养猪废水中磺胺嘧啶对湿地底泥中氮转化微生物及过程影响

为探讨养殖废水中兽用抗生素对湿地系统中氮素转化及相关微生物过程的影响，以养殖废水中常见的抗生素SD（磺胺嘧啶）为例，设置0、10、100和1 000 μg/L 4个添加浓度开展模拟试验.通过qPCR（实时荧光定量PCR）技术，测定了湿地底泥中氨氧化和反硝化功能基因丰度，结合Pearson相关分析，分析了养殖废水中不同氮素形态与底泥中氮转化功能基因丰度的关联性.结果表明:①与CK组比较，添加SD对湿地TN的最终去除效果无显著性差异，4个处理组的TN去除率为75.4%~80.5%，但在培养前期（0~14 d），SD对水体NH₄+-N和NO₃--N转化的抑制率最高分别达53.0%和99.5%，随着SD浓度的增加，抑制作用越强，到培养后期（14~28 d），各处理水体中不同形态的氮浓度无显著差异.②由qPCR测试结果得出，湿地底泥中AOA（氨氧化古菌）的丰度比AOB（氨氧化细菌）高出1~2个数量级，表明AOA在氨氧化过程中起主导作用，另外在培养第7天，AOB发生显著抑制现象，对SD更敏感；与CK相比，在第7天和第14天，反硝化基因narG、nirS、nirK和nosZ丰度随SD浓度的增加而逐渐降低.③相关性分析结果表明，AOA与ρ（NH₄+-N）呈极显著正相关（P < 0.01），AOB与ρ（NO₃--N）呈极显著正相关（P < 0.01），nirK与ρ（NO₂--N）呈极显著正相关（P < 0.01）.研究显示，SD能抑制湿地底泥中氮转化微生物及相关氮转化过程，且SD浓度越大，抑制作用也越大，但随着培养时间的增加抑制作用会减弱. 

Effects of Sulfadiazine in Swine Wastewater on Microorganisms and Nitrogen Transformation Processes in Wetland Sediment

In order to explore the effects of antibiotics in swine wastewater on nitrogen transformation and the related microbial processes, this study selected the common antibiotic sulfadiazine (SD) in swine wastewater for laboratory simulation experiments with four SD concentrations of 0 (CK), 10, 100 and 1000 μg/L. The abundance of ammonia-oxidizing and denitrifying genes was determined by qPCR (real-time fluorescent quantitative PCR), and the relationship between the content of nitrogen compounds in wastewater and nitrogen transforming functional gene abundance in sediments was analyzed by the Pearson correlation analysis. The results indicated that: (1) There was no significant difference in the final TN removal performance between CK and the three SD-spiked treatments, and removal efficiency of the four treatments was 75.4%-80.5%. However, the highest inhibition ratios of NH₄+-N and NO₃--N transformation were 53.0% and 99.5% respectively during the early incubation period (0-14 d). The inhibition of NH₄+-N and NO₃--N transformation was more significant when SD concentration increased. There was no significant difference in the nitrogen content in the wastewater in all treatments during the later period (14-28 d). (2) The qPCR results showed that the abundance of ammonia-oxidizing archaea (AOA) was 1-2 orders of magnitude higher than that of ammonia-oxidizing bacteria (AOB), indicating that AOA may play a dominant role in the ammonia oxidation process. In addition, AOB was more sensitive to SD because significant inhibitory effect of AOB by SD was observed on day 7 of incubation. Compared with CK, the abundance of denitrification genes of narG, nirK, nirS and nosZ decreased gradually with increasing SD concentration on day 7 and day 14. (3) Pearson correlation analysis showed that the abundance of AOA was significantly positively correlated with ρ(NH₄+-N) (P < 0.01), and the abundance of AOB was significantly positively correlated with ρ(NO₃--N). Meanwhile, there was a significant positive correlation between the abundance of nirK gene and ρ(NO₂--N) (P < 0.01). These findings indicated that SD in swine wastewater had an obvious inhibitory effect on the nitrogen transformation microorganisms and processes. The greater the SD concentration, the higher the inhibition, but the inhibition effect will be weakened with the increase of culture time.