不同浓度NH_3对富营养化湖泊水体硝化作用的影响

Effects of Different NH_3 Concentrations on Nitrification in Waters of Eutrophic Lake

通过室内培养试验,研究了不同浓度非离子态氨(NH3)条件下富营养化湖泊——太湖梅粱湾水体硝化作用的2个过程,即氨氧化和亚硝酸盐氧化的发生情况。结果表明,在试验设计的NH3浓度范围内,颗粒态氨氧化和自由态氨氧化速率都随着NH3浓度的升高而显著增加,同时在高浓度NH3(0.65和0.85mg/L)下,颗粒态氨氧化速率在总氨氧化速率中所占比例也显著增加。而亚硝酸盐氧化过程的发生却具有明显的阶段性,当NH3浓度从0.05增加到0.15mg/L时,自由态亚硝酸盐氧化速率有一定的降低,但是颗粒态亚硝酸盐氧化速率却显著增加,导致总亚硝酸盐氧化速率也显著上升;当NH3浓度从0.15增加到0.85mg/L,自由态亚硝酸盐氧化速率随着NH3浓度的升高而进一步降低,同时颗粒态亚硝酸盐氧化速率也随着NH3浓度的增加开始显著降低,导致总亚硝酸盐氧化速率急剧降低。

Two processes of nitrification, namely ammonia oxidation and nitrite oxidation in waters of an eutrophic lake-Meiliang Bay, Taihu Lake were systematically studied under different unionized ammonia （NH3） concentrations by in-door incubation experiment. The results showed that in the range of NH3 concentrations designed for the experiment, ammonia oxidation rates in both particle and free states increased significantly with NH3 concentrations increasing, and the proportion of particulate ammonia oxidation activity in the total activity also increased significantly in the high NH3 concentrations （0.65 and 0.85 mg/L）. But the occurrence of nitrite oxidation process showed an obvious characteristic stage. When NH3 concentrations increased from 0.05 to 0.15 mg/L, nitrite oxidation rates in free state decreased to a certain extent, while the particulate nitrite oxidation activity increased significantly, also leading to total nitrite oxidation rate increasing significantly; when NH3 concentrations increased from 0.15 to 0.85 mg/L, nitrite oxidation rates in free state further decreased, and the particulate nitrite oxidation activity also decreased significantly, resulting in sharp decrease of total nitrite oxidation rates.