Holocene Interactions Between Glacier Retreat, Sea Ice Formation, and Atlantic Water Advection at the Inner Northeast Greenland Continental Shelf

• Published in: Paleoceanography and Paleoclimatology
• Main Authors: Syring, Nicole, Lloyd, Jeremy M., Stein, Ruediger, Fahl, Kirsten, Roberts, Dave H., Callard, Louise, O'Cofaigh, Colm
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2020
• Subjects: Foraminifera*; glacier; Global warming; Greenland; Ice Sheet; Ice Shelf; Norske øer; Phytoplankton; Sea ice
• Online Access: https://epic.awi.de/id/eprint/53253/; https://doi.org/10.1029/2020PA004019; https://hdl.handle.net/10013/epic.3dd0d8ef-ff30-4a91-9ab1-50dbf1714a63

During the past four decades significant decrease in Arctic sea ice and a dramatic ice mass loss of the Greenland Ice Sheet (GIS) has been coincident with global warming and an increase in atmospheric CO2. In Northeast Greenland significant mass loss from the outlet glaciers Nioghalvfjerdsbræ (79NG) and Zachariæ Isstrøm (ZI) and intensive seasonal breakup of the local Norske Øer Ice Barrier (NØIB) have also been observed since 2000. In order to better understand the processes driving these modern changes, studies of paleoclimate records are important and of major societal relevance. A multiproxy study including organic‐biogeochemical and micropaleontological proxies was carried out on a marine sediment core recovered directly in front of 79NG. Data from Core PS100/270 evidenced a strong inflow of warm recirculating Atlantic Water across the Northeast Greenland shelf from the early Holocene between ~10 and 7.5 ka. An overall high in phytoplankton productivity occurred within a stable sea ice margin regime, accompanied by 79NG retreat most probably triggered by peak solar insolation and changes in the local ocean circulation. Enhanced basal melt of the underside of 79NG at ~7.5 ka then led to the total disintegration of the ice shelf. The released freshwater would have driven water column stratification and promoted the formation of the local landfast ice barrier, which is shown by lowered biomarker values and foraminifera abundances toward the end of the early Holocene. Near perennial sea ice conditions with short summers and 79NG retreat to the inner fjord then prevailed from ~7.5 to ~0.8 ka.