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    中国百强科技报刊

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    Volume 42 Issue 5
    May  2017
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    Article Contents
    Li Yanyuan, Ge Jiwen, Peng Fengjiao, Zhou Ying, Li Jinqun, Wu Xian, Liu Yiling, Zhang Zhiqi, 2017. Characteristics of Methane Flux and Their Effect Factors on Dajiuhu Peatland of Shennongjia. Earth Science, 42(5): 832-842. doi: 10.3799/dqkx.2017.071
    Citation: Li Yanyuan, Ge Jiwen, Peng Fengjiao, Zhou Ying, Li Jinqun, Wu Xian, Liu Yiling, Zhang Zhiqi, 2017. Characteristics of Methane Flux and Their Effect Factors on Dajiuhu Peatland of Shennongjia. Earth Science, 42(5): 832-842. doi: 10.3799/dqkx.2017.071

    Characteristics of Methane Flux and Their Effect Factors on Dajiuhu Peatland of Shennongjia

    doi: 10.3799/dqkx.2017.071
    • Received Date: 2016-12-17
    • Publish Date: 2017-05-15
    • It is significant to do research on methane flux in Dajiuhu, to understand mechanism of the carbon cycle better, to manage it more scientifically and to assess the carbon balance in wetland ecosystem accurately. By using eddy covariance technique, methane fluxes of Dajiuhu subalpine peatland in Shennongjia Forestry Administrative District of Hubei Province, Central China were observed from August 2015 to May 2016, and temporal variation of methane emission and related affecting factors were investigated. The results show that the peatland ecosystem was methane sources, with the daily average release rate being 15.57 nmol·m-2·s-1. During the sampling period, the mean diurnal variations showed a maximum value at night (2:00 or 22:00) and a three-peak pattern all day (6:00, 12:00 and 22:00). The monthly average emission rate of CH4 decreased rapidly from August(36.46 nmol·m-2·s-1), and its valley in March(3.92 nmol·m-2·s-1), then increasing gradually from April. The correlation analysis indicates that CH4 flux was mainly dominated by air temperature (Ta), soil temperature (Ts), soil water content (SWC) and friction velocity (U*). And their relevance varied with different time scales. The curve fitting shows that CH4 flux was an exponential correlated with Ta and Ts, and had a good conic relationship with SWC.

       

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    • Baldocchi, D., Detto, M., Sonnentag, O., et al., 2012.The Challenges of Measuring Methane Fluxes and Concentrations over a Peatland Pasture.Agricultural and Forest Meteorology, 153:177-187.doi: 10.1016/j.agrformet.2011.04.013
      Chanton, J.P., Martens, C.S., Kelley, C.A., et al., 1992.Methane Transport Mechanisms and Isotopic Fractionation in Emergent Macrophytes of an Alaskan Tundra Lake.Journal of Geophysical Research, 97(D15):16681-16688.doi: 10.1029/90JD01542
      Chasar, L.S., Chanton, J.P., Glaser, P.H., et al., 2000.Radiocarbon and Stable Carbon Isotopic Evidence for Transport and Transformation of Dissolved Organic Carbon, Dissolved Inorganic Carbon, and CH4 in a Northern Minnesota Peatland.Global Biogeochemical Cycles, 14(4):1095-1108.doi: 10.1029/1999GB001221
      Chen, H., Gao, Y.H., Yao, S.P., et al., 2008.Spatiotemporal Variation of Methane Emissions from Alpine Wetlands in Zoige Plateau.Acta Ecologica Sinica, 28(7):3425-3437(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-STXB200807056.htm
      Chen, H., Yao, S.P., Wu, N., et al., 2008.Determinants Influencing Seasonal Variations of Methane Emissions from Alpine Wetlands in Zoigê Plateau and Their Implications.Journal of Geophysical Research, 113(D12):253-264.doi: 10.1029/2006JD008072
