Changing sea ice distribution in the northeastern Nordic Seas over Greenland Stadial 9 and Greenland Interstadial 8

To investigate the extent of sea ice changes taking place in association with Dansgaard-Oechger events, we present high-resolution biomarker records from the Fram Strait sediment core MD99-2304 (1300 m water depth; 77°37‘15.6“N, 9°56’54.0”E). The results document changes in sea ice dynamics during Greenland Stadial (GS) 9 and Greenland Interstadial (GI) 8, at unprecedented detail. In addition, we present δ18ON. pachyderma and ice rafted debris (IRD) records. The combined results suggest an extended sea ice cover in the northeastern Nordic Seas during GS-9, with possible occurrence of polynyas. The existence of polynyas in the eastern Fram Strait during stadial conditions is also found in a freshwater forced transient model run of the Norwegian Earth System Model (NorESM). Towards the end of GS-9, the sea ice cover in the Fram Strat expanded, likely related to increased freshwater supply. The sea ice retreated after the GS-GI transition, reached its minimum extent and formed a stable ice edge in the eastern Fram Strait. From mid GI-8, there was an extensive seasonal sea ice cover in the eastern Fram Strait towards the end of GI-8.