Beryllium-7 concentrations in seawater during the MOSAiC expedition

Pumps were used to collect seawater within the upper 60 m of the ocean for Be-7analysis. Unfiltered seawater was drawn through a pvc hose to the surface where it was passed through iron-oxide impregnated acrylic fiber filters, which adsorb the Be-7. A flow meter attached in-line to the filter compar...

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Bibliographic Details
Main Author: Stephens, Mark
Format: Dataset
Language:English
Published: PANGAEA 2022
Subjects:
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.945403
https://doi.org/10.1594/PANGAEA.945403
Description
Summary:Pumps were used to collect seawater within the upper 60 m of the ocean for Be-7analysis. Unfiltered seawater was drawn through a pvc hose to the surface where it was passed through iron-oxide impregnated acrylic fiber filters, which adsorb the Be-7. A flow meter attached in-line to the filter compartment recorded the amount of seawater passed through each filter. To maximize Be-7 collection, two or three fibers filtering approximately 600- 700 L of seawater apiece were collected from each depth and later combined. For the mixed layer samples, water was collected from the ship's seawater intake (~8m) into barrels from which the water was passed through the iron-oxide filters as described above. The fibers were dried and shipped to Florida International University. There, the fibers were ashed, placed in a Marinelli beaker and analyzed with a high purity germanium (HPGe) gamma detector. Be-7 has a readily identifiable gamma peak at 478 keV. The detector is calibrated by adding a commercially prepared mixed solution of known gamma activities to an ashed fiber and counting it in the Marinelli geometry.