Coupling methane oxidation and N₂ fixation under methanogenic conditions in contrasting environments

authored by

Yongliang Mo, Jiwei Li, Xiaotong Peng, Adrian Ho, Zhongjun Jia

Abstract

Microbial methane oxidation under widespread suboxic environment is crucial for understanding methane emission. However, the role of aerobic methanotrophs in mediating methane oxidation and nitrogen fixation is less understood in oxygen-limiting environments. In this study, we identified diazotrophic methanotrophs under oxygen-limited conditions (initial O₂ of 6–8 μM) in two contrasting habitats (paddy soil and marine sediment) using DNA-based stable isotope probing combined with amplicon sequencing. Consistently, we documented significant ¹³CH₄ oxidation and ¹⁵N₂ fixation after 740 days of suboxic isotope labeling. Sequencing analysis revealed the predominance of Methylobacter–affiliated aerobic methanotrophs in the ¹³C-labeled DNA fractions. These Methylobacter-like OTUs accounted for 97.86 % in paddy soil and 99.49 % in marine sediment of the total pmoA gene sequences; while relative abundances for the nifH gene sequences were 91.59 % in paddy soil and 99.49 % in marine sediment. Taken together, our analyses revealed that Methylobacter is responsible for methane oxidation and nitrogen fixation under oxygen limitation in both habitats, demonstrating convergent emergence of this aerobic methanotroph under oxygen deficiency.

Organisation(s)

Institute of Microbiology

External Organisation(s)

Chinese Academy of Sciences (CAS)
China West Normal University
Institute of Deep-Sea Science and Engineering

Type

Article

Journal

European journal of soil biology

Volume

123

No. of pages

4

ISSN

1164-5563

Publication date

12.2024

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Microbiology, Soil Science, Insect Science

Sustainable Development Goals

SDG 14 - Life Below Water

Electronic version(s)

https://doi.org/10.1016/j.ejsobi.2024.103693 (Access: Closed)