Dataset: Radium Data for South Atlantic Bight Bottom Waters

Name: Radium isotope measurements from bottom waters in the South Atlantic Bight from 2015-2020 (SAB BMA project)
Published: 2022-10-24
Keywords: dissolved oxygen, Radium isotopes, Submarine groundwater discharge, thermal monitoring, continental shelf aquifers, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.882140.1

Spatial Extent: N:32 E:-79 S:32 W:-79

Temporal Extent: 2015-06-02 - 2020-05-11

Project:

Groundwater sources of "new" N for benthic microalgal production in the South Atlantic bight (SAB BMA)

Principal Investigator:

James L. Pinckney (University of South Carolina at Columbia)

Scientist:

Willard S. Moore (University of South Carolina at Columbia)

Contact:

Willard S. Moore (University of South Carolina at Columbia)

BCO-DMO Data Manager:

Sawyer Newman (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2022-10-24

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Radium isotope measurements from bottom waters in the South Atlantic Bight from 2015-2020 (SAB BMA project)

Abstract:

These are measurements of radium isotopes collected from bottom waters in the South Atlantic Bight during 2015-2020. These data were used to verify an episode of submarine groundwater discharge that occurred in August 2019.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2022-10-24	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.882140.1	2022-11-02

Methods & Sampling

Methods & Sampling

Bottom water samples were obtained by lowering a submersible pump to near the seafloor and filling two 26-liter carboys. Subsamples for salinity were usually taken from each sample and measured with a YSI conductivity meter to confirm the CTD measurement. Radium samples were filtered through a column of Mn-fiber to quantitatively remove Ra [Moore, 1976]. The Mn-fiber was returned to the lab, where short-lived radium isotopes (223Ra, half-life = 11.4 days, and 224Ra, half-life = 3.66 days) were measured using a delayed-coincidence counting system [Moore and Arnold, 1996]. After the short-lived measurements were complete, Ra and Mn were stripped from the Mn-fiber and radium was coprecipitated with BaSO4 and transferred to a small tube. 226Ra and 228Ra were measured by gamma spectrometry after 222Rn had equilibrated with 226Ra [Moore et al., 1985]. The RaDeCC systems were calibrated for 224Ra with a NIST standard solution of 232Th adsorbed to Mn-fiber and for 223Ra by the technique of Moore and Cai [2013]. The gamma detector was calibrated with NIST standard solutions for 226Ra and 228Ra in a BaSO4 matrix [Moore, 1984].

Samples were taken from R/V Trinity, owned by a private charter company called Charleston SCUBA. This company is no longer in operation.

Data Processing Description

Processing notes from researcher:

The 224Ra and 223Ra counting data were analyzed using the procedure detailed in Moore and Arnold [1996] to correct for chance coincidence events. The gamma spectra for 228Ra and 226Ra were analyzed using the program HYPERMET, which employs multiple iterations to fit each peak in the spectra to an energy range [Phillips and Marlow, 1996]. The energy ranges are assigned to specific radionuclides based on the measurements of NIST standards.

BCO-DMO processing notes:

Added a date field (a concatenation of the year, day and month fields)
Replaced spaces in column names with underscores "_"
Removed units and special characters from column names
Renamed column names that started with numerical characters (e.g., 226Ra is now Measured_226_Ra)

Data Files

File
ra_data_report-1.csv (Comma Separated Values (.csv), 2.56 KB) MD5:613fb39569b43301e0fd8da18edcef36 Primary data file for dataset ID 882140

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1736557

Deployments

None available yet

Instruments

Gamma Ray Spectrometer

Supplied Name: Gamma Spectrometer, ORTEC

Supplied Description:

After the short-lived measurements were complete, Ra and Mn were stripped from the Mn-fiber and radium was coprecipitated with BaSO4 and transferred to a small tube. 226Ra and 228Ra were measured by gamma spectrometry after 222Rn had equilibrated with 226Ra [Moore et al., 1985].

Instrument Type

Generic Name: Gamma Ray Spectrometer

Generic Description:

Instruments measuring the relative levels of electromagnetic radiation of different wavelengths in the gamma-ray waveband.

Pump

Supplied Name: Submersible pump, Granger

Supplied Description:

Bottom water samples were obtained by lowering a submersible pump to near the seafloor and filling two 26-liter carboys.

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 Name: RaDeCC System

Supplied Description:

The Mn-fiber was returned to the lab, where short-lived radium isotopes (223Ra, half-life = 11.4 days, and 224Ra, half-life = 3.66 days) were measured using a delayed-coincidence counting system [Moore and Arnold, 1996].

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
Sample_Number	Expedition-based sample identifier	unitless	sample
Station	Reference sites	unitless	station
Latitude	Latitude; a positive value indicates a Northern coordinate	decimal degrees	lat
Longitude	Longitude; a negative values indicates a Western coordinate	decimal degrees	lon
Year	Year sample collected	unitless	year
Month	Month sample collected	unitless	month
Day	Day sample collected	unitless	day
Date	Date sample collected Format: %Y-%m-%d	unitless	date
Total_Depth	Depth of water column	meters	depth
Sample_Depth	Depth of sampling	meters	depth
Measured_226Ra	Measured Radium-226 activity in the bottom water	decays per minute per liter	Ra226
Measured_228Ra	Measured Radium-228 activity in the bottom water	decays per minute per liter	Ra228
Measured_224Ra	Measured Radium-224 activity in the bottom water	decays per minute per liter	Ra224
Measured_223Ra	Measured Radium-223 activity in the bottom water	decays per minute per liter	Ra223

Database

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Dataset: Radium Data for South Atlantic Bight Bottom Waters