Environmental responses of the Northeast Antarctic Peninsula to the Holocene climate variability

Abstract

International audienceIn this study, we present a unique high-resolution Holocene record of oceanographic and climatic change based on analyses of diatom assemblages combined with biomarker data from a sediment core collected from the Vega Drift, eastern Antarctic Peninsula (EAP). These data add to the climate framework already established by high-resolution marine sedimentary records from the Palmer Deep, western Antarctic Peninsula (WAP). Heavy sea ice conditions and reduced primary productivity were observed prior to 7.4 ka B.P. in relation with the proximity of the glacial ice melt and calving. Subsequent Holocene oceanographic conditions were controlled by the interactions between the Westerlies-Antarctic Circumpolar Current (ACC)-Weddell Gyre dynamics. A warm period characterized by short seasonal sea ice duration associated with a southern shift of both ACC and Westerlies field persisted until 5 ka B.P. This warm episode was then followed by climate deterioration during the middle-to-late Holocene (5 to 1.9 ka B.P.) with a gradual increase in annual sea ice duration triggered by the expansion of the Weddell Gyre and a strong oceanic connection from the EAP to the WAP. Increase of benthic diatom species during this period was indicative of more summer/autumn storms, which was consistent with changes in synoptic atmospheric circulation and the establishment of low- to high-latitude teleconnections. Finally, the multicentennial scale variability of the Weddell Gyre intensity and storm frequency during the late Holocene appeared to be associated with the increased El Niño–Southern Oscillation frequency

Source identification and distribution reveals the potential of the geochemical Antarctic sea ice proxy IPSO25

“…Previous palaeo sea ice reconstructions based on IPSO 25 have largely been conducted on sediment cores retrieved from near-coastal locations around the Antarctic Peninsula (AP)131416, Adélie Land1118 and Prydz Bay10, so its occurrence in these is consistent with the source and surface sediment data presented herein. Interestingly, however, B. adeliensis was not reported in the taxonomic inventories of any of these previous studies, which presumably reflects the susceptibility of this species towards dissolution in the water column and in sediments.…”

Autoxidation of the sea ice biomarker proxy IPSO25 in the near-surface oxic layers of Arctic and Antarctic sediments

“…As such, diene II has been proposed as a proxy measure for sea ice in the Southern Ocean, and the term IPSO25 (Ice Proxy for the Southern Ocean with 25 carbon atoms) has been recently proposed (Belt et al, 2016). Although IPSO25 appears to be a common constituent of Antarctic surface sediments (for near-coastal regions, at least; Nichols et al, 1993;Johns et al, 1999;Belt et al, 2016;Belt, 2018Belt, ,2019, analysis of IPSO25 in downcore Antarctic archives has so far resulted in only a relatively small number of palaeo sea ice reconstructions, at least in comparison with IP25 for the Arctic (e.g., Collins et al, 2013;Etourneau et al, 2013;Barbara et al, 2016;Campagne et al, 2016; see also Belt, 2018Belt, ,2019 for a recent review and summary). Finally, in the Arctic, the ratio IPSO25/IP25 (sometimes referred to as DIP25) has previously been proposed as a possible indicator of variability in sea ice conditions or even of sea surface temperatures (SST) (e.g.…”

Ocean temperature impact on ice shelf extent in the eastern Antarctic Peninsula

“…To investigate such a potential link, we provide the first EAP SOT record spanning the last 9000 years at a 100-year resolution. We use the well-dated marine 20-m-long Jumbo Piston core NBP99–03–38 (JPC-38) 36 drilled within the Vega Drift in the northern Prince Gustav Channel (Fig. 1).…”