<?xml version="1.0" encoding="UTF-8"?>
<gmi:MI_Metadata  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="https://www.isotc211.org/2005/gmi https://data.noaa.gov/resources/iso19139/schema.xsd"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:gco="http://www.isotc211.org/2005/gco"
  xmlns:gmd="http://www.isotc211.org/2005/gmd"
  xmlns:gmx="http://www.isotc211.org/2005/gmx"
  xmlns:gml="http://www.opengis.net/gml/3.2"
  xmlns:gss="http://www.isotc211.org/2005/gss"
  xmlns:gts="http://www.isotc211.org/2005/gts"
  xmlns:gsr="http://www.isotc211.org/2005/gsr"
  xmlns:gmi="http://www.isotc211.org/2005/gmi"
  xmlns:srv="http://www.isotc211.org/2005/srv">
  <gmd:fileIdentifier>
    <gco:CharacterString>bcodmo_dataset_885506_v2</gco:CharacterString>
  </gmd:fileIdentifier>
  <gmd:language>
    <gmd:LanguageCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:LanguageCode" codeListValue="eng">eng</gmd:LanguageCode>
  </gmd:language>
  <gmd:characterSet>
    <gmd:MD_CharacterSetCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_CharacterSetCode" codeListValue="UTF8">UTF8</gmd:MD_CharacterSetCode>
  </gmd:characterSet>
  <gmd:hierarchyLevel>
    <gmd:MD_ScopeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_ScopeCode" codeListValue="dataset">dataset</gmd:MD_ScopeCode>
  </gmd:hierarchyLevel>
  <gmd:hierarchyLevel>
    <gmd:MD_ScopeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_ScopeCode" codeListValue="service">service</gmd:MD_ScopeCode>
  </gmd:hierarchyLevel>
  <gmd:contact>
    <gmd:CI_ResponsibleParty>
      <gmd:individualName>
        <gco:CharacterString>Adam Shepherd</gco:CharacterString>
      </gmd:individualName>
      <gmd:organisationName>
        <gco:CharacterString>BCO-DMO</gco:CharacterString>
      </gmd:organisationName>
      <gmd:contactInfo>
        <gmd:CI_Contact>
          <gmd:phone>
            <gmd:CI_Telephone>
              <gmd:voice>
                <gco:CharacterString>508-289-2772</gco:CharacterString>
              </gmd:voice>
            </gmd:CI_Telephone>
          </gmd:phone>
          <gmd:address>
            <gmd:CI_Address>
              <gmd:deliveryPoint>
                <gco:CharacterString>266 Woods Hole Rd. MS#36</gco:CharacterString>
              </gmd:deliveryPoint>
              <gmd:city>
                <gco:CharacterString>Woods Hole</gco:CharacterString>
              </gmd:city>
              <gmd:administrativeArea>
                <gco:CharacterString>MA</gco:CharacterString>
              </gmd:administrativeArea>
              <gmd:postalCode>
                <gco:CharacterString>02543</gco:CharacterString>
              </gmd:postalCode>
              <gmd:country>
                <gco:CharacterString>USA</gco:CharacterString>
              </gmd:country>
              <gmd:electronicMailAddress>
                <gco:CharacterString>erddap@bco-dmo.org</gco:CharacterString>
              </gmd:electronicMailAddress>
            </gmd:CI_Address>
          </gmd:address>
        </gmd:CI_Contact>
      </gmd:contactInfo>
      <gmd:role>
        <gmd:CI_RoleCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_RoleCode" codeListValue="pointOfContact">pointOfContact</gmd:CI_RoleCode>
      </gmd:role>
    </gmd:CI_ResponsibleParty>
  </gmd:contact>
  <gmd:dateStamp>
    <gco:Date>2026-04-08</gco:Date>
  </gmd:dateStamp>
  <gmd:metadataStandardName>
    <gco:CharacterString>ISO 19115-2 Geographic Information - Metadata Part 2 Extensions for Imagery and Gridded Data</gco:CharacterString>
  </gmd:metadataStandardName>
  <gmd:metadataStandardVersion>
    <gco:CharacterString>ISO 19115-2:2009(E)</gco:CharacterString>
  </gmd:metadataStandardVersion>
  <gmd:spatialRepresentationInfo>
    <gmd:MD_GridSpatialRepresentation>
      <gmd:numberOfDimensions>
        <gco:Integer>2</gco:Integer>
      </gmd:numberOfDimensions>
      <gmd:axisDimensionProperties>
        <gmd:MD_Dimension>
          <gmd:dimensionName>
