from surface water of Xiangxi River in Three Gorges Reservoir region,China[J].Ecological Engineering,2015,83:28-32.
[6]Sawakuchi H O,Neu V,Ward N D,et al.Carbon dioxide emissions along the lower Amazon river[J].Frontiers in Marine Science,2017,4:76.
[7]Neal C,Harrow M,Williams R J.Dissolved carbon dioxide and oxygen in the river Thames:spring-summer 1997[J].Science of the Total Environment,1998,210-211:205-217.
[8]Li S Y,Lu X X,Bush R T.CO2partial pressure and CO2emission in the Lower Mekong River[J].Journal of Hydrology,2013,504:40-56.
[9]Abril G,Martinez J M,Artigas L F,et al.Amazon River carbon dioxide outgassing fuelled by wetlands[J].Nature,2014,505(7483):395-398.
[10]Li S Y,Lu X X,He M,et al.Daily CO2partial pressure and CO2outgassing in the upper Yangtze River basin:a case study of the Longchuan River,China[J].Journal of Hydrology,2012,466-467:141-150.
[11]Van Geldern R,Schulte P,Mader M,et al.Spatial and temporal variations of p CO2,dissolved inorganic carbon and stable isotopes along a temperate karstic watercourse[J].Hydrological Processes,2015,29(15):3423-3440.
[12]张陶,李建鸿,蒲俊兵,等.桂江流域夏季水-气界面CO2脱气的空间变化及其影响因素[J].环境科学,2017,38(7):2773-2783.Zhang T,Li J H,Pu J B,et al.Spatial variations of CO2degassing across water-air interface and its impact factors in summer in Guijiang river,China[J].Environmental Science,2017,38(7):2773-2783.
[13]Dai M H,Yin Z Q,Meng F F,et al.Spatial distribution of riverine DOC inputs to the ocean:an updated global synthesis[J].Current Opinion in Environmental Sustainability,2012,4(2):170-178.
[14]吴学谦,操满,傅家楠,等.三峡水库夏季干流、支流(草堂河)水体的二氧化碳分压及扩散通量[J].上海大学学报(自然科学版),2015,21(3):311-318.Wu X Q,Cao M,Fu J N,et al.Partial pressure and diffusion flux of dissolved carbon dioxide in the main stream of the Three Gorge Reservoir and the Caotang River in summer[J].Journal of Shanghai University(Natural Science),2015,21(3):311-318.
[15]张军伟,雷丹,肖尚斌,等.三峡库区香溪河秋末至中冬CO2和CH4分压特征分析[J].环境科学,2016,37(8):2924-2931.Zhang J W,Lei D,Xiao S B,et al.Partial pressure of carbon dioxide and methane from autumn to winter in Xiangxi Bay of the Three Gorges Reservoir[J].Environmental Science,2016,37(8):2924-2931.
[16]Hunt C W,Salisbury J E,Vandemark D.Contribution of noncarbonate anions to total alkalinity and overestimation of p CO2in New England and New Brunswick rivers[J].Biogeosciences,2011,8(10):3069-3076.
[17]Soumis N,Canuel R,Lucotte M.Evaluation of two current approaches for the measurement of carbon dioxide diffusive fluxes from lentic ecosystems[J].Environmental Science&Technology,2008,42(8):2964-2969.
[18]UNESCO/IHA GHG.Greenhouse gas emissions related to freshwater reservoirs[R].World Bank Report.Washington,DC:The World Bank,2010.64-127.
[19]Cole J J,Caraco N F.Atmospheric exchange of carbon dioxide in a low-wind oligotrophic lake measured by the addition of SF6[J].Limnology and Oceanography,1998,43(4):647-656.
[20]奚姗姗,周春财,刘桂建,等.巢湖水体氮磷营养盐时空分布特征[J].环境科学,2016,37(2):542-547.Xi S S,Zhou C C,Liu G J,et al.Spatial and temporal distributions of nitrogen and phosphate in the Chaohu Lake[J].Environmental Science,2016,37(2):542-547.
