Contributors | Affiliation | Role |
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Church, Matthew J. | University of Montana | Principal Investigator |
Ferrón, Sara | University of Hawaiʻi at Mānoa (SOEST) | Co-Principal Investigator |
Goetze, Erica | University of Hawaiʻi at Mānoa (SOEST) | Co-Principal Investigator |
White, Angelicque E. | University of Hawai'i (UH) | Co-Principal Investigator |
Black, Erin E. | Columbia University | Scientist, Contact |
Kenyon, Jennifer | Woods Hole Oceanographic Institution (WHOI) | Student, Contact |
Heyl, Taylor | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Rauch, Shannon | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Particle flux measurements from the Chief Scientist Training cruise generally followed the methods of the Hawaii Ocean Time-Series (HOT). Measurements were made at 75 meters, 150 meters, and 300 meters using multiple cylindrical particle interceptor traps deployed on a free-floating array for approximately 3 days twice during cruise KM1910 at station ALOHA. Sediment trap design and collection methods are described in Winn et al. (1991). Sediment trap tubes were split, with roughly 50% of the split going to Th-234 particulate analysis.
All thorium-234 data were decay corrected back to mid-deployment times. The subsampled trap material was gradually poured into 25 millimeter (mm) filter funnels containing 25 mm QMA or GFF filters (most were QMA and efficiency differences were taken into account). Once all the trap subsample liquid was filtered, the 25 mm filter was dried at low temperature for a few hours (<60 degrees Celsius). Samples were mounted and prepared for beta counting according to the techniques noted in Pike et al., 2005 and Clevenger et al., 2021.
Data were flagged with quality indicators: 1 = Good Value.
Data flags are according to the SeaDataNet scheme (https://www.geotraces.org/geotraces-quality-flag-policy/).
BCO-DMO processing description:
- Adjusted field/parameter names to comply with BCO-DMO naming conventions;
- Added a conventional header with dataset name, PI names, version date;
- Converted dates to ISO8601 format: YYYY-MM-DDThh:mmZ;
- Converted longitude values from positive degrees West to negative degrees East;
- Rounded fields as requested by data submitter.
File |
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Th-234_traps.csv (Comma Separated Values (.csv), 2.62 KB) MD5:69fec28e290dd980110158542f8c9b95 Primary data file for dataset ID 854241 |
Parameter | Description | Units |
Trap_Event_ID | Sediment trap deployments were indicated with a T, followed by the deployment number (1 or 2) | Unitless |
Depth | Depth of trap below water surface (zero = water surface and all values are reported as positive) | Meters |
Tube_ID | Each letter represents trap material from a different tube at a given depth | Unitless |
Start_Date_HAST | Date and time (Hawaii-Aleutian Standard Time, GMT-10) of deployment start; format: MM/DD/YYYY hh:mm | Unitless |
End_Date_HAST | Date and time (Hawaii-Aleutian Standard Time, GMT-10) of deployment end; format: MM/DD/YYYY hh:mm | Unitless |
Start_ISO_DateTime_UTC | Date and time (UTC) of deployment start in ISO8601 format: YYYY-MM-DDThh:mmZ | Unitless |
End_ISO_DateTime_UTC | Date and time (UTC) of deployment end in ISO8601 format: YYYY-MM-DDThh:mmZ | Unitless |
Latitude_In | Latitude at time of trap deployment in degrees North | Decimal degrees |
Longitude_In | Longitude at time of trap deployment in degrees East | Decimal degrees |
Latitude_Out | Latitude at time of trap recovery in degrees North | Decimal degrees |
Longitude_Out | Longitude at time of trap recovery in degrees East | Decimal degrees |
Volume | Volume of the water sample from the trap tube that was analyzed for thorium-234 | Liters |
Fraction_Trap_Material_Coll | The G, H, I tubes were subsampled. Approximately 1/2 was used for the thorium-234 measurements. The absolute fraction of the total tube volume (i.e. the total sample collected) is indicated here. | Decimal fraction |
Th234_Flux | Sinking flux of 234Th calculated from sediment trap samples | Decays per minute (dpm) per square meter per day (dpm m-2 d-1) |
