1,1,1,4,6,1,5- 1Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- 2Geological Survey of Norway, Trondheim, Norway
- 3iC3: Centre for ice, Cryosphere, Carbon and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø, Norway
- 4Faculty of Physics, University of Bremen, Bremen, Germany
- 5Department of Geoscience, University of Bremen, Bremen, Germany
- 6MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
- 7Division of Glacier and Earth Sciences, Korea Polar Research Institute, Incheon, Republic of Korea
The Fram Strait is a unique deep-sea gateway connecting the Arctic Ocean to the North Atlantic. Under modern conditions, the eastern Fram Strait remains largely ice-free due to the influx of warm Atlantic water via the West Spitsbergen Current (WSC). Conversely, the western Fram Strait is characterized by the export of cold, fresh Arctic water masses and sea ice from the central Arctic Ocean via the East Greenland Current (EGC), thereby impacting the North Atlantic thermohaline circulation. Paleoceanographic records, however, suggest radical departures from this oceanic regime during glacial periods (Geibert et al., 2021; Nørgaard-Pedersen et al., 2003).
Here, we present a high-resolution record of oceanographic conditions during Marine Isotope Stage (MIS) 6 using a sediment core KH14-GPC02, recovered from the eastern Fram Strait (77° 31' 22.7994" N, 8° 24' 4.9674" E) during Expedition CAGE19-3 in 2019. Core KH14-GPC02 was analyzed for biomarker lipids, e.g., highly branched isoprenoids, sterols, and glycerol dialkyl glycerol tetraether lipids, providing the first complete, high-resolution records of sea-ice conditions and ocean temperature during the penultimate glacial maximum from this climatically critical region.
Our results reveal a two-phased evolution of sea-ice conditions in the eastern Fram Strait. Early MIS 6 was dominated by a marginal sea-ice cover with significant seasonal variability, as evidenced by high concentrations of the sea-ice biomarker IP25 and open-ocean biomarkers. From ~165 ka onward, however, a sharp decline in IP25 and open-ocean biomarkers signals a shift to perennial ice cover. To investigate the climatic drivers of this environmental transition, we conducted simulations with the complex Earth system model AWI-ESM. While lowered summer insolation and the closure of the Canadian Arctic Archipelago gateways contribute to regional cooling during glacial climates in the Fram Strait and Nordic Seas (e.g., Lofverstrom et al., 2022), our simulations demonstrate that these factors alone are insufficient to explain the perennial ice cover in the eastern Fram Strait during late MIS 6. Instead, we propose that the closure of the Denmark Strait, driven by ice‑sheet expansion, acted as a critical threshold to explain the heavy sea-ice cover in eastern Fram Strait during late MIS 6. This geographic blockage not only halted sea‑ice export through the Denmark Strait but also diminished the inflow of warm Atlantic water, fundamentally altering sea‑ice dynamics in the Arctic-Atlantic gateway. Our findings highlight the crucial – but often underestimated – role of oceanic gateways in regulating Arctic sea-ice extent during extreme glacial climates.
References
Geibert, W. et al., 2021. Nature 590, 97-102.
Lofverstrom, M. et al., 2022. Nature Geoscience 15, 482-488.
Nørgaard-Pedersen, N. et al., 2003. Paleoceanography 18, 1063.
How to cite: Mikler, M., Song, P., Knies, J., Lohmann, G., Ahn, Y., Nam, S.-I., and Müller, J.: A trapped East Greenland Current: Sea ice expansion during late MIS 6 in the eastern Fram Strait, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11521, https://doi.org/10.5194/egusphere-egu26-11521, 2026.
