The variability of sea ice in the Fram Strait throughout glacial-interglacial transitions of the Late Quaternary (MIS 11 to MIS 1)

• Main Author: Kremer, Anne
• Format: Thesis
• Language: unknown
• Published: 2018
• Subjects: Arctic Ocean; Barents Sea; East Greenland; Fram Strait; Greenland; Ice Sheet; Phytoplankton; Sea ice; Svalbard; Svalbard-Barents Sea Ice sheet; Yermak plateau
• Online Access: https://epic.awi.de/id/eprint/52076/; https://hdl.handle.net/10013/epic.ad7cef1c-067f-41e8-85d0-ca7435b23dfd

Given the pivotal role of Arctic sea ice in the global climate system, its excessive loss over the last decades is highly concerning. According to common climate models, an ice-free Arctic Ocean during summer may be reached by the middle of the century. While these profound changes are clearly visibly in the Arctic realm, the far-reaching consequences remain a matter of speculation. As the reliability of model simulations depend on their data base, the acquisition of comprehensive knowledge about past variation of Arctic sea ice cover is absolutely crucial. An ideal study area in this regard is the Fram Strait reflecting changes in the highly dynamic marginal ice zone of the Arctic Ocean. Therefore, the primary objective of this thesis was the reconstruction of sea ice variability in the Fram Strait throughout glacial-interglacial transitions of the Late Quaternary. For this purpose, analyses of molecular biomarkers were carried out on eight sediment cores along the western and northern Svalbard Shelf (PS93/006-1, PS92/039-2), the East Greenland Shelf (PS93/016-6, PS93/031-4) as well as the central Arctic Ocean (PS87/023-1, PS87/030-1, PS87/070-1, PS87/079-1). These records provided valid insights into the Arctic paleoenvironment since Marine Isotope Stage 11. In order to reconstruct past sea ice cover, the sea ice proxy IP25 was applied in combination with the related phytoplankton-IP25 sea ice index PIP25. Further specific biomarkers were used to reflect the sea surface temperatures (glycerol dialkyl glycerol tetraethers), the marine production (brassicasterol, dinosterol, tri-unsaturated highly-branched isoprenoids) and the input of terrigenous material (campesterol, β-sitosterol). The first study focused on the variation of sea ice at the eastern Yermak Plateau north of Svalbard (Core PS92/039-2) since MIS 6 (~160 ka). Here, the activity of the Svalbard Barents Sea Ice Sheet had a major impact on the sea ice cover. During intervals of ice sheet advance onto the continental shelf (MIS 6, MIS 5d - 5b, MIS 4, ...