Dissolved methane and CO2 concentrations and stable carbon isotopes from the coastal Arctic landscape of the Greiner Lake watershed, Nunavut, Canada in June 2022 and June-July 2023

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Frequently anticipated questions:

What does this data set describe?

Title:
Dissolved methane and CO2 concentrations and stable carbon isotopes from the coastal Arctic landscape of the Greiner Lake watershed, Nunavut, Canada in June 2022 and June-July 2023
Abstract:
A watershed in the coastal Canadian Arctic was sampled for dissolved carbon dioxide and methane concentration and stable carbon (carbon-13) isotopes to trace the transport, production, and consumption of carbon dioxide and methane during the spring thaw across a lake to bay transect. Two field campaigns were conducted in June 2022 and June-July 2023 out of the Canadian High Arctic Research Station (CHARS) in Cambridge Bay, Nunavut, Canada. Gas samples were collected via headspace extraction and transported back to the U.S. Geological Survey (USGS) Woods Hole Coastal and Marine Science Center (WHCMSC), where they were analyzed utilizing the USGS Automated Sample Introduction Module (AutoSIM) interfaced to a Picarro G2201-i CRDS (Cavity Ring-Down Spectrometer) to measure concentrations and stable carbon isotope ratios of methane and carbon dioxide. Field sampling was carried out by researchers from the Woods Hole Oceanographic Institution.
  1. How might this data set be cited?
    Traylor, Shawnee, Pohlman, John W., Casso, Michael, Boze, Lee-Gray, Youngs, Sarah, and Burkitt-Gray, Mary, 20250130, Dissolved methane and CO2 concentrations and stable carbon isotopes from the coastal Arctic landscape of the Greiner Lake watershed, Nunavut, Canada in June 2022 and June-July 2023: data release doi:10.5066/P1UECHWK, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Traylor, S., Pohlman, J.W., Casso, M., Boze, L-G., Youngs, S., and Burkitt-Gray, M., 2025, Dissolved methane and CO2 concentrations and stable carbon isotopes from a coastal Arctic landscape collected in the Greiner Lake watershed of Cambridge Bay, Nunavut, Canada in June 2022 and Jun-July 2023: U.S. Geological Survey data release, https://doi.org/10.5066/P1UECHWK .
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -105.09601
    East_Bounding_Coordinate: -104.80108
    North_Bounding_Coordinate: 69.18619
    South_Bounding_Coordinate: 69.10254
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/671be425d34efed56210dfb1/?name=Cambridge_Bay_Sampling_Locations.png (PNG)
    Browse graphic of the sampling locations in the Greiner Lake watershed from the 2022 (red circles) and 2023 (blue circles) campaigns, with sites that were visited both years in purple. Letters refer to the Station ID name. The frequency of sampling and data collected varied by location. These sites included the lake, river, bay, and six ponds at varying distance from Cambridge Bay. Satellite image from Earthstar Geographics.
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 17-Jun-2022
    Currentness_Reference:
    ground condition of individual sampling events
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: tabular digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (57)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is World Geodetic System 1984.
      The ellipsoid used is WGS-84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Local surface
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    CamBay_auto-sim_data_2022-2023
    Aquatic biogeochemical data from samples collected in the Greiner Lake watershed near the hamlet of Cambridge Bay, Canada in June 2022 and June/July 2023. The data are available in XLSX and CSV. The first row of the XLSX is an explanation of the dataset with the second row being columns headings for the data. The first row of the comma separated values file is the column headings (same as second row of Excel). Fields with NaN indicate data were not obtained. Blank values indicate no text for that field (Source: Producer Defined)
    sample_id
    Internal sample identifier that specifies the year of collection and sample number. (Source: Producer Defined) text field in the format CamBayYY_S where CamBay refers to the location, YY is the year of the sample, and S is the sample number.
    bag_id
