Dataset: Radiocarbon in Methane

Name: Carbon isotopes (13C and 14C) and concentrations of dissolved methane (CH4) in surface waters sampled in June 2019 at the Coal Oil Point seep field of the Santa Barbara Basin
Published: 2020-09-10
Keywords: oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.823720.1

Spatial Extent: N:34.42 E:-119.607 S:34.333 W:-120.015

Temporal Extent: 2019-06-17 - 2019-06-19

Project:

Constraining Global Coastal Ocean Methane Emissions to the Atmosphere (Coastal Methane Emissions)

Principal Investigator:

John D. Kessler (University of Rochester)

Contact:

DongJoo Joung (University of Rochester)

BCO-DMO Data Manager:

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

Version:

Version Date:

2020-09-10

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Carbon isotopes (13C and 14C) and concentrations of dissolved methane (CH4) in surface waters sampled in June 2019 at the Coal Oil Point seep field of the Santa Barbara Basin

Abstract:

Carbon isotopes (13C and 14C) and concentrations of dissolved methane (CH4) in surface waters sampled in June 2019 at the Coal Oil Point seep field of the Santa Barbara Basin.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2020-09-10	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.823720.1	2020-09-21

Methods & Sampling

Samples were collected from the small boat R/V Connell, operated by UCSB. Gases dissolved in seawater were extracted following the procedures outlined in Sparrow and Kessler (2017) and Joung et al (2019). As detailed in these prior publications, surface waters (~ 1 m below sea surface) were pumped through a suction hose with a discharge pump and were passed through multiple filters for removing particles. This water was then continuously passed through a gas-permeable membrane to vacuum extract the dissolved gases in the seawater.

Following these at-sea sample collection procedures, the extracted gas samples were purified and analyzed following vacuum line procedures previously detailed in Sparrow and Kessler (2017).

Please see the Sparrow and Kessler (2017) for detailed descriptions and validation tests for these procedures.

Dissolved methane concentration measurements were conducted using a headspace equilibration technique previously described in Weinstein et al. (2016) and Leonte et al (2017).

Data Processing Description

BCO-DMO Processing:
- modified parameter names;
- converted date and time (local) into ISO 8601 UTC format.

Data Files

File
methane_radiocarbon.csv (Comma Separated Values (.csv), 1.66 KB) MD5:9c43d720b20b8644c7d3eff770f5aaea Primary data file for dataset ID 823720

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1851402

Deployments

None available yet

Instruments

Accelerator Mass Spectrometer

Supplied Description:

14C and 13C were measured by Accelerator Mass Spectrometer (AMS) and Isotope Ratio Mass Spectrometer (IRMS), respectively, at the Keck-Carbon Cycle AMS facility at UC Irvine.

Instrument Type

Generic Name: Accelerator Mass Spectrometer

Acronym: AMS

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB17/

Generic Description:

An AMS measures "long-lived radionuclides that occur naturally in our environment. AMS uses a particle accelerator in conjunction with ion sources, large magnets, and detectors to separate out interferences and count single atoms in the presence of 1x1015 (a thousand million million) stable atoms, measuring the mass-to-charge ratio of the products of sample molecule disassociation, atom ionization and ion acceleration." AMS permits ultra low-level measurement of compound concentrations and isotope ratios that traditional alpha-spectrometry cannot provide. More from Purdue University: http://www.physics.purdue.edu/primelab/introduction/ams.html

Agilent 6850 networked gas chromatograph

Supplied Name: Agilent 6850

Supplied Description:

A gas chromatograph with a flame ionization detector (Agilent 6850) was used for the GC analyses.

Instrument Type

Generic Name: Agilent 6850 networked gas chromatograph

Acronym: Agilent 6850

Generic Description:

A single channel, networked, gas chromatograph that separates and analyses compounds into separate components and can be used for chemical, petrochemical and petroleum analyses. The sample is introduced into the injector and then vaporised in the instrument. A chemically inert gas (e.g. helium and nitrogen) carries the vaporised solute into the column that is maintained in a temperature controlled oven. As the solute elutes from the column, it enters the heated detector. An electronic signal is generated upon interaction of the solute with the detector. The Agilent 6850 has a similar performance to the Agilent 6890N GC, but is half as wide. The local interface provides run control and status information and the instrument comes network-ready with a built-in LAN communications interface. There is a choice of detectors available, the Flame Ionization Detector (FID), Thermal Conductivity Detector (TCD) or Mass Selective Detector (MSD). There is an option of split/splitless or packed inlets, a variety of automated sample introduction systems and products available for headspace analysis. This model is no longer in production.

Isotope-ratio Mass Spectrometer

Supplied Name: Isotope Ratio Mass Spectrometer

Supplied Description:

14C and 13C were measured by Accelerator Mass Spectrometer (AMS) and Isotope Ratio Mass Spectrometer (IRMS), respectively, at the Keck-Carbon Cycle AMS facility at UC Irvine.

Instrument Type

Generic Name: Isotope-ratio Mass Spectrometer

Acronym: IR Mass Spec; IRMS

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

Generic Description:

The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer).

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
STATION	Station ID	unitless	station
LAT	Latitude	decimal degrees North	lat
LONG	Longitude	decimal degrees East	lon
DATE	Date local (PDT); format: MM/DD/YYYY	unitless	date
TIME	Time local (PDT); format: hh:mm	unitless	time
ISO_DateTime_UTC	Date and time (UTC) formatted to ISO 8601 standard: YYYY-MM-DDThh:mmZ	unitless	ISO_DateTime_UTC
StnDep	Depth of the water column at that station	meters (m)	depth_w
SamDep	Water Depth where sample was collected	meters (m)	depth
FW	Volume of water filtered	liters (L)	vol_filt
GC_CH4	Dissolved CH4 concentrations measured by GC-FID	nanomolar (nM)	CH4
GC_CH4_stdev	Standard deviation of GC_CH4	nanomolar (nM)	CH4
Licor	Extracted Gas concentrations measured by Licor	parts per million (ppm)	sample_volume
d13C	13C in CH4 by AMS	per mil (‰)	d13C
d13C_stdev	Standard deviation of d13C	per mil (‰)	d13C
C14_CH4	14C in CH4 by AMS	percent modern	14C
C14_CH4_stdev	Standard deviation of C14_CH4	percent modern	14C
D14C	14C in CH4 by AMS	per mil (‰)	14C
D14C_stdev	Standard deviation of D14C	per mil (‰)	14C

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Dataset: Radiocarbon in Methane