Quantification of nitrogen reduction of each component in constructed wetland and functional gene analysis
Six groups(three groups without plants)of constructed wetland systems with substrates of ceramic pellets+cinder,ceramic pellets+zeolite,and zeolite+cinder were constructed to investigate the effect of nitrogen removal in Baotou Nanhai Lake and explore the contribution of nitrogen reduction of each component in a constructed wetland and the mechanism of microbial nitrogen removal.Nitrogen stable isotope tracing technology was used to quantify the contribution of plants,substrates,and microorganisms to nitrogen removal in a constructed wetland.High-throughput sequencing technology was used to investigate the microbial community structure and nitrogen metabolism functional genes in the system.The results showed that the constructed wetland with plants comprising ceramic+cinder was the most effective in nitrogen removal,with removal rates of(41.18±2.61)％,(50.44±2.63)％,(40.93±2.32)％,and(74.34±1.97)％for TN,NH4+-N,NO3--N,and NO2--N,respectively.15N tracing revealed that the contribution rates of plants,substrates,and microorganisms to the NO-3-N removal in the constructed wetland system were 27.74％,48.43％,and 23.83％,respectively.High-throughput sequencing and PICRUSt2 functional prediction results revealed that plants significantly impacted microbial composition and metabolic pathways.The dominant phylum was Proteobacteria,most of whose genera are involved in the nitrogen cycle and are crucial in biological denitrification.The abundance of nirS on the substrate and nirK in the plant roots of a planted constructed wetland system increased significantly.Plants effectively promoted the denitrification of microorganisms in constructed wetland systems.
万方数据
维普
