Dataset: GN01 Radium and Thorium

Name: Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise on the USCGC Healy (HLY1502) from August to October 2015
Published: 2021-07-06
Keywords: oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.718440.4

Spatial Extent: N:89.992 E:179.456 S:60.176 W:-180

Temporal Extent: 2015-08-12 - 2015-10-08

Project:

Collaborative Research: GEOTRACES Arctic Section: Radium and Thorium Isotopes as Natural Geochemical Tracers in the Arctic Ocean (Arctic GEOTRACES Ra Th)

U.S. Arctic GEOTRACES Study (GN01) (U.S. GEOTRACES Arctic)

Program:

U.S. GEOTRACES (U.S. GEOTRACES)

Principal Investigator:

Matthew A. Charette (Woods Hole Oceanographic Institution, WHOI)

Co-Principal Investigator:

Willard S. Moore (University of South Carolina)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2021-07-06

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise on the USCGC Healy (HLY1502) from August to October 2015

Abstract:

Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise on the USCGC Healy (HLY1502) from August to October 2015.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2021-07-06	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.718440.4	2021-07-06
2020-04-06	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.718440.3	2020-04-07

Description

Radium and thorium isotopes measured in the Western Arctic as part of the 2015 US GEOTRACES Arctic Cruise.

Please contact the PI and Co-PI (Charette and Moore) prior to use of these data in publications.

Methods & Sampling

Water column sampling:
Radium and thorium isotopes were collected on manganese-coated cartridges filtered at depth using an adapted McLane in situ pump (WTS-LV). The pumps were programmed to filter 1500-2000L of seawater per deployment. Water (15-25 L) was also collected at the same depth using a 30L Niskin bottle; these samples were filtered (at <1L/min) through a manganese-coated acrylic fiber and used to calculate radium extraction efficiency of the pumped samples. The cartridges were rinsed with radium-free fresh water and excess moisture was removed using compressed air. Samples were analyzed three times using a delayed coincidence counter (RaDeCC) for 223Ra, 224Ra, 228Th, and 227Ac. The cartridge and fiber media were ashed at 820 degrees C and measured on gamma detectors for long lived radium (226Ra, 228Ra) and thorium isotopes. 226Ra was determined via alpha scintillation counting of the Niskin bottle Mn fiber samples.

Surface water sampling:
Surface water radium samples (280 L) were collected from approximately 2 m using a submersible surface pump and filtered through a manganese coated acrylic fiber, which quantitatively scavenges radium from the seawater. Fiber samples were then ashed in a muffle furnace at 820 degrees C for 24 hours and the fiber ash was transferred to polystyrene vials, sealed with epoxy (to prevent 222Rn loss), and counted on high purity, well-type germanium detectors to measure 228Ra, using the lines of 228Ac (338 KeV and 911 KeV), and 226Ra, using the line for 214Pb (352 KeV). Detector efficiencies were determined by measuring ashed fiber standards prepared with a standard solution containing 226Ra and 232Th with daughters in equilibrium.

Data Processing Description

Data Processing:
The data were corrected for decay from the time of sampling. 223Raxs was corrected for 227Ac, 224Raxs was corrected for 228Th. When possible, total 228Th was used for the 224Raxs correction (total = dissolved + SSF particulate + LSF particulate); for samples collected using the surface pump, only dissolved 228Th was available. The radium activity of the water samples (cartridges) were corrected from the measured radium on acrylic fiber (<1L/min) using the emanation technique.

Data were flagged using the SeaDataNet quality flag scheme. For more information on SeaDataNet flags, see: https://www.geotraces.org/geotraces-quality-flag-policy/ and https://www.seadatanet.org/Standards/Data-Quality-Control

SeaDataNet quality flag definitions:
0 = No quality control;
1 = Good value;
2 = Probably good value;
3 = Probably bad value;
4 = Bad value;
5 = Changed value;
6 = Value below detection;
7 = Value in excess;
8 = Interpolated value;
9 = Missing value;
A = Value phenomenon uncertain.

Problem report:
Pump failures during sampling resulted in some gaps in data, these samples have been flagged as missing values (quality flag 9). In cases where low volumes (<600L) were filtered due to pump malfunctions, data has been flagged as questionable (quality flag 3). Samples with activities below detection limits have also been flagged (quality flag 6), and no value is reported for those samples.

BCO-DMO Processing:
- replaced blanks (missing data) with "nd"; replaced "ND" with "nd";
- added start and end date/times in ISO 8601 format.
Version history:
- 2019-07-02: replaced version 1 of dataset with version 2 (additional data columns reported; additional columns for units in dpm/L and mBq/kg);
- 2020-04-06: replaced version 2 of dataset with version 3 (GEOTRACES IDP-formatted).
- 2021-07-06: made correction to Sample_Depth for Sample_ID 10509; published as version 4. The depth for 10509 was previously reported as 427, but the correct value is 274.

