title: Microbial nitrogen removal pathways in integrated vertical-flow constructed wetland systems.
abstract: Microbial nitrogen (N) removal pathways in planted (Canna indica L.) and unplanted integrated vertical-flow constructed wetland systems (IVCWs) were investigated. Results of, molecular biological and isotope pairing experiments showed that nitrifying, anammox, and denitrifying bacteria were distributed in both down-flow and up-flow columns of the IVCWs. Further, the N transforming bacteria in the planted IVCWs were significantly higher than that in the unplanted ones (p<0.05). Moreover, the potential nitrification, anammox, and denitrification rates were highest (18.90, 11.75, and 7.84nmolNg(-1)h(-1), respectively) in the down-flow column of the planted IVCWs. Significant correlations between these potential rates and the absolute abundance of N transformation genes further confirmed the existence of simultaneous nitrification, anammox, and denitrification (SNAD) processes in the IVCWs. The anammox process was the major N removal pathway (55.6-60.0%) in the IVCWs. The results will further our understanding of the microbial N removal mechanisms in IVCWs.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. Electronic address: hefeng@ihb.ac.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Zhenbin
authors.initials: Z
authors.lastname: Wu
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D058440:Denitrification; D019684:Magnoliopsida / Q000378:metabolism / Q000382:microbiology; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*; D053833:Wetlands
chemical_list: D009584:Nitrogen; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Anammox; Integrated vertical-flow constructed wetland; Isotope pairing technique; Nitrogen removal pathway; Nitrogen transformation functional gene