Umwelt- und Klimageschichte vor Nordost-Grönland (ECHONEG)
Zusammenfassung der Projektergebnisse
The western Fram Strait, situated between NE Greenland in the west and the Svalbard archipelago in the east, is the major outlet for freshwater from the Arctic Ocean. The export of freshwater occurs both in liquid (water) and solid (ice) form. State-of-the-art climate models suggest that an increasing export of freshwater (e.g., due to melting of ice sheets and glaciers, as well as increasing run-off from circum-Arctic rivers) may affect the global ocean circulation and diminish the heat transport from the tropics to mid- and high latitudes in the Atlantic realm. In the ECHONEG project, the history of freshwater export has been investigated on geological timescales (here: in the last ca. 200.000 years) to improve our understanding of the natural variability as well as the effects on and interactions with ocean circulation, sea ice coverage and the history of the North Greenland ice sheet. This includes both intervals which were climatically similar to modern (e.g., the Holocene (last ~12.000 years)) and events at the end of major terrestrial glaciations which saw the release of extraordinary amounts of meltwater. Several sediment cores from the NE Greenland shelf and deep-sea area were investigated for their sediment components (including microfossils) and geochemistry to reconstruct the past oceanic environmental conditions in this area. The data sets reveal that in the early Holocene (ca. 11.000-8.000 years ago) conditions on the NE Greenland shelf largely resembled the modern ones, with a seasonally open sea ice cover and an enhanced bioproduction, just like today under increasing Arctic warming. It could also be shown that a relatively strong advection of warm Atlantic Water onto the shelf enhanced the melting of the last remains of the ice sheet that had covered the shelf during the ice age. These developments may represent past analogs of modern and future developments at the margin of the Greenland ice sheet. The last 8.000 years saw a persisting cooling trend which led to an almost complete sea ice coverage in the area. The long-term records (last 200.000 years) showed that environments off NE Greenland were highly variable, with periods of seasonally open waters and also times with large numbers of icebergs breaking off from an expanded Greenland ice sheet. The periods with extremely low sea surface salinities in the western Fram Strait were largely coeval with those in the central Arctic and associated with ice sheet decay over northern Eurasia. This shows that much of the freshwater exported during extreme events stemmed from the melting of ice sheets in northern Eurasia and that the contribution from North Greenland was rather minor. The history of the ice sheet over North Greenland and its waxing and waning was strongly connected to the advection of heat and moisture by ocean currents and warm air. Results from the ECHONEG project suggest that the North Greenland ice sheet expanded with some delay (compared to the Eurasian ice sheets) during the major glaciation phases of the last 200.000 years. This may have been related to pathways of atmospheric moisture supply which rather fostered the build-up of ice over northern Eurasia than over North Greenland.
Projektbezogene Publikationen (Auswahl)
- 2017. First high-resolution sediment record from the western Fram Strait - A multiproxy reconstruction of the Holocene water mass history off NE Greenland. 5th International Conference on Palaeo-Arctic Spatial and Temporal (PAST) Gateways. Kristineberg Field Station, Sven Lovén Centre/University of Gothenburg Fiskebackskil (Sweden), May 22-26, 2017
Zehnich, M., Palme, T., Spielhagen, R.F., Hass, H.C., Bauch H.A.
- 2017. Holocene water mass history off NE Greenland - A first high-resolution sediment record from the western Fram Strait. European Geoscienes Union (EGU) General Assembly 2017, Vienna (Austria), April 23-28, 2017
Zehnich, M., Palme, T., Spielhagen, R.F., Hass, H.C., Bauch H.A.
- 2017. Late Quaternary Variability of Arctic Sea Ice: Insights From Biomarker Proxy Records and Model Simulations. AGU Fall Meting 2017, New Orleans, 11-15 Dec. 2017
Stein, R., Kolling, H., Kremer, A., Fahl, K., Gierz, P., Lohmann, G.
- 2018. Holocene water mass history off NE Greenland - New insights from high-resolution sediment record PS93/025 (western Fram Strait). 6th International Conference on Palaeo-Arctic Spatial and Temporal (PAST) Gateways, Durham (UK), April 16-20, 2018
Zehnich, M., Spielhagen, R.F., Hass, H.C., Bauch, H.A., Palme, T.
