Nitrite-and nitrate-coupled anaerobic oxidation of methane(AOM),mediated by Candidatus Methylomirabilis-like bacteria and Methanoperedens-like archaea,respectively,are two recent additions of freshwater carbon and nit...Nitrite-and nitrate-coupled anaerobic oxidation of methane(AOM),mediated by Candidatus Methylomirabilis-like bacteria and Methanoperedens-like archaea,respectively,are two recent additions of freshwater carbon and nitrogen cycles.However,the quantitative roles of the two AOM processes in CH_(4)emission reduction in lakes have not yet been characterized.Here,we explored vertical(0–10,10–20,and 20–30 cm)variation in nitrite-and nitrate-coupled AOM activity,as well as the abundance and community structure of Methylomirabilis-and Methanoperedens-like methanotrophs in freshwater lake sediment.The potential rates of nitrite-and nitrate-coupled AOM quantified via^(13)CH_(4)isotopic experiments were 0.41–3.84 and 0.32–3.88 nmol CH_(4)/(g·d),respectively.The rates of AOM exhibited significant and consistent depth-related variation across different sampling sites,with both peaking in the 10–20 cm layer.The abundance of Methylomirabilis-like bacteria and Methanoperedens-like archaea quantified via quantitative PCR was 3.34×10^(5)–9.17×10^(6)and 1.27×10^(6)–9.46×10^(6)copies/g,respectively.There was no consistent depth-related variation in the abundance of bacteria or archaea.The community composition of both Methylomirabilis-and Methanoperedens-like methanotrophs remained relatively stable along the sediment profile,while the composition significantly changed across sampling sites.Sediment pH and the content of NH4+and organic carbon were key variables influencing the community structure of Methylomirabilis-and Methanoperedens-like methanotrophs.Overall,we characterized vertical variation in nitrite-and nitrate-coupled AOM processes in lake sediment,which helps quantify their role in CH_(4)consumption in freshwater aquatic ecosystems.展开更多
基金supported by the National Natural Science Foundation of China(No.42377116)the R&D Foundation of Jiangsu Province,China(No.BK20220021)the 333 High-Level Talents Training Project of Jiangsu Province,China(No.BRA2022023).
文摘Nitrite-and nitrate-coupled anaerobic oxidation of methane(AOM),mediated by Candidatus Methylomirabilis-like bacteria and Methanoperedens-like archaea,respectively,are two recent additions of freshwater carbon and nitrogen cycles.However,the quantitative roles of the two AOM processes in CH_(4)emission reduction in lakes have not yet been characterized.Here,we explored vertical(0–10,10–20,and 20–30 cm)variation in nitrite-and nitrate-coupled AOM activity,as well as the abundance and community structure of Methylomirabilis-and Methanoperedens-like methanotrophs in freshwater lake sediment.The potential rates of nitrite-and nitrate-coupled AOM quantified via^(13)CH_(4)isotopic experiments were 0.41–3.84 and 0.32–3.88 nmol CH_(4)/(g·d),respectively.The rates of AOM exhibited significant and consistent depth-related variation across different sampling sites,with both peaking in the 10–20 cm layer.The abundance of Methylomirabilis-like bacteria and Methanoperedens-like archaea quantified via quantitative PCR was 3.34×10^(5)–9.17×10^(6)and 1.27×10^(6)–9.46×10^(6)copies/g,respectively.There was no consistent depth-related variation in the abundance of bacteria or archaea.The community composition of both Methylomirabilis-and Methanoperedens-like methanotrophs remained relatively stable along the sediment profile,while the composition significantly changed across sampling sites.Sediment pH and the content of NH4+and organic carbon were key variables influencing the community structure of Methylomirabilis-and Methanoperedens-like methanotrophs.Overall,we characterized vertical variation in nitrite-and nitrate-coupled AOM processes in lake sediment,which helps quantify their role in CH_(4)consumption in freshwater aquatic ecosystems.
