DOI: 10.1002/2016GB005613
Scopus记录号: 2-s2.0-85033477130
论文题名: Tropical Dominance of N2 Fixation in the North Atlantic Ocean
作者: Marconi D ; , Sigman D ; M ; , Casciotti K ; L ; , Campbell E ; C ; , Alexandra Weigand M ; , Fawcett S ; E ; , Knapp A ; N ; , Rafter P ; A ; , Ward B ; B ; , Haug G ; H
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2017
卷: 31, 期: 10 起始页码: 1608
结束页码: 1623
语种: 英语
英文关键词: Atlantic
; excess P
; N2 fixation
Scopus关键词: global ocean
; nitrogen cycle
; nitrogen fixation
; phosphorus
; phytoplankton
; residence time
; surface water
; tropical environment
; upwelling
; Atlantic Ocean
; Atlantic Ocean (North)
; Atlantic Ocean (South)
英文摘要: To investigate the controls on N2 fixation and the role of the Atlantic in the global ocean's fixed nitrogen (N) budget, Atlantic N2 fixation is calculated by combining meridional nitrate fluxes across World Ocean Circulation Experiment sections with observed nitrate 15N/14N differences between northward and southward transported nitrate. N2 fixation inputs of 27.1 ± 4.3 Tg N/yr and 3.0 ± 0.5 Tg N/yr are estimated north of 11°S and 24°N, respectively. That is, ~90% of the N2 fixation in the Atlantic north of 11°S occurs south of 24°N in a region with upwelling that imports phosphorus (P) in excess of N relative to phytoplankton requirements. This suggests that, under the modern iron-rich conditions of the equatorial and North Atlantic, N2 fixation occurs predominantly in response to P-bearing, N-poor conditions. We estimate a N2 fixation rate of 30.5 ± 4.9 Tg N/yr north of 30°S, implying only 3 Tg N/yr between 30° and 11°S, despite evidence of P-bearing, N-poor surface waters in this region as well; this is consistent with iron limitation of N2 fixation in the South Atlantic. Since the ocean flows through the Atlantic surface in <2,500 years, similar to the residence time of oceanic fixed N, Atlantic N2 fixation can stabilize the N-to-P ratio of the global ocean. However, the calculated rate of Atlantic N2 fixation is a small fraction of global ocean estimates for either N2 fixation or fixed N loss. This suggests that, in the modern ocean, an approximate balance between N loss and N2 fixation is achieved within the combined Indian and Pacific basins. ©2017. 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/77698
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Geosciences, Princeton University, Princeton, NJ, United States; Department of Environmental Earth System Science, Stanford University, Stanford, CA, United States; School of Oceanography, University of Washington, Seattle, WA, United States; Department of Oceanography, University of Cape Town, Rondebosch, South Africa; Earth, Ocean, and Atmospheric Science Department, Florida State University, Tallahassee, FL, United States; Department of Earth System, University of California, Irvine, CA, United States; Max Planck Institute for Chemistry, Mainz, Germany
Recommended Citation:
Marconi D,, Sigman D,M,et al. Tropical Dominance of N2 Fixation in the North Atlantic Ocean[J]. Global Biogeochemical Cycles,2017-01-01,31(10)