TY - JOUR

T1 - Ice-ocean interactions at the Northeast Greenland Ice stream (NEGIS) over the past 11,000 years

AU - Lloyd, J. M.

AU - Ribeiro, S.

AU - Weckström, K.

AU - Callard, L.

AU - Ó Cofaigh, C.

AU - Leng, M. J.

AU - Gulliver, P.

AU - Roberts, D. H.

N1 - Funding Information: We thank Captains Schwarze and Wunderlich and the crew of RV Polarstern (cruises PS100 and PS109) for excellent support and cooperation during both cruises. We thank Torsten Kanzow (Chief Scientist on cruises PS100 and PS109) for help and support during the both cruises. We thank AWI for support with radiocarbon dating of small samples using the AWI MICADAS system. We gratefully acknowledge support from AWI for ship time via grants AWI_PS100_01 and AWI_PS109_03. Guillaume Massé and Caroline Guilmette are kindly thanked for the IP25 data. This work was funded by NERC Standard Grant NE/N011228/1. Additional support was provided through the NERC National Environmental Isotope Facility for stable isotope analyses (grant IP-1816-0618, analyses performed by Hilary Sloane, BGS) and NERC Radiocarbon Facility NRCF010001 (allocation number 2113.0418). We acknowledge expertise of Dr Xiaomei Xu performing measurements at the KECK Carbon Cycle AMS Facility, University of California. SR received financial support from the Independent Research Council Denmark (grant nr. 9064-00039B) and KW from Arctic Avenue (spearhead research project between the University of Helsinki and Stockholm University). Funding Information: We thank Captains Schwarze and Wunderlich and the crew of RV Polarstern (cruises PS100 and PS109) for excellent support and cooperation during both cruises. We thank Torsten Kanzow (Chief Scientist on cruises PS100 and PS109) for help and support during the both cruises. We thank AWI for support with radiocarbon dating of small samples using the AWI MICADAS system . We gratefully acknowledge support from AWI for ship time via grants AWI_PS100_01 and AWI_PS109_03 . Guillaume Massé and Caroline Guilmette are kindly thanked for the IP25 data. This work was funded by NERC Standard Grant NE/N011228/1 . Additional support was provided through the NERC National Environmental Isotope Facility for stable isotope analyses (grant IP-1816-0618 , analyses performed by Hilary Sloane, BGS) and NERC Radiocarbon Facility NRCF010001 (allocation number 2113.0418 ). We acknowledge expertise of Dr Xiaomei Xu performing measurements at the KECK Carbon Cycle AMS Facility, University of California . SR received financial support from the Independent Research Council Denmark (grant nr. 9064-00039B ) and KW from Arctic Avenue (spearhead research project between the University of Helsinki and Stockholm University ). Publisher Copyright: © 2023 The Authors

PY - 2023

Y1 - 2023

N2 - Recent observations have identified increased mass loss from Greenland marine-terminating outlet glaciers (MTOG) with implications for global sea-level rise and wider ocean circulation. The flow of Atlantic-sourced waters to the Greenland margin is thought to be a major control on MTOG behaviour. Investigation of longer-term records of the role of Atlantic-sourced waters on MOTG dynamics are needed to improve understanding of potential future trends in MTOG behaviour. Here we present a multi-proxy study (benthic and planktic foraminifera, dinoflagellate cysts, diatoms, stable isotopes, sea ice biomarkers and sedimentological analyses) from core PS100-198 on the northeast Greenland shelf to investigate the interaction between the Northeast Greenland Ice Stream (NEGIS) and ocean circulation through the Holocene. Proximal glaciomarine conditions at the base of the core indicate deglaciation before 10.9 ka cal BP with the relatively warm Atlantic Water present through advection of the Return Atlantic Current (RAC) across the shelf. The advection of RAC increased through the early Holocene reaching peak subsurface warmth from 8 to 9 ka cal BP. Surface conditions at this time were characterised by heavy sea-ice cover. During the mid-to late Holocene (c. 7–2 ka cal BP) advection of RAC weakened with cooler subsurface waters, but with an amelioration of surface conditions characterised by seasonal sea ice. From c. 2 ka cal BP, during the late Holocene, surface conditions continued to improve with continued seasonal sea-ice cover while subsurface proxies record an increase in RAC advection. The last c. 100 years represent the most ameliorated surface conditions through the Holocene and with subsurface conditions as warm as the early Holocene peak. This coincided with the final break up of ice within 79N fjord and retreat of NEGIS to the Holocene minimum position. Current conditions, therefore, suggest the present-day ice shelf within 79N fjord is most likely susceptible to collapse in the near future. This study highlights the critical influence of Atlantic-sourced waters on the dynamics of major Greenland MTOGs.

AB - Recent observations have identified increased mass loss from Greenland marine-terminating outlet glaciers (MTOG) with implications for global sea-level rise and wider ocean circulation. The flow of Atlantic-sourced waters to the Greenland margin is thought to be a major control on MTOG behaviour. Investigation of longer-term records of the role of Atlantic-sourced waters on MOTG dynamics are needed to improve understanding of potential future trends in MTOG behaviour. Here we present a multi-proxy study (benthic and planktic foraminifera, dinoflagellate cysts, diatoms, stable isotopes, sea ice biomarkers and sedimentological analyses) from core PS100-198 on the northeast Greenland shelf to investigate the interaction between the Northeast Greenland Ice Stream (NEGIS) and ocean circulation through the Holocene. Proximal glaciomarine conditions at the base of the core indicate deglaciation before 10.9 ka cal BP with the relatively warm Atlantic Water present through advection of the Return Atlantic Current (RAC) across the shelf. The advection of RAC increased through the early Holocene reaching peak subsurface warmth from 8 to 9 ka cal BP. Surface conditions at this time were characterised by heavy sea-ice cover. During the mid-to late Holocene (c. 7–2 ka cal BP) advection of RAC weakened with cooler subsurface waters, but with an amelioration of surface conditions characterised by seasonal sea ice. From c. 2 ka cal BP, during the late Holocene, surface conditions continued to improve with continued seasonal sea-ice cover while subsurface proxies record an increase in RAC advection. The last c. 100 years represent the most ameliorated surface conditions through the Holocene and with subsurface conditions as warm as the early Holocene peak. This coincided with the final break up of ice within 79N fjord and retreat of NEGIS to the Holocene minimum position. Current conditions, therefore, suggest the present-day ice shelf within 79N fjord is most likely susceptible to collapse in the near future. This study highlights the critical influence of Atlantic-sourced waters on the dynamics of major Greenland MTOGs.

KW - Dinocysts

KW - Foraminifera

KW - Greenland

KW - Holocene

KW - Marine cores

KW - Paleoceanography

KW - Sedimentology

U2 - 10.1016/j.quascirev.2023.108068

DO - 10.1016/j.quascirev.2023.108068

M3 - Journal article

AN - SCOPUS:85152490392

VL - 308

JO - Quaternary Science Reviews

JF - Quaternary Science Reviews

SN - 0277-3791

M1 - 108068

ER -