蓄水初期三峡水库草堂河水-气界面CO_2和CH_4通量日变化特征及其影响因素
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摘要
为查明三峡水库蓄水初期典型支流水-气界面CO_2和CH_4通量的日变化特征,采用LGR在线分析仪-通量箱法,于2015年9月初在库腹一级支流草堂河回水区开展连续24 h的定位观测.结果表明,24 h监测期内,支流库湾水-气界面CO_2通量变幅为-81.642~180.991 mg/(m~2·h),呈"昼吸夜放"特征,均值为17.346 mg/(m~2·h),总体为释放特征;CH_4全天均表现为释放状态,释放通量均值为0.064 mg/(m~2·h),呈"昼弱夜强"变化.相关分析结果表明,CH_4和CO_2释放通量与风速呈正相关,与表层水温、溶解氧浓度、叶绿素a浓度呈负相关,说明风速物理扰动、浮游植物光合作用是控制草堂河水-气界面气体通量最重要的环境因素.同时,干-支流相互作用形成的特殊水环境(如异重流、水温分层)也与水-气界面温室气体通量过程密切相关,但是其作用机制更为复杂,应开展进一步系统观测和深入研究.
With the LGR-floating chamber method,a 24-hour continuous monitoring was carried out in the initial impoundment period of Three Gorges Reservoir,in order to understand the greenhouse gases fluxes( carbon dioxide and methane) across the water-air interface of Caotang River which is the primary tributary of the reservoir. The results indicated that the fluxes of carbon dioxide and methane across the water-air interface appeared an obvious characteristic of diurnal variation. The fluxes of carbon dioxide ranged from-81.642 to 180.991 mg/( m~2·h),and the average fluxes of carbon dioxide were 17.346 mg/( m~2·h). As a result,the overall carbon dioxide showed"absorb by day and emit at night". Methane was emitted all day with the average fluxes of methane 0.064 mg/( m~2·h) showed"strong at day and weak at night". The fluxes of carbon dioxide and methane had a positive correlation with wind speed while a negative correlation was observed with water temperature of surface layer,dissolve oxygen and chlorophyll-a. It could be explain the most important factors that influence emissions at water-air interface were phytoplankton photosyn-thesis and bacterial metabolism process in the surface water. The changes in greenhouse gases emissions at water-air interface were also relevant to special environment( density current and thermal stratification) due to the interaction between main current and tributaries. The hydrodynamic factors were the key factors that affect carbon cycle and the greenhouse gases fluxes across the waterair interface in backwaters of tributaries,which would be worth researching.
With the LGR-floating chamber method,a 24-hour continuous monitoring was carried out in the initial impoundment period of Three Gorges Reservoir,in order to understand the greenhouse gases fluxes( carbon dioxide and methane) across the water-air interface of Caotang River which is the primary tributary of the reservoir. The results indicated that the fluxes of carbon dioxide and methane across the water-air interface appeared an obvious characteristic of diurnal variation. The fluxes of carbon dioxide ranged from-81.642 to 180.991 mg/( m~2·h),and the average fluxes of carbon dioxide were 17.346 mg/( m~2·h). As a result,the overall carbon dioxide showed"absorb by day and emit at night". Methane was emitted all day with the average fluxes of methane 0.064 mg/( m~2·h) showed"strong at day and weak at night". The fluxes of carbon dioxide and methane had a positive correlation with wind speed while a negative correlation was observed with water temperature of surface layer,dissolve oxygen and chlorophyll-a. It could be explain the most important factors that influence emissions at water-air interface were phytoplankton photosyn-thesis and bacterial metabolism process in the surface water. The changes in greenhouse gases emissions at water-air interface were also relevant to special environment( density current and thermal stratification) due to the interaction between main current and tributaries. The hydrodynamic factors were the key factors that affect carbon cycle and the greenhouse gases fluxes across the waterair interface in backwaters of tributaries,which would be worth researching.
引文
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[11]Li Zhe,Yao Xiao,He Ping et al.Diel variations of air-water CO2and CH4diffusive fluxes in the Pengxi River,Three Gorges Reservoir.J Lake Sci,2014,26(4):576-584.DOI:10.18307/2014.0412.[李哲,姚骁,何萍等.三峡水库澎溪河水-气界面CO2,CH4扩散通量昼夜动态初探.湖泊科学,2014,26(4):576-584.]
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[13]Luo Guangfu.The influence of hydrodynamics on the exchange of nutrients in estuary of tributaries in Three Gorges Reservoir[Dissertation].Shanghai:East China Normal University,2014.[罗光富.支流河口水动力作用对三峡库区干支流营养盐交换的影响[学位论文].上海:华东师范大学,2014.]