      Chu, H.S., Chen, J.Q., Gottgens, J.F., et al., 2014.Net Ecosystem Methane and Carbon Dioxide Exchanges in a Lake Erie Coastal Marsh and a Nearby Cropland.Journal of Geophysical Research:Biogeosciences, 199(5):722-740.doi: 10.1002/2013JG002520
      Ding, W.X., Cai, Z.C., 2007.Methane Emission from Natural Wetlands in China:Summary of Years 1995—2004 Studies.Pedosphere, 17(4):475-486.doi: 10.1016/s1002-0160(07)60057-5
      Ding, W.X., Cai, Z.C., Tsuruta, H., 2004a.Diel Variation in Methane Emissions from the Stands of Carex Lasiocarpa and Deyeuxia Angustifolia in a Cool Temperate Freshwater Marsh.Atmospheric Environment, 38(2):181-188.doi: 10.1016/j.atmosenv.2003.09.066
      Ding, W.X., Cai, Z.C., Wang, D.X., 2004b.Preliminary Budget of Methane Emissions from Natural Wetlands in China.Atmospheric Environment, 38(5):751-759.doi: 10.1016/j.atmosenv.2003.10.016
      Ding, X.J., Liu, G.D., Huang, Z.L., et al., 2016.Controlling Function of Organic Matter Supply and Preservation on Formation of Source Rocks.Earth Science, 41(5):832-842(in Chinese with English abstract). http://www.en.cnki.com.cn/Article_en/CJFDTotal-DQKX201605009.htm
      Du, H.N., Xie, W.X., Zhao, Q.S., et al., 2016.Characteristics of Methane Emission Fluxes in Wetlands of Dagu River Estuary in Jiaozhou Bay.Wetland Science, 14(1):44-49(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-KXSD201601007.htm
      Duan, X.N., Wang, X.K., Chen, L., et al., 2007.Methane Emission from Aquatic Vegetation Zones of Wuliangsu Lake, Inner Mongolia.Environmental Science, 28(3):455-459(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-HJKZ200703001.htm
      Falge, E., Baldocchi, D., Olson, R., et al., 2001.Gap Filling Strategies for Defensible Annual Sums of Net Ecosystem Exchange.Agricultural and Forest Meteorology, 107(1):43-69.doi: 10.1016/s0168-1923(00)00225-2
      Fechner-Levy, E.J., Hemond, H.F., 1996.Trapped Methane Volume and Potential Effects on Methane Ebullition in a Northern Peatland.Limnology and Oceanography, 41(7):1375-1383.doi: 10.4319/lo.1996.41.7.1375
      Frenzel, P., Rudolph, J., 1998.Methane Emission from a Wetland Plant:The Role of CH4 Oxidation in Eriophorum.Plant and Soil, 202(1):27-32.doi: 10.1023/A:1004348929219
      Gao, S.H., Zhang, X.D., Tang, Y.X., et al., 2016.Dynamics and Regulation of CH4 Fluxes in a Poplar Plantation on a Floodplain.Acta Ecologica Sinica, 36(18):5912-5921(in Chinese with English abstract).
      Gao, Y., Liu, G.H., Du, L.S., et al., 2016.Effects of Water Table Level and Soil Temperature on CH4 Emissions in Zoigê Peatlands.Research of Environmental Sciences, 29(4):516-521(in Chinese with English abstract).
      Hirota, M., Senga, Y., Seike, Y., et al., 2007.Fluxes of Carbon Dioxide, Methane and Nitrous Oxide in Two Contrastive Fringing Zones of Coastal Lagoon, Lake Nakaumi, Japan.Chemosphere, 68(3):597-603.doi: 10.1016/j.chemosphere.2007.01.002
      Hopfensperger, K.N., Gault, C.M., Groffman, P.M., 2009.Influence of Plant Communities and Soil Properties on Trace Gas Fluxes in Riparian Northern Hardwood Forests.Forest Ecology and Management, 258(9):2076-2082.doi: 10.1016/j.foreco.2009.08.004
      IPCC, 2013.Climate Change 2013:The Physical Science Basic.Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.Cambridge University, Cambridge.
      Jia, Q.Y., Liu, J.M., Liang, C.H., et al., 2015.The Characteristics of CH4 Concentration and Flux of the near Surface in Liaohe Delta Rice Region.Ecology and Environmental Sciences, 24(5):804-810 (in Chinese with English abstract).
