DOI: 10.1038/ngeo2162
论文题名: The impact of ocean deoxygenation on iron release from continental margin sediments
作者: Scholz F. ; Mcmanus J. ; Mix A.C. ; Hensen C. ; Schneider R.R.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2014
卷: 7, 期: 6 起始页码: 433
结束页码: 437
语种: 英语
Scopus关键词: bioavailability
; biogeochemistry
; coastal sediment
; continental margin
; iron
; iron sulfide
; molybdenum
; oxygen minimum layer
; oxygenation
; seafloor
; upwelling
; uranium
; Humboldt Current
; Pacific Ocean
; Peru
英文摘要: In the oceans' high-nitrate-low-chlorophyll regions, such as the Peru/Humboldt Current system and the adjacent eastern equatorial Pacific, primary productivity is limited by the micronutrient iron. Within the Peruvian upwelling area, bioavailable iron is released from the reducing continental margin sediments. The magnitude of this seafloor source could change with fluctuations in the extension or intensity of the oxygen minimum zones. Here we show that measurements of molybdenum, uranium and iron concentrations can be used as a proxy for sedimentary iron release, and use this proxy to assess iron release from the sea floor beneath the Peru upwelling system during the past 140,000 years. We observe a coupling between levels of denitrification, as indicated by nitrogen isotopes, trace metal proxies for oxygenation, and sedimentary iron concentrations. Specifically, periods with poor upper ocean oxygenation are characterized by more efficient iron retention in the sediment and a diminished iron supply to the water column. We attribute efficient iron retention under more reducing conditions to widespread sulphidic conditions in the surface sediment and concomitant precipitation of iron sulphides. We argue that iron release from continental margin sediments is most effective in a narrow redox window where neither oxygen nor sulphide is present. We therefore suggest that future deoxygenation in the Peru upwelling area would be unlikely to result in increased iron availability, whereas in weaker oxygen minimum zones partial deoxygenation may enhance the iron supply. © 2014 Macmillan Publishers Limited. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106575
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, 104 CEOAS Administration Building, Corvallis, OR 97331-5503, United States; GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstraße 1-3, 24148 Kiel, Germany; Department of Geoscience, University of Akron, Akron, OH 44325, United States; Institute of Geosciences, Kiel University, Ludewig-Meyn Straße 10, 24118 Kiel, Germany
Recommended Citation:
Scholz F.,Mcmanus J.,Mix A.C.,et al. The impact of ocean deoxygenation on iron release from continental margin sediments[J]. Nature Geoscience,2014-01-01,7(6)