File(s) | Type | Description | Action |
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234Th_flux.csv (1.80 KB) | Comma Separated Values (.csv) | Primary data file for dataset ID 806471 | Download |
234Th flux in epipelagic waters at Station ALOHA and the Equatorial Pacific from R/V Kilo Moana cruises KM1407, KM1418, & KM1515 during 2014-2015.
Total ²³⁴Th was measured in samples of seawater collected at discrete depths using Niskin bottles as described in Umhau et al. (2019). Briefly, 2 L of seawater was collected at each selected depth. Samples were spiked with ²³⁰Th as a yield tracer and acidified to pH ~ 1 using concentrated nitric acid. After equilibration, ~ 6 hours later, KMnO₄ and MnCl₂ were added and the pH adjusted to ~ 9 with concentrated NH₄OH in order to co-precipitate Th via the formation of MnO₂. After eight hours, total ²³⁴Th samples were filtered onto 25 mm QMA filters, air dried, and frozen.
The ²³⁴Th flux (dpm m⁻² d⁻¹) was calculated from the ²³⁴Th:²³⁸U disequilibrium and assuming a steady state (Umhau et al. 2019). The ²³⁴Th flux at each depth was obtained by integrating the flux for the overlying depths using trapezoidal integration.
Thorium counts were made using a low level RISO beta counter within 2 weeks of sample collection.
Benitez-Nelson, C., Drazen, J., Popp, B. (2020) 234Th flux in epipelagic waters at Station ALOHA and the Equatorial Pacific from R/V Kilo Moana cruises KM1407, KM1418, & KM1515 during 2014-2015. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2020-03-19 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.806471.1 [access date]
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