Thomas M. Cronin Robert K. Poirier Christof Pearce Natalia Barrientos Matt O’Regan Carina Johansson Andrey Koshurnikov Martin Jakobsson Laura Gemery 2017 <p>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 <i>Acetabulastoma</i> <i>arcticum</i> (perennial sea ice), <i>Polycopes</i> pp. (variable sea-ice margins, high surface productivity), <i>Krithe hunti</i> (Arctic Ocean deep water), and <i>Rabilimis mirabilis</i> (water mass change/AW inflow). Results indicate periodic 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 new Lomonosov Ridge core site (∼85.15<span>° </span>N, 152<span>° </span>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.</p> application/pdf 10.5194/cp-2017-22 en European Geosciences Union Central Arctic Ocean paleoceanography from  ∼50 ka to present, on the basis of ostracode faunal assemblages from the SWERUS 2014 expedition article