Helium isotope with helium and neon concentration data from Leg 1 (Seattle, WA to Hilo, HI) of the US GEOTRACES Pacific Meridional Transect (PMT) cruise (GP15, RR1814) on R/V Roger Revelle from September to October 2018

Website: https://www.bco-dmo.org/dataset/862182
Data Type: Cruise Results
Version: 1
Version Date: 2021-09-30

Project
» US GEOTRACES Pacific Meridional Transect (U.S. GEOTRACES PMT)
» Measurement of Helium Isotopes on the U.S. GEOTRACES Alaska-Tahiti Section (GP15) (PMT Helium Isotopes)

Program
» U.S. GEOTRACES (U.S. GEOTRACES)
ContributorsAffiliationRole
Jenkins, William J.Woods Hole Oceanographic Institution (WHOI)Principal Investigator
German, Christopher R.Woods Hole Oceanographic Institution (WHOI)Co-Principal Investigator
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
This dataset includes helium isotope, helium, and neon concentration data from Leg 1 (Seattle, WA to Hilo, HI) of the US GEOTRACES Pacific Meridional Transect (PMT) cruise (GP15, RR1814) on R/V Roger Revelle from September to October 2018.


Coverage

Spatial Extent: N:56.059 E:-152 S:19.681 W:-156.963
Temporal Extent: 2018-09-24 - 2018-10-21

Acquisition Description

Water samples were transferred from Niskin bottles and stored in crimped copper tubing. Gases were extracted from the water samples in a shore-based vacuum system and stored in aluminosilicate glass ampoules. The extracted gases were analyzed for helium and neon concentrations using ion counting in a quadrupole mass spectrometer and for helium isotopes using a magnetic sector dual-collecting isotope ratio mass spectrometer. Details are given in Jenkins et al. (2019) and Stanley et al. (2007).

Note: Natural and bomb tritium will decay to 3He in the copper tubing water sample container between the time the water sample was acquired and when the gases were extracted. We account for this using tritium concentrations estimated from a prior (2015) cruise occupation extrapolated in time and interpolated in space to the sample location and time. The size of this effect is significant in shallow, northern waters and vanishingly small in deeper and more southerly waters.


Processing Description

Data Processing:
Raw data were acquired and reduced using custom software written in VB.NET. Data were processed using MATLAB (2020b) and stored in a PostgreSQL V9.3 database.

BCO-DMO Processing:
- renamed fields to comply with BCO-DMO naming conventions;
- converted date field to YYYY-MM-DD format;
- added date/time field in ISO8601 format;
- removed empty columns.


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Related Publications

Jenkins, W. J., Lott, D. E., & Cahill, K. L. (2019). A determination of atmospheric helium, neon, argon, krypton, and xenon solubility concentrations in water and seawater. Marine Chemistry, 211, 94–107. doi:10.1016/j.marchem.2019.03.007
Methods
Stanley, R. H. R., Baschek, B., Lott, D. E., & Jenkins, W. J. (2009). A new automated method for measuring noble gases and their isotopic ratios in water samples. Geochemistry, Geophysics, Geosystems, 10(5), n/a–n/a. doi:10.1029/2009gc002429 https://doi.org/10.1029/2009GC002429
Methods

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Related Datasets

IsContinuedBy
Jenkins, W. J., German, C. R. (2021) Helium isotope with helium and neon concentration data from Leg 2 (Hilo, HI to Papeete, French Polynesia) of the US GEOTRACES Pacific Meridional Transect (PMT) cruise (GP15, RR1815) on R/V Roger Revelle from Oct-Nov 2018. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2021-09-30 doi:10.26008/1912/bco-dmo.862220.1 [view at BCO-DMO]
Relationship Description: GP15 was made up of two cruise legs, RR1814 (Leg 1) and RR1815 (Leg 2).

