Dataset: GT10-11 - Ra Th

Name: Radium and Thorium isotopes sampled by in situ pump on R/V Knorr cruises KN199-04 and KN204-01 in the Subtropical northern Atlantic Ocean from 2010-2011 (U.S. GEOTRACES NAT project)
Published: 2015-01-20
Keywords: oceans

Cite This Dataset

Spatial Extent: N:39.69 E:-9.67 S:17.35 W:-69.81

Project:

U.S. GEOTRACES North Atlantic Transect (GA03) (U.S. GEOTRACES NAT)

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)

Scientist:

Paul J Morris (Woods Hole Oceanographic Institution, WHOI)

Contact:

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

Technician:

Paul B. Henderson (Woods Hole Oceanographic Institution, WHOI)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI)

Version:

20 Jan 2015

Version Date:

2015-01-20

Validated:

Yes

Current State:

Final no updates expected

Radium and Thorium isotopes sampled by in situ pump on R/V Knorr cruises KN199-04 and KN204-01 in the Subtropical northern Atlantic Ocean from 2010-2011 (U.S. GEOTRACES NAT project)

Expand/Collapse All

Description

This dataset contains samples collected on the 2010 and 2011 GEOTRACES cruise on the R/V Knorr (cruises KN199-04 and KN204-01). Radium and Thorium isotopes were collected on manganese oxide impregnated acrylic cartridges using an insitu pump filtering 1500-2000L at depth.

Methods & Sampling

Radium was collected onto a manganese-coated acrylic cartridge filtered at depth using an adapted McLane (WTS-LV). The pumps were programmed to filter 1500-2000L of seawater per deployment. Water was also collected at the same depth using a 30L niskin which was filtered (at <1L/min) through a manganese-coated acrylic fiber 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 an Alpha delayed coincidence counter (RaDeCC) for 223Ra, 224Ra, 228Th, and 227Ac. The cartridges were ashed at 820 degrees C and measured on gamma detectors for long lived radium (226Ra, 228Ra) and thorium isotopes. Cartridge blanks (dip and water rinses) were also measured for potential contamination.

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

Insitu pump modifications reference:
Lam, P.J. and P.J. Morris. In situ marine sample collection system and methods. Patent Pending. U.S. Non
Provisional Patent Application No. 13/864,655, submitted April 17, 2013.

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.

Quality flag definitions:
1 = 228Radium undetectable for 224Radium correction.
2 = No fiber collected, radium efficiency based on silicate correlation.
3 = Below detection.
4 = Vial broken; sample lost.
5 = Efficiency cannot 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.

BCO-DMO made the following modifications:
- Replaced blank cells and #DIV/0! errors with 'nd' to indicate 'no data'.
- Separated original date field into year, month, and day columns.
- Added 'cruise_part' column to distinguish between the 2 legs of KN204-01 cruise.

Additional GEOTRACES Processing:
After the data were submitted to the International Data Management Office, BODC, the office noticed that important identifying information was missing in many datasets. With the agreement of BODC and the US GEOTRACES lead PIs, 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: station_GEOTRC, cast_GEOTRC (bottle and pump data only), event_GEOTRC, sample_GEOTRC, sample_bottle_GEOTRC (bottle data only), bottle_GEOTRC (bottle data only), depth_GEOTRC_CTD (bottle data only), depth_GEOTRC_CTD_rounded (bottle data only), BTL_ISO_DateTime_UTC (bottle data only), and GeoFish_id (GeoFish data only). 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_GT10, GT-C_Bottle_GT11, ODF_Bottle_GT10, and ODF_Bottle_GT11 datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the Event_Log_GT10 and Event_Log_GT11 datasets. McLane pump cast numbers missing in event logs were taken from the Particulate Th-234 dataset submitted by Ken Buesseler.

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
Ra_Th_GT10_joined.csv (Comma Separated Values (.csv), 49.18 KB) MD5:0c44100eb691d678cc18e42d35b26cc9 Primary data file for dataset ID 3846

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-0925158

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
KN199-04	GA03 GT10 USGT-NAT-2010 KN199-4 GNAT U.S. GEOTRACES NAZT Leg 1 knorr199-4/5 Section Cruise (GA03) 316N20101015	2010-10-15	R/V Knorr	William J. Jenkins (Chief Scientist) Edward A. Boyle (Co-Chief Scientist) Gregory A. Cutter (Co-Chief Scientist)	data info
KN204-01	GA03 GT11 KN204-01A KN204-01B USGT-NAT-2011 USGNAZT GNAT 316N20111106 KN204-1	2011-11-06	R/V Knorr	Edward A. Boyle (Chief Scientist) Gregory A. Cutter (Co-Chief Scientist)	data info

Instruments

McLane Large Volume Pumping System WTS-LV

Supplied Name: Large Volume Pumping System -WTS-LV

Supplied Description:

Radium was collected onto a manganese-coated acrylic cartridge filtered at depth using an adapted McLane (WTS-LV) pump programmed to filter 1500-2000L of seawater per deployment.