            <gmd:MD_DimensionNameTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_DimensionNameTypeCode" codeListValue="column">column</gmd:MD_DimensionNameTypeCode>
          </gmd:dimensionName>
          <gmd:dimensionSize gco:nilReason="unknown"/>
        </gmd:MD_Dimension>
      </gmd:axisDimensionProperties>
      <gmd:axisDimensionProperties>
        <gmd:MD_Dimension>
          <gmd:dimensionName>
            <gmd:MD_DimensionNameTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_DimensionNameTypeCode" codeListValue="row">row</gmd:MD_DimensionNameTypeCode>
          </gmd:dimensionName>
          <gmd:dimensionSize gco:nilReason="unknown"/>
        </gmd:MD_Dimension>
      </gmd:axisDimensionProperties>
      <gmd:cellGeometry>
        <gmd:MD_CellGeometryCode codeList="" codeListValue="" codeSpace="" />
      </gmd:cellGeometry>
      <gmd:transformationParameterAvailability gco:nilReason="unknown"/>
    </gmd:MD_GridSpatialRepresentation>
  </gmd:spatialRepresentationInfo>
  <gmd:identificationInfo>
    <gmd:MD_DataIdentification id="DataIdentification">
      <gmd:citation>
        <gmd:CI_Citation>
          <gmd:title>
            <gco:CharacterString>[Distribution of dissolved barium in seawater determined using machine learning] - A spatially and vertically resolved global grid of dissolved barium concentrations in seawater determined using Gaussian Process Regression machine learning (The Speed, Signature, and Significance of Barium Transformations in Seawater)</gco:CharacterString>
          </gmd:title>
          <gmd:date>
            <gmd:CI_Date>
              <gmd:date>
                <gco:Date>2026-04-08</gco:Date>
              </gmd:date>
              <gmd:dateType>
                <gmd:CI_DateTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode>
              </gmd:dateType>
            </gmd:CI_Date>
          </gmd:date>
          <gmd:identifier>
            <gmd:MD_Identifier>
              <gmd:authority>
                <gmd:CI_Citation>
                  <gmd:title>
                    <gco:CharacterString>erddap.bco-dmo.org</gco:CharacterString>
                  </gmd:title>
                  <gmd:date gco:nilReason="inapplicable"/>
                </gmd:CI_Citation>
              </gmd:authority>
              <gmd:code>
                <gco:CharacterString>bcodmo_dataset_885506_v2</gco:CharacterString>
              </gmd:code>
            </gmd:MD_Identifier>
          </gmd:identifier>
          <gmd:citedResponsibleParty>
            <gmd:CI_ResponsibleParty>
              <gmd:individualName gco:nilReason="missing"/>
              <gmd:organisationName>
                <gco:CharacterString>BCO-DMO</gco:CharacterString>
              </gmd:organisationName>
              <gmd:contactInfo>
                <gmd:CI_Contact>
                  <gmd:address>
                    <gmd:CI_Address>
                      <gmd:electronicMailAddress>
                        <gco:CharacterString>info@bco-dmo.org</gco:CharacterString>
                      </gmd:electronicMailAddress>
                    </gmd:CI_Address>
                  </gmd:address>
                  <gmd:onlineResource>
                    <gmd:CI_OnlineResource>
                      <gmd:linkage>
                        <gmd:URL>https://www.bco-dmo.org/dataset/885506</gmd:URL>
                      </gmd:linkage>
                      <gmd:protocol>
                        <gco:CharacterString>information</gco:CharacterString>
                      </gmd:protocol>
                      <gmd:applicationProfile>
                        <gco:CharacterString>web browser</gco:CharacterString>
                      </gmd:applicationProfile>
                      <gmd:name>
                        <gco:CharacterString>Background Information</gco:CharacterString>
                      </gmd:name>
                      <gmd:description>
                        <gco:CharacterString>Background information from the source</gco:CharacterString>