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[15]Goldenfum JA ed.GHG Measurement guidelines for freshwater reservoirs.London:International Hydropower Association.2010.
[16]Wang Dongqi,Chen Zhenlou,Wang Jun et al.Fluxes of CH4,CO2and N2O from Yangtze estuary intertidal flat in summer season.Geochemical,2007,36(1):78-88.[王东启,陈振楼,王军等.夏季长江口潮间带CH4、CO2和N2O通量特征.地球化学,2007,36(1):78-88.]
[17]Huttunen JT,Alm J,Liikanen A et al.Fluxes of methane,carbon dioxide and nitrous oxide in boreal lakes and potential anthropogenic effects on the aquatic greenhouse gas emissions.Chemosphere,2003,52(3):609-621.
[18]Raven JA,Geider RJ.Temperature and algal growth.New Phycologist,1988,110(4):441-461.
[19]Wu Pan,Deng Jianming,Qin Boqiang et al.Effects of enhanced water temperature and nutrient concentration on algal growth in winter and spring season in Lake Taihu,China.Research of Environmental Sciences,2013,26(10):1064-1071.[吴攀,邓建明,秦伯强等.水温和营养盐增加对太湖冬、春季节藻类生长的影响.环境科学研究,2013,26(10):1064-1071.]
[20]Yang Zhengjian,Liu Defu,Ma Jun et al.Effects of special vertical layered water temperatures on algal bloom in Xiangxi Bay of the Three Gorges Reservoir.Engineer Journal of Wuhan University,2012,45(1):1-9.[杨正健,刘德富,马骏等.三峡水库香溪河库湾特殊水温分层对水华的影响.武汉大学学报:工学版,2012,45(1):1-9.]
[21]Reynolds CS,Bellinger EG.Patterns of abundance and dominance of the phytoplankton of Rostherne Mere,England:Evidence from an 18-year data set.Aquatic Sciences,1992,54(1):10-36.
[22]Carpenter SR,Cole JJ,Hodgson JR et al.Trophic cascades,nutrients,and lake productivity:Whole-lake experiments.Ecological Monographs,2001,71(2):163-186.
[23]Burns SJ.Carbon isotopic evidence for coupled sulfate reduction-methane oxidation in Amazon Fan sediments.Geochimica et Cosmochimica Acta,1998,62(5):797-804.
[24]Chen Xiaoyan,Dai Huichao,Jiang Dingguo et al.Research on process of greenhouse gas emission from reservoir.Water Resources and Power,2009,27(5):37-39.[陈小燕,戴会超,蒋定国等.水库温室气体排放过程中若干问题的研究.水电能源科学,2009,27(5):37-39.]
[25]Duchemin E,Lucotte M,Canuel R et al.Production of the greenhouse gases CH4and CO2by hydroelectric reservoirs of the boreal region.Global Biogeochemical Cycles,1995,9(4):529-540.
[2]Rosa LP,Schaeffer R.Greenhouse gas emissions from hydroelectric reservoirs.AMBIO,1994,23(2):164-165.
[3]Fearnside PM.Hydroelectric dams in the Brazilian Amazon as sources of‘greenhouse’gases.Environmental Conservation,1995,22(1):7-19.
[4]Ehrlich HL.Past,present and future of biohydrometallurgy.Process Metallurgy,1999,9:3-12.
[5]Matthews CJD,Joyce EM,Louis VLS et al.Carbon dioxide and methane production in small reservoirs flooding upland boreal forest.Ecosystems,2005,8(3):267-285.
[6]Abril G,Guérin F,Richard S et al.Carbon dioxide and methane emissions and the carbon budget of a 10-year old tropical reservoir(Petit Saut,French Guiana).Global Biogeochemical Cycles,2005,19(4):332-336.
[7]Chen Yonggen,Li Xianghua,Hu Zhixin et al.Carbon dioxide flux on the water-air interface of the eight lakes in China in winter.Ecology and Environment,2006,15(4):665-669.[陈永根,李香华,胡志新等.中国八大湖泊冬季水-气界面CO2通量.生态环境,2006,15(4):665-669.]
[8]Wang Liang,Xiao Shangbin,Liu Defu et al.Fluxes of greenhouse gases from Xiangxi River in summer and their influen-cing factors.Environmental Science,2012,33(5):1471-1475.[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.环境科学,2012,33(5):1471-1475.]
[9]Xiao S,Wang Y,Liu D et al.Diel and seasonal variation of methane and carbon dioxide fluxes at Site Guojiaba,the Three Gorges Reservoir.Journal of Environmental Sciences,2013,25(10):2065-2071.
