气候变化领域集成服务门户(CCPortal): Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods

CCPortal

DOI	10.1073/pnas.1809755115
	Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods
	Shoenfelt E.M.; Winckler G.; Lamy F.; Anderson R.F.; Bostick B.C.
发表日期	2018
ISSN	0027-8424
起始页码	11180
结束页码	11185
卷号	115 期号:44
英文摘要	Changes in bioavailable dust-borne iron (Fe) supply to the ironlimited Southern Ocean may influence climate by modulating phytoplankton growth and CO2 fixation into organic matter that is exported to the deep ocean. The chemical form (speciation) of Fe impacts its bioavailability, and glacial weathering produces highly labile and bioavailable Fe minerals in modern dust sources. However, the speciation of dust-borne Fe reaching the iron-limited Southern Ocean on glacial-interglacial timescales is unknown, and its impact on the bioavailable iron supply over geologic time has not been quantified. Here we use X-ray absorption spectroscopy on subantarctic South Atlantic and South Pacific marine sediments to reconstruct dust-borne Fe speciation over the last glacial cycle, and determine the impact of glacial activity and glaciogenic dust sources on bioavailable Fe supply. We show that the Fe(II) content, as a percentage of total dust-borne Fe, increases from ∼5 to 10% in interglacial periods to ∼25 to 45% in glacial periods. Consequently, the highly bioavailable Fe(II) flux increases by a factor of ∼15 to 20 in glacial periods compared with the current interglacial, whereas the total Fe flux increases only by a factor of ∼3 to 5. The change in Fe speciation is dominated by primary Fe(II) silicates characteristic of glaciogenic dust. Our results suggest that glacial physical weathering increases the proportion of highly bioavailable Fe(II) in dust that reaches the subantarctic Southern Ocean in glacial periods, which represents a positive feedback between glacial activity and cold glacial temperatures. © 2018 National Academy of Sciences. All rights reserved.
英文关键词	Dust; Iron bioavailability; Iron speciation; Productivity; Southern ocean
语种	英语
scopus关键词	biotite; hornblende; iron; mineral; unclassified drug; carbon dioxide; iron; sea water; Article; bioavailability; controlled study; dust; glacial period; glaciogenic dust; interglacial; marine environment; priority journal; sediment; Southern Ocean; weathering; X ray absorption spectroscopy; analysis; atmosphere; chemistry; climate; growth, development and aging; ice cover; phytoplankton; sea; temperature; Atmosphere; Carbon Dioxide; Climate; Dust; Geologic Sediments; Ice Cover; Iron; Minerals; Oceans and Seas; Phytoplankton; Seawater; Temperature
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159047
作者单位	Shoenfelt, E.M., Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States, Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, United States; Winckler, G., Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States, Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, United States; Lamy, F., Helmholtz Centre for Polar and Marine Research, Alfred Wegener Institute, Bremerhaven, 27570, Germany; Anderson, R.F., Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States, Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, United States; Bostick, B.C., Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States
推荐引用方式 GB/T 7714	Shoenfelt E.M.,Winckler G.,Lamy F.,et al. Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods[J],2018,115(44).
APA	Shoenfelt E.M.,Winckler G.,Lamy F.,Anderson R.F.,&Bostick B.C..(2018).Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods.Proceedings of the National Academy of Sciences of the United States of America,115(44).
MLA	Shoenfelt E.M.,et al."Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods".Proceedings of the National Academy of Sciences of the United States of America 115.44(2018).