title: Potential role of anammox in nitrogen removal in a freshwater reservoir, Jiulonghu Reservoir (China).
abstract: Currently, the nitrogen removal potential of anaerobic ammonium oxidation (anammox) and its regulating factors in reservoir systems remain uncertain. Here, we provided the molecular and isotopic evidence for anammox in the freshwater sediment of Jiulonghu Reservoir that is located in Quzhou, Zhejiang Province, China. Diverse 16S rRNA gene sequences related to Candidatus Kuenenia and Candidatus Brocadia were detected by using high-throughput (Illumina MiSeq) sequencing of total bacterial 16S rRNA genes, and the Candidatus Brocadia was the most frequently detected anammox bacterial genus. The anammox bacterial abundance was determined based on quantitative PCR on hzsA (the alpha subunit of the hydrazine synthase) genes and varied from 3.1 × 105to 1.1 × 106copies g-1dry sediment. Homogenized sediments were further incubated with15NO3-amendments to measure the potential anammox rates and determine the contribution of this process to dinitrogen gas (N2) production. The potential rates of anammox ranged between 8.1 and 30.8 nmol N2g-1dry sediment day-1, and anammox accounted for 7.7-20.5% of total N2production in sediment. Higher levels of anammox bacterial diversity, abundance, and activity were observed in the downstream with greater human disturbance than those in the upstream with less human disturbance. Correlation analyses suggested that the inorganic nitrogen level in sediment could be a key factor for the anammox bacterial abundance and activity. The results showed that the nitrogen removal via anammox may not be negligible in the examined reservoir and indicated that human activities could influence the anammox process in reservoir systems.
authors.affiliation: Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Jiangsu Key Laboratory of Agricultural Meteorology, College of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
authors.forename: Li-Dong
authors.initials: LD
authors.lastname: Shen
authors.affiliation: College of Chemistry and Materials Engineering, Quzhou University, Quzhou, 324000, China. haixiangcheng@zju.edu.cn.
authors.forename: Hai-Xiang
authors.initials: HX
authors.lastname: Cheng
authors.affiliation: Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Jiangsu Key Laboratory of Agricultural Meteorology, College of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Quzhou Academy of Agricultural Sciences, Quzhou, 324000, China.
authors.forename: Jian-Hui
authors.initials: JH
authors.lastname: Li
authors.affiliation: Wuxijiang National Wetland Park Service, Quzhou, 324000, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
mesh_terms: D001419:Bacteria / Q000235:genetics; D002681:China; D005618:Fresh Water / Q000737:chemistry*; D009584:Nitrogen / Q000302:isolation & purification*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D012336:RNA, Ribosomal, 16S; D009584:Nitrogen
keywords: Activity; Anammox; Distribution; Human activities; Nitrogen removal; Reservoir