College of Chemistry and Material Engineering, Quzhou University, Quzhou, 324000, China.
Institue of Ecology, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
Chemosphere. 2023 May;324:138295. doi: 10.1016/j.chemosphere.2023.138295. Epub 2023 Mar 7.
Nitrate-driven anaerobic oxidation of methane (AOM), catalyzing by Candidatus Methanoperedens-like archaea, is a new addition in the global CH cycle. This AOM process acts as a novel pathway for CH emission reduction in freshwater aquatic ecosystems; however, its quantitative importance and regulatory factors in riverine ecosystems are nearly unknown. Here, we examined the spatio-temporal changes of the communities of Methanoperedens-like archaea and nitrate-driven AOM activity in sediment of Wuxijiang River, a mountainous river in China. These archaeal community composition varied significantly among reaches (upper, middle, and lower reaches) and between seasons (winter and summer), but their mcrA gene diversity showed no significant spatial or temporal variations. The copy numbers of Methanoperedens-like archaeal mcrA genes were 1.32 × 10-2.47 × 10 copies g (dry weight), and the activity of nitrate-driven AOM was 0.25-1.73 nmol CH g (dry weight) d, which could potentially reduce 10.3% of CH emissions from rivers. Significant spatio-temporal variations of mcrA gene abundance and nitrate-driven AOM activity were found. Both the gene abundance and activity increased significantly from upper to lower reaches in both seasons, and were significantly higher in sediment collected in summer than in winter. In addition, the variations of Methanoperedens-like archaeal communities and nitrate-driven AOM activity were largely impacted by the sediment temperature, NH and organic carbon contents. Taken together, both time and space scales need to be considered for better evaluating the quantitative importance of nitrate-driven AOM in reducing CH emissions from riverine ecosystems.
硝酸盐驱动的甲烷厌氧氧化（AOM），由类似产甲烷泥杆菌的古菌催化，是全球 CH 循环中的一个新补充。该 AOM 过程是淡水水生生态系统中减少 CH 排放的新途径；然而，其在河流生态系统中的定量重要性和调节因素几乎未知。在这里，我们研究了中国山区河流武溪江沉积物中类似产甲烷泥杆菌的古菌群落和硝酸盐驱动的 AOM 活性的时空变化。这些古菌群落组成在不同河段（上游、中游和下游）和不同季节（冬季和夏季）之间差异显著，但 mcrA 基因多样性没有表现出明显的时空变化。类似产甲烷泥杆菌古菌 mcrA 基因的拷贝数为 1.32×10-2.47×10 拷贝 g（干重），硝酸盐驱动的 AOM 活性为 0.25-1.73 nmol CH g（干重）d，这可能会减少河流 CH 排放的 10.3%。发现 mcrA 基因丰度和硝酸盐驱动的 AOM 活性存在显著的时空变化。无论是在冬季还是夏季，mcrA 基因丰度和硝酸盐驱动的 AOM 活性都在上游到下游呈显著增加趋势，夏季采集的沉积物中的丰度和活性显著高于冬季。此外，类似产甲烷泥杆菌古菌群落和硝酸盐驱动的 AOM 活性的变化主要受到沉积物温度、NH 和有机碳含量的影响。综上所述，需要考虑时间和空间尺度，以更好地评估硝酸盐驱动的 AOM 在减少河流生态系统 CH 排放中的定量重要性。
