<rdf:RDF xmlns:foaf="http://xmlns.com/foaf/0.1/" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dcat="http://www.w3.org/ns/dcat#" xmlns:dct="http://purl.org/dc/terms/">
  <dcat:Dataset rdf:about="http://catalog.data.gov/dataset/enviroatlas-biological-nitrogen-fixation-in-natural-semi-natural-ecosystems-by-12-">
    <owl:sameAs rdf:resource="urn:uuid:5f1a6429-aba6-4517-b42a-976a65957171"></owl:sameAs>
    <dct:description>This EnviroAtlas dataset contains data on the mean biological nitrogen fixation in natural/semi-natural ecosystems per 12-digit Hydrologic Unit (HUC) in 2006. Biological N fixation (BNF) in natural/semi-natural ecosystems was estimated using a correlation with actual evapotranspiration (AET). This correlation is based on a global meta-analysis of BNF in natural/semi-natural ecosystems (Cleveland et al. 1999). AET estimates for 2006 were calculated using a regression equation describing the correlation of AET with climate (average annual daily temperature, average annual minimum daily temperature, average annual maximum daily temperature, and annual precipitation) and land use/land cover variables in the conterminous US (Sanford and Selnick 2013). Data describing annual average minimum and maximum daily temperatures and total precipitation for 2006 were acquired from the PRISM climate dataset (http://prism.oregonstate.edu). Average annual climate data were then calculated for individual 12-digit USGS Hydrologic Unit Codes (HUC12s; http://water.usgs.gov/GIS/huc.html; 22 March 2011 release) using the Zonal Statistics tool in ArcMap 10.0. AET for individual HUC12s was estimated using equations described in Sanford and Selnick (2013). BNF in natural/semi-natural ecosystems within individual HUC12s was modeled with an equation describing the statistical relationship between BNF (kg N ha-1 yr-1) and actual evapotranspiration (AET; cm yr-1) and scaled to the proportion of non-developed and non-agricultural land in the HUC12. The first half of the equation represents the most conservative estimate in a meta-analysis of BNF in natural/semi-natural ecosystems (Cleveland et al. 1999), and was chosen over the central and high estimates because recent, top-down global mass balances that suggest that natural BNF rates are less than previous estimates based on scaled-up estimates from individual plots (Vitousek et al. 2013). The land use/land cover modifier is not included in the original Cleveland et al. (1999) analysis. We believe it is appropriate to include so as not to overestimate BNF in HUC12s with large proportions of urban or agricultural development. These data represent an average N input to individual HUC12s, i.e., they are not specific to an individual land use type within the HUC12. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (http://enviroatlas.epa.gov/EnviroAtlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (http://enviroatlas.epa.gov/EnviroAtlas/DataFactSheets).</dct:description>
        <dcat:keyword>12-digit hucs</dcat:keyword>
        <dcat:keyword>wyoming</dcat:keyword>
        <dcat:keyword>colorado</dcat:keyword>
        <dcat:keyword>washington</dcat:keyword>
        <dcat:keyword>rhode island</dcat:keyword>
        <dcat:keyword>united states</dcat:keyword>
        <dcat:keyword>tennessee</dcat:keyword>
        <dcat:keyword>wisconsin</dcat:keyword>
        <dcat:keyword>nevada</dcat:keyword>
        <dcat:keyword>maine</dcat:keyword>
        <dcat:keyword>north dakota</dcat:keyword>
        <dcat:keyword>mississippi</dcat:keyword>
        <dcat:keyword>south dakota</dcat:keyword>
        <dcat:keyword>new jersey</dcat:keyword>
        <dcat:keyword>oklahoma</dcat:keyword>
        <dcat:keyword>delaware</dcat:keyword>
        <dcat:keyword>minnesota</dcat:keyword>
        <dcat:keyword>north carolina</dcat:keyword>
        <dcat:keyword>illinois</dcat:keyword>
        <dcat:keyword>environment</dcat:keyword>
        <dcat:keyword>new york</dcat:keyword>
        <dcat:keyword>arkansas</dcat:keyword>
        <dcat:keyword>washington dc</dcat:keyword>
        <dcat:keyword>indiana</dcat:keyword>
