Dataset: GP16 Radium

Name: Radium isotopes collected on R/V Thomas G. Thompson cruise TN303 in the Eastern Tropical Pacific in 2013 (U.S. GEOTRACES EPZT project)
Published: 2016-06-29
Keywords: oceans

Cite This Dataset

Spatial Extent: N:-10.50017 E:-77.376 S:-16.00058 W:-152.00059

Project:

U.S. GEOTRACES East Pacific Zonal Transect (GP16) (U.S. GEOTRACES EPZT)

US GEOTRACES Pacific Zonal Transect: Rates of supply, removal and internal cycling of trace elements and isotopes (EPZT TEI Rates)

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:

29 June 2016

Version Date:

2016-06-29

Restricted:

Validated:

Yes

Current State:

Final with updates expected

Radium isotopes collected on R/V Thomas G. Thompson cruise TN303 in the Eastern Tropical Pacific in 2013 (U.S. GEOTRACES EPZT project)

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Description

Radium and Thorium isotopes were collected on manganese oxide impregnated cartridges using an in situ pump filtering 1500-2000L at depth, while ~1000L surface samples were collected by hanging manganese oxide impregnated acrylic fibers over the side of the ship. Samples were collected for Radium Isotopes ex223Ra (227Ac corrected), ex224Ra (228Th corrected), 226Ra, 228Ra, 228Th (particulate), 228Th (dissolved), and 228Th (total). Only 226Ra and 228Ra are reported in this version of the dataset. Future versions will include the other Ra isotopes and 228Th.

Related files and references:
Cartridge preparation:
Henderson, P. B., Morris, P. J., Moore, W. S., and Charette, M. A.: Methodological advances for measuring low-level radium isotopes in seawater, J. Radioanal. Nucl. Chem., 293, 1–6, doi:10.1007/s10967-012-2047-9, 2012.

Particulate and dissolved 228Th determination:
Maiti, K., Charette, M.A., Buesseler, K.O., Zhou, K., Henderson, P., Moore, W.S., Morris, P., Kipp, L., 2015. Determination of particulate and dissolved 228Th in seawater using a delayed coincidence counter. Mar. Chem. doi:10.1016/j.marchem. 2014.12.001.

Methods & Sampling

Radium was collected onto an manganese coated cartridge filtered at depth using an adapted McLane (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 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 an Alpha 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.

Data Processing Description

The data were corrected for decay from the time of sampling. 223Ra was corrected for 227Ac (ex223Ra), 224Ra was corrected for 228Th (ex224Ra). The radium activity of the water samples (cartridges) were corrected from the measured radium on acrylic fiber (<1L/min) using the emanation technique.

Information on data quality and intercalibration can be found in the intercalibration report (PDF).

Quality flag definitions:
1 = 228Radium measured in Modane (France),
2 = Radium efficiency based on Silicate/radium correlation,
3 = Below detection,
4 = vial broken, sample lost,
5 = efficiency can not be determined,
6 = 228Radium measured through 228Thorium (gamma spectroscopy),
7 = 228Radium measured through 228Actinium (gamma spectroscopy),
8 = Pump Failure, no sample collected,
9 = Interpolated value based on neighboring data points,
10 = based on the Barium / Radium relationship
11 = Questionable quality.

BCO-DMO Processing:
- converted date format to YYYYmmdd;
- modified parameter names to conform with BCO-DMO and GEOTRACES naming conventions.

Additional GEOTRACES Processing by BCO-DMO:
As was done for the GEOTRACES-NAT data, BCO-DMO added standard US GEOTRACES information, such as the US GEOTRACES event number, to each submitted dataset lacking this information. To accomplish this, BCO-DMO compiled a 'master' dataset composed of the following parameters:
cruise_id, EXPOCODE,SECT_ID, STNNBR, CASTNO, GEOTRC_EVENTNO, GEOTRC_SAMPNO, GEOTRC_INSTR, SAMPNO, GF_NO, BTLNBR, BTLNBR_FLAG_W, DATE_START_EVENT, TIME_START_EVENT, ISO_DATETIME_UTC_START_EVENT, EVENT_LAT, EVENT_LON, DEPTH_MIN, DEPTH_MAX, BTL_DATE, BTL_TIME, BTL_ISO_DATETIME_UTC, BTL_LAT, BTL_LON, ODF_CTDPRS, SMDEPTH, FMDEPTH, BTMDEPTH, CTDPRS, CTDDEPTH.

