DOI: 10.1002/gbc.20075
Scopus记录号: 2-s2.0-84884472540
论文题名: The proportion of remineralized nitrate on the ice-covered eastern Bering Sea shelf evidenced from the oxygen isotope ratio of nitrate
作者: Granger J ; , Prokopenko M ; G ; , Mordy C ; W ; , Sigman D ; M
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2013
卷: 27, 期: 3 起始页码: 962
结束页码: 971
语种: 英语
英文关键词: benthic
; Bering Sea shelf
; denitrification
; nitrate isotopes
; remineralization
; sea ice
Scopus关键词: benthic
; Bering sea
; Eastern bering sea shelves
; Nitrate concentration
; Nitrate isotopes
; Oxygen isotope composition
; Oxygen isotope ratios
; Remineralization
; Denitrification
; Isotopes
; Nutrients
; Oxygen
; Sea ice
; Water recycling
; Nitrates
; benthos
; biogeochemistry
; concentration (composition)
; continental shelf
; denitrification
; ice cover
; isotopic composition
; isotopic ratio
; nitrate
; nutrient cycling
; oxygen isotope
; phytoplankton
; remineralization
; seasonality
; Bering Sea
; Pacific Ocean
; algae
英文摘要: We present measurements of nitrate and its natural abundance oxygen isotope composition (18O/16O) in the water column of the broad and shallow eastern Bering Sea shelf in the late winter and early spring of 2007 and 2008. In both years, nitrate concentrations showed a characteristic decrease, from 25 μM at the slope to ≤5 μM inshore. The 18O/16O ratio of nitrate (δ18O NO3 versus SMOW) also decreased from 3.2‰ at the slope to 1.5‰ inshore in 2007 and to as low as -1‰ inshore in 2008, indicating that nitrate inshore was nitrified at least once since having been entrained as nitrate from the slope. The shoreward decrease was less pronounced in 2007 due to 18O enrichment of nitrate from incident phytoplankton assimilation in the ice-covered water column, whereas little to no algal growth in the water column was evident in 2008. By comparing the δ18O of nitrate to that of ambient water in spring 2008, we estimate the fraction of nitrate that was remineralized in situ rather than recently advected from the slope. These estimates indicate that 20%-100% of the nitrate in winter water of the middle and inner shelves derives from regeneration directly on the shelf rather than from the seasonal entrainment of slope waters, with recycling being the dominant mode of seasonal nitrate recharge from the 70 m isobath shoreward. These observations indicate substantial nutrient recycling on the shallow shelf, which has direct implications for the extent of fixed N loss to benthic denitrification and the fertility of the eastern shelf. Key Points Nitrate 18O/16O ratios decrease shoreward in ice-covered shelf watersNitrate inshore originates from nitrification in situRemineralization dominates seasonal nutrient replenishment on much of the shelf ©2013. 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/77572
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Marine Sciences, University of Connecticut, Groton, CT 06340, United States; Department of Geology, Pomona College California, Claremont, CA, United States; Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, WA, United States; Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, WA, United States; Geosciences Department, Princeton University, Princeton, NJ, United States
Recommended Citation:
Granger J,, Prokopenko M,G,et al. The proportion of remineralized nitrate on the ice-covered eastern Bering Sea shelf evidenced from the oxygen isotope ratio of nitrate[J]. Global Biogeochemical Cycles,2013-01-01,27(3)