旱地土壤反硝化厌氧甲烷氧化菌的垂向分布特性与活性分析

发布时间：2018-09-16 19:04

【摘要】：在厌氧条件下,以亚硝酸盐作为电子受体将甲烷氧化的反硝化厌氧甲烷氧化反应(nitrite-dependent anaerobic methane-oxidizing,n-damo)的发现,彻底颠覆了人们对甲烷循环的传统理解.通过分子生物学方法及13C和15N稳定同位素示踪技术,对河北省北澧河附近的旱地农田土壤(0~1 m)中n-damo菌的群落结构、丰度和活性进行了研究,深入探究了n-damo菌的亚硝酸盐底物来源.结果显示,n-damo菌更多存在于旱地浅层土壤中,并且随季节变化分布在不同深度的土壤中.针对其pmo A基因的系统发育分析显示,旱地土壤中n-damo菌的群落结构具有明显的空间异质性,来自土壤0~20 cm和40~60 cm土层的序列完全分开,处于系统发育树不同分枝.针对其16S rRNA基因的实时荧光定量PCR结果显示,n-damo菌丰度随土壤深度的增加而降低,夏季丰度(1.44×10~4~1.02×10~5copies·g~(-1))低于冬季(3.66×104~2.67×105copies·g-1).在浅层土壤(0~20 cm)中,硝化反应和反硝化反应共同为n-damo菌提供亚硝酸盐底物来源;而在深层土壤(60~80 cm)中,亚硝酸盐底物主要来源于硝化反应.n-damo菌的活性(0.18 nmol·g~(-1)·d~(-1),以CO_2计)只能在夏季表层土壤(0~20 cm)中检测到,其余深度均未检测到其活性.在旱地农田土壤中,反硝化厌氧甲烷氧化菌对农田碳循环的影响可能不大.
[Abstract]:Under anaerobic conditions, the discovery of denitrifying anaerobic methane oxidation (nitrite-dependent anaerobic methane-oxidizing,n-damo) by nitrite as an electron acceptor completely overturned the traditional understanding of methane cycle. The community structure, abundance and activity of n-damo bacteria in dryland farmland soil (0 ~ 1 m) near Beili River in Hebei Province were studied by molecular biological method and stable isotope tracing technique of 13C and 15N. The source of nitrite substrate of n-damo bacteria was studied. The results showed that the n-damo bacteria were more present in the shallow soil of dryland and distributed in different depth with seasonal variation. Phylogenetic analysis of its pmo A gene showed that the community structure of n-damo bacteria in dryland soils had obvious spatial heterogeneity. The sequences from soil layers of 0 ~ 20 cm and 40 ~ 60 cm were completely separated and were in different branches of phylogenetic tree. The results of real-time fluorescence quantitative PCR for 16s rRNA gene showed that the abundance of n-damo bacteria decreased with the increase of soil depth, and the abundance in summer (1.44 脳 10 ~ 4) was lower than that in winter (3.66 脳 10 ~ (4) C ~ (2.67) 脳 105copies g ~ (-1), and that in summer (1.44 脳 10 ~ (4) was lower than that in winter (2.67 脳 105copies ~ (-1). Nitrification and denitrification provided nitrite substrates for n-damo bacteria in shallow soil (0 ~ 20 cm), while in deep soil (6080 cm), nitrification and denitrification provided nitrite substrates for n-damo bacteria. Nitrite substrate was mainly derived from nitrification. N-damo bacteria activity (0.18 nmol g ~ (-1) d ~ (-1), measured by CO_2) could only be detected in surface soil (0 ~ 20 cm) in summer, but no activity was detected in other depths. The effect of denitrifying anaerobic methane-oxidizing bacteria on the carbon cycle in dry land soils may not be significant.
【作者单位】：青岛理工大学环境与市政工程学院;中国科学院生态环境研究中心饮用水科学与技术重点实验室;
【基金】：国家自然科学基金(No.41322012,21277156) 中国科学院战略性先导科技专项(No.XDB15020303);中国科学院青藏高原环境变化与地表过程重点实验室开放基金(No.TEL201304);中国科学院青年创新促进会资助项目;中国科学院饮用水科学与技术重点实验室2015年度自由研究课题(No.15Z07KLDWST) 环境模拟与污染控制国家重点联合实验室专项经费项目(No.14L01ESPC) 洪堡奖学金(No.1152633)~~
【分类号】：S154.3

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