      Jiang, C.S., Wang, Y.S., Zheng, X.H., et al., 2004.Advances in the Research on Methane Emission from Paddy Fields and Its Affecting Factors.Chinese Journal of Soil Science, 35(5):663-669(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-TRTB200405032.htm
      Käki, T., Ojala, A., Kankaala, P., 2001.Diel Variation in Methane Emissions from Stands of Phragmites australis (Cav.) Trin.Ex Steud.and Typha latifolia L.in a Boreal Lake.Aquatic Botany, 71(4):259-271.doi: 10.1016/s0304-3770(01)00186-3
      Kutzbach, L., Wagner, D., Pfeiffer, E.M., 2004.Effect of Microrelief and Vegetation on Methane Emission from Wet Polygonal Tundra, Lena Delta, Northern Siberia.Biogeochemistry, 69(3):341-362.doi: 10.1023/b:biog.0000031053.81520.db
      Le Mer, J., Roger, P., 2001.Production, Oxidation, Emission and Consumption of Methane by Soils:A Review.European Journal of Soil Biology, 37(1):25-50.doi: 10.1016/s1164-5563(01)01067-6
      Liu, D.Y., Ding, W.X., 2011.Progress on Spatial Variation of Methanogens and Their Influencing Factors in Natural Wetlands.Scientia Geographica Sinica, 31(2):136-142 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DLKX201102003.htm
      Nakagawa, F., Yoshida, N., Nojiri, Y., et al., 2002.Production of Methane from Alasses in Eastern Siberia:Implications from Its 14C and Stable Isotopic Compositions.Global Biogeochemical Cycles, 16(3):14-1-14-15.doi: 10.1029/2000gb001384
      Olson, D.M., Griffis, T.J., Noormets, A., et al., 2013.Interannual, Seasonal, and Retrospective Analysis of the Methane and Carbon Dioxide Budgets of a Temperate Peatland.Journal of Geophysical Research:Biogeosciences, 118(1):226-238.doi: 10.1002/jgrg.20031
      Rask, H., Schoenau, J., Anderson, D., 2002.Factors Influencing Methane Flux from a Boreal Forest Wetland in Saskatchewan, Canada.Soil Biology and Biochemistry, 34(4):435-443.doi: 10.1016/s0038-0717(01)00197-3
      Rinne, J., Riutta, T., Pihlatie, M., et al., 2007.Annual Cycle of Methane Emission from a Boreal Fen Measured by the Eddy Covariance Technique.Tellus B:Chemical and Physical Meteorology, 59(3):449-457.doi: 10.1111/j.1600-0889.2007.00261.x
      Schrier-Uijl, A.P., Kroon, P.S., Hensen, A., et al., 2010.Comparison of Chamber and Eddy Covariance-Based CO2 and CH4 Emission Estimates in a Heterogeneous Grass Ecosystem on Peat.Agricultural and Forest Meteorology, 150(6):825-831.doi: 10.1016/j.agrformet.2009.11.007
      Schütz, H., Seiler, W., Conrad, R., 1990.Influence of Soil Temperature on Methane Emission from Rice Paddy Fields.Biogeochemistry, 11(2):77-95.doi: 10.1007/bf00002060
      Shi, L.Y., Mu, C.C., Tian, X.M., et al., 2010.CH4 Emission and It's Driving Factors from Different Marshs in Xiaoxing'an Mountains, Northeast China.Acta Ecologica Sinica, 30(19):5289-5295(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-STXB201019021.htm
      Smeets, C.J.P.P., Holzinger, R., Vigano, I., et al., 2009.Eddy Covariance Methane Measurements at a Ponderosa Pine Plantation in California.Atmospheric Chemistry and Physics Discussions, 9(1):5201-5229.doi: 10.5194/acpd-9-5201-2009
      Song, C.C., Wang, Y.Y., Wang, Y.S., et al., 2005.Dynamics of CO2, CH4 and N2O Emission Fluxes from Mires during Freezing and Thawing Season.Environmental Science, 26(4):7-12(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-HJKZ200504002.htm
      Sun, X.X., Mu, C.C., Shi, L.Y., et al., 2009.Methane Emission from Forested Swamps in Xiaoxing'an Mountains, Northeastern China.Chinese Journal of Plant Ecology, 33(3):535-545(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-ZWSB200903013.htm
