Particulate Th-234 collected using large volume McLane pumps (LVPs) as part of the EAGER chief scientist training cruise (KM1910) at Station ALOHA, subtropical North Pacific gyre in June 2019

Website: https://www.bco-dmo.org/dataset/854150
Data Type: Cruise Results
Version: 1
Version Date: 2021-07-13

Project
» EAGER Collaborative Research: Early career chief scientist training for biological and chemical oceanographers (Chief Sci KM1910)
ContributorsAffiliationRole
Church, Matthew J.University of MontanaPrincipal Investigator
Ferron, SaraUniversity of Hawaii at Manoa (HIGP)Co-Principal Investigator
Goetze, EricaUniversity of Hawaii at Manoa (HIGP)Co-Principal Investigator
White, Angelicque E.University of HawaiiCo-Principal Investigator
Black, ErinColumbia UniversityScientist, Contact
Kenyon, JenniferWoods Hole Oceanographic Institution (WHOI)Student, Contact
Heyl, TaylorWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
This dataset includes particulate Th-234 collected using large volume McLane pumps (LVPs) as part of the EAGER chief scientist training cruise at Station ALOHA in the subtropical North Pacific gyre in June 2019.


Coverage

Spatial Extent: N:22.833 E:-157.922 S:22.709 W:-158.067
Temporal Extent: 2019-06-17 - 2019-06-22

Acquisition Description

In-situ particulate material was collected using McLane pumps. All thorium data were decay-corrected back to mid-pumping times. See Pike et al., 2005 and Clevenger et al., 2021 for detailed methods and counting techniques.

>51 micrometer (µm) Th-234 (LSF, large particulate Thorium): The entire 142 millimeter (mm) mesh screen was rinsed onto a 25 mm silver filter and dried in a low temperature oven before beta counting. The mean volume pumped through the 142 mm mesh screens was ~640 liters (L).

1-51 micrometer (µm) Th-234 (SSF, small particulate Thorium): Whole 142 mm QMAs, located below the mesh screen in the filter head housing, were dried in a low temperature oven. A 25 mm subsample was taken from this 142 mm filter for beta counting for Th-234.


Processing Description

Data were flagged with quality indicators: 1 = Good Value; 2 = Probably Good Value.

Empty fields marked ‘nd’ denote that there were pump or filterhead issues that resulted in a compromised sample or no sample at this depth for either the QMA or screen or both. Data were originally calculated in dpm per L and were converted to mBq per kiligram (kg) using the standard ocean rho = 1.025 kg/L and 1 dpm = 16.667 mBq.

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.


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Related Publications

Clevenger, C., Benitez-Nelson, C., Drysdale, J., Pike, S., Puigcorbe, V., Buesseler, K. (2021). Review of the analysis of 234Th in small volume (2-4 L) seawater samples: improvements and recommendations. Journal of Radioanalytical and Nuclear Chemistry.
Methods
Pike, S. M., Buesseler, K. O., Andrews, J., & Savoye, N. (2005). Quantification of 234Th recovery in small volume sea water samples by inductively coupled plasma-mass spectrometry. Journal of Radioanalytical and Nuclear Chemistry, 263(2), 355–360. doi:10.1007/s10967-005-0062-9 https://doi.org/10.1007/s10967-005-0594-z
Methods
Winn, C., C. Sabine, D. Hebel, F. Mackenzie and D. M. Karl. (1991) Inorganic carbon system dynamics in the central Pacific Ocean: Results of the Hawaii Ocean Time-series program. EOS, Transactions of the American Geophysical Union 72, 70.
Results

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Related Datasets

IsRelatedTo
Kenyon, J., Black, E., Church, M. J. (2021) Particulate Th-234 collected with surface-tethered sediment traps at Station ALOHA as part of the EAGER chief scientist training cruise (KM1910) in the subtropical North Pacific gyre in June 2019. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2021-07-20 doi:10.26008/1912/bco-dmo.854241.1 [view at BCO-DMO]

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Parameters

ParameterDescriptionUnits
Pump_Event_IDPump casts were indicated with a P, followed by the cast number (1 to 5) Unitless
DepthDepth below water surface (zero = water surface and all values are reported as positive) Meters
LatitudeLatitude North Decimal degrees
LongitudeLongitude East Decimal degrees
Date_Pump_On_HASTDate and Time in Hawaiian-Aleutian Standard Time (GMT-10) when large volume pumps were programmed to turn on; format: MM/DD/YYYY hh:mm Unitless
Date_Pump_Off_HASTDate and Time in Hawaiian-Aleutian Standard Time (GMT-10) when large volume pumps were programmed to turn off; format: format: MM/DD/YYYY hh:mm Unitless
Pump_On_ISO_DateTime_UTCDate and Time in UTC when large volume pumps were programmed to turn on in ISO8601 format: YYYY-MM-DDThh:mmZ Unitless
Pump_Off_ISO_DateTime_UTCDate and time in UTC when large volume pumps were programmed to turn off in ISO8601 format: YYYY-MM-DDThh:mmZ Unitless
Filtered_VolumeVolume of water passing through the filterhead. Liters
Th234_LSF>51 µm Thorium-234 (large particle activity) mBq/kg
LSF_ErrError of Th234_LSF. Error is propagated from the counting uncertainty and uncertainties associated with sample processing. mBq/kg
LSF_QFQuality flag for Th234_LSF Unitless
Th234_SSF1-51 µm Thorium-234 (small particle activity) mBq/kg
SSF_ErrError of Th234_SSF. Error is propagated from the counting uncertainty and uncertainties associated with sample processing. mBq/kg
SSF_QFQuality flag for Th234_SSF Unitless


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Instruments

Dataset-specific Instrument Name
Generic Instrument Name
McLane Pump
Dataset-specific Description
McLane pumps sample large volumes of seawater at depth. They are attached to a wire and lowered to different depths in the ocean. As the water is pumped through the filter, particles suspended in the ocean are collected on the filters. The pumps are then retrieved, and the contents of the filters are analyzed in a lab.
Generic Instrument Description
McLane pumps sample large volumes of seawater at depth. They are attached to a wire and lowered to different depths in the ocean. As the water is pumped through the filter, particles suspended in the ocean are collected on the filters. The pumps are then retrieved and the contents of the filters are analyzed in a lab.

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%. 


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Deployments

KM1910

Website
Platform
R/V Kilo Moana
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)


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Project Information

EAGER Collaborative Research: Early career chief scientist training for biological and chemical oceanographers (Chief Sci KM1910)

Coverage: Station ALOHA (22.75N, 158W), North Pacific Ocean


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.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)
NSF Division of Ocean Sciences (NSF OCE)

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