| 陈汉,饶旭东,滕钊军,张耀鸿,贾仲君.崇明东滩湿地CH4与N2O双消减的耦合过程研究[J].农业环境科学学报,2023,42(11):2604-2613. |
| 崇明东滩湿地CH4与N2O双消减的耦合过程研究 |
| Coupling process of CH4 and N2O double reduction in the Chongming Dongtan Wetland,China |
| 投稿时间：2023-07-30 |
| DOI：10.11654/jaes.2023-0606 |
| 中文关键词: 滨海湿地 CH4厌氧氧化 N2O还原 耦合反应 mcrA基因 nosZ Ⅱ基因 |
| 英文关键词: coastal wetland anaerobic CH4 oxidation N2O reduction coupling reaction mcrA nosZ Ⅱ |
| 基金项目:国家自然科学基金项目(42377295,42175138,41671247) |
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| 中文摘要: |
| N2O还原驱动的CH4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(13CH4,13CH4+N2O,N2O)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N2O型CH4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N2O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N2O驱动CH4厌氧氧化的13C-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。13CH4+N2O添加条件下,供试土壤中硝酸盐型和硫酸盐型CH4厌氧氧化古菌的mcrA功能基因丰度分别为(1.08~2.29)×107copies·g-1和(2.55~14.30)×107copies·g-1,比只添加13CH4处理分别高出25.8%~64.1%和41.0%~50.1%;相反,亚硝酸盐型CH4厌氧氧化细菌的pmoA功能基因丰度则无明显变化。相关性分析发现N2O驱动的AOM速率与nosZ Ⅱ基因和硝酸盐型mcrA基因均呈显著正相关,表明nosZ Ⅱ型N2O还原微生物和硝酸盐型CH4厌氧氧化古菌可能共同参与了N2O驱动的CH4厌氧氧化过程,而硫酸盐型CH4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N2O驱动的CH4厌氧氧化作用。 |
| 英文摘要: |
| Anaerobic oxidation of methane (AOM) driven by N2O 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 (13CH4, 13CH4+N2O, and N2O) 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 N2O reduction and its carbon sequestration potential in different wetland soils, and to study the quantitative characteristics of their related functional genes. The rates of CH4 anaerobic oxidation driven by N2O 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 (13C-SOC) derived from anaerobic CH4 oxidation driven by N2O reduction was 18.1-49.4 nmol·g-1, indicating the strong carbon sequestration potential of the process. For nitrateand sulfate-dependent anaerobic CH4-oxidizing archaea in the tested soils, mcrA numbers under 13CH4+N2O addition conditions ranged from (1.08-2.29)×107 copies·g-1 and(2.55-14.30)×107 copies·g-1, which were 25.8%-64.1% and 41.0%-50.1% higher than those under 13CH4 treatment, respectively. In contrast, pmoA numbers of nitrite-dependent CH4 anaerobic oxidizing bacteria did not change significantly between the two addition treatments. Correlation analysis revealed that N2O-dependent AOM rates were significantly and positively correlated with both nosZ Ⅱ and the nitrate-dependent mcrA numbers, suggesting that nosZ Ⅱ N2O-reducing microorganisms and nitrate-dependent anaerobic CH4-oxidizing archaea may jointly participate in the coupling reaction of anaerobic CH4 oxidation and N2O reduction, whereas sulfate-dependent anaerobic CH4-oxidizing archaea play an important role in natural coastal wetlands. In conclusion, the reclamation of coastal wetlands into paddy fields promotes the N2O-driven anaerobic CH4 oxidation process, which makes a remarkably positive contribution to the dual reduction of CH4 and N2O in coastal wetlands. |
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