Ice core Be7 concentrations from the MOSAIC expedition on the R/V Polarstern in the Central Arctic Ocean from October 2019 to May 2020 (NCEI Accession 0278686)

This dataset contains physical data collected on R/V Polarstern during cruise PS122 from 2019-10-28 to 2020-05-04. These data include depth and ice_thickness. The instruments used to collect these data include Gamma Ray Spectrometer, Ice Corer, and Mass Spectrometer. These data were collected by David C. Kadko and Mark Stephens of Florida International University as part of the "Collaborative Research: Defining the Atmospheric Deposition of Trace Elements Into The Arctic Ocean-Ice Ecosystem During The Year-Long MOSAiC Ice Drift (MOSAiC)" project. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2022-07-18.

The following is the text of the dataset description provided by BCO-DMO:

MOSAIC Expedition Ice Core Be7

Dataset Description:
Acquisition Description:
Ice cores were collected using a Kovacs Mark II 9 cm diameter corer (area = 63.62 cm2). Snow was swept away from the ice surface before drilling through the ice column. Once recovered, cores were laid out on a cradle to measure length (ice thickness) and then put in a plastic sleeve before being transported to Polarstern where they were placed in buckets for melting.

We generally took three ice cores (total sample area = 190.85 cm2, 11 samples) from a site and combined them into one sample, but for some samples we took 4 cores (area = 254.5 cm2, 5 samples) or 6 cores (area = 381.7 cm2, 3 samples).

For two samples (Core11 and Core13), cores were cut into segments before melting. For example, Core11 consists of 6 cores, each of which was cut into three segments (Core11a = 0-40cm, Core11b = 40-80cm, and Core11c = 80-123cm, where depth = 0cm at the snow-ice surface). For all other samples, the full length of each core was melted without segmenting.

Shipboard Laboratory Procedure: After placing the cores in buckets, we added the following solutions: 5 ml hydrochloric acid, 2 ml iron chloride solution, and 1 ml of 1000 ppm stable beryllium AA standard (chemical yield tracer). After melting at room temperature, the water volume was measured using a graduated cylinder. Next, the sample was precipitated using ammonium hydroxide. After allowing the precipitate to settle, excess water was removed by decanting and centrifugation. Finally, the samples were transferred to petri dishes and placed in an oven for drying.

Gamma Analysis: Dried samples in petri dishes were counted by gamma spectroscopy. Be-7 has a readily identifiable gamma peak at 478 keV. The counting system was calibrated for all samples by preparing a commercial standard in a geometry identical to the samples.

Chemical Yield Determination: After gamma counting, samples were brought up to 1 liter in 1% nitric acid solution. The beryllium concentrations were then determined using a Perkin Elmer Optima 7300 DV ICP-OES. Our chemical yields averaged over 80% (Kadko et al., 2019).