铁输入对泥炭土甲烷生成的影响及其驱动机理  

Influences and mechanisms of iron input for methane productions in peatlands

作　　者：胡馨艺 王红岩 湛甜 徐祎婕 孙国新[2] 于志国[1] HU Xinyi;WANG Hong-yan;ZHAN Tian;XU Yijie;SUN Guoxin;YU Zhiguo(School of Hydrology and Water Resource,Nanjing University of Information Science and Technology,Nanjing 210044,China;Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;Wuhan Regional Climate Center,Wuhan 430074,China)

机构地区：[1]南京信息工程大学水文与水资源学院,南京210044 [2]中国科学院生态环境研究中心,北京100085 [3]武汉区域气候中心,武汉430074

出　　处：《应用生态学报》2024年第9期2599-2608,共10页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(42207268,41877337);江苏省自然基金项目(SBK2022044914)资助。

摘　　要：大气沉降是泥炭地中铁的重要来源,然而铁沉降对泥炭地中甲烷(CH_(4))生成的影响及其机理尚不清楚。本研究以青藏高原泥炭土为研究对象,采用室内微宇宙培养实验,通过^(57)Fe-穆斯保尔谱、三维荧光光谱等地球化学分析手段结合16S rRNA高通量测序、实时荧光定量PCR(qPCR)等分析方法,探究了水铁矿添加对泥炭地CH_(4)生成的影响及其微生物驱动机理。结果表明:水铁矿添加显著提高了泥炭土中CH_(4)的生成速率,水铁矿添加组CH_(4)的生成速率约为对照组的30倍。铁氧化物的选择性提取及^(57)Fe-穆斯保尔谱表征表明,水铁矿还原过程中并无结晶型二次铁氧化物生成。水铁矿的添加增加了泥炭土可溶性有机质(DOM)的降解,可溶性有机碳(DOC)浓度随之降低;泥炭土中典型发酵微生物包括酸杆菌门和拟杆菌门的丰度显著增加,表明水铁矿的添加加快了有机质的分解,增加了产甲烷菌代谢所需的底物浓度。此外,地杆菌属、地发菌属和甲烷杆菌属丰度在水铁矿添加组协同增加,表明它们之间的互营作用潜在促进了CH_(4)的生成。综上,大气沉降导致的铁输入可显著促进泥炭土中CH_(4)的生成,本研究结果对气候变化背景下调控泥炭地CH_(4)排放具有重要意义。Atmospheric deposition provides a stable iron source for peatlands.The influences of Fe input on meth-ane(CH_(4))productions and the underlying mechanisms remain unclear.We conducted a microcosm experiment with peat sediments collected from the Qinghai-Tibet Plateau of China to explore the effects of ferrihydrite reduction-for CH_(4) productions in peatlands by using geochemical analyses including ^(57)Fe Mössbauer spectroscopy and three-dimensional fluorescence spectroscopy(3D-EEM)in combination with high-throughput sequencing of 16S rRNA and real-time fluorescence quantitative PCR(qPCR).Results showed that ferrihydrite reduction significantly in-creased CH_(4) production,being 30 times of that under the control.Selective extractions for iron oxides and ^(57)Fe Mössbauer spectroscopy measurements revealed that no crystalline secondary iron minerals were formed during the ferrihydrite reduction process.The addition of ferrihydrite enhanced the degradation of dissolved organic matter(DOM)in peat soil,resulting in a reduction in the concentration of dissolved organic carbon(DOC).Further-more,the relative abundance of typical fermentative microorganisms in peat sediments,including Acidobacteriota and Bacteroidota,significantly increased.Such a result indicated that reduction of ferrihydrite accelerated organic matter decomposition and increased substrate concentration required for methanogenesis.Furthermore,a co-increase in relative abundance of Geobacter,Geothrix,and Methanobacterium in the ferrihydrite-amended group suggested a potential synergistic interaction that may promote the CH_(4) production.Our results demonstrated that ferrihydrite re-duction could significantly enhance CH_(4) production and play a vital role in regulating CH_(4) emissions in peatlands.

关 键 词：泥炭土壤 水铁矿 甲烷 有机碳 微生物 

分 类 号：X144[环境科学与工程—环境科学]