    Internal identifier that specifies the sample bag used. (Source: Producer Defined) text value of the sample bag ID used by the lab. For the 2022 campaign, these numbers increase sequentially from 601. The 2023 campaign utilized a different nomenclature, starting with WHOI_#SS, where SS is the sample number.
    collectedby_last_first
    The name of the person who collected the sample in the format of last name, first name. (Source: Producer Defined) Text value in the format of last name, first name of the person who collected the sample in the field.
    analyzedby_last_first
    The name of the person who analyzed the sample in the format last name, first name. (Source: Producer Defined) Text value in the format of last name, first name of the person who analyzed the sample at the USGS laboratory.
    sample_type
    The type of sample based on the context in and purpose for which the sample was taken. (Source: Producer Defined)
    ValueDefinition
    environmentalScientific sample taken in natural waters.
    location_type
    Habitat where the sample was taken. (Source: Producer Defined)
    ValueDefinition
    PondA shallow, still, natural body of inland water. Here, refers to small freshwater bodies that appear separate from the
    LakeNatural body of inland water. Here, refers to Greiner Lake exclusively.
    RiverA linear flowing body of water. Here, exclusively referring to the waterway which directly drains water from Greiner Lake and ends in Cambridge Bay.
    BayIndentation of a coastline or shoreline enclosing a part of a body of water; a body of water partly surrounded by land. Here, exclusively refers to samples taken in Cambridge Bay.
    CreekA small, shallow waterway connecting the terrestrial system to larger bodies of water such as a river or lake.
    station
    Alphabetical station ID. (Source: Producer Defined) Stations were sampled with varying frequency. Samples were generally taken in duplicate, but this occasionally was not feasible. Some stations were sampled only once (as demonstrated by a single occurrence of a letter), while others were repeated during the field campaign and in both years.
    latitude
    Latitude where sample was taken in decimal degrees with the positive values representing northern hemisphere. (Source: Producer Defined)
    Range of values
    Minimum:69.1025400
    Maximum:69.1861921
    Units:decimal degrees
    Resolution:0.0000001
    longitude
    Longitude where sample was taken in decimal degrees with the negative values representing western hemisphere (Source: Producer Defined)
    Range of values
    Minimum:-105.0960100
    Maximum:-104.8010798
    Units:decimal degrees
    Resolution:0.0000001
    date
    Date on which the sample was taken in mm/dd/yy format. (Source: Producer Defined) numeric values presented as text
    sample_depth_m
    Depth below the surface at which sample was taken in meters, estimated based on depth of sampling apparatus. (Source: Producer Defined)
    Range of values
    Minimum:0.1
    Maximum:1.0
    Units:meters
    Resolution:.1
    salinity_psu
    Salinity of sample at time of sample collection as measured by an RBR Concerto conductivity, temperature, and depth probe, expressed in practical salinity units. (Source: Producer Defined)
    Range of values
    Minimum:0.07
    Maximum:3.22
    Units:practical salinity units
    Resolution:.01
    in_situtemp_C
    Temperature of sample at time of sample collection as measured by an RBR Concerto conductivity, temperature, and depth probe, expressed in degrees Celsius. (Source: Producer Defined)
    Range of values
    Minimum:0.00
    Maximum:16.95
    Units:degrees Celsius
    Resolution:.01
    extract_temp_C
    Temperature of sample at time of gas extraction as measured by a handheld thermometer, expressed in degrees Celsius. (Source: Producer Defined)
    Range of values
    Minimum:0.00
    Maximum:19.00
    Units:degrees Celsius
    Resolution:.01
    samp_gas_vol_mL
    Volume of headspace sample collected from extraction in the field, in mL. (Source: Producer Defined)
    Range of values
    Minimum:72
    Maximum:130
    Units:milli-Liters
    Resolution:1
    auto-sim_job
    Job number under which the samples were processed on the AutoSIM (Source: Producer Defined)
    ValueDefinition
