Western Arctic Ocean temperature variability during the last 8000 years

We reconstructed subsurface (∼200–400 m) ocean temperature and sea‐ice cover in the Canada Basin, western Arctic Ocean from foraminiferal δ18O, ostracode Mg/Ca ratios, and dinocyst assemblages from two sediment core records covering the last 8000 years. Results show mean temperature varied from −1 t...

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Bibliographic Details
Published in:Geophysical research letters 2011-12, Vol.38 (24), p.n/a
Main Authors: Farmer, Jesse R., Cronin, Thomas M., de Vernal, Anne, Dwyer, Gary S., Keigwin, Lloyd D., Thunell, Robert C.
Format: Article
Language:English
Subjects:
Arctic Ocean
Atlantic Layer
Basins
Biological oceanography
Chemical oceanography
Climate change
Earth
Earth sciences
Earth, ocean, space
Exact sciences and technology
Geophysics
Ocean temperature
Oceanography
Sea ice
Sediments
Summer
temperature
variability
Water depth
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Summary:We reconstructed subsurface (∼200–400 m) ocean temperature and sea‐ice cover in the Canada Basin, western Arctic Ocean from foraminiferal δ18O, ostracode Mg/Ca ratios, and dinocyst assemblages from two sediment core records covering the last 8000 years. Results show mean temperature varied from −1 to 0.5°C and −0.5 to 1.5°C at 203 and 369 m water depths, respectively. Centennial‐scale warm periods in subsurface temperature records correspond to reductions in summer sea‐ice cover inferred from dinocyst assemblages around 6.5 ka, 3.5 ka, 1.8 ka and during the 15th century Common Era. These changes may reflect centennial changes in the temperature and/or strength of inflowing Atlantic Layer water originating in the eastern Arctic Ocean. By comparison, the 0.5 to 0.7°C warm temperature anomaly identified in oceanographic records from the Atlantic Layer of the Canada Basin exceeded reconstructed Atlantic Layer temperatures for the last 1200 years by about 0.5°C. Key Points Periods of reduced sea ice correspond with increased Atlantic Layer temperature The modern thermal structure of the western Arctic Ocean has existed since 7 ka Modern‐day Atlantic Layer temperatures are the warmest of the past millennium
ISSN:0094-8276
1944-8007
DOI:10.1029/2011GL049714