This added information will facilitate subsequent analysis and inter-comparison of the datasets.

Bottle parameters in the master file were taken from the GT-C_Bottle and ODF_Bottle datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the TN303 Event Log (version 30 Oct 2014). Where applicable, pump information was taken from the PUMP_Nuts_Sals dataset.

A standardized BCO-DMO method (called "join") was then used to merge the missing parameters to each US GEOTRACES dataset, most often by matching on sample_GEOTRC or on some unique combination of other parameters.

If the master parameters were included in the original data file and the values did not differ from the master file, the original data columns were retained and the names of the parameters were changed from the PI-submitted names to the standardized master names. If there were differences between the PI-supplied parameter values and those in the master file, both columns were retained. If the original data submission included all of the master parameters, no additional columns were added, but parameter names were modified to match the naming conventions of the master file.

See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.

Data Files

File
Radium_joined.csv (Comma Separated Values (.csv), 51.70 KB) MD5:4c406b022d5f658edc9f4a7f30d9df21 Primary data file for dataset ID 650340

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1232669

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
TN303	GP16 GEOTRACES EPZT GEOTRACES East Pacific Zonal Transect (EPZT) GT13 325020131025	2013-10-25	R/V Thomas G. Thompson	James W. Moffett (Chief Scientist) Gregory A. Cutter (Co-Chief Scientist) Christopher R. German (Co-Chief Scientist)	data info

Instruments

McLane Large Volume Pumping System WTS-LV

Supplied Name: McLane (WTS-LV)

Supplied Description:

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.

Radium Delayed Coincidence Counter

Supplied Name: Alpha delayed coincidence counter (RaDeCC)

Supplied Description:

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	Cruise identification	unitless	cruise_id
cruise_name	Alternate cruise identifier	unitless	cruise_name
STNNBR	Station number	unitless	station
GEOTRC_EVENTNO	GEOTRACES event number; added from the EPZT master file.	unitless	event
DATE_PI	Date in YYYYmmdd format; provided by the PI.	unitless	date
LAT_PI	Latitude ; provided by the PI.	decimal degrees	lat
LON_PI	Longitude; provided by the PI.	decimal degrees	lon
ISO_DATETIME_UTC_START_EVENT	Date and time, formatted to the ISO 8601 standard, at the start of the sampling event, according to the event log.	YYYY-MM-DDTHH:MM:SS[.xx]Z	ISO_DateTime_UTC
EVENT_LAT	Latitude at the start of the event; north is positive. Added from the EPZT master file.	decimal degrees	lat
EVENT_LON	Longitude at the start of the event; east is positive. Added from the EPZT master file.	decimal degrees	lon
GEOTRC_SAMPNO	Unique GEOTRACES sample number	unitless	sample
CASTNO	Cast number; added from the EPZT master file.	unitless	cast
SAMPNO	Sequential sample number within the cast (usually corresponds to bottle number); added from the EPZT master file.	unitless	bottle
GEOTRC_INSTR	Sampling instrument	unitless	instrument
DEPTH	Depth; provided by the PI.	meters	depth
Ra_228_D_CONC_PUMP	Concentration of 228-Radium (dissolved).	disintegrations per minute (dpm) per 100 liters (dpm/100L)	radioactive_isotope_conc
Ra_228_D_CONC_PUMP_FLAG	Quality flag for Ra_228_D_CONC_PUMP. See Processing Description for quality flag definitions.	unitless	flag
Ra_228_D_CONC_PUMP_ERR	Error for Ra_228_D_CONC_PUMP.	disintegrations per minute (dpm) per 100 liters (dpm/100L)	std_err
Ra_226_D_CONC_PUMP	Concentration of 226-Radium (dissolved).	disintegrations per minute (dpm) per 100 liters (dpm/100L)	radioactive_isotope_conc
Ra_226_CONC_D_PUMP_FLAG	Quality flag for Ra_226_D_CONC_PUMP. See Processing Description for quality flag definitions.	unitless	flag
Ra_226_CONC_D_PUMP_ERR	Error for Ra_226_D_CONC_PUMP.	disintegrations per minute (dpm) per 100 liters (dpm/100L)	std_err

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Dataset: GP16 Radium