      Sundh, I., Mikkelä, C., Nilsson, M., et al., 1995.Potential Aerobic Methane Oxidation in a Sphagnum-Dominated Peatland—Controlling Factors and Relation to Methane Emission.Soil Biology and Biochemistry, 27(6):829-837.doi: 10.1016/0038-0717(94)00222-m
      Thomas, K.L., Benstead, J., Davies, K.L., et al., 1996.Role of Wetland Plants in the Diurnal Control of CH4 and CO2 Fluxes in Peat.Soil Biology and Biochemistry, 28(1):17-23.doi: 10.1016/0038-0717(95)00103-4
      Tong, C., Liu, Z.Z., Zeng, C.S., et al., 2010.Effects of Simulated Sulfate Deposition on CH4 Fluxes from Tidal Wetland in the Min River Estuary.China Environmental Science, 30(3):302-308 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-ZGHJ201003006.htm
      Tsuyuzaki, S., Nakano, T., Kuniyoshi, S.I., et al., 2001.Methane Flux in Grassy Marshlands near Kolyma River, North-Eastern Siberia.Soil Biology and Biochemistry, 33(10):1419-1423.doi: 10.1016/s0038-0717(01)00058-x
      Wang, D.X., Lü, X.G., Ding, W.X., et al., 2002.Comparison of Methane Emission from Marsh and Paddy Field in Sanjiang Plain.Scientia Geographica Sinica, 22(4):500-503(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DLKX200204022.htm
      Wang, H., Zhao, H.D., Zhang, S.Y., et al., 2012.Research on Methane Fluxes and Effect Factorsin the Wetland of Sunada glauca.Marine Environmental Science, 31(2):173-175(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-HYHJ201202005.htm
      Wang, W.Q., Zeng, C.S., Tong, C., et al., 2012.Stoichiometry of Carbon Dioxide and Methane Emissions in Minjiang River Estuarine Tidal Wetland.Acta Ecologica Sinica, 32(14):4396-4402(in Chinese with English abstract). doi: 10.5846/stxb
      Wang, Y.Y., Zhao, Z.C., Song, C.C., 2005.Methane Emission from Carex lasiocarpa Wetland in the Sanjiang Plain, China.Wetland Science, 3(1):37-41(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-KXSD200501006.htm
      Wang, Z.P., Han, X.G., 2005.Diurnal Variation in Methane Emissions in Relation to Plants and Environmental Variables in the Inner Mongolia Marshes.Atmospheric Environment, 39(34):6295-6305.doi: 10.1016/j.atmosenv.2005.07.010
      Whalen, S.C., 2005.Biogeochemistry of Methane Exchange between Natural Wetlands and the Atmosphere.Environmental Engineering Science, 22(1):73-94.doi: 10.1089/ees.2005.22.73
      Yang, G.F., Wu, F.D., Chen, Z.H., et al., 2015.n-Alkane Distribution and Their Palaeoenvironmental Implications in Fluvial-Lacustrine Sediments in Dengkou, Inner Mongolia.Earth Science, 40(2):327-333(in Chinese with English abstract). https://www.researchgate.net/publication/281667257_n-Alkane_distribution_and_their_palaeoenvironmental_implications_in_fluvial-lacustrine_sediments_in_Dengkou_Inner_Mongolia
      Yang, H.X., Wang, D.Q., Chen, Z.L., et al., 2007.Seasonal Variation of CH4 Emission from Chongming East Intertidal Flat of Yangtze River Estuary.Scientia Geographica Sinica, 27(3):408-413(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DLKX200703020.htm
      Yang, W.Y., Song, C.C., Luan, Z.Q., et al., 2006.Methane Emission from Freshwater Marshes in Sanjiang Plain and Its Affecting Factors in Arid Year.Chinese Journal of Ecology, 25(4):423-427(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-STXZ200604014.htm
      Zhou, W.C., Cui, L.J., Wang, Y.F., et al., 2016.Characteristics of Methane Emission Fluxes in the Zoigê Plateau Wetland on Microtopography.Chinese Journal of Plant Ecology, 40(9):902-911 (in Chinese with English abstract). doi: 10.17521/cjpe.2016.0029
      Zhu, X.Y., Song, C.C., Guo, Y.D., et al., 2015.The Porewater Methane Concentration and Controlling Factors from the Peatlands in the Sanjiang Plain.Acta Scientiae Circumstantiae, 35(7):2233-2239 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-HJXX201507037.htm