- 2018. Reconstruction of Arctic sea ice cover: New insights and questions from biomarker and microfossil proxy records. 6th International Conference on Palaeo-Arctic Spatial and Temporal (PAST) Gateways, Durham (UK), April 16-20, 2018
Stein, R., Kolling, H., Kremer, A., Saini, J., Syring, N., Wu, J., Fahl, K., Krawczyk, D., de Vernal, A.
- 2018. Sea ice variability off NE Greenland over the past 10 ka. 6th International Conference on Palaeo-Arctic Spatial and Temporal (PAST) Gateways, Durham (UK), April 16-20, 201
Syring, N., Stein, R., Fahl, K.
- 2019. Environmental variability off NE Greenland (western Fram Strait) during the Holocene. European Geoscienes Union (EGU), General Assembly 2019, Vienna (Austria), April 7-12, 2019
Zehnich M., Spielhagen R.F., Bauch H.A., Forwick M., Hass H.C., Mollenhauer G., Palme T., Stein R., Syring N.
- 2019. Holocene environmental variability in the Wandel Sea, off NE-Greenland. 1st international conference on Processes and Palaeo-environmental changes in the Arctic: from past to present (PalaeoArc). Poznan (Poland), May 20-24, 2019
Lemmel, F., Zehnich, M., Spielhagen, R.F.
- 2019. Late Glacial to Holocene variability of ocean stratification and Arctic freshwater export off Northeast Greenland. 1st international conference on Processes and Palaeo-environmental changes in the Arctic: from past to present (PalaeoArc). Poznan (Poland), May 20-24, 2019
Spielhagen, R.F., Polyak, L., Mackensen, A., Zehnich, M.
- 2020. Environmental variability off NE Greenland (western Fram Strait) during the past 10,000 years. The Holocene 30 (12), 1752-1766
Zehnich, M., Spielhagen, R.F., Bauch, H.A., Forwick, M., Hass, H.C., Palme, T., Stein, R., Syring, N.
(Siehe online unter https://doi.org/10.1177/0959683620950393) - 2020. Holocene biomarker- and microfossil-based sea-ice reconstructions off the eastern North Greenland continental shelf (western Fram Strait). EGU General Assembly 2020, Vienna (Austria), May 4-8, 2020
Syring, N., Stein, R., Lloyd, J.M., Fahl, K., Vahlenkamp, M., Zehnich, M., Spielhagen, R.F., Niessen, F.
(Siehe online unter https://doi.org/10.5194/egusphere-egu2020-5473) - 2020. Holocene changes in sea-ice cover and polynya formation along the northern NE-Greenland shelf: New insights from biomarker records. Quat. Sci. Rev. 231, 106173
Syring, N., Stein, R., Fahl, K., Vahlenkamp, M., Zehnich, M., Spielhagen, R.F., Niessen, F.
(Siehe online unter https://doi.org/10.1016/j.quascirev.2020.106173) - 2020. Holocene interactions between glacier retreat, sea-ice formation and Atlantic Water advection at the inner Northeast Greenland continental shelf. Paleoceanogr. Paleoclim. 35, e2020PA004019
Syring, N., Lloyd, J.M., Stein, R., Fahl, K., Roberts, D.H., Callard, L., O’Cofaigh, C.
(Siehe online unter https://doi.org/10.1029/2020PA004019) - 2020. Variability of ocean stratification, sea ice coverage and bioproduction off NE Greenland in the Late Glacial to Holocene reconstructed from planktic foraminifer morphotypes. European Geoscienes Union (EGU), General Assembly 2020, Vienna (Austria) May 4-8, 2020
Spielhagen, R.F., Mackensen, A.
- 2021. Low salinity in the western Fram Strait (79°N) at 12.7 - 10.2 ka related to NE Greenland continental shelf deglaciation. 2nd Int. Conf. PalaeoArc (Processes and Palaeo-environmental changes in the Arctic: from past to present), Pisa (Italy), May 2428, 2021
Spielhagen R.F., Forwick M., Lemmel F. & Mackensen A.
- 2021. Upper ocean variability off NE Greenland (79°N) since the last glacial maximum reconstructed from stable isotopes in planktic foraminifer morphotypes. Quat. Sci. Rev. 265, 107070
Spielhagen, R.F., Mackensen, A.
(Siehe online unter https://doi.org/10.1016/j.quascirev.2021.107070)
