title: Comparison of different ecological remediation methods for removing nitrate and ammonium in Qinshui River, Gonghu Bay, Taihu Lake.
abstract: Ecological remediation is one of the most practical methods for removing nutrients from river ecosystems. In this study, transformation and fate of nitrate and ammonium among four different ecological restoration treatments were investigated by stable15N isotope pairing technique combined with quantitative polymerase chain reaction and high-throughput sequencing technology. The results of15N mass-balance model showed that there were three ways to the fate of nitrogen: precipitated in the sediment, absorbed by Elodea nuttallii (E. nuttallii), and consumed by microbial processes (denitrification and anaerobic ammonium oxidation (anammox)). The results shown that the storage of15NH4+in sediments was about 1.5 times as much as that of15NO3-. And much more15NH4+was assimilated by E. nuttallii, about 2 times as much as15NO3-. Contrarily, the rate of microbial consuming15NO3-was higher than converting15NH4+. As for the group with15NO3-added, 29.61, 45.26, 30.66, and 51.95 % were accounted for15N-labeled gas emission. The proportions of15NH4+loss as15N-labeled gas were 16.06, 28.86, 16.93, and 33.09 % in four different treatments, respectively. Denitrification and anammox were the bacterial primary processes in N2and N2O production. The abundances of denitrifying and anammox functional genes were relatively higher in the treatment with E. nuttallii-immobilized nitrogen cycling bacteria (E-INCB) assemblage technology applied. Besides, microbial diversity increased in the treatment with E. nuttallii and INCB added. The15NO3-removal rates were 35.27, 49.42, 50.02, and 65.46 % in four different treatments. And the removal rates of15NH4+were 24, 34.38, 48.84, and 57.74 % in treatments A, B, C, and D, respectively. The results indicated that E-INCB assemblage technology could significantly promote the nitrogen cycling and improve nitrogen removal efficiency.
authors: State Key Laboratory of Pollutant Control and Resources Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, People's Republic of China.
authors: Hao
authors: H
authors: Wang
authors: State Key Laboratory of Pollutant Control and Resources Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, People's Republic of China. zhkuili@nju.edu.cn.
authors: Zhengkui
authors: Z
authors: Li
authors: State Key Laboratory of Pollutant Control and Resources Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, People's Republic of China.
authors: Huayang
authors: H
authors: Han
mesh_terms: D064751:Ammonium Compounds / Q000302:isolation & purification* / Q000378:metabolism; D061006:Bays; D001673:Biodegradation, Environmental; D002681:China; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism; D058440:Denitrification; D005798:Genes, Bacterial; D031321:Hydrocharitaceae / Q000378:metabolism / Q000382:microbiology; D060106:Lakes; D058889:Molecular Typing; D009566:Nitrates / Q000302:isolation & purification* / Q000378:metabolism; D010802:Phylogeny; D020560:Proteobacteria / Q000235:genetics / Q000378:metabolism; D045483:Rivers; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification
chemical_list: D064751:Ammonium Compounds; D009566:Nitrates; D014874:Water Pollutants, Chemical
keywords: Elodea nuttallii-INCB assemblage; N2 and N2O emission; NO3 − and NH4 +; Nitrogen fate; Plant assimilation; River; Sediment storage