                      </gmd:description>
                      <gmd:function>
                        <gmd:CI_OnLineFunctionCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_OnLineFunctionCode" codeListValue="information">information</gmd:CI_OnLineFunctionCode>
                      </gmd:function>
                    </gmd:CI_OnlineResource>
                  </gmd:onlineResource>
                </gmd:CI_Contact>
              </gmd:contactInfo>
              <gmd:role>
                <gmd:CI_RoleCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_RoleCode" codeListValue="originator">originator</gmd:CI_RoleCode>
              </gmd:role>
            </gmd:CI_ResponsibleParty>
          </gmd:citedResponsibleParty>
        </gmd:CI_Citation>
      </gmd:citation>
      <gmd:abstract>
        <gco:CharacterString>We present a spatially and vertically resolved global grid of dissolved barium concentrations ([Ba]) in seawater determined using Gaussian Process Regression machine learning. This model was trained using 4,345 quality-controlled GEOTRACES data from the Arctic, Atlantic, Pacific, and Southern Oceans. Model output was validated by assessing the accuracy of [Ba] simulations in the Indian Ocean, noting that none of the Indian Ocean data were seen by the model during training. We identify a model that can accurate predict [Ba] in the Indian Ocean using seven features: depth, temperature, salinity, as well as dissolved dioxygen, phosphate, nitrate, and silicate concentrations. This model achieves a mean absolute percentage error of 6.0 &#37;, which we assume represents the generalization error. This model was used to simulate [Ba] on a global basis using predictor data from the World Ocean Atlas 2018. The global model of [Ba] is on a 1°x 1° grid with 102 depth levels from 0 to 5,500 m. The dissolved [Ba] output was then used to simulate dissolved Ba* (barium-star), which is the difference between &#39;observed&#39; and [Ba] predicted from co-located [Si]. Lastly, [Ba] data were combined with temperature, salinity, and pressure data from the World Ocean Atlas to calculate the saturation state of seawater with respect to barite. The model reveals that the volume-weighted mean oceanic [Ba] and and saturation state are 89 nmol/kg and 0.82, respectively. These results imply that the total marine Ba inventory is 122(±7) ×10¹² mol and that the ocean below 1,000 m is at barite equilibrium.</gco:CharacterString>
      </gmd:abstract>
      <gmd:credit gco:nilReason="missing"/>
      <gmd:pointOfContact>
        <gmd:CI_ResponsibleParty>
          <gmd:individualName gco:nilReason="missing"/>
          <gmd:organisationName>
            <gco:CharacterString>BCO-DMO</gco:CharacterString>
          </gmd:organisationName>
          <gmd:contactInfo>
            <gmd:CI_Contact>
              <gmd:address>
                <gmd:CI_Address>
                  <gmd:electronicMailAddress>
                    <gco:CharacterString>info@bco-dmo.org</gco:CharacterString>
                  </gmd:electronicMailAddress>
                </gmd:CI_Address>
              </gmd:address>
              <gmd:onlineResource>
                <gmd:CI_OnlineResource>
                  <gmd:linkage>
                    <gmd:URL>https://www.bco-dmo.org/dataset/885506</gmd:URL>
                  </gmd:linkage>
                  <gmd:protocol>
                    <gco:CharacterString>information</gco:CharacterString>
                  </gmd:protocol>
                  <gmd:applicationProfile>
                    <gco:CharacterString>web browser</gco:CharacterString>
                  </gmd:applicationProfile>
                  <gmd:name>
                    <gco:CharacterString>Background Information</gco:CharacterString>
                  </gmd:name>
                  <gmd:description>
                    <gco:CharacterString>Background information from the source</gco:CharacterString>