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Parameters

ParameterDescriptionUnits
Station_IDStation number unitless
Start_Date_UTCStart date; format: YYYY-MM-DD unitless
Start_Time_UTCStart time (UTC); format: hh:mm unitless
Start_ISO_DateTime_UTCStart date and time (UTC) in ISO8601 format: YYYY-MM-DDThh:mmZ unitless
Start_LatitudeStart latitude decimal degrees North
Start_LongitudeStart longitude decimal degrees East
Event_IDEvent number unitless
Sample_IDGEOTRACES sample number unitless
Sample_DepthSample depth meters (m)
Ne_D_CONC_BOTTLE_leeb4yConcentration of dissolved Neon nanomoles per kilogram (nmol/kg)
SD1_Ne_D_CONC_BOTTLE_leeb4yStandard deviation of Ne_D_CONC_BOTTLE_leeb4y nanomoles per kilogram (nmol/kg)
Flag_Ne_D_CONC_BOTTLE_leeb4yODF quality flag for Ne_D_CONC_BOTTLE_leeb4y unitless
He_D_CONC_BOTTLE_saee1dConcentration of dissolved Helium nanomoles per kilogram (nmol/kg)
SD1_He_D_CONC_BOTTLE_saee1dStandard deviation of He_D_CONC_BOTTLE_saee1d nanomoles per kilogram (nmol/kg)
Flag_He_D_CONC_BOTTLE_saee1dODF quality flag for He_D_CONC_BOTTLE_saee1d unitless
He_3_4_D_DELTA_BOTTLE_xgifq8Delta 3He of dissolved He referenced to air; corrected for in-storage tritium decay percent (%)
SD1_He_3_4_D_DELTA_BOTTLE_xgifq8Standard deviation of He_3_4_D_DELTA_BOTTLE_xgifq8 percent (%)
Flag_He_3_4_D_DELTA_BOTTLE_xgifq8ODF quality flag for He_3_4_D_DELTA_BOTTLE_xgifq8 unitless


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Instruments

Dataset-specific Instrument Name
Niskin bottles
Generic Instrument Name
Niskin bottle
Generic Instrument 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.

Dataset-specific Instrument Name
magnetic sector dual-collecting isotope ratio mass spectrometer
Generic Instrument Name
Isotope-ratio Mass Spectrometer
Dataset-specific Description
The helium isotope mass spectrometer is a custom-built unit manufactured at the Woods Hole Oceanographic Institution.
Generic Instrument 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).

Dataset-specific Instrument Name
quadrupole mass spectrometer
Generic Instrument Name
Quadrupole Mass Spectrometer
Dataset-specific Description
The quadrupole mass spectrometer model is HIDEN P/N PCI 1000 1.2HAL/3F 1301-9 PIC type 570,309.
Generic Instrument 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.  


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Deployments

RR1814

Website
Platform
R/V Roger Revelle
Report
Start Date
2018-09-18
End Date
2018-10-21
Description
Additional cruise information is available from the Rolling Deck to Repository (R2R): https://www.rvdata.us/search/cruise/RR1814


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Project Information

US GEOTRACES Pacific Meridional Transect (U.S. GEOTRACES PMT)


Coverage: Pacific Meridional Transect along 152W (GP15)


A 60-day research cruise took place in 2018 along a transect form Alaska to Tahiti at 152° W. A description of the project titled "Collaborative Research: Management and implementation of the US GEOTRACES Pacific Meridional Transect", funded by NSF, is below. Further project information is available on the US GEOTRACES website and on the cruise blog. A detailed cruise report is also available as a PDF.

Description from NSF award abstract:
GEOTRACES is a global effort in the field of Chemical Oceanography in which the United States plays a major role. The goal of the GEOTRACES program is to understand the distributions of many elements and their isotopes in the ocean. Until quite recently, these elements could not be measured at a global scale. Understanding the distributions of these elements and isotopes will increase the understanding of processes that shape their distributions and also the processes that depend on these elements. For example, many "trace elements" (elements that are present in very low amounts) are also important for life, and their presence or absence can play a vital role in the population of marine ecosystems. This project will launch the next major U.S. GEOTRACES expedition in the Pacific Ocean between Alaska and Tahiti. The award made here would support all of the major infrastructure for this expedition, including the research vessel, the sampling equipment, and some of the core oceanographic measurements. This project will also support the personnel needed to lead the expedition and collect the samples.

This project would support the essential sampling operations and infrastructure for the U.S. GEOTRACES Pacific Meridional Transect along 152° W to support a large variety of individual science projects on trace element and isotope (TEI) biogeochemistry that will follow. Thus, the major objectives of this management proposal are: (1) plan and coordinate a 60 day research cruise in 2018; (2) obtain representative samples for a wide variety of TEIs using a conventional CTD/rosette, GEOTRACES Trace Element Sampling Systems, and in situ pumps; (3) acquire conventional CTD hydrographic data along with discrete samples for salinity, dissolved oxygen, algal pigments, and dissolved nutrients at micro- and nanomolar levels; (4) ensure that proper QA/QC protocols are followed and reported, as well as fulfilling all GEOTRACES intercalibration protocols; (5) prepare and deliver all hydrographic data to the GEOTRACES Data Assembly Centre (via the US BCO-DMO data center); and (6) coordinate all cruise communications between investigators, including preparation of a hydrographic report/publication. This project would also provide baseline measurements of TEIs in the Clarion-Clipperton fracture zone (~7.5°N-17°N, ~155°W-115°W) where large-scale deep sea mining is planned. Environmental impact assessments are underway in partnership with the mining industry, but the effect of mining activities on TEIs in the water column is one that could be uniquely assessed by the GEOTRACES community. In support of efforts to communicate the science to a wide audience the investigators will recruit an early career freelance science journalist with interests in marine science and oceanography to participate on the cruise and do public outreach, photography and/or videography, and social media from the ship, as well as to submit articles about the research to national media. The project would also support several graduate students.


