Variability of hydrographic conditions and sea-ice in the Nordic seas during the Holocene

• Main Authors: Bonnet, Sophie, De Vernal, Anne, Henry, Maryse, Bauch, Henning, Husum, Katrine, Spielhagen, Robert, Van Nieuwenhove, Nicolas, Zamelczyk, Katarzyna
• Format: Conference Object
• Language: unknown
• Published: GEOTOP, Université du Québec 2011
• Subjects: Arctic; Greenland; East Greenland; east greenland current; Nordic Seas; North Atlantic; Sea ice; Spitsbergen
• Online Access: https://oceanrep.geomar.de/id/eprint/12161/; http://www.arcticworkshop2011.uqam.ca/upload/files/41aw_abstact_volume.pdf

The Nordic Seas are a key area at the hemispheric scale since they constitute a transitional basin between the North Atlantic and Arctic Oceans (Figure 1a). The warm and salty North Atlantic waters contribute to the poleward heat transport via the Norwegian (NwAC-W, NwAC-E) and West Spitsbergen (WSC) currents, whereas the Arctic waters carry cool and fresh waters into the Nordic Seas via the East Greenland current (EGC). The interaction between these two surface currents determines the extent of the Polar and Arctic Fronts and acts on the deep-water formation. Several studies have shown large-amplitude variations in sea-surface conditions of the Nordic Seas, during the Holocene, due to changes in the strength and/or thermal characteristics of the NwAC and EGC. However, variability along the EGC is still poorly documented contrary to the NwAC where records depict warmer conditions than present along the main axis during the early Holocene, when summer insolation was higher. Nevertheless, data are not unequivocal since they show regional differences suggesting changes in atmospheric and oceanic circulation patterns. This study aims at documenting the impact of the last deglaciation on surface water masses in the Nordic Seas by reconstructing hydrographic parameters and sea-ice along the NwAC and EGC as well as to discuss the influence of the Arctic vs. North Atlantic fluxes. Here, we report the results from centennial resolution analyses performed on cores M23323, MSM 5/5-712-2 and JM06-WP-16MC (Figure 1a). Dinocyst assemblages were used as a proxy for the reconstructions of sea-surface conditions. We employed the Modern Analogue Technique (MAT) and the Northern Hemisphere dinocyst database that includes 1429 sites. The reconstructed past sea-surface conditions include the temperatures and salinities in summer, as well as the sea-ice cover duration. Likewise, redundancy analyses were done on dinocyst assemblages and environmental parameters in order to determine the statistical weight of changes observed in the ...