DOI: 10.1002/2013GB004729
Scopus记录号: 2-s2.0-84894345782
论文题名: New insights into sea ice nitrogen biogeochemical dynamics from the nitrogen isotopes
作者: Fripiat F ; , Sigman D ; M ; , Fawcett S ; E ; , Rafter P ; A ; , Weigand M ; A ; , Tison J ; -L
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2014
卷: 28, 期: 2 起始页码: 115
结束页码: 130
语种: 英语
英文关键词: Antarctic
; isotopes
; nitrification
; nitrogen
; paleoceanography
; sea ice
Scopus关键词: Biogeochemistry
; Biological materials
; Isotopes
; Nitrates
; Nitrification
; Nitrogen
; Organic compounds
; Seawater
; Antarctic
; Biogeochemical dynamics
; Dissolved nitrogen
; Isotopic measurement
; Nitrate assimilation
; Nitrate consumption
; Paleoceanography
; Primary production
; Sea ice
; isotopic analysis
; isotopic fractionation
; nitrogen cycle
; nitrogen isotope
; organic matter
; paleoceanography
; Pleistocene
; primary production
; sea ice
; Antarctica
英文摘要: We report nitrogen (N) isotopic measurements of nitrate, total dissolved nitrogen, and particulate nitrogen from Antarctic pack ice in early and late spring. Salinity-normalized concentrations of total fixed N are approximately twofold higher than in seawater, indicating that sea ice exchanges fixed N with seawater after its formation. The production of low-δ15N immobile organic matter by partial nitrate assimilation and the subsequent loss of high-δ15N nitrate during brine convection lowers the δ15N of total fixed N relative to the winter-supplied nitrate. The effect of incomplete nitrate consumption in sea ice is thus similar to that in the summertime surface ocean, but the degree of nitrate consumption is greater in ice, leading to a higher δ15N for organic N (~3.9‰) than in the open Antarctic Zone (~0.6‰). Relative to previous findings of very high-δ15N organic matter in sea ice (up to 41‰), this study indicates that it would be difficult for sea ice to explain the high δ15N of ice age Antarctic sediments. The partitioning of N isotopes between particulate and dissolved forms of reduced N suggests that primary production evolved from new to regenerated production from early to late spring. Even though nitrate assimilation raises the δ15N of nitrate, the δ15N of sea ice nitrate is frequently lower than that of seawater, providing direct evidence that the regeneration of reduced N in the ice includes nitrification, with mass and isotopic balances suggesting that nitrification supplies a substantial fraction (up to ~70%) of nitrate assimilated within Antarctic spring sea ice. Key Points Nitrate is mainly regenerated in spring sea ice Evolution in spring from new to regenerated sea ice primary production Sea ice alone is unlikely to explain δ15N variation in Antarctic sediments ©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/77486
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Earth and Environmental Sciences, Université Libre de Bruxelles, Brussels, Belgium; Department of Geosciences, Princeton University, Princeton NJ, United States; Earth and System Sciences and Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
Recommended Citation:
Fripiat F,, Sigman D,M,et al. New insights into sea ice nitrogen biogeochemical dynamics from the nitrogen isotopes[J]. Global Biogeochemical Cycles,2014-01-01,28(2)