Highly branched isoprenoids, radiocarbon ages and diatom asmblages in surface sediments from Southern Ocean ...

• Main Authors: Vorrath, Maria-Elena, Müller, Juliane, Esper, Oliver, Mollenhauer, Gesine, Haas, Christian, Schefuß, Enno, Fahl, Kirsten
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2019
• Subjects: Antarc*; Antarctic; Antarctic Peninsula; Bransfield Strait; Drake Passage; Sea ice; Southern Ocean
• Online Access: https://dx.doi.org/10.1594/pangaea.897165; https://doi.pangaea.de/10.1594/PANGAEA.897165

Organic geochemical and micropaleontological analyses of surface sediments collected in the southern Drake Passage and the Bransfield Strait, Antarctic Peninsula, enable a proxy-based reconstruction of recent sea ice conditions in this climate sensitive area. The distribution of the sea ice biomarker IPSO25 supports earlier suggestions that the source diatoms seem to be common in near-coastal environments characterized by an annually recurring sea ice cover. We here propose and evaluate the combination of IPSO25 with a more unsaturated highly branched isoprenoid alkene and phytosterols and introduce the PIPSO25 index as a potentially semi-quantitative sea ice proxy. This organic geochemical approach is complemented with diatom data. PIPSO25 sea ice estimates are used to discriminate between areas characterized by permanently ice-free conditions, seasonal sea ice cover and extended sea ice cover. These trends are consistent with satellite sea ice data and winter sea ice concentrations estimated by diatom ...