Salinity and density were measured using a CTD. 4-L Samples for total water-column 234Th activity were collected using Go-Flo bottles at 7 depths from the surface to 100 m. Sample volume was determined gravimetrically and then samples were acidified to a pH < 2 with nitric acid and a Th-230 tracer spike was added. Samples were shaken and allowed to equilibrate for 4 – 9 hours. Samples were then re-basified with ammonium hydroxide to a pH of 8 – 9, shaken, and allowed to equilibrate for >8 hours. Samples were then vacuum filtered at high vacuum pressure through a quartz (QMA) filter. Filters were mounted in RISO planchets and counted on a RISO low-level beta multi-counter at Palmer Station. Following a background count >6 months later, samples were dissolved in 8M nitric acid / 10% hydrogen peroxide solution and a Th-229 tracer spike was added. Samples were then shipped to the Woods Hole Analytical laboratory for analysis of the Th-229:Th-230 ratio, which was used to calculate the initial precipitation and filtration yield of Th-234. For additional details, see Stukel et al. (2015) and Stukel et al. (2022).
Stukel, M. (2022) Total water column 234Th during the 2012-2013 Palmer Field Season (WAP Carbon export project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2022-08-02 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/881459 [access date]
Terms of Use
This dataset is licensed under Creative Commons Attribution 4.0.
If you wish to use this dataset, it is highly recommended that you contact the original principal investigators (PI). Should the relevant PI be unavailable, please contact BCO-DMO (info@bco-dmo.org) for additional guidance. For general guidance please see the BCO-DMO Terms of Use document.