NOAA/WDS Paleoclimatology - Bering Sea, Chukchi Sea Diatom Abundances and Sea Ice Reconstructions 28 ka to present and 369-430 ka

Sea ice is an important component of Earth’s climate system, affecting it on both regional and global scales. Its incorporation into climate models is a necessary step to achieve more accurate predictions of future climate. However, instrumental records of sea ice concentration do not extend earlier than 1978. In an effort to extend this record, we constructed a proxy using the Generalized Additive Model based on relative abundances of five diatom species found in sediment samples across the Bering and Chukchi seas. Here we present the first quantitative diatom-based sea ice proxy developed for Beringia. The developed proxy has been applied to two sediment cores in the Bering Sea ranging from 0 to 25.7 ka and 369 to 430 ka and one in the Chukchi Sea ranging from 2.7 to 10 ka. The obtained reconstruction of sea ice concentration is similar, but not identical to previously published qualitative and nearby records. The proxy is publicly available as an R Shiny app and can be applied to any diatom count from marine sediments in the region.