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区域环境与生态

刘霞,牟长城,李婉姝,冯登军,于波.小兴安岭毛赤杨沼泽CH₄、N₂O排放规律及其对人为干扰的响应[J].环境科学学报,2009,29(12):2642-2650

Emissions of CH₄ and N₂O from Alnus sibirica swamps and the response to human disturbance in the Xiaoxing'an Mountains

摘要：选择小兴安岭山区毛赤杨(Alnus sibirica)沼泽为研究对象,利用静态暗箱-气相色谱法,研究两个生长季内(2007年和2008年)沼泽湿地在自然状态下CH₄、N₂O排放通量的变化规律及其主要影响因素,以及在不同采伐干扰(皆伐、45%择伐)方式下,CH₄和N₂O排放通量的变化过程.结果表明,2007年CH₄和N₂O平均排放通量分别为1.03mg·m^{-2·h^-1和58.56μg·m^-2·h^-1,2008年分别为20.57mg·m^-2·h^-1和17.41μg·m^-2·h^-1;CH₄排放高峰期均发生在夏、秋两季,N₂O排放规律不明显.皆伐沼泽和45%择伐沼泽CH₄平均排放量分别为597.06、237.05μg·m^-2·h^-1,N₂O平均排放量分别为35.84、114.51μg·m^-2·h^-1;与天然沼泽相比,CH₄排放量明显下降,N₂O排放通量明显升高.水位是CH₄排放的主要影响因子,但当水位达到一定高度时不再成为限制因子,土壤温度与CH₄排放相关性显著,相对较低水位与相对较高土壤温度有利于N₂O排放;积水水位是影响沼泽不同年份CH₄和N₂O通量排放差异的主要影响因子,采伐引起的土壤温度和水位的变化是干扰地与对照地CH₄和N₂O排放产生差异的主要原因.}

Abstract：Methane(CH₄) and nitrous oxide(N₂O) emissions from an Alnus sibirica swamp were studied using a static opaque chamber and gas chromatography during the growing season of 2007 and 2008 in the Xiaoxing'an Mountains.The effects of cutting(clear cutting,selective cutting with an intensity of 45%) on CH₄ and N₂O emission from the Alnus swamp were also measured.The results showed that:the mean fluxes of CH₄ and N₂O in 2007 were 1.03 mg·m^-2·h^-1 and 58.56μg·m^-2·h^-1,respectively;while those in 2008 were 20.57 mg·m^-2·h^-1 and 17.41μg·m^-2·h^-1,respectively.The maximum CH₄ fluxes occurred in the summer and autumn,but there was no clear seasonal pattern for N₂O.The mean CH₄ fluxes due to clear cutting and selective cutting were 597.06 and 237.05μg·m^-2·h^-1,and those of N₂O were 35.84 and 114.51μg·m^-2·h^-1,respectively.The CH₄ fluxes decreased due to the disturbances,while the N₂O flux increased.Water table level was the main factor for CH₄ emission,but soil temperature became the limiting factor when the water level reached a certain height.Low water level and high soil temperatures favored N₂O emission.The water level significantly contributed to the annual variations of CH₄ and N₂O emission.Changes in soil temperature and water level resulting from the disturbances were the main reason for the differences of CH₄ and N₂O fluxes between disturbed and control plots.