title: Effects of sulfamethazine on denitrification and the associated N2O release in estuarine and coastal sediments.
abstract: Denitrification is an important pathway of nitrogen removal and nitrous oxide (N2O) production in estuarine and coastal ecosystems, and plays a significant role in counteracting aquatic eutrophication induced by excessive nitrogen loads. Estuarine and coastal environments also suffer from increasing antibiotic contamination because of the growing production and usage of antibiotics. In this study, sediment slurry incubation experiments were conducted to determine the influence of sulfamethazine (SMT, a sulphonamide antibiotic) on denitrification and the associated N2O production. Genes important for denitrification and antibiotic resistance were quantified to investigate the microbial physiological mechanisms underlying SMT's effects on denitrification. SMT was observed to significantly inhibit denitrification rates, but increasing concentrations of SMT enhanced N2O release rates. The negative exponential relationships between denitrifying gene abundances and SMT concentrations showed that SMT reduced denitrification rates by restricting the growth of denitrifying bacteria, although the presence of the antibiotic resistance gene was detected during the incubation period. These results imply that the wide occurrence of residual antibiotics in estuarine and coastal ecosystems may influence eutrophication control, greenhouse effects, and atmospheric ozone depletion by inhibiting denitrification and stimulating the release of N2O.
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University , 3663 North Zhongshan Road, Shanghai, 200062, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Hou
authors.forename: Guoyu
authors.initials: G
authors.lastname: Yin
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Junliang
authors.initials: J
authors.lastname: Zhou
authors.forename: Yanling
authors.initials: Y
authors.lastname: Zheng
authors.forename: Juan
authors.initials: J
authors.lastname: Gao
authors.forename: Haibo
authors.initials: H
authors.lastname: Zong
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: Lei
authors.initials: L
authors.lastname: Gao
authors.forename: Chunfu
authors.initials: C
authors.lastname: Tong
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D058440:Denitrification; D024881:Drug Resistance, Bacterial; D017753:Ecosystem; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry*; D009584:Nitrogen / Q000378:metabolism; D009609:Nitrous Oxide / Q000737:chemistry*; D013418:Sulfamethazine / Q000737:chemistry* / Q000494:pharmacology*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D014874:Water Pollutants, Chemical; D013418:Sulfamethazine; D009609:Nitrous Oxide; D009584:Nitrogen