摘要:为研究北方泥炭沼泽湿地二氧化碳（CO₂）和甲烷（CH₄）浓度随深度的变化规律及其影响因素，选取欧洲北部典型雨养泥炭地贝尔山湿地（BBM）和舒特兹山湿地（SBM）两个采样点，通过原位采集泥炭剖面温室气体、孔隙水以及土壤样品，结合傅里叶变换红外光谱（FTIR）技术、碳氮同位素技术，探讨泥炭土壤的分解程度及温室气体浓度变化的关系。研究结果表明：（1）BBM采样点地下部的CO₂浓度变化规律总体呈现随深度波动减少趋势，值多在3000 μmol/L附近波动，最大值为4210.74 μmol/L（120 cm），SBM采样点的CO₂浓度随深度先增后减，60 cm以上在1800 μmol/L附近波动，60 cm以下在3000 μmol/L附近波动，最大值为4191.94 μmol/L（90 cm）；BBM和SBM地下部CH₄浓度都随深度增大，并且在60cm以下浓度增加较快，BBM最大值为735.90 μmol/L（260 cm），SBM最大值为543.51 μmol/L（170 cm）。（2）BBM和SBM的δ¹³C_CH4的值均较小，表明大部分的¹²CH₄仍被储存在泥炭土壤中，而两个采样点的δ¹³C_CO2和分馏系数α_c均随深度增加，表明泥炭土中产甲烷方式为浅层以乙酸产甲烷为主，深层以H₂还原CO₂为主。（3）C/N、碳氮同位素比值、FTIR均显示SBM和BBM的有机质分解程度较低，因为两个采样点的低可溶性有机碳浓度和低pH值不利于分解，表明该地储存着大量有机碳。通过探讨北温带典型泥炭地温室气体的浓度变化规律及其影响因素，结果可为全球泥炭湿地碳排放提供理论支撑。



Abstract:In this study, the variation of greenhouse gas (particularly, carbon dioxide (CO₂) and methane (CH₄)) emissions and key factors influencing emission within the depth profile of two typical ombrotrophic bogs (BBM and SBM) were investigated by the Fourier Transform Infrared Spectroscopy (FTIR) technique and isotopic signature (δ¹³C and δ¹⁴N). The results showed that (1) CO₂ concentration was decreasing with the depth in BBM where value mostly fluctuates at 3000 μmol/L, with a maximum value of 4210.74 μmol/L at 120 cm depth while CO₂ concentration of SBM increased first and then decreased with the depth. Moreover, CO₂ concentration of SBM fluctuated slightly above 60 cm, and fluctuated greatly below 60 cm, with a maximum value of 4191.94 μmol/L at 90 cm depth. Similarly, concentrations of CH₄ were increasing with depth in both sites and rapidly increased below 60 cm, the maximum values of CH₄ were 753.90 μmol/L at 260 cm depth and 543.51 μmol/L at 170 cm, respectively. (2) δ¹³C_CH4 of the investigated two sites had a low value, which demonstrated that a large amount of ¹²CH₄ was stored and behaves like carbon sink. Thereafter, value of δ¹³C_CO2 and the fractionation factor α_{c w} ere increasing with the depth in the two sites, which revealed that acetate fermentation might serve as a key methanogenic pathway of shallow layer, while CO₂ reduction was dominant in deeper layer. (3) The investigated results of C/N ratios, stable isotope, and FTIR indicating a low degree of organic matter decomposition, which may be due to the low dissolved organic carbon and pH values restrained the peat decomposition. This study provides scientific data supporting where contribution of northern peatland as an important carbon sink and further helps in regional/global carbon budgeting.





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