Salinity significantly affects methane oxidation and methanotrophic community in Inner Mongolia lake sediments

Shaohua Zhang; Lei Yan; Jiahui Cao; Kexin Wang; Ying Luo; Haiyang Hu; Lixin Wang; Ruihong Yu; Baozhu Pan; Ke Yu; Ji Zhao; Zhihua Bao

doi:10.3389/fmicb.2022.1067017

Salinity significantly affects methane oxidation and methanotrophic community in Inner Mongolia lake sediments

Front Microbiol. 2023 Jan 6:13:1067017. doi: 10.3389/fmicb.2022.1067017. eCollection 2022.

Authors

Shaohua Zhang¹, Lei Yan¹, Jiahui Cao¹, Kexin Wang¹, Ying Luo¹, Haiyang Hu¹, Lixin Wang^{1

2}, Ruihong Yu², Baozhu Pan³, Ke Yu⁴, Ji Zhao^{1

2}, Zhihua Bao^{1

2}

Affiliations

¹ Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau & Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China.
² Inner Mongolia Key Laboratory of Environmental Pollution Control & Waste Resource Reuse, Inner Mongolia University, Hohhot, China.
³ Institute of Water Resources and Hydro-electric Engineering, Xi'an University of Technology, Xi'an, Shaanxi, China.
⁴ School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen, China.

Abstract

Methanotrophs oxidize methane (CH₄) and greatly help in mitigating greenhouse effect. Increased temperatures due to global climate change can facilitate lake salinization, particularly in the regions with cold semiarid climate. However, the effects of salinity on the CH₄ oxidation activity and diversity and composition of methanotrophic community in the sediment of natural lakes at a regional scale are still unclear. Therefore, we collected lake sediment samples from 13 sites in Mongolian Plateau; CH₄ oxidation activities of methanotrophs were investigated, and the diversity and abundance of methanotrophs were analyzed using real-time quantitative polymerase chain reaction and high throughput sequencing approach. The results revealed that the diversity of methanotrophic community decreased with increasing salinity, and community structure of methanotrophs was clearly different between the hypersaline sediment samples (HRS; salinity > 0.69%) and hyposaline sediment samples (HOS; salinity < 0.69%). Types II and I methanotrophs were predominant in HRS and HOS, respectively. Salinity was significantly positively correlated with the relative abundance of Methylosinus and negatively correlated with that of Methylococcus. In addition, CH₄ oxidation rate and pmoA gene abundance decreased with increasing salinity, and salinity directly and indirectly affected CH₄ oxidation rate via regulating the community diversity. Moreover, high salinity decreased cooperative association among methanotrophs and number of key methanotrophic species (Methylosinus and Methylococcus, e.g). These results suggested that salinity is a major driver of CH₄ oxidation in lake sediments and acts by regulating the diversity of methanotrophic community and accociation among the methanotrophic species.

Keywords: CH4 oxidation potential; Inner Mongolia; co-occurrence; methanotrophic community; salinity.