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.
• Language: unknown
• Published: 2023
• Subjects: 54 ENVIRONMENTAL SCIENCES; Arctic
• Online Access: http://www.osti.gov/servlets/purl/1904488; https://www.osti.gov/biblio/1904488; https://doi.org/10.1038/s41467-021-25983-9

Northern post-glacial lakes are significant, increasing sources of atmospheric carbon through ebullition (bubbling) of microbially-produced methane (CH 4 ) from sediments. Ebullitive CH 4 flux correlates strongly with temperature, reflecting that solar radiation drives emissions. However, here we show that the slope of the temperature-CH 4 flux relationship differs spatially across two post-glacial lakes in Sweden. We compared these CH 4 emission patterns with sediment microbial (metagenomic and amplicon), isotopic, and geochemical data. The temperature-associated increase in CH 4 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 CH 4 -cycling microorganisms and syntrophs, were predictive of porewater CH 4 concentrations. Results suggest that deeper lake regions, which currently emit less CH 4 than shallower edges, could add substantially to CH 4 emissions in a warmer Arctic and that CH 4 emission predictions may be improved by accounting for spatial variations in sediment microbiota.