@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dct: <http://purl.org/dc/terms/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix gsp: <http://www.opengis.net/ont/geosparql#> .
@prefix locn: <http://www.w3.org/ns/locn#> .
@prefix vcard: <http://www.w3.org/2006/vcard/ns#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

<https://data.amerigeoss.org/dataset/3f4fd846-c6ad-49da-af7e-4c4864ce0b4c> a dcat:Dataset ;
    dct:description "The tetraether index of C86 (TEX86) and alkenone unsaturation index (Uk37Õ) molecular biomarker proxies have been broadly applied in down-core marine sediments to reconstruct past sea surface temperature (SST). Although both TEX86 and Uk37 have been interpreted as proxies for mean annual SST throughout the global ocean, regional studies of glycerol dibiphytanyl glycerol tetraethers (GDGT)s and alkenones in sinking particulate matter (SPM) are required to understand the influence of seasonality, depth distribution and diagenesis on downcore variability. USGS scientists measured GDGT and alkenone flux, as well as the TEX86 and Uk37Õ indices in a 4-year sediment trap time series (2010-2014) in the northern Gulf of Mexico (nGoM), with weekly-to-monthly resolution, and compared these data with core-top sediments at the same location. GDGT and alkenone fluxes do not show a consistent seasonal cycle; however, the largest flux peaks for both occurs in winter. Uk37 co-varies with SST over the 4-year sampling interval, but the U-SST relationship in this dataset implies a smaller slope or non-linearity at high temperatures when compared with existing calibrations. Furthermore, the flux-weighted Uk37 value from sinking particles is significantly lower than that of underlying core-top sediments, suggesting preferential diagenetic loss of the tri-unsaturated alkenone in sediments. TEX86 does not co-vary with SST, suggesting production in the subsurface ocean. The flux-weighted mean TEX86 matches that of core-top sediments, suggesting that sedimentary TEX86 in the Gulf of Mexico reflects local autochthonous production. We explore these potential sources of uncertainty in both proxies in the GoM, but demonstrate that they show nearly identical trends in 20th century SST, despite these factors." ;
    dct:identifier "USGS:77befd4c-d6ea-4224-9aec-7d7a9ae3d26c" ;
    dct:issued "2025-11-21T04:51:25.763670"^^xsd:dateTime ;
    dct:modified "20201013"^^xsd:gYear ;
    dct:publisher <https://data.amerigeoss.org/organization/727dbdd5-3f98-4ac0-9d28-5e344558139b> ;
    dct:spatial [ a dct:Location ;
            locn:geometry "POLYGON ((91.0000 27.0000, 91.0000 28.0000, 90.0000 28.0000, 90.0000 27.0000, 91.0000 27.0000))"^^gsp:wktLiteral ] ;
    dct:title "Sediment Trap Time Series of GDGT and alkenone flux in the Gulf of Mexico" ;
    dcat:contactPoint [ a vcard:Organization ;
            vcard:fn "Julie Richey" ;
            vcard:hasEmail <mailto:jrichey@usgs.gov> ] ;
    dcat:distribution <https://data.amerigeoss.org/dataset/3f4fd846-c6ad-49da-af7e-4c4864ce0b4c/resource/5f67f851-2bad-49ec-8914-b51cc3f44920>,
        <https://data.amerigeoss.org/dataset/3f4fd846-c6ad-49da-af7e-4c4864ce0b4c/resource/8ce66616-a4f4-458e-8b72-fad9df58d93c> ;
    dcat:keyword "alkenone",
        "amerigeo",
        "amerigeoss",
        "aquatic-biology",
        "biota",
        "ckan",
        "environment",
        "gdgt",
        "geo",
        "geochemistry",
        "geoscientificinformation",
        "geoss",
        "marine-geology",
        "national",
        "north-america",
        "oceans",
        "sediment-trap",
        "tex86",
        "uk37",
        "united-states",
        "usgs-77befd4c-d6ea-4224-9aec-7d7a9ae3d26c" ;
    dcat:theme <%7Bgeospatial%7D> .

<https://data.amerigeoss.org/dataset/3f4fd846-c6ad-49da-af7e-4c4864ce0b4c/resource/5f67f851-2bad-49ec-8914-b51cc3f44920> a dcat:Distribution ;
    dct:description "The metadata original format" ;
    dct:format "XML" ;
    dct:issued "2022-07-28T19:40:25.930834"^^xsd:dateTime ;
    dct:modified "2025-11-21T04:51:25.752218"^^xsd:dateTime ;
    dct:title "Original Metadata" ;
    dcat:accessURL <https://data.usgs.gov/datacatalog/metadata/USGS.77befd4c-d6ea-4224-9aec-7d7a9ae3d26c.xml> ;
    dcat:mediaType "text/xml" .

<https://data.amerigeoss.org/dataset/3f4fd846-c6ad-49da-af7e-4c4864ce0b4c/resource/8ce66616-a4f4-458e-8b72-fad9df58d93c> a dcat:Distribution ;
    dct:description "Landing page for access to the data" ;
    dct:format "XML" ;
    dct:issued "2022-07-28T19:40:25.930845"^^xsd:dateTime ;
    dct:modified "2025-11-21T04:51:25.752645"^^xsd:dateTime ;
    dct:title "Digital Data" ;
    dcat:accessURL <https://doi.org/10.5066/F76M350W> ;
    dcat:mediaType "application/http" .

<https://data.amerigeoss.org/organization/727dbdd5-3f98-4ac0-9d28-5e344558139b> a foaf:Agent ;
    foaf:name "US Migrating" .