                  </gmd:description>
                  <gmd:function>
                    <gmd:CI_OnLineFunctionCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_OnLineFunctionCode" codeListValue="information">information</gmd:CI_OnLineFunctionCode>
                  </gmd:function>
                </gmd:CI_OnlineResource>
              </gmd:onlineResource>
            </gmd:CI_Contact>
          </gmd:contactInfo>
          <gmd:role>
            <gmd:CI_RoleCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_RoleCode" codeListValue="pointOfContact">pointOfContact</gmd:CI_RoleCode>
          </gmd:role>
        </gmd:CI_ResponsibleParty>
      </gmd:pointOfContact>
      <gmd:descriptiveKeywords>
        <gmd:MD_Keywords>
          <gmd:keyword>
            <gco:CharacterString>earth science</gco:CharacterString>
          </gmd:keyword>
          <gmd:keyword>
            <gco:CharacterString>atmosphere</gco:CharacterString>
          </gmd:keyword>
          <gmd:keyword>
            <gco:CharacterString>ocean</gco:CharacterString>
          </gmd:keyword>
          <gmd:keyword>
            <gco:CharacterString>biosphere</gco:CharacterString>
          </gmd:keyword>
          <gmd:keyword>
            <gco:CharacterString>biology</gco:CharacterString>
          </gmd:keyword>
          <gmd:keyword>
            <gco:CharacterString>environment</gco:CharacterString>
          </gmd:keyword>
          <gmd:type>
            <gmd:MD_KeywordTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_KeywordTypeCode" codeListValue="theme">theme</gmd:MD_KeywordTypeCode>
          </gmd:type>
          <gmd:thesaurusName gco:nilReason="unknown"/>
        </gmd:MD_Keywords>
      </gmd:descriptiveKeywords>
      <gmd:descriptiveKeywords>
        <gmd:MD_Keywords>
          <gmd:keyword>
            <gco:CharacterString>BCO-DMO</gco:CharacterString>
          </gmd:keyword>
          <gmd:type>
            <gmd:MD_KeywordTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_KeywordTypeCode" codeListValue="project">project</gmd:MD_KeywordTypeCode>
          </gmd:type>
          <gmd:thesaurusName gco:nilReason="unknown"/>
        </gmd:MD_Keywords>
      </gmd:descriptiveKeywords>
      <gmd:descriptiveKeywords>
        <gmd:MD_Keywords>
          <gmd:keyword>
            <gco:CharacterString>longitude</gco:CharacterString>
          </gmd:keyword>
          <gmd:keyword>
            <gco:CharacterString>latitude</gco:CharacterString>
          </gmd:keyword>
          <gmd:type>
            <gmd:MD_KeywordTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_KeywordTypeCode" codeListValue="theme">theme</gmd:MD_KeywordTypeCode>
          </gmd:type>
          <gmd:thesaurusName>
            <gmd:CI_Citation>
              <gmd:title>
                <gco:CharacterString>CF</gco:CharacterString>
              </gmd:title>
              <gmd:date gco:nilReason="unknown"/>
            </gmd:CI_Citation>
          </gmd:thesaurusName>
        </gmd:MD_Keywords>
      </gmd:descriptiveKeywords>
      <gmd:resourceConstraints>
        <gmd:MD_LegalConstraints>
          <gmd:useLimitation>
            <gco:CharacterString>The data may be used and redistributed for free but is not intended
for legal use, since it may contain inaccuracies. Neither the data
Contributor, ERD, NOAA, nor the United States Government, nor any
of their employees or contractors, makes any warranty, express or
implied, including warranties of merchantability and fitness for a
particular purpose, or assumes any legal liability for the accuracy,
completeness, or usefulness, of this information.</gco:CharacterString>
          </gmd:useLimitation>
        </gmd:MD_LegalConstraints>
      </gmd:resourceConstraints>
      <gmd:aggregationInfo>
        <gmd:MD_AggregateInformation>
          <gmd:aggregateDataSetName>
            <gmd:CI_Citation>
              <gmd:title>
                <gco:CharacterString>BCO-DMO</gco:CharacterString>
