{
    "tag": 6402,
    "title": "Eelgrass distributions derived from a towed underwater video survey of the Nisqually River delta, 2017",
    "pubdate": "20200721",
    "sername": null,
    "series_name": null,
    "issue": "DOI:10.5066\/P9N9K2I1",
    "publish": null,
    "publisher_name": null,
    "onlink": "https:\/\/cmgds.marine.usgs.gov\/catalog\/pcmsc\/DataReleases\/ScienceBase\/DR_P9N9K2I1\/nq17_video_metadata.faq.html",
    "format": null,
    "email": null,
    "descript": "This portion of the USGS data release presents eelgrass distributions derived from towed underwater video surveys of the Nisqually River delta, Washington in 2017 (USGS Field Activity Number 2017-614-FA). Eelgrass data were collected from the R\/V George Davidson equipped with a towed underwater video system and global navigation satellite system (GNSS) receiver. The underwater video system consisted of a Splashcam standard definition video camera connected to a Sony GV-D1000 video monitor and tape recorder. Positioning of the survey vessel was determined at 1 Hz intervals using a Trimble R7 GNSS receiver and Trimble Zephyr Model 2 antenna. The positioning data from the GNSS were encoded onto the audio track of the digital video recording using Red Hen Systems (RHS) VMS200 hardware.  Underwater video data were recorded as the vessel navigated along a series of shore-perpendicular transects at speeds between 1 and 2 knots. The underwater video recording was later reviewed and the presence or absence of eelgrass was determined for each 1-s segment of video tape. These data were used to evaluate the classification of single-beam sonar data acquired during the same time period.",
    "lang": null,
    "journal": null,
    "pwid": null,
    "originator": [
        {
            "name": "Stevens, Andrew W.",
            "role": "Author"
        },
        {
            "name": "Takesue, Renee K.",
            "role": "Author"
        },
        {
            "name": "Grossman, Eric E.",
            "role": "Author"
        }
    ],
    "index_term": [
        {
            "thcode": 2,
            "code": "1705",
            "name": "aquatic vegetation",
            "scope": "Plants living primarily in or under water."
        },
        {
            "thcode": 2,
            "code": "492",
            "name": "GPS measurement",
            "scope": "Determination of distance and location using instruments receiving signals from the Global Positioning System, a system of satellites for identifying earth locations."
        },
        {
            "thcode": 2,
            "code": "1025",
            "name": "sea-floor characteristics",
            "scope": "Geomorphic features and geographic, compositional, and textural variation in the materials composing the ocean floor. Includes both large-scale structures (such as seamounts and rises) and fine-scale variations in rocks and deposits on the sea floor."
        },
        {
            "thcode": 2,
            "code": "1201",
            "name": "underwater photography",
            "scope": "Photographs taken below the water surface, usually in marine, lacustrine, and estuarine environments.  Subjects are typically benthic organisms and sedimentary structures on the bottom."
        },
        {
            "thcode": 15,
            "code": "002",
            "name": "biota",
            "scope": "Flora or fauna in natural environment, for example wildlife, vegetation, biological sciences, ecology, wilderness, sea life, wetlands, habitat, biological resources"
        },
        {
            "thcode": 23,
            "code": "34",
            "name": "Flora",
            "scope": "Vascular plants, macroalgae, phytoplankton, or microbial communities."
        },
        {
            "thcode": 61,
            "code": "484",
            "name": "video observation",
            "scope": "video documentation of natural features and processes."
        }
    ],
    "place_term": [],
    "image": [],
    "fan": [
        "2017-614-FA"
    ]
}