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 Description:

Samples were analyzed three times using an Alpha delayed coincidence counter (RaDeCC) for 223Ra, 224Ra, 228Th, and 227Ac.

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	Official cruise identifier e.g. KN199-04 = R/V Knorr cruise number 199-04.	text	cruise_id
lat	Latitude. South is negative.	decimal degrees	lat
lon	Longitude. West is negative.	decimal degrees	lon
event_GEOTRC	Unique identifying number for US GEOTRACES sampling events; ranges from 2001 to 2225 for KN199-04 events and from 3001 to 3282 for KN204-01 events. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	integer	event
sample_GEOTRC	Unique identifying number for US GEOTRACES samples; ranges from 5033 to 6078 for KN199-04 and from 6112 to 8148 for KN204-01. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Originally submitted as 'GT No.', this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions.	integer	sample
station_GEOTRC	GEOTRACES station number; ranges from 1 through 12 for KN199-04 and 1 through 24 for KN204-01. Stations 7 and 9 were skipped on KN204-01. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	integer	station
cast_GEOTRC	Cast identifier, numbered consecutively within a station. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	integer	cast
instr	Type of sampling instrument used.	text	instrument
depth_w	Bottom depth.	meters	depth_w
depth	Sample depth; provided by PI in original data submission.	meters	depth
Ra223	Radium-223 disintegrations per minute per 100 liters.	dpm/100L	radioactive_isotope_conc
Ra223_flag	Quality flag for Ra223. See 'Processing Description' for code definitions.	unitless	q_flag
Ra224	Radium-224 disintegrations per minute per 100 liters.	dpm/100L	radioactive_isotope_conc
Ra224_flag	Quality flag for Ra224. See 'Processing Description' for code definitions.	unitless	q_flag
Ra228	Radium-228 disintegrations per minute per 100 liters.	dpm/100L	radioactive_isotope_conc
Ra228_flag	Quality flag for Ra228. See 'Processing Description' for code definitions.	unitless	q_flag
Ra226	Radium-226 disintegrations per minute per 100 liters.	dpm/100L	radioactive_isotope_conc
Ra226_flag	Quality flag for Ra226. See 'Processing Description' for code definitions.	unitless	q_flag
Th228_tot	Total Thorium-228 disintegrations per minute per 100 liters.	dpm/100L	radioactive_isotope_conc
Th228_tot_flag	Quality flag for Th228_tot. See 'Processing Description' for code definitions.	unitless	q_flag
Th228_part	Particulate Thorium-228 disintegrations per minute per 100 liters.	dpm/100L	radioactive_isotope_conc
Th228_part_flag	Quality flag for Th228_part. See 'Processing Description' for code definitions.	unitless	q_flag
Th228_diss	Dissolved Thorium-228 disintegrations per minute per 100 liters.	dpm/100L	radioactive_isotope_conc
Th228_diss_flag	Quality flag for Th228_diss. See 'Processing Description' for code definitions.	unitless	q_flag
exRa224	Radium-224 corrected for 228Th.	dpm/100L	radioactive_isotope_conc
exRa224_flag	Quality flag for exRa224. See 'Processing Description' for code definitions.	unitless	q_flag
exRa223	Radium-223 corrected for 227Ac .	dpm/100L	radioactive_isotope_conc
exRa223_flag	Quality flag for exRa223. See 'Processing Description' for code definitions.	unitless	q_flag
year	4-digit year (UTC).	YYYY	year
month	2-digit month of year (UTC).	mm (01 to 12)	month_utc
day	2-digit day of month (UTC).	dd (01 to 31)	day_utc
depth_GEOTRC_CTD	Observation/sample depth in meters, calculated from CTD pressure. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	meters	depth
sample_bottle_GEOTRC	Unique identification numbers given to samples taken from bottles; ranges from 1 to 24; often used synonymously with bottle number. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	unitless	bot_Nis
bottle_GEOTRC	Alphanumeric characters identifying bottle type (e.g., NIS representing Niskin and GF representing GOFLO) and position on a CTD rosette. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	unitless	bottle
BTL_ISO_DateTime_UTC	Date and time (UTC) variable recorded at the bottle sampling time in ISO compliant format. Values were added from the intermediate US GEOTRACES master file (see Processing Description). This standard is based on ISO 8601:2004(E) and takes on the following form: 2009-08-30T14:05:00[.xx]Z (UTC time)	YYYY-mm-ddTHH:MM:SS.ssZ	ISO_DateTime_UTC
cruise_part	Part of cruise. For KN204-01: A = 11/6/2011 to 11/18/2011 (Woods Hole to Bermuda); B = 11/19/2011 to 12/11/2011 (Bermuda to Praia, Cabo Verde).	A or B	cruise_part

Status message

Database

Contribute Data

Dataset: GT10-11 - Ra Th