Diverse sediment microbiota shape methane emission temperature sensitivity in Arctic lakes

• Published in: Nature Communications
• Main Authors: Emerson, Joanne B., Varner, Ruth K., Wik, Martin, Parks, Donovan H., Neumann, Rebecca B., Johnson, Joel E., Singleton, Caitlin M., Woodcroft, Ben J., Tollerson, Rodney, Owusu-Dommey, Akosua, Binder, Morgan, Freitas, Nancy L., Crill, Patrick M., Saleska, Scott R., Tyson, Gene W., Rich, Virginia I.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2021
• Subjects: Arctic
• Online Access: https://authors.library.caltech.edu/111569/; https://authors.library.caltech.edu/111569/1/s41467-021-25983-9.pdf; https://authors.library.caltech.edu/111569/2/2020.02.08.934661v1.full.pdf; https://authors.library.caltech.edu/111569/3/41467_2021_25983_MOESM1_ESM.pdf; https://authors.library.caltech.edu/111569/4/41467_2021_25983_MOESM2_ESM.xlsx; https://authors.library.caltech.edu/111569/5/41467_2021_25983_MOESM3_ESM.pdf; https://resolver.caltech.edu/CaltechAUTHORS:20211021-152810415

Northern post-glacial lakes are significant, increasing sources of atmospheric carbon through ebullition (bubbling) of microbially-produced methane (CH₄) from sediments. Ebullitive CH₄ flux correlates strongly with temperature, reflecting that solar radiation drives emissions. However, here we show that the slope of the temperature-CH₄ flux relationship differs spatially across two post-glacial lakes in Sweden. We compared these CH₄ emission patterns with sediment microbial (metagenomic and amplicon), isotopic, and geochemical data. The temperature-associated increase in CH₄ emissions was greater in lake middles—where methanogens were more abundant—than edges, and sediment communities were distinct between edges and middles. Microbial abundances, including those of CH₄-cycling microorganisms and syntrophs, were predictive of porewater CH₄ concentrations. Results suggest that deeper lake regions, which currently emit less CH₄ than shallower edges, could add substantially to CH₄ emissions in a warmer Arctic and that CH₄ emission predictions may be improved by accounting for spatial variations in sediment microbiota.