              </gmd:title>
              <gmd:date gco:nilReason="inapplicable"/>
            </gmd:CI_Citation>
          </gmd:aggregateDataSetName>
          <gmd:associationType>
            <gmd:DS_AssociationTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:DS_AssociationTypeCode" codeListValue="largerWorkCitation">largerWorkCitation</gmd:DS_AssociationTypeCode>
          </gmd:associationType>
          <gmd:initiativeType>
            <gmd:DS_InitiativeTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:DS_InitiativeTypeCode" codeListValue="project">project</gmd:DS_InitiativeTypeCode>
          </gmd:initiativeType>
        </gmd:MD_AggregateInformation>
      </gmd:aggregationInfo>
      <gmd:language>
        <gco:CharacterString>eng</gco:CharacterString>
      </gmd:language>
      <gmd:topicCategory>
        <gmd:MD_TopicCategoryCode>geoscientificInformation</gmd:MD_TopicCategoryCode>
      </gmd:topicCategory>
      <gmd:extent>
        <gmd:EX_Extent id="boundingExtent">
          <gmd:geographicElement>
            <gmd:EX_GeographicBoundingBox id="boundingGeographicBoundingBox">
              <gmd:extentTypeCode>
                <gco:Boolean>1</gco:Boolean>
              </gmd:extentTypeCode>
              <gmd:westBoundLongitude>
                <gco:Decimal>-180.0</gco:Decimal>
              </gmd:westBoundLongitude>
              <gmd:eastBoundLongitude>
                <gco:Decimal>180.0</gco:Decimal>
              </gmd:eastBoundLongitude>
              <gmd:southBoundLatitude>
                <gco:Decimal>-77.5</gco:Decimal>
              </gmd:southBoundLatitude>
              <gmd:northBoundLatitude>
                <gco:Decimal>89.5</gco:Decimal>
              </gmd:northBoundLatitude>
            </gmd:EX_GeographicBoundingBox>
          </gmd:geographicElement>
        </gmd:EX_Extent>
      </gmd:extent>
    </gmd:MD_DataIdentification>
  </gmd:identificationInfo>
  <gmd:identificationInfo>
    <srv:SV_ServiceIdentification id="ERDDAP-tabledap">
      <gmd:citation>
        <gmd:CI_Citation>
          <gmd:title>
            <gco:CharacterString>[Distribution of dissolved barium in seawater determined using machine learning] - A spatially and vertically resolved global grid of dissolved barium concentrations in seawater determined using Gaussian Process Regression machine learning (The Speed, Signature, and Significance of Barium Transformations in Seawater)</gco:CharacterString>
          </gmd:title>
          <gmd:date>
            <gmd:CI_Date>
              <gmd:date>
                <gco:Date>2026-04-08</gco:Date>
              </gmd:date>
              <gmd:dateType>
                <gmd:CI_DateTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode>
              </gmd:dateType>
            </gmd:CI_Date>
          </gmd:date>
          <gmd:citedResponsibleParty>
            <gmd:CI_ResponsibleParty>
              <gmd:individualName gco:nilReason="missing"/>
              <gmd:organisationName>
                <gco:CharacterString>BCO-DMO</gco:CharacterString>
              </gmd:organisationName>
              <gmd:contactInfo>
                <gmd:CI_Contact>
                  <gmd:address>
                    <gmd:CI_Address>
                      <gmd:electronicMailAddress>
                        <gco:CharacterString>info@bco-dmo.org</gco:CharacterString>
                      </gmd:electronicMailAddress>
                    </gmd:CI_Address>
                  </gmd:address>
                  <gmd:onlineResource>
                    <gmd:CI_OnlineResource>
                      <gmd:linkage>
                        <gmd:URL>https://www.bco-dmo.org/dataset/885506</gmd:URL>
                      </gmd:linkage>
                      <gmd:protocol>
                        <gco:CharacterString>information</gco:CharacterString>
                      </gmd:protocol>
                      <gmd:applicationProfile>
                        <gco:CharacterString>web browser</gco:CharacterString>
