Cai Min, Hong Yiguo, Wu Jiapeng, Moore Selina Sterup, Vamerali Teofilo, Ye Fei, Wang Yu
Institute of Environmental Research at Greater Bay Area, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China.
Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, 35122 Padova, Italy.
Microorganisms. 2022 Jul 15;10(7):1429. doi: 10.3390/microorganisms10071429.
Denitrification and anammox occur widely in aquatic ecosystems serving vital roles in nitrogen pollution removal. However, small waterbodies are sensitive to external influences; stormwater runoff carrying nutrients and oxygen, flows into waterbodies resulting in a disruption of geochemical and microbial processes. Nonetheless, little is known about how these short-term external inputs affect the microbial processes of nitrogen removal in small waterbodies. To investigate the effects of NO, NH, dissolved oxygen (DO) and organic C on microbial nitrogen removal in pond sediments, regulation experiments have been conducted using slurry incubation experiments and N tracer techniques in this study. It was demonstrated the addition of NO (50 to 800 μmol L) significantly promoted denitrification rates, as expected by Michaelis-Menten kinetics. Ponds with higher NO concentrations in the overlying water responded more greatly to NO additions. Moreover, NO production was also promoted by such an addition of NO. Denitrification was significantly inhibited by the elevation of DO concentration from 0 to 2 mg L, after which no significant increase in inhibition was observed. Denitrification rates increased when organic C was introduced. Due to the abundant NH in pond sediments, the addition demonstrated little influence on nitrogen removal. Moreover, anammox rates showed no significant changes to any amendment.
反硝化作用和厌氧氨氧化在水生生态系统中广泛存在，对去除氮污染起着至关重要的作用。然而，小型水体对外部影响较为敏感；携带营养物质和氧气的雨水径流流入水体，导致地球化学和微生物过程受到干扰。尽管如此，对于这些短期外部输入如何影响小型水体中氮去除的微生物过程，人们了解甚少。为了研究NO、NH、溶解氧（DO）和有机碳对池塘沉积物中微生物氮去除的影响，本研究采用泥浆培养实验和氮示踪技术进行了调控实验。结果表明，添加NO（50至800 μmol L）显著提高了反硝化速率，这与米氏动力学预期一致。上覆水中NO浓度较高的池塘对添加NO的反应更为强烈。此外，添加NO也促进了NO的产生。当DO浓度从0升高到2 mg L时，反硝化作用受到显著抑制，此后抑制作用没有显著增加。引入有机碳时反硝化速率增加。由于池塘沉积物中NH含量丰富，添加NH对氮去除的影响不大。此外，厌氧氨氧化速率对任何添加物均无显著变化。
