中文摘要：

采用分子荧光定量PCR对北运河闸坝区（上游沙河闸和下游杨洼闸）水体中氨氧化细菌（AOB）的amoA基因拷贝数进行定量测定,并研究了闸坝设置和排污口污水排放对AOB的amoA基因拷贝数,硝化活性（NA）和氮素转化的影响.结果表明,1在沙河闸段,AOB的amoA基因拷贝数呈现先上升后下降,排污口处又显著上升的空间变化特征,其变化范围为（1.84±0.09）×10~8~（7.12±0.36）×10~8copies·L~（-1）,排污口处最高;在杨洼闸段,amoA基因拷贝数呈现先上升后下降最后趋于平稳的空间变化特征,其变化范围为（3.05±0.15）×10~8~（6.83±0.34）×10~8copies·L~（-1）,下游100 m处最高.闸坝的设置和排污口污水的排放对AOB的amoA基因拷贝数和空间分布具有显著影响.2硝化活性（NA）的空间变化特征与AOB的变化特征相同.闸坝的设置和污水排放能促进水体的硝化过程,加快污染物质的降解.3沙河闸排污口处排放的NH_4~＋-N可以作为AOB生长的氮源,提高硝化活性,加快NH_4~＋-N全向NO_3~--N的转化,促进硝化过程的完全进行;杨洼闸段闸门的开启导致溶解氧的升高和内源NO_3~--N的释放,为AOB的生长提供氮源,提高硝化活性,但造成了NO_2~--N的积累.

英文摘要：

The number of amoA gene copies of ammonia-oxidizing bacteria（ AOB）, the characteristics of nitrification activity（ NA）, and N transformation in Shahe Gate and Yangwa Gate in Beiyun River were investigated by using molecular fluorescence quantitative PCR. The results indicated that： 1 In the section of Shahe Gate,the number of amoA gene copies increased first and decreased,then significant increase in sewage discharge outlet（ the highest number of amoA gene copies）,and the amoA gene copies were in the range from（ 1. 84 ± 0. 09） ×10~8to（ 7. 12 ± 0. 36） ×10~8copies·L~（-1）.In the section of Yangwa Gate,there was similar trend of amoA gene copies in Shahe Gate,which first increase and then decrease in the range from（ 3.05 ± 0. 15） ×10~8to（ 6. 83 ± 0. 34） ×10~8copies·L~（-1）,with the highest number of amoA gene copies at 100 m downstream behind the gate. The abundance and distribution of AOB was affected significantly by gate setting and sewage effluent. 2 Nitrification activity in the section of Shahe Gate were in the range from 0. 52 to 1. 46 mg·dm~（-3）·d~（-1）,showing similar pattern with those of amoA gene copies numbers. NA in the section of Yangwa Gate were in the range from 1. 14 to 2. 87 mg·dm~（-3）·d~（-1）,which increase first then decrease,similar to the trends of AOB in the section of Yangwa Gate. Gate setting and sewage effluents could promote the process of nitrification and the degradation of pollutants. 3 The NH_4~＋-N around sewage discharge outlet in the section of Shahe Gate was in high concentration to become nitrogen source for AOB,to improve the nitrifying activities. The decrease of NH_4~＋-N was equal to the increase of NO_3~--N. In Yangwa Gate,due to the gate setting,the concentration of DO and NO_3~--N was so high that can be nitrogen sourcesfor AOB. It could improve the nitrifying activities,but cause the accumulation of NO_2~--N.