珠江河口湿地沉积物硝化作用强度及影响因素研究

Study on nitrification and impact factors in Pearl River estuarine wetlands

采用现场调查和实验室模拟的方法,研究了珠江河口红树林、芦苇和光滩表层湿地沉积物氨氧化细菌(AOB)的分布、硝化强度及其主要影响因素。研究结果表明:三种不同生态环境中AOB数量差别较大。温度、pH、盐度和氨氮的浓度对沉积物硝化作用均有影响。其中盐度和pH对沉积物硝化强度影响最为显著,较高的盐度和较低的pH对硝化过程有明显的抑制作用。偏碱性环境下(pH=8.5)红树林、芦苇和光滩的硝化强度分别是偏酸性环境(pH=6.5)时2.5倍。最适宜的硝化温度在28℃左右,氨氮对氨氧化细菌的生长有促进作用,在含氨氮浓度较高的培养液中硝化强度较强。大型植物根系对硝化作用有明显的促进作用,对河口湿地氮循环具有重要的意义。

The distributions of ammonia-oxidizing bacteria （AOB）, performance of nitrification and its impact factors in mangrove, phragnaites and tidal fiats areas of Pearl River estuarine wetlands were investigated based on field investigation and laboratory simulation experiments. The results indicated that the numbers of AOB had significant difference at three kinds of ecological environments. The laboratory simulation experiments showed that temperature, pH, salinity and the concentration of ammonia influenced the process of nitrification; especially pH and salinity had significant effect on nitrifying capacity. Higher salinity and lower temperature could inhibit the process of nitrification. Alkaline condition （pH=8.5） was suitable for nitrification in all experiment areas with the nitrifying capacity of about 2.5 times higher than acidic condition （pH=6.5） . The optimum temperature for nitrification was about 28 ℃ and the content of ammonia nitrogen could improve the growth of AOB. The macrophyte was important in nitrogen cycle in the Pearl River estuarine wetlands.