Th234_Flux_SD | Standard deviation of Th234_Flux | Decays per minute (dpm) per square meter per day (dpm m-2 d-1) |
Th234_Flux_QF | Quality flag for Th234_Flux (1 = good data) | Unitless |
Dataset-specific Instrument Name | |
Generic Instrument Name | Riso Laboratory Anti-coincidence Beta Counters |
Dataset-specific Description | Low-level beta detectors manufactured by Risø (now Nutech) in Denmark. These instruments accept samples that can be mounted on a 25mm filter holder. These detectors have very low backgrounds, 0.17 counts per minute, and can have counting efficiencies as high as 55%. Efficiency Calibrations: The detectors are intercalibrated with each other and across the transect using low-energy U standards. Limits of Detection: Limits of detection are not reported because they are not applicable to the 234Th beta counting method. A ‘non-detect’ for 234Th or a case where there is no 234Th present (initially or after 6 months of decay) will still result in a measurable amount of background radioactivity due to the beta decay of long lived natural radionuclides that are also present. These background values are utilized and therefore, they are not reported as a non-detections of 234Th.
See: https://cafethorium.whoi.edu/services/ and https://www.nutech.dtu.dk/english/products-and-services/radiation-instru... |
Generic Instrument Description | Low-level beta detectors manufactured by Riso (now Nutech) in Denmark. These instruments accept samples that can be mounted on a 25mm filter holder. These detectors have very low backgrounds, 0.17 counts per minute, and can have counting efficiencies as high as 55%. |
Dataset-specific Instrument Name | |
Generic Instrument Name | Sediment Trap |
Dataset-specific Description | Sediment trap array (spar buoy, radiotransmitter, strobe light, floats, trap supports, collector tubes) |
Generic Instrument Description | Sediment traps are specially designed containers deployed in the water column for periods of time to collect particles from the water column falling toward the sea floor. In general a sediment trap has a jar at the bottom to collect the sample and a broad funnel-shaped opening at the top with baffles to keep out very large objects and help prevent the funnel from clogging. This designation is used when the specific type of sediment trap was not specified by the contributing investigator. |
Website | |
Platform | R/V Kilo Moana |
Report | |
Start Date | 2019-06-15 |
End Date | 2019-06-24 |
Description | NSF Chief Scientist Training Cruise. For more information, see Rolling Deck to Repository (R2R): https://www.rvdata.us/search/cruise/KM1910 (cruise DOI: 10.7284/908380) |
NSF Award Abstract:
Intellectual Merit
The PIs request funds to provide training in leading and organizing research cruises to early career researchers in the areas of Biological and Chemical Oceanography. Participants in this training program would be introduced to pre-cruise planning and logistics, receive training in commonly used oceanographic sampling equipment, and conduct shipboard measurements during a 10-day oceanographic cruise to the North Pacific Subtropical Gyre (NPSG). The goal of this training program is to prepare early career scientists for leading and participating in interdisciplinary oceanographic research at sea.
Broader Impacts
The proposed program addresses the broader impacts criteria successfully. The research cruise and follow-up reports and publications focus on interdisciplinary questions important for advancing the field. Given the rapid changes that oceanic systems are undergoing, it is important to have a cadre of junior scientists who are adept at managing interdisciplinary collaborations and conducting research at sea. The PIs are considering ways to connect with diverse audiences in recruiting participants. The impact on early career oceanographers will be very strong. This will create an experience that will be a major impact on the careers of the trainees, especially if they stay in the oceanography field.
Funding Source | Award |
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NSF Division of Ocean Sciences (NSF OCE) | |
NSF Division of Ocean Sciences (NSF OCE) |