Bam, Wokil (2026): Total Thorium-234 Activity in water column along the equatorial Atlantic collected on RV METEOR during cruise M181 Cape Town - Mindelo, 2022-04-17 - 2022-05-27 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.990366
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Published: 2026-02-11 • DOI registered: 2026-03-12
Abstract:
Total water-column Thorium-234 was determined by following the methods of Pike, et al. (2005) and Clevenger, et al. (2021) on 2-liter (L) water column samples, as mentioned in International GEOTRACES cookbook. An exact 1-milliliter (mL) aliquot of 230Th (50.03 disintegrations per minute per gram (dpm g⁻¹)) was used as the yield monitor and added during initial acidification of the samples. QMAs were used to collect the precipitate from the 2 L process and immediately dried. Once dried, they were mounted onto plastic 25-millimeter (mm) discs, covered with a mylar layer and two layers of aluminum foil, and immediately beta counted at sea. The filters were counted again, 5 to 6 months later to quantify the background radioactivity due to the beta decay of long-lived natural radionuclides that are also precipitated. The mean value of the at-sea counts (decay-corrected to the time of collection) minus the background value for each filter is reported as the 234Th activity (dpm L⁻¹). Activities for 234Th are generally reported in disintegrations per minute per liter (dpm L⁻¹). Data are decay-corrected to the mid-point time between when the first and last bottles were fired for shallow casts, when the messenger was dropped for deep casts, and the time of collection for fish tow samples. All data have been recovery-corrected using the 230Th /229Th recovery method (see References) to account for any loss of sample material during processing. All samples were analyzed using Risø Laboratory Anti-Coincidence Beta Counters, using a helium/1% butane mixture. Uranium-238 is calculated as a function of salinity described in Owens et al., 2011.
References:
Clevenger, Samantha J; Benitez-Nelson, Claudia R; Drysdale, Jessica A; Pike, Steven M; Puigcorbé, Viena; Buesseler, Ken O (2021): Review of the analysis of 234Th in small volume (2–4 L) seawater samples: improvements and recommendations. Journal of Radioanalytical and Nuclear Chemistry, 329(1), 1-13, https://doi.org/10.1007/s10967-021-07772-2
Owens, Stephanie A; Buesseler, Ken O; Sims, Kenneth W W (2011): Re-evaluating the 238U-salinity relationship in seawater: Implications for the 238U–234Th disequilibrium method. Marine Chemistry, 127(1-4), 31-39, https://doi.org/10.1016/j.marchem.2011.07.005
Pike, Steven M; Buesseler, Ken O; Andrews, J; Savoye, N (2005): Quantification of Th-234 recovery in small volume sea water samples by inductively coupled plasma-mass spectrometry. Journal of Radioanalytical and Nuclear Chemistry, 263, 355-360
Project(s):
Coverage:
Median Latitude: 0.000000 * Median Longitude: -21.287500 * South-bound Latitude: 0.000000 * West-bound Longitude: -44.000000 * North-bound Latitude: 0.000000 * East-bound Longitude: 2.000000
Date/Time Start: 2022-04-30T08:20:00 * Date/Time End: 2022-05-20T10:50:00
Minimum DEPTH, water: 5 m * Maximum DEPTH, water: 6000 m
Event(s):
M181_71-1 (CTD025) * Latitude: 0.000030 * Longitude: 2.000070 * Date/Time: 2022-04-30T07:30:42 * Elevation: -4610.0 m * Location: North Atlantic Ocean * Campaign: M181 (TRATLEQ 2) * Basis: Meteor (1986) * Method/Device: CTD/Rosette (CTD-RO)
M181_76-1 (CTD026) * Latitude: 0.000430 * Longitude: 1.000170 * Date/Time: 2022-04-30T17:39:54 * Elevation: -4820.0 m * Location: North Atlantic Ocean * Campaign: M181 (TRATLEQ 2) * Basis: Meteor (1986) * Method/Device: CTD/Rosette (CTD-RO)
M181_81-1 (CTD027) * Latitude: 0.000370 * Longitude: -0.000280 * Date/Time: 2022-05-01T04:31:10 * Location: North Atlantic Ocean * Campaign: M181 (TRATLEQ 2) * Basis: Meteor (1986) * Method/Device: CTD/Rosette (CTD-RO)
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | LATITUDE | Latitude | Bam, Wokil | Geocode | ||
| 2 | LONGITUDE | Longitude | Bam, Wokil | Geocode | ||
| 3 | Event label | Event | Bam, Wokil | Station | ||
| 4 | Identification | ID | Bam, Wokil | CTD# | ||
| 5 | Sample ID | Sample ID | Bam, Wokil | |||
| 6 | DATE/TIME | Date/Time | Bam, Wokil | Geocode | ||
| 7 | DEPTH, water | Depth water | m | Bam, Wokil | Geocode | |
| 8 | Thorium-234 | 234Th | dpm/l | Bam, Wokil | Anti-coincidence beta counters, Risø Laboratory | |
| 9 | Thorium-234, error | 234Th e | ± | Bam, Wokil | Anti-coincidence beta counters, Risø Laboratory | |
| 10 | Uranium-238 | 238U | dpm/l | Bam, Wokil | Calculated from salinity | |
| 11 | Uranium-238, error | 238U e | ± | Bam, Wokil | Calculated from salinity |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0) (License comes into effect after moratorium ends)
Status:
Curation Level: Enhanced curation (CurationLevelC)
Size:
2664 data points
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