        <dcat:keyword>maryland</dcat:keyword>
        <dcat:keyword>louisiana</dcat:keyword>
        <dcat:keyword>michigan</dcat:keyword>
        <dcat:keyword>idaho</dcat:keyword>
        <dcat:keyword>ecosystem services</dcat:keyword>
        <dcat:keyword>arizona</dcat:keyword>
        <dcat:keyword>iowa</dcat:keyword>
        <dcat:keyword>west virginia</dcat:keyword>
        <dcat:keyword>environmental atlas</dcat:keyword>
        <dcat:keyword>kansas</dcat:keyword>
        <dcat:keyword>utah</dcat:keyword>
        <dcat:keyword>virginia</dcat:keyword>
        <dcat:keyword>oregon</dcat:keyword>
        <dcat:keyword>connecticut</dcat:keyword>
        <dcat:keyword>montana</dcat:keyword>
        <dcat:keyword>california</dcat:keyword>
        <dcat:keyword>massachusetts</dcat:keyword>
        <dcat:keyword>enviroatlas</dcat:keyword>
        <dcat:keyword>vermont</dcat:keyword>
        <dcat:keyword>georgia</dcat:keyword>
        <dcat:keyword>pennsylvania</dcat:keyword>
        <dcat:keyword>ecosystem</dcat:keyword>
        <dcat:keyword>florida</dcat:keyword>
        <dcat:keyword>kentucky</dcat:keyword>
        <dcat:keyword>nebraska</dcat:keyword>
        <dcat:keyword>new hampshire</dcat:keyword>
        <dcat:keyword>texas</dcat:keyword>
        <dcat:keyword>missouri</dcat:keyword>
        <dcat:keyword>south carolina</dcat:keyword>
        <dcat:keyword>ohio</dcat:keyword>
        <dcat:keyword>alabama</dcat:keyword>
        <dcat:keyword>new mexico</dcat:keyword>
    <foaf:homepage rdf:resource="http://catalog.data.gov/dataset/enviroatlas-biological-nitrogen-fixation-in-natural-semi-natural-ecosystems-by-12-"></foaf:homepage>
    <rdfs:label>enviroatlas-biological-nitrogen-fixation-in-natural-semi-natural-ecosystems-by-12-</rdfs:label>
    <dct:identifier>enviroatlas-biological-nitrogen-fixation-in-natural-semi-natural-ecosystems-by-12-</dct:identifier>
    <dct:title>EnviroAtlas - Biological nitrogen fixation in natural/semi-natural ecosystems by 12-digit HUC for the Conterminous United States, 2006</dct:title>
        <dcat:distribution>
            <dcat:Distribution>
                <dcat:accessURL rdf:resource="https://edg.epa.gov/data/Public/ORD/EnviroAtlas/National_metrics_Nov2014.zip"></dcat:accessURL>
                    <dct:format>
                        <dct:IMT>
                            <rdf:value>ZIP</rdf:value>
                            <rdfs:label>ZIP</rdfs:label>
                        </dct:IMT>
                    </dct:format>
               <dct:title>Zip File</dct:title>
            </dcat:Distribution>
        </dcat:distribution>
        <dcat:distribution>
            <dcat:Distribution>
                <dcat:accessURL rdf:resource="http://enviroatlas.epa.gov/arcgis/rest/services/National"></dcat:accessURL>
                    <dct:format>
                        <dct:IMT>
                            <rdf:value>Esri REST</rdf:value>
                            <rdfs:label>Esri REST</rdfs:label>
                        </dct:IMT>
                    </dct:format>
               <dct:title>Esri Rest API Endpoint</dct:title>
            </dcat:Distribution>
        </dcat:distribution>
        <dcat:distribution>
            <dcat:Distribution>
                <dcat:accessURL rdf:resource="http://enviroatlas.epa.gov/enviroatlas/Data/index.html"></dcat:accessURL>
                    <dct:format>
                        <dct:IMT>
                            <rdf:value>HTML</rdf:value>
                            <rdfs:label>HTML</rdfs:label>
                        </dct:IMT>
                    </dct:format>
               <dct:title>Web Page</dct:title>
            </dcat:Distribution>
        </dcat:distribution>
        <dcat:distribution>
            <dcat:Distribution>
                <dcat:accessURL rdf:resource="http://enviroatlas.epa.gov/EnviroAtlas"></dcat:accessURL>
               <dct:title>Web Page</dct:title>
            </dcat:Distribution>
        </dcat:distribution>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>bbox-east-long</rdfs:label>
            <rdf:value>-65.20336449</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>resource-type</rdfs:label>
