| DOI: | 10.1002/grl.50250
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| 论文题名: | Equatorial upwelling enhances nitrogen fixation in the Atlantic Ocean |
| 作者: | Subramaniam A.; Mahaffey C.; Johns W.; Mahowald N.
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| 刊名: | Geophysical Research Letters
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| ISSN: | 0094-9128
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| EISSN: | 1944-8859
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| 出版年: | 2013
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| 卷: | 40, 期:9 | | 起始页码: | 1766
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| 结束页码: | 1771
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| 语种: | 英语
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| 英文关键词: | equatorial Atlantic
; Gulf of Guinea
; nitrate to phosphate ratios
; nitrogen fixation
; upwelling regions
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| Scopus关键词: | Atlantic Ocean
; Eastern equatorial Atlantic
; equatorial Atlantic
; Equatorial upwelling
; Fixation rates
; Gulf of Guinea
; Upwelling regimes
; Upwelling region
; Iron
; Nitrates
; Nitrogen
; Offshore oil wells
; Surface waters
; Nitrogen fixation
; ammonia
; gyre
; iron
; nitrate
; nitrogen fixation
; phosphate
; phytoplankton
; surface water
; upwelling
; Atlantic Ocean
; Atlantic Ocean (Equatorial)
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| 英文摘要: | Surface waters in upwelling regions are thought to be nutrient rich and hence inhibit nitrogen fixation (diazotrophy) because diazotrophs can preferentially assimilate nitrate and ammonia instead of expending energy to fix dinitrogen. We found average nitrogen fixation rates to be two to seven times higher in the surface waters of the upwelling region of the eastern equatorial Atlantic than typically measured here during non-upwelling periods. We posit that in this region, low nitrate-phosphate ratio waters are upwelled, and an initial bloom of non-diazotrophic phytoplankton removes recently upwelled nitrate. Thereby, diazotrophy is fuelled by residual phosphate and by a combination of aeolian and upwelled sources of iron. Annually, we estimate that approximately 47 Gmol of new nitrogen is introduced by diazotrophy in upwelled waters alone and 195 Gmol N is fixed in the equatorial Atlantic region. Our findings challenge the paradigm that the highest nitrogen fixation rates occur in oligotrophic gyres and instead provide evidence of its importance in upwelling regimes where phosphate- and iron-rich waters rich are upwelled. Key PointsNitrogen fixation rates are higher during upwelling than non-upwelling timesDiazotrophy is fueled by low N:P, iron rich water that is upwelledAnnually, 47 Gmol of new nitrogen is fixed in upwelled waters ©2013. American Geophysical Union. All Rights Reserved. |
| URL: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879116352&doi=10.1002%2fgrl.50250&partnerID=40&md5=9276f16448c8683ad03074b6569b53b6
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| Citation statistics: |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/6392
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| Appears in Collections: | 气候减缓与适应
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作者单位: | Lamont Doherty Earth Observatory, Columbia University, 61 Rt 9W, Palisades, NY 10964, United States
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| Recommended Citation: | |
Subramaniam A.,Mahaffey C.,Johns W.,et al. Equatorial upwelling enhances nitrogen fixation in the Atlantic Ocean[J]. Geophysical Research Letters,2013-01-01,40(9).
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