    STD-SYSIndividually run on the alternative CRDS (Naushon)
    LAB_MMDDYYNFormat is LAB_MMDDYYN, where MM refers to the month, DD refers to the day, YY refers to the year, and N refers to the which run of the day when more than one run occurred. N is alphabetical, starting at A. These samples were run on the Auto Sampler which processed 16 samples at a time.
    ch4_ppm
    Concentration of methane in the sample in ppm. (Source: Producer Defined)
    Range of values
    Minimum:2.14
    Maximum:735.21
    Units:parts per million
    Resolution:0.01
    ch4_1sigma
    Uncertainty of the concentration of methane (1 sigma) in the sample, determined using a 0.4% accuracy. (Source: Producer Defined)
    Range of values
    Minimum:0.01
    Maximum:2.94
    Units:parts per million
    Resolution:0.01
    co2_ppm
    Concentration of carbon dioxide in the sample in ppm. (Source: Producer Defined)
    Range of values
    Minimum:117.60
    Maximum:3532.01
    Units:parts per million
    Resolution:0.01
    co2_1sigma
    Uncertainty of the concentration of carbon dioxide (1 sigma) in the sample, determined using a 0.4% accuracy, as described in the process step. (Source: Producer Defined)
    Range of values
    Minimum:0.47
    Maximum:14.13
    Units:parts per million
    Resolution:0.01
    d13C_ch4
    Carbon isotopic ratio (13C/12C) of dissolved methane (CH4) in the water sample relative to the Vienna Pee Dee Belemnite (VPDB) standard expressed in the standard per mil notation. (Source: Producer Defined)
    ValueDefinition
    NaNBelow detection limit
    Range of values
    Minimum:-69.8
    Maximum:-42.8
    Units:per mil relative to VPDB
    Resolution:0.1
    d13C_ch4_1sigma
    1 sigma uncertainty of the carbon isotopic ratio (13C/12C) of dissolved methane (CH4) in the water sample relative to the Vienna Pee Dee Belemnite (VPDB) standard expressed in the standard permil notation. (Source: Producer Defined)
    ValueDefinition
    NaNBelow detection limit
    Range of values
    Minimum:0.6
    Maximum:0.6
    Units:per mil relative to VPDB
    Resolution:0.1
    d13C_co2
    Carbon isotopic ratio (13C/12C) of dissolved carbon dioxide (CO2) in the water sample relative to the Vienna Pee Dee Belemnite (VPDB) standard expressed in the standard permil notation. (Source: Producer Defined)
    Range of values
    Minimum:-31.9
    Maximum:38.3
    Units:per mil relative to VPDB
    Resolution:0.1
    d13C_co2_1sigma
    1 sigma uncertainty of the carbon isotopic ratio (13C/12C) of dissolved carbon dioxide (CO2) in the water sample relative to the Vienna Pee Dee Belemnite (VPDB) standard expressed in the standard permil notation. (Source: Producer Defined)
    Range of values
    Minimum:0.6
    Maximum:1.6
    Units:per mil relative to VPDB
    Resolution:0.1
    ch4_conc_nanomolL-1
    Dissolved methane concentration of the water sample, in nanomoles per liter. (Source: Producer Defined)
    Range of values
    Minimum:18.3
    Maximum:6183.1
    Units:nanmoles per liter
    Resolution:0.1
    co2_conc_micromolL-1
    Dissolved carbon dioxide concentration of the water sample, in micromoles per liter. (Source: Producer Defined)
    Range of values
    Minimum:6.5
    Maximum:295.2
    Units:micromoles per liter
    Resolution:0.1
    comments
    Extraneous comments about sampling and processing procedures. (Source: Producer Defined)
    ValueDefinition
    empty cellNothing noted
    Comments taken during sampling or processing when something diverged from the standard protocol.
    Entity_and_Attribute_Overview:
    These data are available in a XLSX format and as a CSV file. The first line of the Excel spreadsheet gives general information about the dataset, and the second row contains the headers. The first line of the CSV file is a header line and those labels are the same as the second row of the corresponding Excel spreadsheet.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Shawnee Traylor
    • John W. Pohlman
    • Michael Casso
    • Lee-Gray Boze
    • Sarah Youngs
    • Mary Burkitt-Gray
  2. Who also contributed to the data set?
    U.S. Geological Survey, Woods Hole Oceanographic Institution
  3. To whom should users address questions about the data?
    John Pohlman
    U.S. Geological Survey
    Research Geochemist
    USGS, 384 Woods Hole Road.
    Woods Hole, MA
    USA

