Biomarker Distributions in (Sub)‐Arctic Surface Sediments and Their Potential for Sea Ice Reconstructions

• Published in: Geochemistry, Geophysics, Geosystems
• Main Authors: Kolling, Henriette, Stein, Rüdiger, Fahl, Kirsten, Sadatzki, Henrik, de Vernal, Anne, Xiao, Xiaotong
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley 2020
• Subjects: Arctic; Baffin Bay; Baffin; Fram Strait; Phytoplankton; Sea ice
• Online Access: https://epic.awi.de/id/eprint/52904/; https://hdl.handle.net/10013/epic.9505b9d9-632f-4411-9bca-e1337abe4046

To evaluate the present sea-ice changes in a longer-term perspective the knowledge of sea-ice variability on pre-industrial and geological time scales is essential. For the interpretation of proxy reconstructions it is necessary to understand the recent signals of different sea-ice proxies from various regions. We present 260 new sediment surface samples collected in the (sub-) Arctic Oceans that were analysed for specific sea-ice (IP25) and open-water phytoplankton biomarkers (brassicasterol, dinosterol, HBI III). This new biomarker dataset was combined with 615 previously published biomarker surface samples into a pan-Arctic database. The resulting pan-Arctic biomarker and sea-ice index (PIP25) database shows a spatial distribution correlating well with the diverse modern sea-ice concentrations. We find correlations of PBIP25, PDIP25 and PIIIIP25 with spring and autumn concentrations. Similar correlations with modern sea-ice concentrations are observed in Baffin Bay. However, the correlations of the PIP25 indices with modern sea-ice concentrations differ in Fram Strait from those of the (sub-) Arctic dataset, which is likely caused by region-specific differences in sea-ice variability, nutrient availability and other environmental conditions. The extended (sea-ice) biomarker database strengthens the validity of biomarker sea-ice reconstructions in different Arctic regions and shows how different sea-ice proxies combined may resolve specific seasonal sea-ice signals.