Dataset: OSNAP Noble Gases 2016

Name: Noble gas concentrations from water samples collected in August and September 2016 during R/V Neil Armstrong cruise AR7-02 as part of the Overturning in the Subpolar North Atlantic Project (O-SNAP)
Published: 2023-10-24
Keywords: noble gas, Greenland, meltwater, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.913904.1

Spatial Extent: N:61.2882 E:-41.4207 S:59.39 W:-48.5147

Temporal Extent: 2016-08-08 - 2016-09-01

Project:

Tracking Greenland Melt in the Ocean Using Noble Gas Fingerprints (Greenland Melt Noble Gases)

Principal Investigator:

Nicholas Beaird (Woods Hole Oceanographic Institution, WHOI)

Co-Principal Investigator:

William J. Jenkins (Woods Hole Oceanographic Institution, WHOI)

Fiamma Straneo (Woods Hole Oceanographic Institution, WHOI)

BCO-DMO Data Manager:

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

Version:

Version Date:

2023-10-24

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Noble gas concentrations from water samples collected in August and September 2016 during R/V Neil Armstrong cruise AR7-02 as part of the Overturning in the Subpolar North Atlantic Project (O-SNAP)

Abstract:

This noble gas dataset was collected around Southern Greenland in August and September of 2016 aboard the R/V Neil Armstrong as part of the Overturning in the Subpolar North Atlantic Project (O-SNAP). Parameters include the concentrations of Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), along with the co-located temperature, salinity, and pressure data from the CTD at the sample collection point. During the cruise, 391 noble gas water samples were collected, of which funding was available for 86 to be analyzed at Woods Hole Oceanographic Institution's Isotope Geochemistry Facility. Those processed samples are archived in this dataset. The 86 analyzed noble gas samples are concentrated along five sections across the shelfbreak on the east and west sides of Cape Farewell in southern Greenland. Noble gas samples were acquired from 10-liter Niskin bottles using gravity feed-through TYGON tubing to fill lengths of 5/8" copper refrigeration tubing (trapping ~45 grams water in replicate pairs), then each was hydraulically crimp sealed.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2023-10-24	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.913904.1	2023-10-25

Methods & Sampling

At each station, conductivity-temperature-depth (CTD) casts were made with a SeaBird 911Plus equipped with additional sensors measuring oxygen, beam transmission, fluorescence, and turbidity. Sensors were calibrated by the manufacturer before and after the cruise. The conductivity sensors were further calibrated using water sample salinity measurements. A rosette with twelve 10-liter Niskin bottles was deployed with the CTD to collect water samples. Noble gas samples were acquired from the Niskin bottles using gravity feed-through TYGON tubing to fill lengths of 5/8" copper refrigeration tubing (trapping ~45 grams water in replicate pairs), then each was crimp sealed using a hydraulic press.

The extracted gases are purified, separated, and measured mass spectrometrically using a third-generation, WHOI-constructed, statically operated, helium isotope mass spectrometer of branch tube design for fully simultaneous collection of 3He and 4He with improved ion optics. It employs a high-emission Nier-type ion source. The 4He branch has a Faraday Cup detector with a low-noise FET-input electrometer and precision high-frequency VFC for digital signal integration. The 3He branch uses a Galileo Channeltron operating in pulse counting mode, with high-speed preamplifier and discriminator electronics. The fully automated sample processing line is optimized for processing extracted water samples, and combines a three-stage cryogenics system (Stanley 2009) with a Pd-catalyst and dual SAES-707 getters for the removal of water vapor, the purification of reactive gases, and the quantitatively reproducible separation of the 5 noble gases (He, Ne, Ar, Kr, and Xe). Helium isotopes (3He, 4He) are measured using the magnetic sector dual-collecting mass spectrometer to a reproducibility of 0.1%, and the other noble gases using a quadrupole mass spectrometer (QMS) with a triple mass filter and an electron multiplier operated in pulse counting mode. The lighter noble gases (He, Ne, and Ar) are determined using peak-height manometry while the heavier noble gases (Kr and Xe) are measured using a newly developed, modified ratiometric multi-isotope dilution method. The system achieves reproducibility of gas standards of 0.1% for He, Ne, Ar, Kr, and Xe.

BCO-DMO Processing

- Imported original file "osnap2016_noble_gases.csv" into the BCO-DMO system.
- Converted the date/time field to ISO8601 format.
- Renamed fields to comply with BCO-DMO naming conventions.
- Converted the "bottle" column to integer format.
- Rounded He3_sat_anomaly column to 3 decimal places.
- Saved the final file as "913904_v1_osnap_noble_gases_2016.csv".

