大兴安岭地区岛状林沼泽CH4和N2O排放及其影响因子

沼泽湿地CH₄、N₂O的排放，尤其是高纬度沼泽湿地，对于评估北半球温室气体排放具有重要意义。在2011 年生长季利用野外静态箱-气相色谱法对大兴安岭地区两种典型湿地岛状林沼泽（白桦和兴安落叶松岛状林沼泽）CH₄、N₂O排放通量进行了研究，分析CH₄、N₂O排放通量的季节特征，并探讨温度、水位主控因子对CH₄、N₂O排放通量的影响。结果表明：①生长季白桦（Betula platyphylla）和兴安落叶松（Larix gmelinii）岛状林沼泽CH₄通量除春季白桦岛状林沼泽出现排放峰值外，两样地CH₄都处于弱吸收现象；N₂O排放高峰期分别在初夏、春两季。白桦和兴安落叶松岛状林沼泽CH₄、N₂O 排放通量依次为-60.61、-93.21 μg·m^-2 ·h^-1 和82.92、 45.06 μg·m^-2 ·h^-1。②兴安落叶松岛状林沼泽生长季CH₄、N₂O 排放通量分别与10~40 cm 和 15~40 cm土壤温度呈显著负相关性；而白桦岛状林沼泽CH₄排放通量仅与40 cm土壤温度呈显著负相关，两种类型沼泽均与土壤含水率未呈显著相关性。③白桦和兴安落叶松岛状林沼泽生长季CH₄、N₂O总通量分别为-2.21、-2.74 kg·hm^-2和2.74、0.93 kg·hm^-2；表现为大气CH₄弱吸收的汇，N₂O弱排放的源。

Emissions of CH4 and N2O from Island Forested Swampin Da Hinggan Mountains

Emissions of CH₄ and N₂O in swamps especially at high latitudes are significant toevaluate greenhouse gases emissions at the northern latitudes. During the growing season of2011, using a static opaque chamber-GC technique, we researched CH₄ and N₂O emission fluxesin two typical island-forested swamps (Betula platyphylla-Carex schmidtii swamp and Larixgmelinii-Carex schmidtii swamp) in Da Hinggan Mountains of China, analyzed the seasonal characteristics of CH₄ and N₂O fluxes, and investigated the influences from temperature and watermaster factors to the emission fluxes. The results showed that: CH₄ was in weak absorption during growing season in both B. platyphylla-C. schmidtii swamp and Larix gmelinii-Carex schmidtiiswamp except that CH₄ fluxes had emission peaks in spring; while N₂O emissionpeaks appeared in early summer and spring in two swamps. The average emission fluxes were -60.61,-93.21 μg·m^-2·h^-1 and 82.92, 45.06 μg· m^-2·h^-1 respectively. CH₄ and N₂O emissionfluxes during growing season in L. gmelinii-C. schmidtii swamp were in negative correlationwith 10-40 cm and 15-40 cm soil temperatures respectively; while CH₄ and N₂O emissionfluxes during growing season in B. platyphylla-C. schmidtii swamp were only in negative correlationwith 40 cm soil temperature. Neither two types of swamp and soil water ratio had approachedstrong correlations. CH₄ and N₂O emission fluxes during growing seasonwere-2.21,-2.74 kg·hm^-2 and 2.74, 0.93 kg·hm^-2 respectively in B. platyphylla-C. schmidtii swamp and L. gmelinii-C. schmidtii swamp, which became the sinks of CH₄ weak absorptionand the sources of N₂O weak emission.