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OAS accession Detail for 0294390
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| accessions_id: | 0294390 | archive |
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| Title: | 234Th flux in epipelagic waters at Station ALOHA and the Equatorial Pacific from R/V Kilo Moana cruises KM1407, KM1418, & KM1515 during 2014-2015 (NCEI Accession 0294390) |
| Abstract: | This dataset contains chemical data collected on R/V Kilo Moana during cruises KM1407, KM1418, and KM1515 in the North Pacific Ocean from 2014-02-19 to 2015-09-08. These data include depth and thorium-234 activity. The instruments used to collect these data include Niskin bottle and Riso Laboratory Anti-coincidence Beta Counters. These data were collected by Brian N. Popp and Jeffrey C. Drazen of University of Hawaii at Manoa and Claudia R. Benitez-Nelson of University of South Carolina as part of the "Collaborative Research: Isotopic insights to mercury in marine food webs and how it varies with ocean biogeochemistry (Hg_Biogeochemistry)" and "Evaluating the relative importance of suspended and sinking particles to the meso and bathypelagic food web in the central North Pacific (SuspendSinkPart)" projects. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2020-03-31. The following is the text of the dataset description provided by BCO-DMO: 234Th flux in epipelagic waters of Station Aloha and the Equatorial North Pacific Dataset Description: Acquisition Description: 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. |
| Date received: | 20200331 |
| Start date: | 20140219 |
| End date: | 20150908 |
| Seanames: | North Pacific Ocean |
| West boundary: | -158 |
| East boundary: | -155 |
| North boundary: | 22 |
| South boundary: | 5 |
| Observation types: | chemical |
| Instrument types: | Niskin bottle |
| Datatypes: | thorium isotope |
| Submitter: | |
| Submitting institution: | Biological and Chemical Oceanography Data Management Office |
| Collecting institutions: | University of Hawai'i at Mānoa, University of South Carolina |
| Contributing projects: | |
| Platforms: | KILO MOANA (33KB) |
| Number of observations: | |
| Supplementary information: | |
| Availability date: | |
| Metadata version: | 1 |
| Keydate: | 2024-06-27 20:29:14+00 |
| Editdate: | 2024-06-27 20:30:02+00 |