Dataset: Palmer Station Particulate Thorium

Name: Particulate organic carbon, nitrogen, and Thorium-234 collected during the 2012-2013 Palmer Field Season (WAP Carbon export project)
Published: 2022-08-02
Keywords: oceans

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Spatial Extent: N:-64.7795 E:-64.0405 S:-64.815 W:-64.0725

Western Antarctic Peninsula near Anvers Island

Temporal Extent: 2012-11-10 - 2013-03-21

Project:

Quantifying Processes Driving Interannual Variability in the Biological Carbon Pump in the Western Antarctic Peninsula (WAP Carbon export)

Principal Investigator:

Michael Stukel (Florida State University, FSU - EOAS)

Contact:

Michael Stukel (Florida State University, FSU - EOAS)

BCO-DMO Data Manager:

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

Version:

Version Date:

2022-08-02

Restricted:

Validated:

Current State:

Preliminary and in progress

Particulate organic carbon, nitrogen, and Thorium-234 collected during the 2012-2013 Palmer Field Season (WAP Carbon export project)

Abstract:

Particle-bound Th-234 measurements and C:234Th ratios for particles (seston) collected during the 2012-2013 field season of the Palmer LTER program near Anvers Island in the Western Antarctic Peninsula. Particle-bound Th-234 is a useful tracer for particle scavenging and sinking processes in the ocean. Vertical profiles of particle-bound Th-234 and C:234Th ratios were measured approximately weekly. Measurements typically spanned from the surface to a depth of 65 m.

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Description

The detection limit set for POC measurements in the data file is: 30, and the detection limit for PN measurements is 2.

Methods & Sampling

Particulate organic carbon, nitrogen, and ²³⁴Th adsorbed onto particles were measured at 6 depths spanning the euphotic zone (surface to 65 m depth). 4-L samples were vacuum filtered through pre-combusted quartz microfiber (QMA) filters. Filtrate after filtration was collected and filtered through another filter to serve as an adsorption blank. Filters were dried and mounted in RISO planchets. Samples were then counted in a RISO low-level beta multi-counter to determine activity of ²³⁴Th. Background counts were conducted >6 half-lives after collection. Samples were then acidified to remove CaCO₃ and analyzed in an elemental analyzer to determine particulate organic carbon and particulate nitrogen on filters. For additional details, see Stukel et al. (2015) and Stukel et al. (2022).

BCO-DMO Processing

- Spaces removed from column names and replaced with underscores ("_")
- Row containing units removed from the data file
- Converted date times in the data file from %m-%d-%y %H:%M format to %Y-%M-%DT%H:%M format
- Added a column Collection_Datetime_UTC representing datetime values in UTC
- 'below detection' values removed from the POC and PN columns of the data file and two new fields were created called POC_flag and PN_flag; these new columns indicate if a blank POC or PN values indicate if measurements were 'below detection' limits

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Office of Polar Programs (formerly NSF PLR)	OPP-1951090
NSF Division of Ocean Sciences	OCE-1756610
NSF Office of Polar Programs (formerly NSF PLR)	OPP-1340886
NSF Office of Polar Programs (formerly NSF PLR)	OPP-1440435

Deployments

None available yet

Instruments

Elemental Analyzer

Supplied Description:

After subsequent background counts using the RISO low-level beta multi-counter, samples were acidified to remove calcium carbonate and analyzed for carbon and nitrogen on an elemental analyzer.

Instrument Type

Generic Name: Elemental Analyzer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB01/

Generic Description:

Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material.

GM multicounter

Supplied Name: Riso low-level GM beta multi-counter

Supplied Description:

Samples from six euphotic zone depths (surface to 65 meters) were counted in a RISO low-level beta multi-counter to determine the activity of 234Th.

Instrument Type

Generic Name: GM multicounter

Generic Description:

A gas flow multicounter (GM multicounter) is used for counting low-level beta doses. GM multicounters can be used for gas proportional counting of 32Si to 32P. For more information about GM multicounter usage see Krause et. al. 2011.

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Station	Palmer LTER Station Name from which sample was collected.	unitless	station
Latitude	Station Latitude in decimal degrees; a positive value indicates a Northern coordinate.	decimal degrees	lat
Longitude	Station Longitude in decimal degrees; a positive value indicates an Eastern coordinate.	decimal degrees	lon
Collection_Datetime_Local	Date and time of collection in local time at Palmer Station (UTC-3). Format: %Y-%m-%d %H:%M	unitless	DateTime
Collection_Datetime_UTC	Date and time of collection in UTC time. Format: %Y-%m-%dT%H:%MZ	unitless	DateTime
Depth	Depth.	meters (m)	depth
Particulate_Th234	Thorium isotope 234Th adsorbed into particles.	decays per minute per liter (dpm/L^-1)	Th234
Uncertainty	Uncertainty in Thorium 234TH adsorbed into particles.	decays per minute per liter (dpm/L^-1)	Th234
POC	Particulate organic carbon.	milligrams of carbon per cubic meter (mg C / m^-3)	POC
POC_flag	Flag column indicating rows where blank POC values indicate that a measurement was "below detection."	unitless	q_flag
PN	Particulate nitrogen.	milligrams of carbon per cubic meter (mg C / m^-3)	TPN
PN_flag	Flag column indicating rows where blank PN values indicate that a measurement was "below detection."	unitless	q_flag

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Dataset: Palmer Station Particulate Thorium