College of Water Sciences, Beijing Normal University, Beijing, 100875, China.
School of Water Conservancy and Hydroelectric Power, Hebei University of Engineering, Handan, 056038, China.
Environ Res. 2023 Oct 1;234:116565. doi: 10.1016/j.envres.2023.116565. Epub 2023 Jul 5.
Complete ammonia oxidation (comammox) is one of the most important biogeochemical processes, with recent studies showing that comammox process dominates nitrification in many ecosystems. However, the abundance, community and driving factor of comammox bacteria and other nitrifying microorganisms in plateau wetland is still unclear. Here, the abundances and community features of comammox bacteria, ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in the wetland sediments of western China plateaus were examined using qPCR and high-throughput sequencing. The results indicate that comammox bacteria were more abundant than AOA and AOB, and dominated the nitrification process. Compared with low-elevation samples (below 3000 m: samples 6-10, 12, 13, 15, 16), the abundance of comammox bacteria was much higher at high-elevation samples (above 3000 m: samples 1-5, 11, 14, 17, 18). The key species of AOA, AOB, and comammox bacteria were Nitrososphaera viennensis, Nitrosomonas europaea, and Nitrospira nitrificans, respectively. The key factor affecting comammox bacteria community was elevation. Elevation could increase the interaction links of key species Nitrospira nitrificans, resulting in high comammox bacterial abundance. The results of this study advance our knowledge of comammox bacteria in natural ecosystems.
完全氨氧化（comammox）是最重要的生物地球化学过程之一，最近的研究表明，在许多生态系统中，comammox 过程主导硝化作用。然而，高原湿地中 comammox 细菌和其他硝化微生物的丰度、群落和驱动因素仍不清楚。本研究采用 qPCR 和高通量测序技术，研究了中国西部高原湿地沉积物中 comammox 细菌、氨氧化古菌（AOA）和氨氧化细菌（AOB）的丰度和群落特征。结果表明，comammox 细菌比 AOA 和 AOB 更丰富，主导硝化作用。与低海拔样本（<3000 m：样本 6-10、12、13、15、16）相比，高海拔样本（>3000 m：样本 1-5、11、14、17、18）中 comammox 细菌的丰度高得多。AOA、AOB 和 comammox 细菌的关键种分别为 Nitrososphaera viennensis、Nitrosomonas europaea 和 Nitrospira nitrificans。影响 comammox 细菌群落的关键因素是海拔。海拔可以增加关键种 Nitrospira nitrificans 的相互作用联系，导致 comammox 细菌丰度高。本研究结果提高了我们对自然生态系统中 comammox 细菌的认识。