Data Files

File
Ra_Th.csv (Comma Separated Values (.csv), 69.16 KB) MD5:810e8e364c36521658bd97ae06e6de64 Primary data file for dataset ID 718440

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1458305
NSF Division of Ocean Sciences	OCE-1458424

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
HLY1502	GN01 U.S. GEOTRACES Arctic 32H120150809	2015-08-09	USCGC Healy	David C. Kadko (Chief Scientist) William M. Landing (Co-Chief Scientist)	data info

Instruments

McLane Large Volume Pumping System WTS-LV

Supplied Name: McLane WTS-LV

Supplied Description:

Water column samples were collected using McLane in situ pumps (McLane WTS-LV).

Instrument Type

Generic Name: McLane Large Volume Pumping System WTS-LV

Acronym: WTS-LV

Generic Description:

The WTS-LV is a Water Transfer System (WTS) Large Volume (LV) pumping instrument designed and manufactured by McLane Research Labs (Falmouth, MA, USA). It is a large-volume, single-event sampler that collects suspended and dissolved particulate samples in situ.

Ambient water is drawn through a modular filter holder onto a 142-millimeter (mm) membrane without passing through the pump. The standard two-tier filter holder provides prefiltering and size fractioning. Collection targets include chlorophyll maximum, particulate trace metals, and phytoplankton. It features different flow rates and filter porosity to support a range of specimen collection. Sampling can be programmed to start at a scheduled time or begin with a countdown delay. It also features a dynamic pump speed algorithm that adjusts flow to protect the sample as material accumulates on the filter. Several pump options range from 0.5 to 30 liters per minute, with a max volume of 2,500 to 36,000 liters depending on the pump and battery pack used. The standard model is depth rated to 5,500 meters, with a deeper 7,000-meter option available. The operating temperature is -4 to 35 degrees Celsius.

The WTS-LV is available in four different configurations: Standard, Upright, Bore Hole, and Dual Filter Sampler. The high-capacity upright WTS-LV model provides three times the battery life of the standard model. The Bore-Hole WTS-LV is designed to fit through a narrow opening such as a 30-centimeter borehole. The dual filter WTS-LV features two vertical intake 142 mm filter holders to allow simultaneous filtering using two different porosities.

Niskin bottle

Supplied Name: 30L Niskin bottles

Supplied Description:

In addition to water collected by pump, water (15-25 L) was also collected using a 30L Niskin bottles.

Instrument Type

Generic Name: Niskin bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/

Generic Description:

A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.

Pump

Supplied Name: Finish Thompson Magnetic Drive pump

Supplied Description:

Surface samples were collected using a Finish Thompson 1/2 HP Polypropylene 115V Magnetic Drive pump.

Instrument Type

Generic Name: Pump

Generic Description:

A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action. Pumps can be classified into three major groups according to the method they use to move the fluid: direct lift, displacement, and gravity pumps

Radium Delayed Coincidence Counter

Supplied Description:

Samples were analyzed using Radium Delayed Coincidence (RaDeCC) counters and high-purity, well-type germanium detectors.

Instrument Type

Generic Name: Radium Delayed Coincidence Counter

Acronym: RaDeCC

Generic Description:

The RaDeCC is an alpha scintillation counter that distinguishes decay events of short-lived radium daughter products based on their contrasting half-lives. This system was pioneered by Giffin et al. (1963) and adapted for radium measurements by Moore and Arnold (1996).