[10]Huang Wenmin,Zhu Kongxian,Zhao Wei et al.Diurnal changes in greenhouse gases at water-air interface of Xiangxi River in autumn and their influencing factors.Environmental Science,2013,34(4):1270-1276.[黄文敏,朱孔贤,赵玮等.香溪河秋季水-气界面温室气体通量日变化观测及影响因素分析.环境科学,2013,34(4):1270-1276.]
[11]Li Zhe,Yao Xiao,He Ping et al.Diel variations of air-water CO2and CH4diffusive fluxes in the Pengxi River,Three Gorges Reservoir.J Lake Sci,2014,26(4):576-584.DOI:10.18307/2014.0412.[李哲,姚骁,何萍等.三峡水库澎溪河水-气界面CO2,CH4扩散通量昼夜动态初探.湖泊科学,2014,26(4):576-584.]
[12]Ji Daobin,Liu Defu,Yang Zhengjian et al.Hydrodynamic characteristics of Xiangxi Bay in Three Gorges Reservoir.Science China,2010,(1):101-112.[纪道斌,刘德富,杨正健等.三峡水库香溪河库湾水动力特性分析.中国科学:物理学力学天文学,2010,(1):101-112.]
[13]Luo Guangfu.The influence of hydrodynamics on the exchange of nutrients in estuary of tributaries in Three Gorges Reservoir[Dissertation].Shanghai:East China Normal University,2014.[罗光富.支流河口水动力作用对三峡库区干支流营养盐交换的影响[学位论文].上海:华东师范大学,2014.]
[14]Weng Jianzhong,Xu Hengxing eds.Chinese common freshwater planktonic algae atlas.Shanghai:Shanghai Scientific Technology Press,2010.[翁建中,徐恒省.中国常见淡水浮游藻类图谱.上海:上海科学技术出版社,2010.]
[15]Goldenfum JA ed.GHG Measurement guidelines for freshwater reservoirs.London:International Hydropower Association.2010.
[16]Wang Dongqi,Chen Zhenlou,Wang Jun et al.Fluxes of CH4,CO2and N2O from Yangtze estuary intertidal flat in summer season.Geochemical,2007,36(1):78-88.[王东启,陈振楼,王军等.夏季长江口潮间带CH4、CO2和N2O通量特征.地球化学,2007,36(1):78-88.]
[17]Huttunen JT,Alm J,Liikanen A et al.Fluxes of methane,carbon dioxide and nitrous oxide in boreal lakes and potential anthropogenic effects on the aquatic greenhouse gas emissions.Chemosphere,2003,52(3):609-621.
[18]Raven JA,Geider RJ.Temperature and algal growth.New Phycologist,1988,110(4):441-461.
[19]Wu Pan,Deng Jianming,Qin Boqiang et al.Effects of enhanced water temperature and nutrient concentration on algal growth in winter and spring season in Lake Taihu,China.Research of Environmental Sciences,2013,26(10):1064-1071.[吴攀,邓建明,秦伯强等.水温和营养盐增加对太湖冬、春季节藻类生长的影响.环境科学研究,2013,26(10):1064-1071.]
[20]Yang Zhengjian,Liu Defu,Ma Jun et al.Effects of special vertical layered water temperatures on algal bloom in Xiangxi Bay of the Three Gorges Reservoir.Engineer Journal of Wuhan University,2012,45(1):1-9.[杨正健,刘德富,马骏等.三峡水库香溪河库湾特殊水温分层对水华的影响.武汉大学学报:工学版,2012,45(1):1-9.]
[21]Reynolds CS,Bellinger EG.Patterns of abundance and dominance of the phytoplankton of Rostherne Mere,England:Evidence from an 18-year data set.Aquatic Sciences,1992,54(1):10-36.
[22]Carpenter SR,Cole JJ,Hodgson JR et al.Trophic cascades,nutrients,and lake productivity:Whole-lake experiments.Ecological Monographs,2001,71(2):163-186.
[23]Burns SJ.Carbon isotopic evidence for coupled sulfate reduction-methane oxidation in Amazon Fan sediments.Geochimica et Cosmochimica Acta,1998,62(5):797-804.
[24]Chen Xiaoyan,Dai Huichao,Jiang Dingguo et al.Research on process of greenhouse gas emission from reservoir.Water Resources and Power,2009,27(5):37-39.[陈小燕,戴会超,蒋定国等.水库温室气体排放过程中若干问题的研究.水电能源科学,2009,27(5):37-39.]
[25]Duchemin E,Lucotte M,Canuel R et al.Production of the greenhouse gases CH4and CO2by hydroelectric reservoirs of the boreal region.Global Biogeochemical Cycles,1995,9(4):529-540.