            <rdf:value>dataset</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>bbox-north-lat</rdfs:label>
            <rdf:value>51.6773602</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>coupled-resource</rdfs:label>
            <rdf:value>[]</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>guid</rdfs:label>
            <rdf:value></rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>spatial_harvester</rdfs:label>
            <rdf:value>True</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>bbox-south-lat</rdfs:label>
            <rdf:value>22.7348894</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>__category_tag_aa0c01c9-d292-4dc1-8fec-b10c1bb629a9</rdfs:label>
            <rdf:value>["Water"]</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>spatial-reference-system</rdfs:label>
            <rdf:value></rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>spatial</rdfs:label>
            <rdf:value>{"type": "Polygon", "coordinates": [[[-128.02839229, 22.7348894], [-65.20336449, 22.7348894], [-65.20336449, 51.6773602], [-128.02839229, 51.6773602], [-128.02839229, 22.7348894]]]}</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>progress</rdfs:label>
            <rdf:value>completed</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>access_constraints</rdfs:label>
            <rdf:value>["Use Constraints: None. Please check sources, scale, accuracy, currentness and other available information. Please confirm that you are using the most recent copy of both data and metadata. Acknowledgement of the EPA would be appreciated.", "Access Constraints: None."]</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>contact-email</rdfs:label>
            <rdf:value>EnviroAtlas@epa.gov</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>bbox-west-long</rdfs:label>
            <rdf:value>-128.02839229</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>metadata-date</rdfs:label>
            <rdf:value>2014-11-18</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>dataset-reference-date</rdfs:label>
            <rdf:value>[{"type": "publication", "value": "2013-09-27"}]</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>__category_tag_3b2f2e70-3e81-4aa7-8305-a534cd6af6c8</rdfs:label>
            <rdf:value>["Ecosystem Services and Processes",""]</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>frequency-of-update</rdfs:label>
            <rdf:value>asNeeded</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>licence</rdfs:label>
            <rdf:value>["Although these data have been processed successfully on a computer system at the Environmental Protection Agency, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data to evaluate data set limitations, restrictions or intended use. The U.S. Environmental Protection Agency shall not be held liable for improper or incorrect use of the data described and/or contained herein."]</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>metadata_type</rdfs:label>
            <rdf:value>geospatial</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>responsible-party</rdfs:label>
            <rdf:value>[{"name": "US Environmental Protection Agency, Research Triangle Park", "roles": ["pointOfContact"]}]</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>spatial-data-service-type</rdfs:label>
            <rdf:value></rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>metadata-language</rdfs:label>
            <rdf:value></rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>harvest_object_id</rdfs:label>
            <rdf:value>7b1f2617-42fd-4ecf-9cca-03ab5b47dc0c</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>harvest_source_id</rdfs:label>
            <rdf:value>d0d72986-7693-406b-b71d-840540909711</rdf:value>
          </rdf:Description>
        </dct:relation>
        <dct:relation>
          <rdf:Description>
            <rdfs:label>harvest_source_title</rdfs:label>
            <rdf:value>EDG_FGDC_TEST</rdf:value>
          </rdf:Description>
        </dct:relation>
  </dcat:Dataset>
</rdf:RDF>