Methane‐derived carbon flow through microbial communities in arctic lake sediments

• Published in: Environmental Microbiology
• Main Authors: He, Ruo, Wooller, Matthew J., Pohlman, John W., Tiedje, James M., Leigh, Mary Beth
• Other Authors: Office of Fossil Energy
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2015
• Subjects: Arctic; Arctic Lake
• Online Access: http://dx.doi.org/10.1111/1462-2920.12773; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2F1462-2920.12773; https://onlinelibrary.wiley.com/doi/pdf/10.1111/1462-2920.12773; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/1462-2920.12773; https://sfamjournals.onlinelibrary.wiley.com/doi/am-pdf/10.1111/1462-2920.12773

Summary Aerobic methane ( CH 4 ) oxidation mitigates CH 4 release and is a significant pathway for carbon and energy flow into aquatic food webs. Arctic lakes are responsible for an increasing proportion of global CH 4 emissions, but CH 4 assimilation into the aquatic food web in arctic lakes is poorly understood. Using stable isotope probing ( SIP ) based on phospholipid fatty acids ( PLFA‐SIP ) and DNA ( DNA‐SIP ), we tracked carbon flow quantitatively from CH 4 into sediment microorganisms from an arctic lake with an active CH 4 seepage. When 0.025 mmol CH 4 g −1 wet sediment was oxidized, approximately 15.8–32.8% of the CH 4 ‐derived carbon had been incorporated into microorganisms. This CH 4 ‐derived carbon equated to up to 5.7% of total primary production estimates for Alaskan arctic lakes. Type I methanotrophs, including Methylomonas , Methylobacter and unclassified Methylococcaceae , were most active at CH 4 oxidation in this arctic lake. With increasing distance from the active CH 4 seepage, a greater diversity of bacteria incorporated CH 4 ‐derived carbon. Actinomycetes were the most quantitatively important microorganisms involved in secondary feeding on CH 4 ‐derived carbon. These results showed that CH 4 flows through methanotrophs into the broader microbial community and that type I methanotrophs, methylotrophs and actinomycetes are important organisms involved in using CH 4 ‐derived carbon in arctic freshwater ecosystems.