Proxy reconstruction of Arctic Ocean sea ice history - From IRD to IP25


Contact
Ruediger.Stein [ at ] awi.de

Abstract

This review paper focusses on reconstructions of the long- and short-term history of past Arctic Ocean sea-ice cover. Based on commonly used sedimentological, geochemical and micropaleontological proxies (ice-rafted debris (IRD), mineralogical composition of terrigenous sediment frac¬tion, and abundances of specific diatoms and foraminifers), three examples of reconstructions of glacial history, sea-ice cover and surface-water character¬istics are presented and discussed: (1) the onset Arctic Ocean sea-ice cover near 47 Ma and its long-term variability through Cenozoic times; (2) the Quaternary glacial/interglacial variability in Arctic Ocean ice-rafting and its relationship to sea-ice and ice-sheet history; and (3) Last Glacial Maximum (LGM), Deglacial to Holocene changes in Arctic Ocean sea-ice cover and ice-sheet decay. In the second part of this paper we concentrate on Arctic Ocean sea-ice reconstructions, using a recently developed biomarker approach that is based on the determination of sea-ice diatom-specific highly-branched isoprenoids with 25 carbon atoms (IP25; BELT et al. 2007) and IP25 in combination with phytoplankton biomarkers (PIP25; MÜLLER et al. 2009, 2011). The diene/ IP25 ratio might give additional information about sea-surface temperature (SST) in the low temperature Arctic environment (FAHL & STEIN 2012). The high potential of these novel biomarker proxies to improve reconstructions of paleo-sea-ice cover and its variability through time is demonstrated in three examples: (a) the sea-ice variability in Fram Strait over the last 30 ka, (b) the deglacial/Holocene variability of central Arctic sea-ice cover with special emphasis on the Younger Dryas Cooling Event, and (c) a comparison of historical sea-ice observations off northern Iceland over the last millennium and a corresponding high-resolution IP25 record. In a pilot study carried out in a sediment core from the Barents Sea conti-nental slope we were able to prove for the first time that IP25 is even pre-served in sediments as old as 130 to 150 ka (MIS 6), i.e., IP25 can be used for reconstruction of sea-ice variability during older glacial/interglacial intervals (MIS 6/MIS 5). In order to establish the IP25 approach as a key proxy for reconstruction of past Arctic Ocean sea-ice conditions, more basic information about produc-tion, degradation and preservation/burial of the IP25 signal is still needed. Furthermore, the hypothesis that the diene/IP25 ratio might be used as reliable proxy for SST reconstructions in the low temperature Arctic environments has to be verified by a ground-truth study including the IP25 and diene data as well as independent SST proxies like alkenone-derived SST. All these data should be obtained in future investigations of sea-ice, water column, and sediment-trap samples as well as surface sediments and sediment cores with large spatial coverage from different environments of the entire Arctic Ocean.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Peer revision
Peer-reviewed
Publication Status
Published
Eprint ID
31644
Cite as
Stein, R. , Fahl, K. and Müller, J. (2012): Proxy reconstruction of Arctic Ocean sea ice history - From IRD to IP25 , Polarforschung, 82 , pp. 37-71 .


Share

Research Platforms

Campaigns


Actions
Edit Item Edit Item