      Zona, D., Janssens, I.A., Aubinet, M., et al., 2013.Fluxes of the Greenhouse Gases (CO2, CH4 and N2O) above a Short-Rotation Poplar Plantation after Conversion from Agricultural Land.Agricultural and Forest Meteorology, 169:100-110.doi: 10.1016/j.agrformet.2012.10.008
      陈槐, 高永恒, 姚守平, 等, 2008.若尔盖高原湿地甲烷排放的时空异质性.生态学报, 28(7):3425-3437. http://www.cnki.com.cn/Article/CJFDTOTAL-STXB200807056.htm
      丁修建, 柳广弟, 黄志龙, 等, 2016.有机质供给和保存在烃源岩形成中的控制作用.地球科学, 41(5):832-842. http://www.earth-science.net/WebPage/Article.aspx?id=3291
      杜慧娜, 谢文霞, 赵全升, 等, 2016.胶州湾大沽河口湿地CH4排放通量特征.湿地科学, 14(1):44-49. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=kxsd201601007&dbname=CJFD&dbcode=CJFQ
      段晓男, 王效科, 陈琳, 等, 2007.乌梁素海湖泊湿地植物区甲烷排放规律.环境科学, 28(3):455-459. http://www.cnki.com.cn/Article/CJFDTOTAL-HJKZ200703001.htm
      高升华, 张旭东, 汤玉喜, 等, 2016.滩地人工林幼林不同时间尺度CH4通量变化特征——基于涡度相关闭路系统的研究.生态学报, 36(18):5912-5921. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=stxb201618030&dbname=CJFD&dbcode=CJFQ
      高燕, 刘高慧, 杜乐山, 等, 2016.地下水位和土壤温度对若盖尔泥炭地CH4排放的影响.环境科学研究, 29(4):516-521. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=hjkx201604007&dbname=CJFD&dbcode=CJFQ
      贾庆宇, 刘晶淼, 梁成华, 等, 2015.辽河三角洲稻区近地层CH4浓度与通量特征.生态环境学报, 24(5):804-810. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=tryj201505013&dbname=CJFD&dbcode=CJFQ
      江长胜, 王跃思, 郑循华, 等, 2004.稻田甲烷排放影响因素及其研究进展.土壤通报, 35(5):663-669. http://www.cnki.com.cn/Article/CJFDTOTAL-SHLB201003037.htm
      刘德燕, 丁维新, 2011.天然湿地土壤产甲烷菌及其影响因子研究进展.地理科学, 31(2):136-142. http://www.cnki.com.cn/Article/CJFDTOTAL-DLKX201102003.htm
      石兰英, 牟长城, 田新民, 等, 2010.小兴安岭不同沼泽甲烷排放及其影响因子.生态学报, 30(19):5289-5295. http://www.cnki.com.cn/Article/CJFDTOTAL-ZWSB200903013.htm
      宋长春, 王毅勇, 王跃思, 等, 2005.季节性冻融期沼泽湿地CO2、CH4和N2O排放动态.环境科学, 26(4):7-12. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=hjkz200504002&dbname=CJFD&dbcode=CJFQ
      孙晓新, 牟长城, 石兰英, 等, 2009.小兴安岭森林沼泽甲烷排放及其影响因子.植物生态学报, 33(3):535-545. http://www.cnki.com.cn/Article/CJFDTOTAL-ZWSB200903013.htm
      仝川, 柳铮铮, 曾从盛, 等, 2010.模拟SO42-沉降对河口潮汐湿地甲烷排放通量的影响.中国环境科学, 30(3):302-308. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=zghj201003006&dbname=CJFD&dbcode=CJFQ
      王德宣, 吕宪国, 丁维新, 等, 2002.三江平原沼泽湿地与稻田CH4排放对比研究.地理科学, 22(4):500-503. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=dlkx200204022&dbname=CJFD&dbcode=CJFQ
      王慧, 赵化德, 张世宇, 等, 2012.碱蓬湿地CH4排放通量及影响因素研究.海洋环境科学, 31(2):173-175. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=hyhj201202005&dbname=CJFD&dbcode=CJFQ
      王维奇, 曾从盛, 仝川, 等, 2012.闽江河口潮汐湿地二氧化碳和甲烷排放化学计量比.生态学报, 32(14):4396-4402. http://www.cnki.com.cn/Article/CJFDTOTAL-STXB201214013.htm
      王毅勇, 赵志春, 宋长春, 2005.三江平原毛果苔草湿地CH4排放研究.湿地科学, 3(1):37-41. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=kxsd200501006&dbname=CJFD&dbcode=CJFQ
      杨桂芳, 武法东, 陈正洪, 等, 2015.内蒙古磴口河湖相沉积物正构烷烃分布特征及其环境意义.地球科学, 40(2):327-333. http://www.earth-science.net/WebPage/Article.aspx?id=3056
      杨红霞, 王东启, 陈振楼, 等, 2007.长江口崇明东滩潮间带甲烷(CH4)排放及其季节变化.地理科学, 27(3):408-413. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=dlkx200703020&dbname=CJFD&dbcode=CJFQ
      杨文燕, 宋长春, 栾兆擎, 等, 2006.干旱年份三江平原沼泽甲烷(CH4)排放及影响因子.生态学杂志, 25(4):423-427. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=stxz200604014&dbname=CJFD&dbcode=CJFQ
      周文昌, 崔丽娟, 王义飞, 等, 2016.若尔盖高原湿地不同微地貌区甲烷排放通量特征.植物生态学报, 40(9):902-911. doi: 10.17521/cjpe.2016.0029
      朱晓艳, 宋长春, 郭跃东, 等, 2015.三江平原泥炭沼泽孔隙水甲烷浓度变化动态及其影响因子.环境科学学报, 35(7):2233-2239. http://www.cnki.com.cn/Article/CJFDTOTAL-HJXX201507037.htm
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