Dataset: Baltic GasEx (2018) Helium isotopes and Neon

Name: Helium isotope and neon data from seawater samples collected June 2018 during FS Alkor cruise AL510 in the Baltic Sea
Published: 2023-12-05
Keywords: helium isotopes, helium-3, sea-air exchange, Baltic gases, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.915490.1

Spatial Extent: N:54.71 E:10.13 S:54.52 W:10.07

Temporal Extent: 2018-06-03 - 2018-06-15

Project:

Collaborative Research: Influence of Surfactants on Air-Sea Gas Exchange: 3He/SF6 Experiments in the Baltic Sea (Baltic GasEx)

Program:

United States Surface Ocean Lower Atmosphere Study (U.S. SOLAS)

Ocean Carbon and Biogeochemistry (OCB)

Principal Investigator:

Peter Schlosser (Arizona State University, ASU)

Scientist:

Tobias N. Koffman (Lamont-Doherty Earth Observatory, LDEO)

Data Manager:

Angelica Pasqualini

BCO-DMO Data Manager:

Dana Stuart Gerlach (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2023-12-05

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Helium isotope and neon data from seawater samples collected June 2018 during FS Alkor cruise AL510 in the Baltic Sea

Abstract:

This dataset encompasses 145 seawater samples collected from 23 hydrographic stations during the AL510 cruise in the Baltic Sea aboard the research vessel Alkor, from June 6 to June 11, 2018. Helium isotopes and neon measurements were conducted in the Noble Gas Laboratory of the Lamont-Doherty Earth Observatory on a dedicated, fully automated VG5400 mass spectrometer following the procedures described by Ludin et al. (1998). Helium and neon samples were collected from Niskin bottles in copper tubes (40 ml) sealed by stainless steel pinch-off clamps. Shipboard sampling, gas extraction, and isotopic analysis were done by Tobias (Toby) Koffman with data processing by Peter Schlosser.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2023-12-05	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.915490.1	2024-01-05

Methods & Sampling

Field sampling
A total of 145 seawater samples were collected from 23 hydrographic stations aboard the Alkor (AL510) cruise from June 6 to June 11, 2018. Samples were secured in 40 milliliter copper tubes sealed by stainless steel pinch-off clamps. The seawater samples were first degassed in a vacuum extraction unit with an efficiency of ca. 99.9% to extract the dissolved gases helium (He) and neon (Ne). He and Ne were then isolated by cold trapping on activated charcoal.

Laboratory measurements
Helium (He) and Neon (Ne) gas samples were analyzed at the Lamont-Doherty Earth Observatory (LDEO) Noble Gas Laboratory on a dedicated, fully automated VG5400 quadrupole mass spectrometer following the procedures described by Ludin et al. (1998). A fraction of the helium and neon was admitted into a quadrupole analyzer for helium and neon measurements. Separation of neon from helium was achieved using a cryogenic trap, and the separated helium was admitted into the isotope mass spectrometer for isotopic analysis. Air samples and blanks were used to calibrate and monitor the sensitivity changes of the instrument during operation. He and Ne are reported in units of cubic centimeters at standard temperature and pressure per gram (cm3 STP g-1) where standard temperature and pressure is 0 degrees, 101.325 kPa. The precision of the helium and neon concentrations is ±1% of the measured value. Helium isotope ratios were measured with precision of ca. 0.2% and reported as d3He or the percent deviation of the 3He/4He ratio of a measured sample from that of an air standard (Ratm = 1.386 x 106; Clarke et al., 1976).

Processing DRIs (directly responsible individuals):
Shipboard sampling was done by Tobias (Toby) Koffman.
Helium extraction work and isotopic analysis by Tobias (Toby) Koffman.
Data processing by Peter Schlosser.

Problems/Issues
Some samples (indicated in the data table) contained excess air trapped in the copper tube during sampling.
Station 31, AL510_CTD_043, 3100007
Station 31, AL510_CTD_042, 3100006
Station 44, AL510_CTD_107, 4400011
Station 52, AL510_CTD_135, 5200003
Station 54, AL510_CTD_155, 5400011
Station 68, AL510_CTD_227, 6800011
Station 70, AL510_CTD_233, 7000005

Data Processing Description

Standardization (air standards), linearity (measurement of multiple quantities of a standard amount), and stability (repeated standard measurements). Details are described in Ludin et al. (1988)

