title: Evidence for the cooccurrence of nitrite-dependent anaerobic ammonium and methane oxidation processes in a flooded paddy field.
abstract: Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two of the most recent discoveries in the microbial nitrogen cycle. In the present study, we provide direct evidence for the cooccurrence of the anammox and n-damo processes in a flooded paddy field in southeastern China. Stable isotope experiments showed that the potential anammox rates ranged from 5.6 to 22.7 nmol N2 g(-1) (dry weight) day(-1) and the potential n-damo rates varied from 0.2 to 2.1 nmol CO2 g(-1) (dry weight) day(-1) in different layers of soil cores. Quantitative PCR showed that the abundance of anammox bacteria ranged from 1.0 × 10(5) to 2.0 × 10(6) copies g(-1) (dry weight) in different layers of soil cores and the abundance of n-damo bacteria varied from 3.8 × 10(5) to 6.1 × 10(6) copies g(-1) (dry weight). Phylogenetic analyses of the recovered 16S rRNA gene sequences showed that anammox bacteria affiliated with "Candidatus Brocadia" and "Candidatus Kuenenia" and n-damo bacteria related to "Candidatus Methylomirabilis oxyfera" were present in the soil cores. It is estimated that a total loss of 50.7 g N m(-2) per year could be linked to the anammox process, which is at intermediate levels for the nitrogen flux ranges of aerobic ammonium oxidation and denitrification reported in wetland soils. In addition, it is estimated that a total of 0.14 g CH4 m(-2) per year could be oxidized via the n-damo process, while this rate is at the lower end of the aerobic methane oxidation rates reported in wetland soils.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Li-Dong
authors.initials: LD
authors.lastname: Shen
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Lian
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Zhan-Fei
authors.initials: ZF
authors.lastname: He
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Geng
authors.affiliation: Department of Environmental Science, Hangzhou Normal University, Hangzhou, China.
authors.forename: Ren-Cun
authors.initials: RC
authors.lastname: Jin
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: He
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Lou
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Xu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou, China blhu@zju.edu.cn.
authors.forename: Bao-Lan
authors.initials: BL
authors.lastname: Hu
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism*; D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D002681:China; D055868:Floods; D008697:Methane / Q000378:metabolism*; D008969:Molecular Sequence Data; D009573:Nitrites / Q000378:metabolism*; D010084:Oxidation-Reduction; D010802:Phylogeny; D012988:Soil Microbiology
chemical_list: D064751:Ammonium Compounds; D009573:Nitrites; D008697:Methane