Central Arctic Ocean paleoceanography from ~ 50 ka to present, on the basis of ostracode faunal assemblages from SWERUS 2014 expedition
Laura Gemery1, Thomas M. Cronin1, Robert K. Poirier1,2, Christof Pearce3,4, Natalia Barrientos3, Matt O’Regan3, Carina Johansson3, Andrey Koshurnikov5,6, and Martin Jakobsson31US Geological Survey, Reston, Virginia, USA 2Rensselaer Polytechnic Institute, Department of Earth & Environmental Sciences, Troy, New York, USA 3Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Stockholm, 10691, Sweden 4Department of Geoscience, Aarhus University, Aarhus, 8000, Denmark 5Tomsk National Research Polytechnic University, Tomsk, Russia 6Moscow State University, Geophysics, Russian Federation
Received: 21 Feb 2017 – Accepted for review: 14 Mar 2017 – Discussion started: 28 Mar 2017
Abstract. Late Quaternary paleoceanographic changes in the central Arctic Ocean were reconstructed from a multicore and gravity core from the Lomonosov Ridge (Arctic Ocean) collected during the 2014 SWERUS-C3 Expedition. Ostracode assemblages dated by accelerator mass spectrometry (AMS) indicate changing sea-ice conditions and warm Atlantic Water (AW) inflow to the Arctic Ocean from ~ 50 ka to present. Key taxa used as environmental indicators include Acetabulastoma arcticum (perennial sea ice), Polycope spp. (productivity and sea ice), Krithe hunti (partially sea-ice free conditions, deep water inflow), and Rabilimis mirabilis (high nutrient, AW inflow). Results indicate seasonally sea-ice free conditions during Marine Isotope Stage (MIS) 3 (~ 57–29 ka), rapid deglacial changes in water mass conditions (15–11 ka), seasonally sea-ice free conditions during the early Holocene (~ 10–7 ka) and perennial sea ice during the late Holocene. Comparisons with faunal records from other cores from the Mendeleev and Lomonosov Ridges suggest generally similar patterns, although sea-ice cover during the last glacial maximum may have been less extensive at the southern Lomonosov Ridge at our core site (~ 85.15° N, 152° E) than farther north and towards Greenland. The new data also provide evidence for abrupt, large-scale shifts in ostracode species depth and geographical distributions during rapid climatic transitions.
Gemery, L., Cronin, T. M., Poirier, R. K., Pearce, C., Barrientos, N., O’Regan, M., Johansson, C., Koshurnikov, A., and Jakobsson, M.: Central Arctic Ocean paleoceanography from ~ 50 ka to present, on the basis of ostracode faunal assemblages from SWERUS 2014 expedition, Clim. Past Discuss., doi:10.5194/cp-2017-22, in review, 2017.