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

• Published in: Geochemistry, Geophysics, Geosystems
• Main Authors: Kolling, Henriette M., Stein, Ruediger, Fahl, Kirsten, Sadatzki, Henrik, de Vernal, Anne, Xiao, Xiaotong
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union
• Subjects: Arctic; Baffin Bay; Baffin; Fram Strait; Phytoplankton; Sea ice
• Online Access: http://hdl.handle.net/1885/261648; https://doi.org/10.1029/2019GC008629; https://openresearch-repository.anu.edu.au/bitstream/1885/261648/3/01_Kolling_Biomarker_Distributions_in_2020.pdf.jpg

To evaluate the present sea ice changes in a longer‐term perspective, the knowledge of sea ice variability on preindustrial 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 analyzed for specific sea ice (IP25) and open‐water phytoplankton biomarkers (brassicasterol, dinosterol, and highly branched isoprenoid [HBI] III). This new biomarker data set 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 sea ice 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 data set, 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 conditions. This study was funded by the Deutsche Forschungsgemeinschaft (DFG) through “ArcTrain” (GRK 1904). The research of H. S. leading to these results has received funding from the European Research Council under European Union's Seventh Framework Programme (FP7/2007–2013)/ERC Grant Agreement 610055 as part of the Ice2Ice project