DOI: 10.1002/2013GB004790
Scopus记录号: 2-s2.0-84916927762
论文题名: N2O production in the eastern South Atlantic: Analysis of N2O stable isotopic and concentration data
作者: Frame C ; H ; , Deal E ; , Nevison C ; D ; , Casciotti K ; L
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2014
卷: 28, 期: 11 起始页码: 1262
结束页码: 1278
语种: 英语
英文关键词: Coastal upwelling
; Denitrification
; Isotopomer
; Nitrification
; Nitrifier denitrification
; Nitrous oxide (N2o)
Scopus关键词: advection
; concentration (composition)
; denitrification
; flux measurement
; gas exchange
; isotopic composition
; mesopelagic zone
; nitrous oxide
; QuikSCAT
; stable isotope
; wind velocity
; Atlantic Ocean
; Atlantic Ocean (South)
英文摘要: The stable isotopic composition of dissolved nitrous oxide (N2O) is a tracer for the production, transport, and consumption of this greenhouse gas in the ocean. Here we present dissolved N2O concentration and isotope data from the South Atlantic Ocean, spanning from the western side of the mid-Atlantic Ridge to the upwelling zone off the southern African coast. In the eastern South Atlantic, shallow N2O production by nitrifier denitrification contributed a flux of isotopically depleted N2O to the atmosphere. Along the African coast, N2O fluxes to the atmosphere of up to 46 μmol/m2/d were calculated using satellite-derived QuikSCAT wind speed data, while fluxes at the offshore stations averaged 0.04 μmol/m2/d. Comparison of the isotopic composition of the deeper N2O in the South Atlantic (800m to 1000 m) to measurements made in other regions suggests that water advected from one or more of the major oxygen deficient zones contributed N2O to the mesopelagic South Atlantic via the Southern Ocean. This deeper N2O was isotopically and isotopomerically enriched (δ15Nbulk - N2O = 8.7 ± 0.1‰, δ18O - N2O = 46.5 ± 0.2‰, and. Site Preference = 18.7 ± 0.6‰) relative to the shallow N2O source, indicating that N2O consumption by denitrification influenced its isotopic composition. The N2O concentration maximum was observed between 200 m and 400 m and reached 49 nM near the Angolan coast. The depths of the N2O concentration maximum coincided with those of sedimentary particle resuspension along the coast. The isotopic composition of this N2O (δ15Nbulk - N2O = 5.8 ± 0.1‰, δ18O - N2O = 39.7 ± 0.1‰, and Site Preference = 9.8 ± 1.0‰) was consistent with production by diffusion-limited nitrate (NO3 -) reduction to nitrite (NO2 -), followed by NO2 - reduction to N2O by denitrification and/or nitrifier denitrification, with additional N2O production by NH2OH decomposition during NH3 oxidation. The sediment surface, benthic boundary layer, or particles resuspended from the sediments are likely to have provided the physical and chemical conditions necessary to produce this N2O. ©2014. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/77518
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Environmental Sciences, University of Basel, Basel, Switzerland; Institut des Sciences de la Terre, Université Joseph Fourier, Grenoble, France; Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, United States; Department of Environmental Earth System Science, Stanford University, Palo Alto, CA, United States
Recommended Citation:
Frame C,H,, Deal E,et al. N2O production in the eastern South Atlantic: Analysis of N2O stable isotopic and concentration data[J]. Global Biogeochemical Cycles,2014-01-01,28(11)