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OAS accession Detail for 0278122
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| accessions_id: | 0278122 | archive |
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| Title: | Water column Th-234 activity determined using a 4-L technique from samples collected on R/V Melville cruise MV1008 in the Costa Rica Dome in 2010 (CRD FLUZiE project) (NCEI Accession 0278122) |
| Abstract: | This dataset contains physical data collected on R/V Melville during cruise MV1008 in the North Pacific Ocean from 2010-06-27 to 2010-07-23. These data include density, depth, and salinity calculated from CTD primary sensors. The instruments used to collect these data include Mass Spectrometer and Riso Laboratory Anti-coincidence Beta Counters. These data were collected by Michael R. Landry of University of California-San Diego as part of the "Costa Rica Dome FLUx and Zinc Experiments (CRD FLUZiE)" project and "Integrated Marine Biogeochemistry and Ecosystem Research -US (IMBER-US)" and "Ocean Carbon and Biogeochemistry (OCB)" programs. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2019-12-11. The following is the text of the dataset description provided by BCO-DMO: Water column Th-234 activity determined using a 4-L technique. Dataset Description: Water column Thorium-234 and Uranium-238 measured on the MV1008 cruise in the Costa Rica Dome (CRD) region of the Eastern Tropical Pacific Ocean. |
| Date received: | 20191211 |
| Start date: | 20100627 |
| End date: | 20100723 |
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| West boundary: | -92.92 |
| East boundary: | -86.76 |
| North boundary: | 10.33 |
| South boundary: | 8.37 |
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| Submitting institution: | Biological and Chemical Oceanography Data Management Office |
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| Supplementary information: | Acquisition Description: 4-L samples for analysis of water column 234 Th concentrations were typically taken at 12 depths spanning the upper 150 m on two casts per experimental cycle. On two cycles in the core of the CRD, an additional set of 8 samples was taken to assess 234 Th deficiency down to 500-m depth. Samples were analyzed by standard small volume procedures (Benitez-Nelson et al. 2001, Buesseler et al. 2001, Pike et al. 2005). Immediately after collection, samples were acidified to a pH 8 hours as Th co-precipitated with manganese oxide. Samples were then filtered at high pressure onto a quartz microfiber (QMA) filter, dried in a drying oven, and mounted into RISO sample holders for beta counting. Samples were beta counted at the University of South Carolina on a RISO low-level beta multi-counter within two months of the collection date. After an additional 8 months, samples were recounted to determine background beta emissions. Detector efficiency was calibrated using four samples taken from 2000-m depth (in water columns exceeding 3000-m depth), which were assumed to be at equilibrium with respect to 234 Th and 238 U. After background counts yield analyses were conducted as follows. Manganese oxide precipitate was dissolved from filters in 10 mL 8M HNO 3 /10% H 2 O 2 . 1 mL of 229 Th (1.66 Bq g -1 ) tracer was then added gravimetrically, and the sample was sonicated for 20 minutes and allowed to sit for >6 hours. An aliquot of this solution was then filtered through a 0.1-mm syringe filter and diluted with 2.2M HNO 3 /1%HF for mass spec analysis of the 229:230 Th tracer ratio at the Woods Hole Oceanographic Institution Analytical Facility. |
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| Metadata version: | 1 |
| Keydate: | 2023-05-13 04:08:57+00 |
| Editdate: | 2023-05-13 04:09:33+00 |