多年冻土退化地区湿地土壤温室气体排放及其影响因子

采用野外原位实验静态箱-气相色谱法,研究了兴安岭多年冻土不同程度退化地区生长季湿地土壤温室气体CH4、CO2和N2O的排放通量特征,同时分析了环境因子对土壤温室气体排放的影响。结果表明:1)3种类型冻土区(季节性冻土区、岛状多年冻土区、连续多年冻土区,分别用D1、D2、D3表示)土壤在生长季时期表现为CO2和N2O的源;D1和D3为CH4的源,D2为CH4的汇。D1、D2、D3土壤在生长季中平均CH4排放通量分别为(0.127±0.021)、(-0.020±0.006)、(0.082±0.019)mg·m^-2·h^-1;CO2排放通量分别为(371.50±66.73)、(318.43±55.67)、(213.19±37.05)mg·m^-2·h^-1;N2O排放通量分别为(24.05±2.62)、(8.07±2.42)、(2.17±0.25)μg·m-2·h-1。土壤CO2和N2O排放通量随多年冻土退化程度的加剧呈现出升高的趋势。2)细根生物量、凋落物生物量、全碳、全氮、可溶性有机碳、总可溶性氮、土壤容重、土壤温度、土壤含水量等均影响温室气体排放,3种不同类型冻土区土壤CH4、CO2和N2O的排放差异是诸多影响因子综合作用的结果。

Greenhouse gas emission of wetland soils and its influencing factors in permafrost degradation area

We measured the emission fluxes of greenhouse gases(CH4,CO2,and N2O)during the growing season from wetland soils of differently degrading permafrost(seasonally frozen soil,perennially discontinuously frozen soil and continuous permafrost,represented by D1,D2 and D3,respectively)around Xing’an Mountains by in-situ static chamber-gas chromatography method.The effects of environmental factors on greenhouse gas emission were analyzed.The results showed that:(1)During the growing season,the wetland soils of all the three frozen-soil regions were sources of CO2 and N2O,the soils in D1 and D3 were the sources of CH4,while soil in D2 was CH4 sink.The average fluxes of CH4 during the growing season in the three frozen soils were(0.127±0.021),(-0.020±0.006)and(0.082±0.019)mg·m^-2·h^-1,respectively.The average CO2 fluxes were(371.50±66.73),(318.43±55.67)and(213.19±37.05)mg·m^-2·h^-1,respectively.The average N2O fluxes were(24.05±2.62),(8.07±2.42)and(2.17±0.25)μg·m-2·h-1,respectively.The emission fluxes of CO2 and N2O increased with the degradation of permafrost.(2)Fine root biomass,litter biomass,total carbon content,total nitrogen content,dissolved organic carbon content,total dissolved nitrogen content,soil bulk density,soil temperature and soil moisture were the factors driving greenhouse gas emission.Variations in emissionfluxes of CH4,CO2 and N2O were the results of the interactions among different factors in the three frozen soil regions.