Absolute sedimentary concentrations of highly branched isoprenoids, PIP25 indices with derived spring sea ice concentrations, and classification tree predictions of sea ice conditions in three Barents Sea sediment cores ...

• Main Authors: Köseoğlu, Denizcan, Belt, Simon T, Husum, Katrine, Knies, Jochen
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2018
• Subjects: Barents Sea; Paleo-Arctic; Phytoplankton; Sea ice
• Online Access: https://dx.doi.org/10.1594/pangaea.891102; https://doi.pangaea.de/10.1594/PANGAEA.891102

The development of various combinative methods for Arctic sea ice reconstruction using the sympagic highly-branched isoprenoid IP25 in conjunction with pelagic biomarkers has often facilitated more detailed descriptions of sea ice conditions than using IP25 alone. Here, we investigated the complementary application of the Phytoplankton-IP25 index (PIP25) and a recently proposed Classification Tree (CT) model for describing shifts in sea ice conditions to assess the consistency of both methods. Based on biomarker data from three downcore records from the Barents Sea spanning millennial timescales, we showcase apparent and potential limitations of both approaches, and provide recommendations for their identification or prevention. Both methods provided generally consistent outcomes and, within the studied cores, captured abrupt shifts in sea ice regimes, such as those evident during the Younger Dryas, as well as more gradual trends in sea ice conditions during the Holocene. The most significant discrepancies ... : Supplement to: Köseoğlu, Denizcan; Belt, Simon T; Husum, Katrine; Knies, Jochen (2018): An assessment of biomarker-based multivariate classification methods versus the PIP25 index for paleo Arctic sea ice reconstruction. Organic Geochemistry, 125, 82-94 ...