DOI: 10.1002/2013GB004579
Scopus记录号: 2-s2.0-84893642871
论文题名: The counterintuitive effect of summer-to-fall mixed layer deepening on eukaryotic new production in the Sargasso Sea
作者: Fawcett S ; E ; , Lomas M ; W ; , Ward B ; B ; , Sigman D ; M
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2014
卷: 28, 期: 2 起始页码: 86
结束页码: 102
语种: 英语
英文关键词: eukaryotic phytoplankton
; mixed layer depth
; nitrate assimilation
; nitrogen isotopes
Scopus关键词: Isotopes
; Nitrogen
; Nutrients
; Phytoplankton
; Recycling
; Tropics
; Density difference
; High-latitude regions
; Mixed layer deepening
; Mixed layer depths
; Nitrate assimilation
; Nitrate consumption
; Nitrogen isotopes
; Nutrient-rich water
; Nitrates
; biological uptake
; eukaryote
; euphotic zone
; flow cytometry
; latitude
; mixed layer
; nitrate
; nitrogen isotope
; nutrient enrichment
; phytoplankton
; prokaryote
; Atlantic Ocean
; Sargasso Sea
; Eukaryota
; Prochlorococcus
; Prokaryota
; Synechococcus
英文摘要: The Sargasso Sea is characterized by strong summertime stratification that is thought to drive oligotrophy, but export production is surprisingly similar to that of high-latitude regions with ample major nutrient supply. Here we use the summer-to-fall progression in the northwestern Sargasso Sea to investigate the relationship between upper ocean stratification and phytoplankton nitrogen (N) uptake. Euphotic zone particles collected in July, October, and December were sorted by flow cytometry, and the 15N/14N of separated prokaryotic and eukaryotic phytoplankton was analyzed. The 15N/14N of Prochlorococcus and Synechococcus was always low, indicating uniform reliance on recycled N. In July and in two fall profiles, the 15N/14N of eukaryotic phytoplankton was high, reflecting consumption of subsurface nitrate. In three other fall profiles, eukaryotic 15N/14N was similar to prokaryote 15N/14N, suggesting a shift toward more complete reliance on recycled N. The progressive deepening of the mixed layer from summer to fall, although reducing the surface-to-deep density contrast, increases the density difference of the euphotic zone as a whole from underlying nutrient-rich waters, which may play a role in the observed decline in euphotic zone nitrate supply into the fall. The apparent summertime nitrate supply to the euphotic zone, when the mixed layer is shallowest, may help to explain the surprisingly high export production of the subtropical and tropical ocean. Key Points Eukaryotic phytoplankton dominate nitrate consumption and new production at BATS Fall eukaryote 15N/14N suggests less nitrate supply with mixed layer deepening Summer nitrate supply may help to explain high export of the subtropical ocean ©2014. 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/77512
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; Bermuda Institute of Ocean Sciences, St. George's, Bermuda; Bigelow Laboratory for Ocean Sciences, East Boothbay ME, United States
Recommended Citation:
Fawcett S,E,, Lomas M,et al. The counterintuitive effect of summer-to-fall mixed layer deepening on eukaryotic new production in the Sargasso Sea[J]. Global Biogeochemical Cycles,2014-01-01,28(2)