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DOI | 10.1073/pnas.1809755115 |
Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods | |
Shoenfelt, Elizabeth M.1,2; Winckler, Gisela1,2; Lamy, Frank3; Anderson, Robert F.1,2; Bostick, Benjamin C.1 | |
2018-10-30 | |
发表期刊 | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
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ISSN | 0027-8424 |
出版年 | 2018 |
卷号 | 115期号:44页码:11180-11185 |
文章类型 | Article |
语种 | 英语 |
国家 | USA; Germany |
英文摘要 | Changes in bioavailable dust-borne iron (Fe) supply to the iron-limited 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 similar to 5 to 10% in interglacial periods to similar to 25 to 45% in glacial periods. Consequently, the highly bioavailable Fe(II) flux increases by a factor of similar to 15 to 20 in glacial periods compared with the current interglacial, whereas the total Fe flux increases only by a factor of similar to 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. |
英文关键词 | iron speciation Southern Ocean iron bioavailability dust productivity |
领域 | 地球科学 ; 气候变化 ; 资源环境 |
收录类别 | SCI-E |
WOS记录号 | WOS:000448713200040 |
WOS关键词 | DEEP-SEA ; DEPOSITION ; CLIMATE ; RECORD ; PROVENANCE ; PACIFIC ; FLUXES |
WOS类目 | Multidisciplinary Sciences |
WOS研究方向 | Science & Technology - Other Topics |
URL | 查看原文 |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/205004 |
专题 | 地球科学 资源环境科学 气候变化 |
作者单位 | 1.Columbia Univ, Lamont Doherty Geol Observ, Palisades, NY 10964 USA; 2.Columbia Univ, Dept Earth & Environm Sci, New York, NY 10027 USA; 3.Alfred Wegener Inst, Helmholtz Ctr Polar & Marine Res, D-27570 Bremerhaven, Germany |
推荐引用方式 GB/T 7714 | Shoenfelt, Elizabeth M.,Winckler, Gisela,Lamy, Frank,et al. Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,2018,115(44):11180-11185. |
APA | Shoenfelt, Elizabeth M.,Winckler, Gisela,Lamy, Frank,Anderson, Robert F.,&Bostick, Benjamin 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),11180-11185. |
MLA | Shoenfelt, Elizabeth 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):11180-11185. |
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