Emission of CO2, CH4 and N2O from freshwater marsh during freeze–thaw period in Northeast of China
Emission of CO2, CH4 and N2O from freshwater marsh during freeze–thaw period in Northeast of China
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DOI：
10.1016/j.atmosenv.2005.08.028
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发表时间：
2006-11
影响因子：
5
通讯作者：
C. Song;Yuesi Wang;Yiyon Wang;Zhi-chun Zhao
中科院分区：
文献类型：
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作者：
C. Song;Yuesi Wang;Yiyon Wang;Zhi-chun Zhao
三江平原冻融期为7~8个月，对温室气体排放影响较大。采用静态箱技术，辅以气相色谱，研究了三江平原淡水沼泽湿地CO2、CH4和N2O的排放特征。结果表明，三江平原冬季有明显的CH4和CO2排放，且CH4排放对冬季不同类型淡水沼泽总CH4通量的贡献较大。在解冻过程中，CH4和CO2排放有明显的峰值。季节性淹水淡水沼泽的CH4和CO2排放量大于解冻期间连续淹水淡水湿地的CH4和CO2排放量。相反，冬季持续淹水的淡水沼泽的CH4和CO2排放量大于季节性淹水的淡水沼泽。解冻过程中，CO2通量与土壤温度(5 Cm)呈指数关系(R2=0.912，P<；0.001)。同时，生态系统呼吸与CH4通量显著相关(R2=0.751，P<；0.001)。结果表明，冬季淡水沼泽为N2O汇，随着融化温度的升高，淡水沼泽逐渐成为N2O源。三江平原冻融期间温室气体排放特征与冬季微生物活动及融化对土壤碳矿化、硝化和反硝化作用的影响有关。
The freeze–thaw period, 7–8 months in Sanjiang Plain, influences the greenhouse gases fluxes greatly. The static chamber technique aided by gas chromatogram was used for investigating characteristics of emission of CO2, CH4and N2O from freshwater marsh wetlands located in the Sanjiang Plain. The results showed that there were obvious CH4and CO2emissions in winter and the CH4emission made a relatively large contribution to the total CH4flux in the different type freshwater marshes during winter in Sanjiang Plain. And there were significant CH4and CO2emission peak values during thawing time. The CH4and CO2emissions from freshwater marsh seasonal flooded were larger than that from freshwater marsh continuously flooded during thawing time. On the contrary, the CH4and CO2emissions from freshwater marsh continuously flooded were larger than that from freshwater marsh seasonal flooded in winter. During thawing, there was exponential relationship between CO2fluxes and the soil temperature (5cm) (R2=0.912, P<0.001). Meanwhile, ecosystem respiration was obviously correlated with the CH4fluxes (R2=0.751, P<0.001). We found that the freshwater marshs were N2O sink in winter and gradually became N2O source, with increasing temperature during thaw. The characters of the greenhouse gases emission, during freeze–thaw in the Sanjiang Plain, responded to the microbial activity in winter and the effects of thawing on soil carbon mineralization, nitrification and denitrification.