    508-548-8700 x2213 (voice)
    jpohlman@usgs.gov

Why was the data set created?

These data are used to investigate how carbon cycling evolves across a coastal Arctic landscape during the spring thaw.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2022 (process 1 of 3)
    Discrete water samples were collected from the study area during two field campaigns. The first between June 17-29, 2022, and the second from June 20 to July 4th, 2023. Station replicates between seasons were collected from the same water body, with proximity determined by ice cover and other local conditions. Sampling protocol followed that outlined in Pohlman and others, 2021. Samples were collected by filling 1-Liter (L) plastic syringes fitted with 3-way stopcocks with 880 milli-Liters (mL) of natural water and 120 mL of Zero Air. A headspace extraction was performed by shaking the syringes for two minutes and collecting the headspace into 250 cc multi-layer foil bags (Cali-5 Bond). These samples were transported back to the lab, stored at room temperature, and processed for measurements within two months of collection. Additional measurements were made with the CTD (RBR Concerto conductivity, temperature, and depth probe.) Person who carried out this activity:
    John Pohlman
    U.S. Geological Survey, Northeast Region
    research geochemist
    USGS, 384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2213 (voice)
    jpohlman@usgs.gov
    Date: 2023 (process 2 of 3)
    Sample analysis was performed at the U.S. Geological Survey (USGS) Woods Hole Coastal and Marine Science Center, utilizing the USGS Automated Sample Introduction Module (AutoSIM) interfaced to a Picarro G2201-i CRDS that simultaneously measures CH4, CO2, and stable carbon isotope ratios reported in the d-notation relative to Vienna Pee Dee Belemnite (VPDB) referenced gas standards (δ13C-CO2, δ13C-CH4). Check standards for concentration and stable isotopic composition were run approximately every 4-5 samples and corrected as described by Pohlman and others (2021). Concentrations are reported with a relative standard deviation of 0.4% and isotopic ratios are reported with an analytical precision of 0.6‰ based on the precision reported in Pohlman and others (2021).
    For CO2 concentrations below 300 parts per million (ppm), the analytical precision of the isotopic ratio (d13C_co2) decreases exponentially and was characterized by laboratory measurements. This decrease is be described by the equation: Error = 2.2501*exp(-0.003*pCO2) Where pCO2 is the concentration of the headspace in ppm (co2_ppm). For samples with a concentration under 300 ppm, the reported precision is calculated using this formula.
    Sample analyses were performed by Shawnee Traylor and Michael Casso under the supervision of John Pohlman. Sample processing occurred in August 2022 and November 2023. Person who carried out this activity:
    John Pohlman
    U.S. Geological Survey, Northeast Region
    research geochemist
    USGS, 384 Woods Hole Road
    Woods Hole, MA
    USA

    508-548-8700 x2213 (voice)
    jpohlman@usgs.gov
    Date: 14-Nov-2023 (process 3 of 3)
    Headspace concentrations were converted to dissolved concentrations using the method of Magen and others, 2014.
    Explicitly, the following equations were used to calculate dissolved concentrations: ((pCO2 * 10^-6 * 0.120) / (R * T_extraction) + (0.880 * pCO2 * 10^-6 * Sol_CO2)) / 0.880 * 10^6 = [CO2]
    Where pCO2 is the headspace concentration of carbon dioxide in ppm, 0.120 is the volume of gas sample in mL, R is the gas constant in L-atm/mol-K, T_extraction is the extraction temperature in Kelvin, 0.880 is the volume of water sample that was extracted in mL, Sol_CO2 is the solubility of carbon dioxide in mol/L-atm (Weiss, 1974), and [CO2] is the dissolved concentration of carbon dioxide in the original natural water sample, in micromoles per liter.
    ((pCH4 * 10^-6 * 0.120) / (R * T_extraction) + (0.880 * pCO2 * 10^-6 * Sol_CH4)) / 0.880 * 10^9 = [CH4]
    Where pCH4 is the headspace concentration of methane in ppm, 0.120 is the volume of gas sample in mL, R is the gas constant in L-atm/mol-K, T_extraction is the extraction temperature in Kelvin, 0.880 is the volume of water sample that was extracted in mL, Sol_CH4 is the solubility of methane in mol/L-atm (Wiesenburg & Guinasso, 1979; Yamamoto et al., 1976), and [CH4] is the dissolved concentration of methane in the original natural water sample, in nanomoles per liter.
    The data were organized into a Microsoft Excel spreadsheet (Microsoft Excel for Mac) and are available in both XLSX and CSV formats. Person who carried out this activity:
    John Pohlman
    U.S. Geological Survey, Northeast Region
    research geochemist
    USGS, 384 Woods Hole Road
    Woods Hole, MA
    United States

