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: 2021
• Subjects: Arctic
• Online Access: https://vbn.aau.dk/da/publications/b85a70ee-5a3c-4c76-b754-9603ee06e2d4; https://doi.org/10.1038/s41467-021-25983-9; https://vbn.aau.dk/ws/files/467108164/s41467_021_25983_9.pdf; http://www.scopus.com/inward/record.url?scp=85116373672&partnerID=8YFLogxK

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.