{
    "tag": 17735,
    "title": "Comparison of methane concentration and stable carbon isotope data for natural samples analyzed by discrete sample introduction module - cavity ring down spectroscopy (DSIM-CRDS) and traditional methods",
    "pubdate": "20210827",
    "sername": null,
    "series_name": null,
    "issue": "DOI:10.5066\/P99B34V1",
    "publish": null,
    "publisher_name": null,
    "onlink": "https:\/\/cmgds.marine.usgs.gov\/catalog\/whcmsc\/SB_data_release\/DR_P99B34V1\/DSIM_EnvironmentalDataMethodComparision_2021_meta.faq.html",
    "format": null,
    "email": null,
    "descript": "A discrete sample introduction module (DSIM) was developed and interfaced to a cavity ring-down spectrometer to enable measurements of methane and CO2 concentrations and 13C values with a commercially available cavity ring-down spectrometer (CRDS). The DSIM-CRDS system permits the analysis of limited volume (5 - 100-ml) samples ranging six orders-of-magnitude from 100% analyte to the lower limit of instrument detection (2 ppm). We demonstrate system performance for methane by comparing concentrations and 13C results obtained by the DSIM and traditional methods for a variety of sample types, including low concentration (nanomolar) seawater and high concentration (> 90%) natural gas. The expansive concentration range the CRDS is able to analyze while being packaged in a field-portable analytical system greatly enhances functionality for investigating methane and CO2 dynamics, as well as other gases measured by laser absorption spectroscopy.",
    "lang": null,
    "journal": null,
    "pwid": null,
    "originator": [
        {
            "name": "Pohlman, John W.",
            "role": "Author"
        },
        {
            "name": "Casso, Michael A.",
            "role": "Author"
        }
    ],
    "index_term": [
        {
            "thcode": 2,
            "code": "141",
            "name": "carbon cycling",
            "scope": "The circulation of carbon in the biosphere, atmosphere, and hydrosphere through a series of processes that include photosynthesis, consumption, and respiration."
        },
        {
            "thcode": 2,
            "code": "142",
            "name": "carbon isotope analysis",
            "scope": "Experimental determination of the proportion of a given stable carbon isotope (C12 or C13) in a sample."
        },
        {
            "thcode": 2,
            "code": "427",
            "name": "gas hydrate resources",
            "scope": "Deposits of a crystalline solid in which water molecules trap gas molecules, usually methane, in a cagelike structure known as a clathrate occurring in sediments overlain by cold deep water."
        },
        {
            "thcode": 2,
            "code": "437",
            "name": "geochemistry",
            "scope": "Study of the distribution of chemical elements and natural compounds on the earth and in the atmosphere and the chemical processes that affect the earth."
        },
        {
            "thcode": 2,
            "code": "703",
            "name": "marine chemistry",
            "scope": "Branch of chemistry that deals with the properties, composition, structure, and interaction of substances in the seas and oceans."
        },
        {
            "thcode": 2,
            "code": "810",
            "name": "ocean characteristics",
            "scope": "The attributes and process of seas and oceans."
        },
        {
            "thcode": 15,
            "code": "007",
            "name": "environment",
            "scope": "Environmental resources, protection and conservation, for example environmental pollution, waste storage and treatment, environmental impact assessment, monitoring environmental risk, nature reserves, landscape, water quality, air quality, environmental modeling"
        },
        {
            "thcode": 15,
            "code": "014",
            "name": "oceans",
            "scope": "Features and characteristics of salt water bodies (excluding inland waters), for example tides, tidal waves, coastal information, reefs, maritime, outer continental shelf submerged lands, shoreline"
        },
        {
            "thcode": 61,
            "code": "270",
            "name": "carbon cycle",
            "scope": "used to describe the complex global exchange of carbon through the biosphere, atmosphere, hydrosphere (primarily oceans), and geosphere (primarily sediments and sedimentary rocks)."
        },
        {
            "thcode": 61,
            "code": "699",
            "name": "isotope geochemistry",
            "scope": "used for both stable isotope geochemistry (to understand chemical fractionation in earth materials and processes) and radiogenic isotope geochemistry (to determine the ages and origins of earth materials)."
        },
        {
            "thcode": 61,
            "code": "700",
            "name": "sediment geochemistry",
            "scope": "the study of the chemical composition and cycling of sedimentary systems."
        },
        {
            "thcode": 62,
            "code": "BS-002",
            "name": "Temperate Northern Atlantic",
            "scope": "Realm"
        },
        {
            "thcode": 62,
            "code": "BS-003",
            "name": "Temperate Northern Pacific",
            "scope": "Realm"
        }
    ],
    "place_term": [],
    "image": [
        {
            "name": "https:\/\/www.sciencebase.gov\/catalog\/file\/get\/60d60d72d34e960393674818?name=DSIM-CRDS_system.png",
            "description": "Image of Michael Casso operating the DSIM-CRDS system on a ship during field work."
        }
    ],
    "fan": [
        "2015-005-FA"
    ]
}