                      </gmd:applicationProfile>
                      <gmd:name>
                        <gco:CharacterString>Background Information</gco:CharacterString>
                      </gmd:name>
                      <gmd:description>
                        <gco:CharacterString>Background information from the source</gco:CharacterString>
                      </gmd:description>
                      <gmd:function>
                        <gmd:CI_OnLineFunctionCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_OnLineFunctionCode" codeListValue="information">information</gmd:CI_OnLineFunctionCode>
                      </gmd:function>
                    </gmd:CI_OnlineResource>
                  </gmd:onlineResource>
                </gmd:CI_Contact>
              </gmd:contactInfo>
              <gmd:role>
                <gmd:CI_RoleCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_RoleCode" codeListValue="originator">originator</gmd:CI_RoleCode>
              </gmd:role>
            </gmd:CI_ResponsibleParty>
          </gmd:citedResponsibleParty>
        </gmd:CI_Citation>
      </gmd:citation>
      <gmd:abstract>
        <gco:CharacterString>We present a spatially and vertically resolved global grid of dissolved barium concentrations ([Ba]) in seawater determined using Gaussian Process Regression machine learning. This model was trained using 4,345 quality-controlled GEOTRACES data from the Arctic, Atlantic, Pacific, and Southern Oceans. Model output was validated by assessing the accuracy of [Ba] simulations in the Indian Ocean, noting that none of the Indian Ocean data were seen by the model during training. We identify a model that can accurate predict [Ba] in the Indian Ocean using seven features: depth, temperature, salinity, as well as dissolved dioxygen, phosphate, nitrate, and silicate concentrations. This model achieves a mean absolute percentage error of 6.0 &#37;, which we assume represents the generalization error. This model was used to simulate [Ba] on a global basis using predictor data from the World Ocean Atlas 2018. The global model of [Ba] is on a 1°x 1° grid with 102 depth levels from 0 to 5,500 m. The dissolved [Ba] output was then used to simulate dissolved Ba* (barium-star), which is the difference between &#39;observed&#39; and [Ba] predicted from co-located [Si]. Lastly, [Ba] data were combined with temperature, salinity, and pressure data from the World Ocean Atlas to calculate the saturation state of seawater with respect to barite. The model reveals that the volume-weighted mean oceanic [Ba] and and saturation state are 89 nmol/kg and 0.82, respectively. These results imply that the total marine Ba inventory is 122(±7) ×10¹² mol and that the ocean below 1,000 m is at barite equilibrium.</gco:CharacterString>
      </gmd:abstract>
      <srv:serviceType>
        <gco:LocalName>ERDDAP tabledap</gco:LocalName>
      </srv:serviceType>
      <srv:extent>
        <gmd:EX_Extent>
          <gmd:geographicElement>
            <gmd:EX_GeographicBoundingBox>
              <gmd:extentTypeCode>
                <gco:Boolean>1</gco:Boolean>
              </gmd:extentTypeCode>
              <gmd:westBoundLongitude>
                <gco:Decimal>-180.0</gco:Decimal>
              </gmd:westBoundLongitude>
              <gmd:eastBoundLongitude>
                <gco:Decimal>180.0</gco:Decimal>
              </gmd:eastBoundLongitude>
              <gmd:southBoundLatitude>
                <gco:Decimal>-77.5</gco:Decimal>
              </gmd:southBoundLatitude>
              <gmd:northBoundLatitude>
                <gco:Decimal>89.5</gco:Decimal>
              </gmd:northBoundLatitude>
            </gmd:EX_GeographicBoundingBox>
          </gmd:geographicElement>
        </gmd:EX_Extent>
      </srv:extent>
      <srv:couplingType>
        <srv:SV_CouplingType codeList="https://data.noaa.gov/ISO19139/resources/codeList.xml#SV_CouplingType" codeListValue="tight">tight</srv:SV_CouplingType>
