Dataset: Barium-isotopic profile SAFe
Deployment: KN195-08

Barium concentration and isotopic data from SAFe, collected during the 2nd GEOTRACES Intercalibration cruise.

Principal Investigator:

Tristan J. Horner (Woods Hole Oceanographic Institution, WHOI)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

U.S. GEOTRACES Pacific Meridional Transect: Tracing Basin-scale Nutrient Cycling and Carbon Export with Dissolved and Particulate Barium-isotopic Distributions (GEOTRACES PMT Barium)

Current State:

Final no updates expected

Deployment Synonyms:

GEOTRACES IC2, KN195-8, InterCal 2

Data URL:

https://www.bco-dmo.org/dataset-deployment/770371/data

Expand/Collapse All

Description

Methods & Sampling

Dataset acquisition description

Samples were collected on the GEOTRACES carousel, filtered to 0.2 μm or 0.45 μm (depending on filter type), acidified to pH ≈ 2 with hydrochloric acid, and stored for several years prior to processing. Aliquots containing five milliliters of seawater were cleanly subsampled from each sample, weighed, and an appropriate quantity of ¹³⁶Ba–¹³⁵Ba double spike added. Following spike–sample equilibration, barium was co-precipitated with calcium carbonate via dropwise addition of sodium carbonate. The resultant precipitate was dissolved in hydrochloric acid and twice passed through cation-exchange columns to purify Ba from matrix elements.

Samples were aspirated, desolvated, and analyzed using a 100 μL/min nebulizer, Aridus II desolvation system, and ThermoFisher Neptune multi-collector ICP-MS, respectively. All instrumentation was sitated at the WHOI Plasma Facility. Barium-isotopic compositions were calculated from simultaneous monitoring of ion beams corresponding to m/z 131 (Xe, xenon), 135 (Ba), 136 (Xe; Ba; Ce, cerium), 137 (Ba), 138 (Ba; La, lanthanum; Ce), 139 (La) and 140 (Ce).

Problem report:
Sample 4722 (surface) unclear if sample was filtered, and—if so—what filter cutoff was used.

Data Processing Description

Dataset Processing Description

Data reduction was performed in MATLAB using the baseline-corrected ion beam output from the instrument software. Barium-isotopic compositions were calculated using an iterative, three-dimensional geometric interpretation of the double spike problem, with additional nested loops for interference corrections. All sample compositions are reported as parts per one thousand deviations (i.e., ‰; per mille) relative to NIST SRM 3104a.

Quality Control: Refer to the Certified Reference Materials (CRMs) supplemental file (PDF).

"_FLAG" columns follow the ODV flag scheme, defined as:
1 = Good Value: Used when replicate samples were analyzed for a particular concentration/isotopic composition.
2 = Probably Good Value: Used when the reported value reflects analysis of a single replicate.
3 = Probably Bad Value: Used when a value appears abnormally high or low (oceanographically inconsistent) based on adjacent depths or typical profile variability and shape using the context of relevant nearby stations.
6 = Value Below Detection Limit: Used when value is below the detection limit for that given element. Empty values are reported rather than zero or a detection limit value.

BCO-DMO Processing:
- modified parameter names (replaced spaces w/ underscores; removed units);
- replaced blanks (no data) with "nd";
- 06 August 2019: replaced version 1 with version 2 of dataset (corrections made in Ba_138_134_D_DELTA_BOTTLE column).

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1736949	NSF Division of Ocean Sciences

Instruments

GeoFish Towed near-Surface Sampler

Supplied Name:

Supplied Description:

Instrument Type

Generic Name: GeoFish Towed near-Surface Sampler

Acronym: GeoFish

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

Generic Description:

The GeoFish towed sampler is a custom designed near surface (<2m) sampling system for the collection of trace metal clean seawater. It consists of a PVC encapsulated lead weighted torpedo and separate PVC depressor vane supporting the intake utilizing all PFA Teflon tubing connected to a deck mounted, air-driven, PFA Teflon dual-diaphragm pump which provides trace-metal clean seawater at up to 3.7L/min. The GeoFish is towed at up to 13kts off to the side of the vessel outside of the ship's wake to avoid possible contamination from the ship's hull. It was developed by Geoffrey Smith and Ken Bruland (University of California, Santa Cruz).

GO-FLO Bottle

Supplied Name: GEOTRACES carousel

Supplied Description:

Instrument Type

Generic Name: GO-FLO Bottle

Acronym: GO-FLO

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/30/

Generic Description:

GO-FLO bottle cast used to collect water samples for pigment, nutrient, plankton, etc. The GO-FLO sampling bottle is specially designed to avoid sample contamination at the surface, internal spring contamination, loss of sample on deck (internal seals), and exchange of water from different depths.

Inductively Coupled Plasma Mass Spectrometer

Supplied Name: ThermoFisher Neptune multi-collector ICP-MS

Supplied Description:

Instrument Type

Generic Name: Inductively Coupled Plasma Mass Spectrometer

Acronym: ICP Mass Spec

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB15/

Generic Description:

An ICP Mass Spec is an instrument that passes nebulized samples into an inductively-coupled gas plasma (8-10000 K) where they are atomized and ionized. Ions of specific mass-to-charge ratios are quantified in a quadrupole mass spectrometer.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
GEOTRC_EVENTNO	The event # from the cruise report	unitless	event
lat	Latitude (positive values = North)	decimal degrees	lat
long	Longitude (negative values = West)	decimal degrees	lon
Filter_type	Type (and cutoff) of filter used	unitless	filter_size
GEOTRC_SAMPNO	Unique GEOTRACES sample ID	unitless	sample
Depth	Sample depth	meters (m)	depth
Ba_D_CONC_BOTTLE	Dissolved Ba (barium) concentration	nanomoles per kilogram (nmol/kg)	Ba
Ba_D_CONC_BOTTLE_stdev	One-sigma uncertainty about the barium concentration	nmol/kg	Ba
Ba_D_CONC_BOTTLE_FLAG	ODV quality flag for Ba_D_CONC_BOTTLE	unitless	q_flag
Ba_138_134_D_DELTA_BOTTLE	Dissolved Ba-isotopic composition	per mil deviation rel. to NIST SRM 3104a	Ba
Ba_138_134_D_DELTA_BOTTLE_stdev	One-sigma uncertainty about the dissolved Ba-isotopic composition	per mil	Ba
Ba_138_134_D_DELTA_BOTTLE_FLAG	ODV quality flag for Ba_138_134_D_DELTA_BOTTLE	unitless	q_flag
Notes	Any issues or concerns	unitless	comment

Database

Contribute Data

Dataset: Barium-isotopic profile SAFe
Deployment: KN195-08

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: Barium-isotopic profile SAFeDeployment: KN195-08

Dataset acquisition description

Dataset Processing Description

Dataset: Barium-isotopic profile SAFe
Deployment: KN195-08