Data Files

File
913904_v1_osnap_noble_gases_2016.csv (Comma Separated Values (.csv), 14.33 KB) MD5:f93056c67e8cc83f0942ffa014016e20 Primary data file for dataset ID 913904, version 1.

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1536856

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
AR7-02	OSNAP 14	2016-08-03	R/V Neil Armstrong	Robert S. Pickart (Chief Scientist)	data info

Instruments

CTD Sea-Bird SBE 911plus

Supplied Name: SeaBird 911Plus

Supplied Description:

Instrument Type

Generic Name: CTD Sea-Bird SBE 911plus

Acronym: CTD SBE 911plus

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0058/

Generic Description:

The Sea-Bird SBE 911 plus is a type of CTD instrument package for continuous measurement of conductivity, temperature and pressure. The SBE 911 plus includes the SBE 9plus Underwater Unit and the SBE 11plus Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9 plus and SBE 11 plus is called a SBE 911 plus. The SBE 9 plus uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3 plus and SBE 4). The SBE 9 plus CTD can be configured with up to eight auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.). more information from Sea-Bird Electronics

Faraday cup

Supplied Name: Faraday Cup detector

Supplied Description:

Instrument Type

Generic Name: Faraday cup

Acronym: FC

Generic Description:

A Faraday cup is a metal (conductive) cup designed to catch charged particles in a vacuum. The resulting current can be measured and used to determine the number of ions or electrons hitting the cup.

Mass Spectrometer

Supplied Name: helium isotope mass spectrometer

Supplied Description:

Description obtained from the Woods Hole Oceanographic Institution (WHOI) Isotope Geochemistry Facility website (https://www2.whoi.edu/site/igffacility/):

Our helium isotope and tritium measurement mass spectrometer system (MS1) was first designed and built in 1975, and has evolved, grown, and been modernized over the years. It is fully automated and runs 24/7. Cryogenic traps are used to transfer and purify Helium (He) and Neon (Ne). The magnetic sector mass spectrometer analyzes the helium isotopes, while the QMS previews samples and measures He and Ne. The automanifold allows the "mounting" of up to 32 samples for measurement and unattended operation.

Instrument Type

Generic Name: Mass Spectrometer

Acronym: Mass Spec

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/

Generic Description:

General term for instruments used to measure the mass-to-charge ratio of ions; generally used to find the composition of a sample by generating a mass spectrum representing the masses of sample components.

Niskin bottle

Supplied Name: Niskin bottles

Supplied Description:

A rosette with twelve 10-liter Niskin bottles was deployed with the CTD to collect water samples.

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.

Quadrupole Mass Spectrometer

Supplied Name: quadrupole mass spectrometer (QMS)

Supplied Description:

Instrument Type

Generic Name: Quadrupole Mass Spectrometer

Acronym: QMS

Generic Description:

A piece of apparatus that consists of an ion source, a mass-to-charge analyser, a detector and a vacuum system and is used to measure mass spectra. The detector is a quadrupole mass-to-charge analyser, which holds the ions in a stable orbit by an electric field generated by four parallel electrodes.

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
station	station number	unitless	station
lat	latitude of sample collection; positive values = North	decimal degrees	lat
lon	longitude of sample collection; negative values = West	decimal degrees	lon
ISO_DateTime_UTC	date and time (UTC) of sample collection in ISO 8601 format Format: %Y-%m-%dT%H:%M:%SZ	unitless	ISO_DateTime_UTC
bottle	bottle number	unitless	bottle
pressure	pressure	decibars (dbar)	press
temperature	temperature	degrees Celsius	temp
salinity	salinity	PSU	sal
He3_sat_anomaly	Helium-3 saturation anomoly	percent (%)	diss_noble_gas_conc
Helium_concentration	Helium concentration	moles per kilogram (mol/kg)	diss_noble_gas_conc
Neon_concentration	Neon concentration	moles per kilogram (mol/kg)	diss_noble_gas_conc
Argon_concentration	Argon concentration	moles per kilogram (mol/kg)	diss_noble_gas_conc
Krypton_concentration	Krypton concentration	moles per kilogram (mol/kg)	diss_noble_gas_conc
Xenon_concentration	Xenon concentration	moles per kilogram (mol/kg)	diss_noble_gas_conc

Database

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Dataset: OSNAP Noble Gases 2016