典型温带雨养泥炭沼泽湿地地下部二氧化碳和甲烷浓度变化规律及其影响因素  

The variation of CO and CH concentrations and their influencing factors in the underground of typical temperate ombrotrophic bogs

作　　者：张尹 于志国 金彪 ZHANG Yin;YU Zhiguo;JIN Biao(School of Hydrology and Water Resources,Nanjing University of Information Science and Technology,Nanjing 210044,China;Bureau of Hydrology and Water Resources,Pearl River Water Resources Commission of the Ministry of Water Resources,Guangzhou 510611,China;Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China)

机构地区：[1]南京信息工程大学水文与水资源工程学院,南京210044 [2]水利部珠江水利委员会水文水资源局,广州510611 [3]中国科学院广州地球化学研究所,广州510640

出　　处：《生态学报》2020年第24期8936-8947,共12页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(41877337);江苏省自然科学基金项目(BK20160950);有机地球化学国家重点实验室开放课题(SKLOG-201912);国家生态系统观测研究共享服务平台能力建设项目。

摘　　要：为研究北方泥炭沼泽湿地二氧化碳(CO_(2))和甲烷(CH_(4))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CO_(2)浓度变化规律总体呈现随深度波动减少趋势,值多在3000μmol/L附近波动,最大值为4210.74μmol/L(120 cm),SBM采样点的CO_(2)浓度随深度先增后减,60 cm以上在1800μmol/L附近波动,60 cm以下在3000μmol/L附近波动,最大值为4191.94μmol/L(90 cm);BBM和SBM地下部CH_(4)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735.90μmol/L(260 cm),SBM最大值为543.51μmol/L(170 cm)。(2)BBM和SBM的δ13CCH_(4)的值均较小,表明大部分的12CH_(4)仍被储存在泥炭土壤中,而两个采样点的δ13CCO_(2)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CO_(2)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。In this study, the variation of greenhouse gas(particularly, carbon dioxide(CO_(2)) and methane(CH_(4))) 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) CO_(2) 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 CO_(2) concentration of SBM increased first and then decreased with the depth. Moreover, CO_(2) 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 CH_(4) were increasing with depth in both sites and rapidly increased below 60 cm, the maximum values of CH_(4) were 753.90 μmol/L at 260 cm depth and 543.51 μmol/L at 170 cm, respectively.(2) δ13CCH_(4) of the investigated two sites had a low value, which demonstrated that a large amount of 12CH_(4) was stored and behaves like carbon sink. Thereafter, value of δ13CCO_(2) and the fractionation factor α_(c) were increasing with the depth in the two sites, which revealed that acetate fermentation might serve as a key methanogenic pathway of shallow layer, while CO_(2) 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.

关 键 词：泥炭沼泽湿地 二氧化碳 甲烷 有机质分解 

分 类 号：X16[环境科学与工程—环境科学]