Seasonal sea ice persisted through the Holocene Thermal Maximum at 80°N

• Published in: Communications Earth & Environment
• Main Authors: Pieńkowski, Anna J., Husum, Katrine, Belt, Simon T., Ninnemann, Ulysses S, Köseoğlu, Denizcan, Divine, Dmitry V., Smik, Lukas, Knies, Jochen, Hogan, Kelly, Noormets, Riko
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Research 2021
• Subjects: VDP::Mathematics and natural science: 400::Geosciences: 450; VDP::Matematikk og Naturvitenskap: 400::Geofag: 450; Arctic; Barents Sea; Foraminifera*; Phytoplankton; Sea ice
• Online Access: https://hdl.handle.net/10037/21769; https://doi.org/10.1038/s43247-021-00191-x

The cryospheric response to climatic warming responsible for recent Arctic sea ice decline can be elucidated using marine geological archives which offer an important long-term perspective. The Holocene Thermal Maximum, between 10 and 6 thousand years ago, provides an opportunity to investigate sea ice during a warmer-than-present interval. Here we use organic biomarkers and benthic foraminiferal stable isotope data from two sediment cores in the northernmost Barents Sea (>80 °N) to reconstruct seasonal sea ice between 11.7 and 9.1 thousand years ago. We identify the continued persistence of sea-ice biomarkers which suggest spring sea ice concentrations as high as 55%. During the same period, high foraminiferal oxygen stable isotopes and elevated phytoplankton biomarker concentrations indicate the influence of warm Atlantic-derived bottom water and peak biological productivity, respectively. We conclude that seasonal sea ice persisted in the northern Barents Sea during the Holocene Thermal Maximum, despite warmer-than-present conditions and Atlantic Water inflow.