摘要
N_(2)O还原驱动的CH_(4)厌氧氧化作用(AOM)是湿地系统温室气体双减排的一种新途径,而基于滨海围垦开发的稻田利用方式对该途径的影响效应尚不清楚。本研究选取长江入海口崇明东滩湿地的自然滩涂(光滩湿地和芦苇湿地)和围垦稻田(围垦种稻19 a和86 a)为研究对象,设置3个试验处理(^(13)CH_(4),^(13)CH_(4)+N_(2)O,N_(2)O)进行室内厌氧培养。采用稳定性同位素标记结合定量PCR等手段,分析不同湿地土壤的N_(2)O型CH_(4)厌氧氧化速率及其固碳潜力,研究其相关功能基因的数量特征。结果发现,围垦稻田土壤中N_(2)O驱动的AOM速率为6.10^(7).51 ng·g^(-1)·d^(-1),显著高于自然滩涂湿地。供试土壤N_(2)O驱动CH_(4)厌氧氧化的^(13)C-SOC固碳量为18.1~49.4 nmol·g^(-1),表明该过程具有较强的固碳潜力。^(13)CH_(4)+N_(2)O添加条件下,供试土壤中硝酸盐型和硫酸盐型CH_(4)厌氧氧化古菌的mcr A功能基因丰度分别为(1.08~2.29)×10^(7) copies·g^(-1)和(2.55~14.30)×10^(7)copies·g^(-1),比只添加^(13)CH_(4)处理分别高出25.8%~64.1%和41.0%~50.1%;相反,亚硝酸盐型CH_(4)厌氧氧化细菌的pmo A功能基因丰度则无明显变化。相关性分析发现N_(2)O驱动的AOM速率与nos ZⅡ基因和硝酸盐型mcr A基因均呈显著正相关,表明nos ZⅡ型N_(2)O还原微生物和硝酸盐型CH_(4)厌氧氧化古菌可能共同参与了N_(2)O驱动的CH_(4)厌氧氧化过程,而硫酸盐型CH_(4)厌氧氧化古菌则在自然滩涂湿地中发挥着重要作用。研究表明,围垦植稻在一定程度上促进了N_(2)O驱动的CH_(4)厌氧氧化作用。
Anaerobic oxidation of methane(AOM)driven by N_(2)O reduction is a new pathway for greenhouse gas reduction in wetland systems;however the effect on paddy field utilization after the reclamation of coastal natural wetland using this pathway is unclear.In this study,three experimental treatments(^(13)CH_(4),^(13)CH_(4)+N_(2)O,and N_(2)O)were set up for anaerobic incubation of natural coastal wetlands(bare wetlands and reed wetlands)and reclaimed rice fields(19 and 86 years of rice cultivation)in the Chongming Dongtan Natural Wetland in the Yangtze River Estuary.Stable isotope labelling combined with quantitative PCR was used to analyze AOM rates driven by N_(2)O reduction and its carbon sequestration potential in different wetland soils,and to study the quantitative characteristics of their related functional genes.The rates of CH_(4) anaerobic oxidation driven by N_(2)O reduction in the reclaimed paddy fields ranged from 6.10 ng·g^(-1)·d^(-1) to 7.51 ng·g^(-1)·d^(-1),much higher than those in natural marsh wetlands.The sequestered organic carbon(^(13)C-SOC)derived from anaerobic CH_(4) oxidation driven by N_(2)O reduction was 18.1–49.4 nmol·g^(-1),indicating the strong carbon sequestration potential of the process.For nitrate-and sulfate-dependent anaerobic CH_(4)-oxidizing archaea in the tested soils,mcrA numbers under ^(13)CH_(4)+N_(2)O addition conditions ranged from(1.08–2.29)×10^(7) copies·g^(-1) and(2.55–14.30)×10^(7) copies·g^(-1),which were 25.8%–64.1%and 41.0%–50.1%higher than those under ^(13)CH_(4) treatment,respectively.In contrast,pmoA numbers of nitrite-dependent CH_(4) anaerobic oxidizing bacteria did not change significantly between the two addition treatments.Correlation analysis revealed that N_(2)O-dependent AOM rates were significantly and positively correlated with both nosZⅡand the nitrate-dependent mcrA numbers,suggesting that nosZⅡN_(2)O-reducing microorganisms and nitrate-dependent anaerobic CH_(4)-oxidizing archaea may jointly participate in the coupling reaction of anaerobic CH_(4) oxidation and N_(2)O reduction,whereas sulfate-dependent anaerobic CH_(4)-oxidizing archaea play an important role in natural coastal wetlands.In conclusion,the reclamation of coastal wetlands into paddy fields promotes the N_(2)O-driven anaerobic CH_(4) oxidation process,which makes a remarkably positive contribution to the dual reduction of CH_(4) and N_(2)O in coastal wetlands.
作者
陈汉
饶旭东
滕钊军
张耀鸿
贾仲君
CHEN Han;RAO Xudong;TENG Zhaojun;ZHANG Yaohong;JIA Zhongjun(School of Applied Meteorology/Jiangsu Provincial Key Laboratory of Agricultural Meteorology,Nanjing University of Information Science and Technology,Nanjing 210044,China;State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2023年第11期2604-2613,共10页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(42377295,42175138,41671247)。