[21]鲍林林,李叙勇.河流沉积物磷的吸附释放特征及其影响因素[J].生态环境学报,2017,26(2):350-356.Bao L L,Li X Y.Release and absorption characteristics of phosphorus in river sediment and their influential factors[J].Ecology and Environmental Sciences,2017,26(2):350-356.
[22]杨平,仝川.淡水水生生态系统温室气体排放的主要途径及影响因素研究进展[J].生态学报,2015,35(20):6868-6880.Yang P,Tong C.Emission paths and measurement methods for greenhouse gas fluxes from freshwater ecosystems:a review[J].Acta Ecologica Sinica,2015,35(20):6868-6880.
[23]Finlay K,Vogt R J,Bogard M J,et al.Decrease in CO2efflux from northern hardwater lakes with increasing atmospheric warming[J].Nature,2015,519(7542):215-218.
[24]Cole J J,Caraco N F.Carbon in catchments:connecting terrestrial carbon losses with aquatic metabolism[J].Marine and Freshwater Research,2001,52(1):101-110.
[25]彭昱.重庆三峡库区支流河口回水区富营养化研究[D].重庆:重庆大学,2005.2-52.Peng Y.Eutrophication investigation on the backwater reach of the branch river of the Three Gorges Reservoir[D].Chongqing:Chongqing University,2005.2-52.
[26]刘文,蒲俊兵,于奭,等.广西五里峡水库夏季溶解无机碳行为的初步研究[J].环境科学,2014,35(8):2959-2966.Liu W,Pu J B,Yu S,et al.Preliminary research on the feature of dissolved inorganic carbon in Wulixia reservoir in summer,Guangxi,China[J].Environmental Science,2014,35(8):2959-2966.
[27]李丽,蒲俊兵,李建鸿,等.亚热带典型岩溶溪流水气界面CO2交换通量变化过程及其环境影响[J].环境科学,2016,37(7):2487-2495.Li L,Pu J B,Li J H,et al.Variations of CO2exchange fluxes across water-air interface and environmental meaning in a surface stream in subtropical karst area,SW China[J].Environmental Science,2016,37(7):2487-2495.
[28]蒋滔,郭劲松,李哲,等.三峡水库不同运行状态下支流澎溪河水-气界面温室气体通量特征初探[J].环境科学,2012,33(5):1463-1470.Jiang T,Guo J S,Li Z,et al.Air-water surface greenhouse gas flux in Pengxi river at different operational stages of the Three Gorges Reservoir[J].Environmental Science,2012,33(5):1463-1470.
[29]王亮,肖尚斌,刘德富,等.香溪河库湾夏季温室气体通量及影响因素分析[J].环境科学,2012,33(5):1471-1475.Wang L,Xiao S B,Liu F D,et al.Fluxes of greenhouse gases from Xiangxi river in summer and their influencing factors[J].Environmental Science,2012,33(5):1471-1475.
[30]李凌宇,于瑞宏,田明扬,等.黄河二氧化碳逸出时空变化及其影响因素——以头道拐水文站为例[J].生态学报,2017,37(22):7636-7646.Li L Y,Yu R H,Tian M Y,et al.Spatial-temporal variations and influencing factors of carbon dioxide evasion from the Yellow river:an example of the Toudaoguai Gauging Station[J].Acta Ecologica Sinica,2017,37(22):7636-7646.
[31]Dos Santos M A,Rosa L P,Sikar B,et al.Gross greenhouse gas fluxes from hydro-power reservoir compared to thermo-power plants[J].Energy Policy,2006,34(4):481-488.
[32]St Louis V L,Kelly C A,Ducheminé,et al.Reservoir surfaces as sources of greenhouse gases to the atmosphere:a global estimate:reservoirs are sources of greenhouse gases to the atmosphere,and their surface areas have increased to the point where they should be included in global inventories of anthropogenic emissions of greenhouse gases[J].Bio Science,2000,50(9):766-775.
[33]Richey J E,Melack J M,Aufdenkampe A K,et al.Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2[J].Nature,2002,416(6881):617-620.