不同类型稻田亚硝酸型CH4厌氧氧化潜力的比较研究

甲烷(CH₄)厌氧氧化是稻田土壤中消减温室气体排放的重要过程.本试验选择内陆性南京稻田和滨海性上海崇明岛围垦稻田，比较研究稻田耕层(0～10 cm)和深层(50～60 cm)土壤中亚硝酸盐型CH₄厌氧氧化(n-DAMO)潜力的差异及其微生物驱动机制.结果表明，南京稻田耕层土壤的n-DAMO速率为3.51 nmol·g^-1·d^-1(以¹³CO₂计),显著高于围垦稻田耕层土壤(1.43 nmol·g^-1·d^-1).两种类型稻田耕层土壤的n-DAMO速率均显著高于深层土壤.南京稻田和围垦稻田M.oxyfera-like细菌的16S rRNA基因拷贝数分别为(2.31～4.82)×10⁷和(0.89～2.12)×10⁷ copies·g^-1,与亚硝酸盐型CH₄厌氧氧化速率显著正相关.相关性分析发现，土壤有机碳、总氮、无机态氮是稻田n-...

Comparative study on nitrite-dependent anaerobic methane oxidation in different types of paddy field

Anaerobic methane (CH₄) oxidation is an important process to reduce greenhouse gas emissions in paddy soil.The nitrite-dependent Denitrifying Anaerobic Methane Oxidation (n-DAMO) potential and its microbial mechanism in cultivated layer (0-10 cm) and deep layer (50-60 cm) of inland (Nanjing) and coastal (reclaimed Shanghai Chongming Island) paddy fields were studied.The results showed that n-DAMO rate of topsoil in Nanjing paddy field was 3.51 nmol ¹³CO₂·g^-1·d^-1,which was significantly higher than that of topsoil in reclaimed paddy field (1.43 nmol ¹³CO₂·g^-1·d^-1).The n-DAMO rates in the cultivated layer soil were significantly higher than those in the deep layer soil in the two types of paddy field.The copy numbers of 16S rRNA gene of functional microorganism M.oxyfera-like bacteria in Nanjing paddy field and reclaimed paddy field were 2.31×10⁷-4.82×10⁷ copies·g^-1 and 0.89×10⁷-2.12×10⁷ copies·g^-1,respectively,which was significantly positively correlated with nitrite-dependent anaerobic CH₄ oxidation rate.Regression analysis showed that soil organic carbon,total nitrogen and inorganic nitrogen were important factors for n-DAMO rate differentiation in paddy fields.In conclusion,the n-DAMO potential of inland paddy soil is higher than that in reclaimed paddy field,which is mainly caused by the different levels of soil background carbon and nitrogen and the abundance of functional microorganisms.