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Research article - Peer-reviewed, 2021

Candidatus Methylumidiphilus Drives Peaks in Methanotrophic Relative Abundance in Stratified Lakes and Ponds Across Northern Landscapes

Martin, Gaetan; Rissanen, Antti J.; Garcia, Sarahi L.; Mehrshad, Maliheh; Buck, Moritz; Peura, Sari;

Abstract

Boreal lakes and ponds produce two-thirds of the total natural methane emissions above the latitude of 50 degrees North. These lake emissions are regulated by methanotrophs which can oxidize up to 99% of the methane produced in the sediments and the water column. Despite their importance, the diversity and distribution of the methanotrophs in lakes are still poorly understood. Here, we used shotgun metagenomic data to explore the diversity and distribution of methanotrophs in 40 oxygen-stratified water bodies in boreal and subarctic areas in Europe and North America. In our data, gammaproteobacterial methanotrophs (order Methylococcales) generally dominated the methanotrophic communities throughout the water columns. A recently discovered lineage of Methylococcales, Candidatus Methylumidiphilus, was present in all the studied water bodies and dominated the methanotrophic community in lakes with a high relative abundance of methanotrophs. Alphaproteobacterial methanotrophs were the second most abundant group of methanotrophs. In the top layer of the lakes, characterized by low CH4 concentration, their abundance could surpass that of the gammaproteobacterial methanotrophs. These results support the theory that the alphaproteobacterial methanotrophs have a high affinity for CH4 and can be considered stress-tolerant strategists. In contrast, the gammaproteobacterial methanotrophs are competitive strategists. In addition, relative abundances of anaerobic methanotrophs, Candidatus Methanoperedenaceae and Candidatus Methylomirabilis, were strongly correlated, suggesting possible co-metabolism. Our data also suggest that these anaerobic methanotrophs could be active even in the oxic layers. In non-metric multidimensional scaling, alpha- and gammaproteobacterial methanotrophs formed separate clusters based on their abundances in the samples, except for the gammaproteobacterial Candidatus Methylumidiphilus, which was separated from these two clusters. This may reflect similarities in the niche and environmental requirements of the different genera within alpha- and gammaproteobacterial methanotrophs. Our study confirms the importance of O-2 and CH4 in shaping the methanotrophic communities and suggests that one variable cannot explain the diversity and distribution of the methanotrophs across lakes. Instead, we suggest that the diversity and distribution of freshwater methanotrophs are regulated by lake-specific factors.

Keywords

methanotroph; greenhouse gas; metagenomics; thaw ponds; microbial diversity; lakes

Published in

Frontiers in Microbiology

2021, volume: 12, article number: 669937
Publisher: FRONTIERS MEDIA SA

Authors' information

Martin, Gaëtan
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Rissanen, Antti J.
Tampere University
Garcia, Sarahi L.
Stockholm University
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Peura, Sari
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology

UKÄ Subject classification

Microbiology

Publication Identifiers

DOI: https://doi.org/10.3389/fmicb.2021.669937

URI (permanent link to this page)

https://res.slu.se/id/publ/113516