Dataset: Amazon Plume Radium-2018
Deployment: EN614

Radium isotope (223Ra, 224Ra, and 226Ra) measurements from CTD and underway water samples.

View Data: For data, See Dataset Metadata Page: https://www.bco-dmo.org/dataset/753837

Principal Investigator:

Richard N. Peterson (Coastal Carolina University)

Co-Principal Investigator:

Joseph Montoya (Georgia Institute of Technology, GA Tech)

Ajit Subramaniam (Lamont-Doherty Earth Observatory, LDEO)

BCO-DMO Data Manager:

Mathew Biddle (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Collaborative Research: Impact of the Amazon River Plume on Nitrogen Availability and Planktonic Food Web Dynamics in the Western Tropical North Atlantic (Amazon River Plume Nitrogen)

Current State:

Preliminary and in progress

Version:

Deployment Synonyms:

May18atl

Version Date:

2019-01-28

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Description

Water samples for radium isotope analysis were collected from both the ship’s clean underway intake system (‘U’ designator in data sheet) and niskin bottles attached to the CTD rosette (‘C’ designator in data sheet). Salinity data derived from ship’s clean underway intake system with SBE 21 SEACAT Thermosaliograph.

Methods & Sampling

Dataset acquisition description

Water samples were filtered through 47 mm GFF filters (unless otherwise noted), then passed slowly through 25 g (dry) acrylic fibers impregnated with MnO2 (Moore, 1976). Fibers were then washed 10x with Ra-free freshwater to remove salts and dried to a mass between 35 and 57 g for optimal humidity levels (Sun and Torgersen, 1998). Fibers were then immediately counted on a Radium Delayed Coincidence Counter (RaDeCC; Moore and Arnold, 1996) for total Ra-224 and Ra-223. Roughly 3 weeks later, fibers were counted again for supported Ra-224. Thus, excess (‘XS’) Ra-224 is the difference between total and supported Ra-224 measurements. Ra-226 activities were then measured on a radon emanation line as per Peterson et al. (2009).

Minimum detectable activities (dpm/100L) are calculated based on Currie (1968). Any measured values lower than the minimum detectable activity is labeled ‘BD’

Data Processing Description

Dataset Processing Description

BCO-DMO Processing Notes:
- adjusted the date format from mm/dd/yy to yyyy-mm-dd in the columns date and date_time
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1736947	NSF Division of Ocean Sciences

Instruments

Niskin bottle

Supplied Name: niskin bottles

Supplied Description:

niskin bottles attached to the CTD rosette (‘C’ designator in data sheet).

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 - Surface Underway Ship Intake

Supplied Name: ship’s clean underway intake system

Supplied Description:

Water samples for radium isotope analysis were collected from both the ship’s clean underway intake system (‘U’ designator in data sheet)

Instrument Type

Generic Name: Pump - Surface Underway Ship Intake

Acronym: Pump-Ship Intake

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/31/

Generic Description:

The 'Pump-underway ship intake' system indicates that samples are from the ship's clean water intake pump. This is essentially a surface water sample from a source of uncontaminated near-surface (commonly 3 to 7 m) seawater that can be pumped continuously to shipboard laboratories on research vessels. There is typically a temperature sensor near the intake (known as the hull temperature) to provide measurements that are as close as possible to the ambient water temperature. The flow from the supply is typically directed through continuously logged sensors such as a thermosalinograph and a fluorometer. Water samples are often collected from the underway supply that may also be referred to as the non-toxic supply. Ideally the data contributor has specified the depth in the ship's hull at which the pump is mounted.

Radium Delayed Coincidence Counter

Supplied Description:

Radium isotopes (224Ra and 223Ra) were analyzed with a Radium Delayed Coincidence Counter (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.

Sea-Bird SeaCAT Thermosalinograph SBE 21

Supplied Name: SBE 21 SEACAT Thermosaliograph

Supplied Description:

Salinity data derived from ship’s clean underway intake system with SBE 21 SEACAT Thermosaliograph.

Instrument Type

Generic Name: Sea-Bird SeaCAT Thermosalinograph SBE 21

Acronym: SeaBird SBE-21 Seacat

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0667/

Generic Description:

A platinum-electrode conductivity sensor and a thermistor mounted in a corrosion-resistant plastic and titanium housing designed to be continuously plumbed into a vessel's pumped seawater supply. The instrument may be interfaced to a remote SBE 38 temperature sensor mounted either on the hull or in the seawater inlet. Data are both stored in internal memory and output to a serial port for external logging. Conductivity is measured in the range 0-7 S/m with an accuracy of 0.001 S/m and a resolution of 0.0001 S/m. Housing temperature is measured in the range -5-35C with an accuracy of 0.01 C and a resolution of 0.001 C. Remote temperature is measured in the range -5-35C with an accuracy of 0.001 C and a resolution of 0.0003 C. More information at http://www.seabird.com/products/spec_sheets/21data.htm.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
U_or_C	Underway (surface) or CTD sample designator	unitless	sample_descrip
Station	Station #	unitless	station
Cast	Cast # at each station	unitless	cast
Date	Local date (EST) sample collected	unitless	date
Time	Local time (EST) sample collected	unitless	time
Date_Time	Date and time (GMT) sample collected	yyyy-MM-dd HH:mm	ISO_DateTime_UTC
Latitude	Sampling latitude	decimal degrees	lat
Longitude	Sampling longitude	decimal degrees	lon
Depth	Water depth of sample collection	meters (m)	depth
Salinity	Salinity of ship’s seawater intake system	unitless	sal
Sample_Volume	Water sample volume	liters (L)	volume
Ra223_Activity	Radium-223 activity	dpm/100L	radioactive_isotope_conc
Ra223_Unc	1-σ analytical uncertainty for Ra223	dpm/100L	radioactive_isotope_conc
XS_Ra224_Activity	Excess radium-224 activity	dpm/100L	radioactive_isotope_conc
XS_Ra224_Unc	1-σ analytical uncertainty for Ra224	dpm/100L	radioactive_isotope_conc
Ra226_Activity	Radium-226 activity	dpm/100L	radioactive_isotope_conc
Ra226_Unc	1-σ analytical uncertainty for Ra226	dpm/100L	radioactive_isotope_conc
Comments	Pertinent notes regarding sample collection	unitless	comment

Database

Contribute Data

Dataset: Amazon Plume Radium-2018
Deployment: EN614

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: Amazon Plume Radium-2018Deployment: EN614

Dataset acquisition description

Dataset Processing Description

Dataset: Amazon Plume Radium-2018
Deployment: EN614