DOI: 10.1029/2018JC014110
Scopus记录号: 2-s2.0-85052453244
论文题名: On the Properties of the Arctic Halocline and Deep Water Masses of the Canada Basin from Nitrate Isotope Ratios
作者: Granger J. ; Sigman D.M. ; Gagnon J. ; Tremblay J.-E. ; Mucci A.
刊名: Journal of Geophysical Research: Oceans
ISSN: 21699275
出版年: 2018
卷: 123, 期: 8 起始页码: 5443
结束页码: 5458
语种: 英语
英文关键词: Arctic Ocean
; halocline
; nitrate isotopes
; nutrients
; remineralization
; ventilation
英文摘要: Nitrogen is a limiting nutrient for primary production in the western Arctic Ocean. Measurements of the nitrogen (15N/14N) and oxygen (18O/16O) isotope ratios of nitrate in the southeastern Beaufort Sea provide insight into biogeochemical cycling of nitrogen in the western Arctic Ocean. Nitrate O isotope ratios in the Pacific halocline evidence a highly regenerated reservoir. Coincident peaks in nutrient concentrations and reduced dissolved oxygen concentrations suggest that nitrate accrues from organic matter remineralization in bottom waters of the Chukchi shelf and that these ventilate the basin predominantly in summer, when isolated from the atmosphere. Preformed nitrate in Pacific Winter Water lacks 18O/16O elevation from nitrate assimilation, contrasting with preformed nitrate in other ocean regions. A reactive N deficit and elevated nitrate N isotope ratios in the Pacific halocline further indicate substantial N loss to coupled nitrification-denitrification in shelf sediments upstream. In the Atlantic Water below, nitrate isotope ratios identify two distinct waters entering the Arctic at Fram Strait, from (1) the surface West Spitsbergen Current, bearing isotopic signatures akin to North Atlantic waters, and (2) deeper inflows of waters ventilated in the Nordic Seas, transporting nitrate O isotope ratios indicative of regenerated nitrate. Poorly ventilated Canada Basin Deep Water shows evidence of nominal accrual of remineralized products, and nitrate isotope ratios suggest an influence of slow benthic denitrification on the sea floor. The observations reveal that shelf processes have a disproportionate influence on tracer properties of the Pacific halocline, while those in Atlantic Water are dominated by processes in the Nordic Seas. ©2018. 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/113349
Appears in Collections: 气候减缓与适应
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作者单位: Department of Marine Sciences, University of Connecticut, Storrs, CT, United States; Geosciences Department, Princeton University, Princeton, NJ, United States; Département de Biologie et Québec-Océan, Université Laval, Quebec, QC, Canada; GEOTOP and Department of Earth and Planetary Sciences, McGill University, Montreal, QC, Canada
Recommended Citation:
Granger J.,Sigman D.M.,Gagnon J.,et al. On the Properties of the Arctic Halocline and Deep Water Masses of the Canada Basin from Nitrate Isotope Ratios[J]. Journal of Geophysical Research: Oceans,2018-01-01,123(8)