Western Arctic Ocean temperature variability during the last 8000 years

We reconstructed subsurface (similar to 200-400 m) ocean temperature and sea-ice cover in the Canada Basin, western Arctic Ocean from foraminiferal delta O-18, 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 degrees C and -0.5 to 1.5 degrees 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 degrees 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 degrees C. Citation: Farmer, J. R., T. M. Cronin, A. de Vernal, G. S. Dwyer, L. D. Keigwin, and R. C. Thunell (2011), Western Arctic Ocean temperature variability during the last 8000 years, Geophys. Res. Lett., 38, L24602, doi: 10.1029/2011GL049714.