    508-548-8700 x2213 (voice)
    jpohlman@usgs.gov
  3. What similar or related data should the user be aware of?
    Magen, Cédric, Lapham, Laura L., Pohlman, John W., Marshall, Kathleen, Bosman, Samantha, Casso, Michael, and Chanton, Jeffrey P., 20140908, A simple headspace equilibration method for measuring dissolved methane: Limnology and Oceanography: Methods vol. 12, issue 9, Wiley, New Jersey.

    Online Links:

    Other_Citation_Details:
    pp. 637-650. Publication describes the method for extracting and analyzing dissolved gas concentrations.
    Pohlman, John W., Casso, Michael, Magen, Cédric, and Bergeron, Emile, 20210825, Discrete Sample Introduction Module for Quantitative and Isotopic Analysis of Methane and Other Gases by Cavity Ring-Down Spectroscopy: Environmental Science and Technology vol. 55, issue 17, American Chemical Society (ACS), n/a.

    Online Links:

    Other_Citation_Details:
    ppg. 12066-12074. Publication describes the method used to measure samples for this release.
    Wiesenberg, Denis, and Guinasso, N., 19790201, Equilibrium solubilities of methane, carbon monoxide, and hydrogen in water and sea water: Journal of Chemical and Engineering Data vol. 24, issue 4, American Chemical Society (ACS), n/a.

    Online Links:

    Other_Citation_Details:
    pp. 356-360. Publication describes solubility of methane in water.
    Yamamoto, Sachio, Alcauskas, James, and Crozier, Thomas, 19760121, Solubility of methane in distilled water and seawater: Journal of Chemical and Engineering Data vol. 21, issue 1, American Chemical Society (ACS), n/a.

    Online Links:

    Other_Citation_Details:
    pp. 78-80. Publication describes solubility of methane in water.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The accuracy of each attribute is determined by that analysis specific to that attribute. The accuracy is provided in the process step for each measurement.
  2. How accurate are the geographic locations?
    The horizontal position (coordinates) of the sites were determined using the native GPS on an Apple iPhone SE, reported to have a precision of 5 meters.
  3. How accurate are the heights or depths?
    The samples were all from the surface and the associated depth was estimated based on the length of the sampling syringe.
  4. Where are the gaps in the data? What is missing?
    Certain samples were not included in this dataset because they were not natural water samples and were used for the calibration of other instrumentation.
  5. How consistent are the relationships among the observations, including topology?
    All data provided in this release were obtained by Shawnee Traylor, Sarah Youngs, and Mary Burkitt-Gray, and processed by Shawnee Traylor, Michael Casso, and John Pohlman. Data were obtained during two field campaigns in consecutive years. Samples were generally taken in duplicate, but occasionally this did not occur or the samples were damaged or lost prior to processing. The obtained data were processed and handled the same way after each deployment. The “Comments” field in the dataset will document any deviation from this practice. This dataset only includes environmental samples that were collected for the purpose of studying the natural environment. Thus, it excludes discrete samples that were collected for the purpose of informing calibration or engineering questions.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None.
Use_Constraints None.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? This dataset contains data in an Excel spreadsheet (CamBay_auto-sim_data_2022-2023.xlsx) and the same information in a CSV file (CamBay_auto-sim_data_2022-2023.csv). Additionally, the dataset contains a browse graphic (Cambridge_Bay_Sampling_Locations.png) and the metadata in XML format.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 30-Jan-2025
Metadata author:
U.S. Geological Survey
Attn: John Pohlman
USGS, 384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 x2213 (voice)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the person is no longer with USGS.
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P1UECHWK/CambridgeBay_Auto-SIMdata_2022-2023_metadata.faq.html>
Generated by mp version 2.9.51 on Tue Feb 4 14:46:47 2025