Diatoms, Grain Size, Magnetic Susceptibility, and Cesium and Lead Isotopes from Short HAPS Cores Collected on the Bering Sea Shelf

Regime shift in the Pacific Decadal Oscillation (PDO) and changes in the intensity of the Aleutian Low have manifest significant impacts on the Bering Sea ecosystem from commercially important fisheries to phytoplankton. This leads us to examine Bering Sea shelf sediments in an effort to determine if recent environmental changes are recorded in the sediments deposited over the past half a century. Samples were collected on board the USCGC Healy Icebreaker during May 2006 and June 2007. Haps cores were collected and subsampled either by slicing the sediments at 1 cm intervals or by pushing a polyvinyl chloride (PVC) pipe into the center of the Haps core. The data set archived here contains diatom counts, detailed grain size analysis, magnetic susceptibility, and x-radiographs for a suite of short cores. One core, DBSB, was dated using 210-Pb and 137-Cs. It was found to reach back to 1949 at 13 cm depth. Forty-six diatom taxa are recorded and diatom counts are presented either as raw counts or as 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 0.01 to 3700 μm. Lead and cesium isotopes are reported in Becquerels per gram and magnetic susceptibility is reported in SI units. X-radiographs are archived as images. These data show that the sediments are moderately bioturbated, but still reflect changing environmental conditions since 1950.