Diatom and Particle Size Analysis from the Bering Sea Shelf

Climate change is amplified in the Arctic, most dramatically seen as a significant reduction in summer sea ice. Unfortunately, satellite observations of sea ice only extend back to 1979, and direct observations before then are spotty at best. Recently, there have been several advances in sea ice proxies. Specifically improvements in diatom-based proxies and the molecular biomarker, IP25, have allowed quantitative reconstructions of Arctic sea ice. Today, the Bering Sea is seasonally covered in sea ice, and diatoms dominate primary productivity there. This makes it an ideal location for a diatom-based sea ice proxy. This proxy is still in development and will be based on the data presented here compared to satellite-derived sea ice concentration averaged over the ten years preceding sampling. The data set archived here contains diatom counts and detailed grain size analysis for a suite of core tops spanning the range of annual sea ice concentration found in the Bering Sea. Samples were collected on board the Healy during May 2006 and June 2007 as well as from two USGS cruises in 1969. Fifty-seven diatom taxa are recorded and diatom counts are presented in relative percent abundances. Grain size is calculated using a laser diffraction particle size analyzer and is reported as weight percent for grain size bins ranging from 0.375 to 1822 μm.