      </srv:couplingType>
      <srv:containsOperations>
        <srv:SV_OperationMetadata>
          <srv:operationName>
            <gco:CharacterString>ERDDAPtabledapDatasetQueryAndAccess</gco:CharacterString>
          </srv:operationName>
          <srv:DCP gco:nilReason="unknown"/>
          <srv:connectPoint>
            <gmd:CI_OnlineResource>
              <gmd:linkage>
                <gmd:URL>https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_885506_v2</gmd:URL>
              </gmd:linkage>
              <gmd:protocol>
                <gco:CharacterString>ERDDAP:tabledap</gco:CharacterString>
              </gmd:protocol>
              <gmd:name>
                <gco:CharacterString>ERDDAP-tabledap</gco:CharacterString>
              </gmd:name>
              <gmd:description>
                <gco:CharacterString>ERDDAP's tabledap service (a flavor of OPeNDAP) for tabular (sequence) data. Add different extensions (e.g., .html, .graph, .das, .dds) to the base URL for different purposes.</gco:CharacterString>
              </gmd:description>
              <gmd:function>
                <gmd:CI_OnLineFunctionCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="download">download</gmd:CI_OnLineFunctionCode>
              </gmd:function>
            </gmd:CI_OnlineResource>
          </srv:connectPoint>
        </srv:SV_OperationMetadata>
      </srv:containsOperations>
      <srv:operatesOn xlink:href="#DataIdentification"/>
    </srv:SV_ServiceIdentification>
  </gmd:identificationInfo>
  <gmd:identificationInfo>
    <srv:SV_ServiceIdentification id="OPeNDAP">
      <gmd:citation>
        <gmd:CI_Citation>
          <gmd:title>
            <gco:CharacterString>[Distribution of dissolved barium in seawater determined using machine learning] - A spatially and vertically resolved global grid of dissolved barium concentrations in seawater determined using Gaussian Process Regression machine learning (The Speed, Signature, and Significance of Barium Transformations in Seawater)</gco:CharacterString>
          </gmd:title>
          <gmd:date>
            <gmd:CI_Date>
              <gmd:date>
                <gco:Date>2026-04-08</gco:Date>
              </gmd:date>
              <gmd:dateType>
                <gmd:CI_DateTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_DateTypeCode" codeListValue="creation">creation</gmd:CI_DateTypeCode>
              </gmd:dateType>
            </gmd:CI_Date>
          </gmd:date>
          <gmd:citedResponsibleParty>
            <gmd:CI_ResponsibleParty>
              <gmd:individualName gco:nilReason="missing"/>
              <gmd:organisationName>
                <gco:CharacterString>BCO-DMO</gco:CharacterString>
              </gmd:organisationName>
              <gmd:contactInfo>
                <gmd:CI_Contact>
                  <gmd:address>
                    <gmd:CI_Address>
                      <gmd:electronicMailAddress>
                        <gco:CharacterString>info@bco-dmo.org</gco:CharacterString>
                      </gmd:electronicMailAddress>
                    </gmd:CI_Address>
                  </gmd:address>
                  <gmd:onlineResource>
                    <gmd:CI_OnlineResource>
                      <gmd:linkage>
                        <gmd:URL>https://www.bco-dmo.org/dataset/885506</gmd:URL>
                      </gmd:linkage>
                      <gmd:protocol>
                        <gco:CharacterString>information</gco:CharacterString>
                      </gmd:protocol>
                      <gmd:applicationProfile>
                        <gco:CharacterString>web browser</gco:CharacterString>
                      </gmd:applicationProfile>
                      <gmd:name>
                        <gco:CharacterString>Background Information</gco:CharacterString>
                      </gmd:name>
                      <gmd:description>