References:
Giffin, C., A. Kaufman, W.S. Broecker (1963). Delayed coincidence counter for the assay of actinon and thoron. J. Geophys. Res., 68, pp. 1749-1757.
Moore, W.S., R. Arnold (1996). Measurement of 223Ra and 224Ra in coastal waters using a delayed coincidence counter. J. Geophys. Res., 101 (1996), pp. 1321-1329.
Charette, Matthew A.; Dulaiova, Henrieta; Gonneea, Meagan E.; Henderson, Paul B.; Moore, Willard S.; Scholten, Jan C.; Pham, M. K. (2012). GEOTRACES radium isotopes interlaboratory comparison experiment. Limnology and Oceanography - Methods, vol 10, pg 451.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
Cruise_ID	GEOTRACES cruise identifier	unitless	cruise_id
GEOTRC_CASTNO	Cast number	unitless	cast
GEOTRC_INSTR	Sampling method	unitless	instrument
Station_ID	Station number	unitless	station
Start_Date_UTC	Date (UTC) at start of sample collection; format: yyyy-mm-dd	unitless	date
Start_Time_UTC	Time (UTC) at start of sample collection; format: HH:MM	unitless	time
Start_ISO_DateTime_UTC	Date and time (UTC) at start of sample collection; format: yyyy-mm-ddTHH:MMZ	unitless	ISO_DateTime_UTC
End_Date_UTC	Date (UTC) at end of sample collection; format: yyyy-mm-dd	unitless	date
End_Time_UTC	Time (UTC) at end of sample collection; format: HH:MM	unitless	time
End_ISO_DateTime_UTC	Date and time (UTC) at end of sample collection; format: yyyy-mm-ddTHH:MMZ	unitless	ISO_DateTime_UTC
Start_Latitude	Latitude at start of sample collection	degrees North	lat
Start_Longitude	Longitude at start of sample collection	degrees East	lon
End_Latitude	Latitude at end of sample collection	degrees North	lat
End_Longitude	Longitude at end of sample collection	degrees East	lon
Event_ID	Event number	unitless	event
Sample_ID	GEOTRACES sample number	unitless	sample
Sample_Depth	Sample depth	meters (m)	depth
Ra_226_D_CONC_PUMP_tmldld	Dissolved radium-226 activity	mBq/kg	radioactive_isotope_conc
SD1_Ra_226_D_CONC_PUMP_tmldld	One standard deviation of Ra_226_D_CONC_PUMP_tmldld	mBq/kg	radioactive_isotope_conc
Flag_Ra_226_D_CONC_PUMP_tmldld	SeaDataNet quality flag for Ra_226_D_CONC_PUMP_tmldld	unitless	q_flag
Ra_228_D_CONC_PUMP_5i7kz7	Dissolved radium-228 activity	mBq/kg	radioactive_isotope_conc
SD1_Ra_228_D_CONC_PUMP_5i7kz7	One standard deviation of Ra_228_D_CONC_PUMP_5i7kz7	mBq/kg	radioactive_isotope_conc
Flag_Ra_228_D_CONC_PUMP_5i7kz7	SeaDataNet quality flag for Ra_228_D_CONC_PUMP_5i7kz7	unitless	q_flag
Ra_224_D_CONC_PUMP_ryelyc	Dissolved radium-224 activity	mBq/kg	radioactive_isotope_conc
SD1_Ra_224_D_CONC_PUMP_ryelyc	One standard deviation of Ra_224_D_CONC_PUMP_ryelyc	mBq/kg	radioactive_isotope_conc
Flag_Ra_224_D_CONC_PUMP_ryelyc	SeaDataNet quality flag for Ra_224_D_CONC_PUMP_ryelyc	unitless	q_flag
Ra_224xs_D_CONC_PUMP	Excess dissolved radium-224 activity	mBq/kg	radioactive_isotope_conc
Ra_224xs_D_CONC_PUMP_ERR	One standard deviation of Ra_224xs_D_CONC_PUMP	mBq/kg	radioactive_isotope_conc
Ra_224xs_D_CONC_PUMP_FLAG	SeaDataNet quality flag for Ra_224xs_D_CONC_PUMP	unitless	q_flag
Ra_223_D_CONC_PUMP_8qp1jk	Dissolved radium-223 activity	mBq/kg	radioactive_isotope_conc
SD1_Ra_223_D_CONC_PUMP_8qp1jk	One standard deviation of Ra_223_D_CONC_PUMP_8qp1jk	mBq/kg	radioactive_isotope_conc
Flag_Ra_223_D_CONC_PUMP_8qp1jk	SeaDataNet quality flag for Ra_223_D_CONC_PUMP_8qp1jk	unitless	q_flag
Ra_223xs_D_CONC_PUMP	Excess dissolved radium-223 actvitiy	mBq/kg	radioactive_isotope_conc
Ra_223xs_D_CONC_PUMP_ERR	One standard deviation of Ra_223xs_D_CONC_PUMP	mBq/kg	radioactive_isotope_conc
Ra_223xs_D_CONC_PUMP_FLAG	SeaDataNet quality flag for Ra_223xs_D_CONC_PUMP	unitless	q_flag
Th_228_D_CONC_PUMP_fejwms	Dissolved thorium-228 activity	mBq/kg	radioactive_isotope_conc
SD1_Th_228_D_CONC_PUMP_fejwms	One standard deviation of Th_228_D_CONC_PUMP_fejwms	mBq/kg	radioactive_isotope_conc
Flag_Th_228_D_CONC_PUMP_fejwms	SeaDataNet quality flag for Th_228_D_CONC_PUMP_fejwms	unitless	q_flag

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Dataset: GN01 Radium and Thorium