BCO-DMO Processing

* Imported data from source file "He_Ne_AL510_2018_120323.xlsx" into the BCO-DMO data system.
* Modified parameter (column) names to conform with BCO-DMO naming conventions.
* Formatted He and Ne concentrations as scientific notation

Data Files

File
915490_v1_helium_neon.csv (Comma Separated Values (.csv), 30.92 KB) MD5:47f7197469cbedb2dc4f3a6881e17147 Primary data file for dataset ID 915490, version 1

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1756757

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
AL510	Alkor 510	2018-06-03	FS Alkor	Dennis Booge (Chief Scientist)	data info

Instruments

Mass Spectrometer

Supplied Name: VG-5400 noble gas mass spectrometer

Supplied Description:

Helium analysis was performed on a VG-5400 (Micromass) noble gas mass spectrometer. The Micromass VG-5400 instrument is a sector field mass spectrometer designed for measurement of all noble gases (He, Ne, Ar, Kr, Xe) and their isotopes.

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 Description:

Baltic Sea seawater was collected in Niskin bottles at 20+ stations

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: Submerged pump for continuous SF6 Analysis system

Supplied Description:

SF6 was monitored continuously from the vessel by pumping water via a submerged pump

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.

Quadrupole Mass Spectrometer

Supplied Name: QMG Pfeiffer PrismaPlus

Supplied Description:

Neon analysis was performed using a QMG Pfeiffer PrismaPlus compact mass spectrometer

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
St_ID	Station ID number	unitless	station
Sa_ID_LDEO	Lamont Doherty Earth Observatory Sample ID number	unitless	sample
Sample_label	Sample ID label from cruise	unitless	sample
Sa_ID	Sample ID is composed of the (station ID # 10^5) + (niskin #)	unitless	sample
Sample_DateTime_UTC	Station timestamp (UTC) in ISO 8601 format yyyy-mm-ddTHH:MMZ Format: %Y-%m-%dT%H:%M:%SZ	unitless	ISO_DateTime_UTC
Lat	Station latitude	decimal degrees	lat
Lon	Station longitude	decimal degrees	lon
Bottom_depth	Sea bottom depth with respect to sea level	meters (m)	depth_bottom
Niskin	Niskin bottle number	unitless	bot_Nis
Depth_uncorr	Planned depth of sample	meters (m)	depth
Depth	Actual depth of seawater sample	meters (m)	depth
Temp	Temperature from CTD	degrees Celsius (°C)	temp
Sal	Salinity from CTD	PSU	sal_ctd
Dens_pot	Potential Density from CTD	kilogram per cubic meter (kg/m3)	sigma_0
d3He	Percent deviation of the 3He/4He ratio of a measured sample from that of an air standard, Ratm = 1.386 x 106 (Clarke et al., 1976)	percent (%)	no_bcodmo_term
d3HeEr	Error associated with d3He measurements	percent (%)	std_err
d3HeFlag	Quality control flag (2 = good; 3 = questionable; 4 = bad)	unitless	flag
He4Conc	Concentration of helium-4 reported in cubic centimeters	cubic centimeters at standard temperature and pressure per gram (ccSTP/g)	diss_noble_gas_conc
He4ConcEr	Error associated with helium-4 concentration	cubic centimeters at standard temperature and pressure per gram (ccSTP/g)	std_err
He4Flag	Quality control flag (2 = good; 3 = questionable; 4 = bad)	unitless	flag
He3Conc	Concentration of helium-3	cubic centimeters at standard temperature and pressure per gram (ccSTP/g)	diss_noble_gas_conc
He3ConcEr	Error associated with helium-3 concentration	cubic centimeters at standard temperature and pressure per gram (ccSTP/g)	std_err
He3He4Ratio	Ratio of helium-3 concentration and helium-4 concentration	unitless	ratio
He3He4Er	Error associated with helium-3/helium-4 ratio	cubic centimeters at standard temperature and pressure per gram (ccSTP/g)	std_err
He4	Helium-4 weight	grams	weight
He4ErRelpercent	Percentage error in measurements of the weight of helium-4	percent (%)	std_err
NeConc	Total neon concentration	cubic centimeters at standard temperature and pressure per gram (ccSTP/g)	diss_noble_gas_conc
NeConcEr	Error associated with total neon concentration	cubic centimeters at standard temperature and pressure per gram (ccSTP/g)	std_err
NeFlag	Quality control flag (2 = good; 3 = questionable; 4 = bad)	unitless	flag
MeasureDate	Date of mass spec analysis Format: %Y-%m-%d	unitless	date
Comment	Lab comments	unitless	comment

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