A wave flume simulator was used to study internal nitrogen release from the surface sediment collected from Taihu Lake, China. Particulate nitrogen concentrations were positively correlated with the concentrations of ...A wave flume simulator was used to study internal nitrogen release from the surface sediment collected from Taihu Lake, China. Particulate nitrogen concentrations were positively correlated with the concentrations of suspended solids, primarily from surface erosion related to the shear stress and duration of wave action. In response to 4 cm- and 10 cm-high wave production representing waves generated in Taihu Lake by gentle and gusty winds, respectively, the mean dynamic release rate of ammonium （NH4＋） from the sediment to the overlying water was 1 × 10-3 mg/（m2.s） and the NH4＋ concentration in the overlying water increased by 0.016 mg/L, indicating that waves resulting from strong wind can induce the rapid release of dissolved nitrogen from Taihu Lake sediments. The decrease in interstitial NH4＋ concentrations at all sediment depths was associated with an increase in NH4＋ concentrations in the overlying water by 0.01 mg/L, showing that sediment below the eroded layer was the main source of internal nitrogen release. Changes in the interstitial dissolved oxygen and NH4＋ concentrations showed that wave-induced pore water movement can greatly increase the diffusion rate, and that these 15 cm. Diffusion induced by pore water movement sediment layer in Taihu Lake. effects can influence the sediment to a depth of at least may be very important for the formation of an active展开更多
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(Nos.41101458, 40825004,40871095,40801200)the Major Project for National Science and Technology Development(No.2010ZX03006-006)the "100-Talent Project" of Chinese Academy of Sciences,China(No.YOBROB045)
文摘A wave flume simulator was used to study internal nitrogen release from the surface sediment collected from Taihu Lake, China. Particulate nitrogen concentrations were positively correlated with the concentrations of suspended solids, primarily from surface erosion related to the shear stress and duration of wave action. In response to 4 cm- and 10 cm-high wave production representing waves generated in Taihu Lake by gentle and gusty winds, respectively, the mean dynamic release rate of ammonium （NH4＋） from the sediment to the overlying water was 1 × 10-3 mg/（m2.s） and the NH4＋ concentration in the overlying water increased by 0.016 mg/L, indicating that waves resulting from strong wind can induce the rapid release of dissolved nitrogen from Taihu Lake sediments. The decrease in interstitial NH4＋ concentrations at all sediment depths was associated with an increase in NH4＋ concentrations in the overlying water by 0.01 mg/L, showing that sediment below the eroded layer was the main source of internal nitrogen release. Changes in the interstitial dissolved oxygen and NH4＋ concentrations showed that wave-induced pore water movement can greatly increase the diffusion rate, and that these 15 cm. Diffusion induced by pore water movement sediment layer in Taihu Lake. effects can influence the sediment to a depth of at least may be very important for the formation of an active
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.
