辽河口湿地沉积物硝化细菌及硝化作用研究

2009年6月和8月,采用现场培养和实验室模拟培养相结合的方法对辽河口湿地表层沉积物硝化细菌数量、硝化速率及影响因素进行了研究.结果表明,辽河口湿地表层沉积物氨氧化细菌(ammonia-oxidizing bacteria,AOB)数量6月在0.54×104～5.69×104个.g-1之间,平均值为(2.21±2.32)×104个.g-1,8月在1.90×104～7.90×104个.g-1之间,平均值为(3.61±2.87)×104个.g-1;沉积物潜在硝化速率6月在9.72～16.45 mmol.(m2.h)-1之间,平均值为(12.54±3.14)mmol.(m2.h)-1,8月在14.66～24.62 mmol.(m2.h)-1之间,平均值为(18.71±4.21)mmol.(m2.h)-1;净硝化作用速率6月(S1站)为0.41 mmol.(m2.h)-1,8月在0.20～0.53 mmol.(m2.h)-1之间,平均值为(0.35±0.16)mmol.(m2.h)-1.潜在硝化速率显著高于净硝化速率,AOB数量、净硝化作用速率和潜在硝化作用速率均表现为8月高于6月,芦苇根际效应对硝化作用有促进作用.通过SPSS 13.0软件统计分析,表明影响辽河口湿地表层沉积物硝化作用的主要环境因子有上覆水NH 4+-N浓度和沉积物pH、有机质、总氮(TN)、总磷(TP)、NH 4+-N含量以及AOB数量(p0.05),其中上覆水NH 4+-N浓度和沉积物总磷(TP)、NH 4+-N含量对硝化作用影响较大,是辽河口湿地硝化作用影响的关键因素.根据研究结果估算辽河口湿地沉积物硝化作用每天可以将1.14×105kg的NH 4+-N转化为NO 3--N,对河口湿地氮的循环具有重要意义.

Studies on Nitrobacteria and Nitrification in Liaohe Estuary Wetland Sediments

Nitrobacteria, nitrification and its impact factors were discussed based on the method of on-site incubation and laboratory simulation in Liaohe estuary wetland sediments in June and August 2009, respectively. The results showed that the number of ammonia-oxidizing bacteria (AOB) ranged from 0.54×10⁴ to 5.69×10⁴ cells·g^-1 with an average of (2.21±2.32)×10⁴ cells·g^-1 in June and ranged from 1.90×10⁴ to 7.90×10⁴ cells·g^-1 with an average of (3.61±2.87)×10⁴ cells·g^-1 in August. The potential nitrification rates ranged from 9.72 to 16.45 mmol·(m²·h)^-1 with an average of (12.54±3.14) mmol·(m²·h)^-1 in June and ranged from 14.66 to 24.62 mmol·(m²·h)^-1 with an average of (18.71±4.21) mmol·(m²·h)^-1 in August. The net nitrification rates were 0.41 mmol·(m²·h)^-1 in June and ranged from 0.20 to 0.53 mmol·(m²·h)^-1 with an average of (0.35±0.16) mmol·(m²·h)^-1 in August. The potential nitrification rates were apparently higher than the net nitrification rates. The AOB abundance and nitrification rates were all higher in August than in June. Ammonia concentration in the overlying water, pH, organic matter, total nitrogen content, total phosphorus content, ammonia nitrogen content and the number of AOB in sediments were the main environmental impact factors on nitrification by SPSS 13.0 statistical analysis (p<0.05), and it also showed ammonia concentration in the overlying water, total phosphorus content and ammonia nitrogen content in sediments were key impact factors on nitrification by partial correlation analysis. The flux of transformed ammonium into nitrate by nitrification process was 1.14×10⁵ kg per day, suggesting that nitrification was important on nitrogen cycle in Liaohe estuary wetland sediments.