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

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 degrees 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. The northern Barents Sea contained seasonal sea ice between 11.7 and 9.1 thousand years ago, even during the warmer-than-present Holocene Thermal Maximum and despite warm Atlantic Water inflow, according to biomarker and benthic foraminiferal stable isotope records.

Automated summary

Research shows that seasonal sea ice persisted in the northern Barents Sea during the Holocene Thermal Maximum, despite warmer conditions than present and the influence of warm Atlantic Water inflow.