Central Arctic Ocean paleoceanography from ~ 50 ka to present, on the basis of ostracode faunal assemblages from the SWERUS 2014 expedition

• Published in: Climate of the Past
• Main Authors: Gemery, Laura, Cronin, Thomas M., Poirier, Robert K., Pearce, Christof, Barrientos, Natalia, O'Regan, Matt, Johansson, Carina, Koshurnikov, Andrey, Jakobsson, Martin
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Arctic; Arctic Ocean; Greenland; Lomonosov Ridge; Sea ice; SWERUS-C3
• Online Access: https://pure.au.dk/portal/da/publications/central-arctic-ocean-paleoceanography-from--50-ka-to-present-on-the-basis-of-ostracode-faunal-assemblages-from-the-swerus-2014-expedition(c1f675b6-5153-4edb-9015-ad457a5e000b).html; https://doi.org/10.5194/cp-13-1473-2017; https://pure.au.dk/ws/files/118734719/cp_13_1473_2017.pdf

Late Quaternary paleoceanographic changes at the Lomonosov Ridge, central Arctic Ocean, were reconstructed from a multicore and gravity core recovered 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. (variable sea-ice margins, high surface productivity), Krithe hunti (Arctic Ocean deep water), and Rabilimis mirabilis (water mass change/AW inflow). Results indicate periodic seasonally sea-ice-free conditions during Marine Isotope Stage (MIS) 3 (57-29ka), rapid deglacial changes in water mass conditions (15-11ka), seasonally sea-ice-free conditions during the early Holocene (10-7ka) 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 new Lomonosov Ridge core site ( 85.15°N, 152°E) than farther north and towards Greenland. The new data provide evidence for abrupt, large-scale shifts in ostracode species depth and geographical distributions during rapid climatic transitions.