School of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088, P. R. China.
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, P. R. China.
J Microbiol. 2021 Jan;59(1):10-19. doi: 10.1007/s12275-021-0287-5. Epub 2020 Nov 17.
Ammonia oxidation, performed by ammonia-oxidizing archaea (AOA) and bacteria (AOB), plays a critical role in the cycle of nitrogen in the ocean. For now, environmental variables controlling distribution of ammonia-oxidizing microbes are still largely unknown in oceanic environments. In this study, we used real-time quantitative PCR and high-throughput sequencing methods to investigate the abundance and diversity of AOA and AOB from sediment and water in Zhanjiang Bay. Phylogenic analysis revealed that the majority of AOA amoA sequences in water and sediment were affiliated with the genus Nitrosopumilus, whereas the Nitrosotalea cluster was only detected with low abundance in water. Nitrosomonas and Nitrosospira dominated AOB amoA sequences in water and sediment, respectively. The amoA copy numbers of both AOA and AOB varied significantly with month for both sediment and water. When water and sediment temperature dropped to 17-20°C in December and February, respectively, the copy number of AOB amoA genes increased markedly and was much higher than for AOA amoA genes. Also, AOA abundance in water peaked in December when water temperature was lowest (17-20°C). Stepwise multiple regression analyses revealed that temperature was the most key factor driving monthly changes of AOA or AOB abundance. It is inferred that low water temperature may inhibit growth of phytoplankton and other microbes and so reduce competition for a common substrate, ammonium.
氨氧化作用由氨氧化古菌（AOA）和细菌（AOB）完成，在海洋氮循环中起着关键作用。目前，海洋环境中控制氨氧化微生物分布的环境变量在很大程度上仍然未知。在这项研究中，我们使用实时定量 PCR 和高通量测序方法调查了湛江湾沉积物和水中 AOA 和 AOB 的丰度和多样性。系统发育分析表明，水中和沉积物中的大多数 AOA amoA 序列与 Nitrosopumilus 属有关，而 Nitrosotalea 群仅在水中以低丰度检测到。在水中和沉积物中，Nitrosomonas 和 Nitrosospira 分别占 AOB amoA 序列的优势。无论是沉积物还是水，AOA 和 AOB 的 amoA 拷贝数都随月份有显著变化。当 12 月和 2 月水温分别降至 17-20°C 时，AOB amoA 基因的拷贝数显著增加，远高于 AOA amoA 基因。此外，当水温最低（17-20°C）时，水中 AOA 的丰度在 12 月达到峰值。逐步多元回归分析表明，温度是驱动 AOA 或 AOB 丰度月度变化的最关键因素。可以推断，低水温可能会抑制浮游植物和其他微生物的生长，从而减少对共同基质铵的竞争。
