title: Abundance and distribution of microorganisms involved in denitrification in sediments of a Myriophyllum elatinoides purification system for treating swine wastewater.
abstract: Environmental pollution from livestock production, particularly swine production, is often managed by the use of constructed wetlands, which incorporate plants such as Myriophyllum elatinoides as a means of treating wastewater. The M. elatinoides purification system has been shown to effectively remove, via nitrification and denitrification, more than 90% of the total nitrogen (TN) and 84% of the NH4 (+)-N produced in swine wastewater. However, the mechanisms of variation in aquatic environmental factors and how the interaction of these factors affects denitrification by microorganisms in sediments remain poorly understood. In this study, the impacts of dissolved oxygen (DO), TN, NH4(+)-N, and NO3(-)-N on the abundance, diversity, and community distribution of denitrifiers in the sediments from different concentrations and types of wastewater including tap water (CK), two strengths of synthetic wastewater: 200 mg NH4(+)-N L(-1) (T1) and 400 mg NH4(+)-N L(-1) (T2), swine wastewater diluted 50% (T3), and swine wastewater (T4) were investigated in a microcosm experiment. A significant improvement was observed in the abundance of denitrification genes (nirK and nirS) in response to increased NO3(-)-N and DO in the swine wastewater sediments. The abundance of these denitrification genes was highest in the T4 sediments compared with other treatments. Terminal restriction fragment length polymorphism (T-RFLP) analysis revealed that the DO, TN, and NH4(+)-N positively impacted the richness index (S) of the nirK denitrifiers in T1, whereas the NO3(-)-N negatively affected the Simpson diversity index (D) of nirK and nirS denitrifiers in T3 and T4. However, the NO3(-)-N positively affected the nirK and nirS denitrifier community distribution, whereas the DO negatively affected the nirK and nirS denitrifier distribution in T3 and T4. These findings will be helpful in that they allow us to recognize the effects of environmental factors on the formation of the denitrifiers in the sediments in a M. elatinoides purification system.
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.|Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.
authors.forename: Xi
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.|Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China. liufeng@isa.ac.cn.|Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China. liufeng@isa.ac.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.|Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.|Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.|Graduate University of Chinese Academy of Sciences, Beijing, 100039, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: He
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.|Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China.|Graduate University of Chinese Academy of Sciences, Beijing, 100039, People's Republic of China.
authors.forename: Shunan
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China. traw2014@yeah.net.|Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, People's Republic of China. traw2014@yeah.net.
authors.forename: Jinshui
authors.initials: J
authors.lastname: Wu
mesh_terms: D000818:Animals; D058440:Denitrification / Q000235:genetics*; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D019684:Magnoliopsida / Q000254:growth & development / Q000378:metabolism*; D050901:Nitrate Reductase / Q000235:genetics; D009572:Nitrite Reductases / Q000235:genetics; D009584:Nitrogen / Q000302:isolation & purification*; D012150:Polymorphism, Restriction Fragment Length; D013552:Swine; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
chemical_list: D050901:Nitrate Reductase; D009572:Nitrite Reductases; D009584:Nitrogen; D062065:Wastewater
keywords: Denitrification; Functional gene diversity; Myriophyllum elatinoides; Real-time PCR; Swine wastewater; T-RFLP