A first southern Lomonosov Ridge (Arctic Ocean) 60 ka IP25 sea-ice record

Here, we present a first (low-resolution) biomarker sea-ice proxy record from the High Arctic (southern Lomonosov Ridge), going back in time to about 60 ka (MIS 3 to MIS 1). Variable concentrations of the sea-ice diatom specific highly branched isoprenoid (HBI) with 25 carbon atoms (“IP25“), in comb...

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Bibliographic Details
Main Authors: Stein, Rüdiger, Fahl, Kirsten
Format: Article in Journal/Newspaper
Language:unknown
Published: Alfred Wegener Institute for Polar and Marine Research 2012
Subjects:
Arctic
Arctic Ocean
Lomonosov Ridge
Phytoplankton
Polarforschung
Sea ice
Online Access:https://epic.awi.de/id/eprint/31646/
https://hdl.handle.net/10013/epic.41493
Description
Summary:Here, we present a first (low-resolution) biomarker sea-ice proxy record from the High Arctic (southern Lomonosov Ridge), going back in time to about 60 ka (MIS 3 to MIS 1). Variable concentrations of the sea-ice diatom specific highly branched isoprenoid (HBI) with 25 carbon atoms (“IP25“), in combination with the phytoplankton biomarker brassicasterol, suggest variable seasonal sea-ice coverage and open-water productivity during MIS 3. During most of MIS 2, the spring to summer sea-ice margin significantly extended towards the south, resulting in a drastic decrease in phytoplankton productivity. During the Early Holocene Climate Optimum, brassicasterol reached its maximum, interpreted as signal for elevated phytoplankton productivity due to a significantly reduced sea-ice cover. During the mid-late Holocene, IP25 increased and brassicasterol decreased, indicating extended sea-ice cover and reduced phytoplankton productivity, respectively. The HBI diene/IP25 ratios probably reached maximum values during the Bølling-Allerød warm period and decreased during the Holocene, suggesting a correlation with sea-surface temperature.

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