A high-resolution elemental record of post-glacial lithic sedimentation in Upernavik Trough, western Greenland: History of ice-sheet dynamics and ocean circulation changes over the last 9100 years

Abstract

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Learning from the past: Impact of the Arctic Oscillation on sea ice and marine productivity off northwest Greenland over the last 9,000 years

“…As illustrated by previous studies based on dinoflagellate cysts, foraminiferal assemblages, and geochemical data (Caron et al, 2019;Giraudeau et al, 2020;Hansen et al, 2020) tion of the marginal ice zone group (Figure 6) and the highest relative abundance of T. nordenskioeldii. This species typically reaches its highest relative abundance after ice breakup and is thought to be a late-spring bloomer (Oksman et al, 2019 Meyers, 1994).…”

“…This signal can suggest increasing nitrate supplies to the surface water due to reduced stratification. A reduced stratification would be consistent with reduced meltwater input from the Greenland Ice Sheet following the early Holocene (Giraudeau et al., 2020). Along northwest Greenland, the ice margin reached its minimum extent between ~5 and 3 kyr BP (Briner, Kaufman, Bennike, & Kosnik, 2014) and reduced meltwater runoff was inferred after 6 kyr BP (Moros et al., 2016 and references therein).…”

“…As illustrated by previous studies based on dinoflagellate cysts, foraminiferal assemblages, and geochemical data (Caron et al, 2019;Giraudeau et al, 2020;Hansen et al, 2020) water (McQuoid & Hobson, 1996). Some Chaetoceros species that are lightly silicified can more easily take up nutrients and can maintain…”

“…Between 7 and 6 kyr BP, a clear excursion in the HBI III fluxes is coeval with a punctual increase in diatom fluxes, a sharp decline in the Atlantic Water foraminiferal species (Hansen et al, 2020; Figure 6) and a short-lived peak in the ice-rafted debris (IRD) content (Caron et al, 2018) (Laskar et al, 2004); (b) oxygen isotopic ratios (‰) at Camp Century (Vinther et al, 2009); (c) abundance of Kara Sea ice-rafted Fe oxide grains in the Beaufort gyre (Darby et al, 2012); (d) relative contribution of the Atlantic water indicator foraminiferal group from core AMD14-204 (%; Hansen et al, 2020); (e) relative contribution of the warm water indicator dinocyst taxon Operculodinium centrocarpum from core AMD14-204 (%; Caron et al, 2019); (f) IP 25 fluxes (ng unit surface −1 year −1 ; this study); (g) HBI III fluxes (ng unit surface −1 year −1 ; this study); (h) relative contribution of the "summer subsurface" assemblage (%; this study); (i) relative contribution of the "marginal ice zone" assemblage (%; this study); (j) relative contribution of the "drift-ice/pack-ice" assemblage (%; this study); and (k) total diatom fluxes (valves unit surface −1 year −1 , dark green includes Chaetoceros spores and light green excludes Chaetoceros spores (this study). The gray areas indicate intervals of persistent positive AO phases (Darby et al, 2012;Funder et al, 2011 input from the Greenland Ice Sheet following the early Holocene (Giraudeau et al, 2020). Along northwest Greenland, the ice margin reached its minimum extent between ~5 and 3 kyr BP (Briner, Kaufman, Bennike, & Kosnik, 2014) and reduced meltwater runoff was inferred after 6 kyr BP (Moros et al, 2016 and references therein).…”

“…Given the key role of northern Baffin Bay as mediator between the Arctic and North Atlantic oceans, a number of studies documenting changes in regional ocean conditions in relation to Holocene climate fluctuations have been conducted (e.g., Caron, Rochon, Montero‐Serrano, & St‐Onge, 2019; Caron et al., 2018; Giraudeau et al., 2020; Hansen, Massé, Giraudeau, Pearce, & Seidenkrantz, 2020; Knudsen, Stabell, Seidenkrantz, Eiríksson, & Blake, 2008; Levac, de Vernal, & Blake, 2001; Mudie, Rochon, & Levac, 2005; Saini et al., 2020; St‐Onge & St‐Onge, 2014). However, the link between atmosphere–ocean forcing as expressed by swings in the dominant mode of the AO and changes in sea‐ice seasonality and primary production in northern Baffin Bay has never been investigated.…”