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: L. Gemery, T. M. Cronin, R. K. Poirier, C. Pearce, N. Barrientos, M. O'Regan, C. Johansson, A. Koshurnikov, M. Jakobsson
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2017
• Subjects: geo; envir; Arctic; Arctic Ocean; Greenland; Lomonosov Ridge; Sea ice; SWERUS-C3
• Online Access: https://doi.org/10.5194/cp-13-1473-2017; https://www.clim-past.net/13/1473/2017/cp-13-1473-2017.pdf; https://doaj.org/article/d3e4541dcb584f69b1da3accf053a975

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 ( ∼ 57–29 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° 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.