Measurement of Helium Isotopes on the U.S. GEOTRACES Alaska-Tahiti Section (GP15) (PMT Helium Isotopes)


NSF Award Abstract:
The goal of the international GEOTRACES program is to understand the distributions of trace chemical elements and their isotopes in the oceans. An essential part of this effort is determining the sources of trace elements to the oceans. One important such source comes from seafloor hydrothermal venting. This project will support the measurement of helium isotopes on the 2018 U.S. GEOTRACES expedition in the Pacific Ocean, running south from Alaska to Tahiti. Helium isotopes provide important information on the presence and dispersion of hydrothermal plumes. On a larger scale, they can also be used to calculate global-scale inputs of hydrothermally-sourced trace elements and isotopes. Thus, the proposed work is closely tied to many other projects associated with this expedition. The measurement of helium isotopes will also allow enable the investigation of physical mixing rates within the upper ocean to help interpret the fate of other trace elements. At the northern end of the section, this approach will also be used to investigate the rate at which other trace elements and isotopes from seafloor hydrothermal venting are delivered to the more biologically productive surface ocean. In addition to supporting the GEOTRACES effort and participating in community-scale outreach efforts associated with the expedition, the investigators will also work with a visual artist to communicate their science to the public in new ways.

The U.S. GEOTRACES Pacific Meridional Transect (56°N to 20°S, along 152°W) in late 2018 will intercept: strong margin fluxes, sub-Arctic high-nutrient, low-chlorophyll waters, the oldest deep waters in the world's oceans, the distal ends of multiple hydrothermal plumes, oxygen minimum zones, subpolar and equatorial upwelling, and, in the South Pacific near 20°S, some of the most oligotrophic waters known. This section, together with the US GEOTRACES East Pacific Zonal Transect (EPZT) conducted in 2013, will also close off a large volume of the Pacific Ocean. Consequently, this work will facilitate new, improved evaluations of regional-scale fluxes of hydrothermally-sourced trace elements and isotopes (TEIs) to the oceans. Because the 2018 expedition will intercept multiple hydrothermal plumes, this project will also allow the investigation of three key questions emerging from the larger U.S. and international GEOTRACES programs: 1) Is there a significant source of hydrothermally-sourced Fe and other TEIs to the euphotic zone in the North Pacific, through upwelling, as was demonstrated for the Southern Ocean from the 2013 EPZT results? 2) How do TEI:He-3 ratios in hydrothermal plumes vary with different geologic settings of their vent-sources? 3) How do the TEI:He-3 ratios imparted to hydrothermal plumes vary along the thermohaline conveyor as a function of varying water column chemistry? Throughout the section the investigators will also combine upper-water column helium-3 measurements with water column tritium concentrations (extrapolated from data collected on past expeditions) to estimate water column ventilation time scales that can be used to quantify rates of TEI transformation across the wide range of biogeochemical regimes to be intercepted (tropical, subtropical, subpolar). In regions characterized by upwelling, precise measurements of helium isotopes can be combined with canonical gas-exchange rate estimates to make flux-gauge determinations of upwelling rates for some key TEIs.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.



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Program Information

U.S. GEOTRACES (U.S. GEOTRACES)


Coverage: Global


GEOTRACES is a SCOR sponsored program; and funding for program infrastructure development is provided by the U.S. National Science Foundation.

GEOTRACES gained momentum following a special symposium, S02: Biogeochemical cycling of trace elements and isotopes in the ocean and applications to constrain contemporary marine processes (GEOSECS II), at a 2003 Goldschmidt meeting convened in Japan. The GEOSECS II acronym referred to the Geochemical Ocean Section Studies To determine full water column distributions of selected trace elements and isotopes, including their concentration, chemical speciation, and physical form, along a sufficient number of sections in each ocean basin to establish the principal relationships between these distributions and with more traditional hydrographic parameters;

* To evaluate the sources, sinks, and internal cycling of these species and thereby characterize more completely the physical, chemical and biological processes regulating their distributions, and the sensitivity of these processes to global change; and

* To understand the processes that control the concentrations of geochemical species used for proxies of the past environment, both in the water column and in the substrates that reflect the water column.

GEOTRACES will be global in scope, consisting of ocean sections complemented by regional process studies. Sections and process studies will combine fieldwork, laboratory experiments and modelling. Beyond realizing the scientific objectives identified above, a natural outcome of this work will be to build a community of marine scientists who understand the processes regulating trace element cycles sufficiently well to exploit this knowledge reliably in future interdisciplinary studies.

Expand "Projects" below for information about and data resulting from individual US GEOTRACES research projects.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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