                        <gco:CharacterString>Background information from the source</gco:CharacterString>
                      </gmd:description>
                      <gmd:function>
                        <gmd:CI_OnLineFunctionCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_OnLineFunctionCode" codeListValue="information">information</gmd:CI_OnLineFunctionCode>
                      </gmd:function>
                    </gmd:CI_OnlineResource>
                  </gmd:onlineResource>
                </gmd:CI_Contact>
              </gmd:contactInfo>
              <gmd:role>
                <gmd:CI_RoleCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_RoleCode" codeListValue="originator">originator</gmd:CI_RoleCode>
              </gmd:role>
            </gmd:CI_ResponsibleParty>
          </gmd:citedResponsibleParty>
        </gmd:CI_Citation>
      </gmd:citation>
      <gmd:abstract>
        <gco:CharacterString>We present a spatially and vertically resolved global grid of dissolved barium concentrations ([Ba]) in seawater determined using Gaussian Process Regression machine learning. This model was trained using 4,345 quality-controlled GEOTRACES data from the Arctic, Atlantic, Pacific, and Southern Oceans. Model output was validated by assessing the accuracy of [Ba] simulations in the Indian Ocean, noting that none of the Indian Ocean data were seen by the model during training. We identify a model that can accurate predict [Ba] in the Indian Ocean using seven features: depth, temperature, salinity, as well as dissolved dioxygen, phosphate, nitrate, and silicate concentrations. This model achieves a mean absolute percentage error of 6.0 &#37;, which we assume represents the generalization error. This model was used to simulate [Ba] on a global basis using predictor data from the World Ocean Atlas 2018. The global model of [Ba] is on a 1°x 1° grid with 102 depth levels from 0 to 5,500 m. The dissolved [Ba] output was then used to simulate dissolved Ba* (barium-star), which is the difference between &#39;observed&#39; and [Ba] predicted from co-located [Si]. Lastly, [Ba] data were combined with temperature, salinity, and pressure data from the World Ocean Atlas to calculate the saturation state of seawater with respect to barite. The model reveals that the volume-weighted mean oceanic [Ba] and and saturation state are 89 nmol/kg and 0.82, respectively. These results imply that the total marine Ba inventory is 122(±7) ×10¹² mol and that the ocean below 1,000 m is at barite equilibrium.</gco:CharacterString>
      </gmd:abstract>
      <srv:serviceType>
        <gco:LocalName>OPeNDAP</gco:LocalName>
      </srv:serviceType>
      <srv:extent>
        <gmd:EX_Extent>
          <gmd:geographicElement>
            <gmd:EX_GeographicBoundingBox>
              <gmd:extentTypeCode>
                <gco:Boolean>1</gco:Boolean>
              </gmd:extentTypeCode>
              <gmd:westBoundLongitude>
                <gco:Decimal>-180.0</gco:Decimal>
              </gmd:westBoundLongitude>
              <gmd:eastBoundLongitude>
                <gco:Decimal>180.0</gco:Decimal>
              </gmd:eastBoundLongitude>
              <gmd:southBoundLatitude>
                <gco:Decimal>-77.5</gco:Decimal>
              </gmd:southBoundLatitude>
              <gmd:northBoundLatitude>
                <gco:Decimal>89.5</gco:Decimal>
              </gmd:northBoundLatitude>
            </gmd:EX_GeographicBoundingBox>
          </gmd:geographicElement>
        </gmd:EX_Extent>
      </srv:extent>
      <srv:couplingType>
        <srv:SV_CouplingType codeList="https://data.noaa.gov/ISO19139/resources/codeList.xml#SV_CouplingType" codeListValue="tight">tight</srv:SV_CouplingType>
      </srv:couplingType>
      <srv:containsOperations>
        <srv:SV_OperationMetadata>
          <srv:operationName>
            <gco:CharacterString>OPeNDAPDatasetQueryAndAccess</gco:CharacterString>
          </srv:operationName>
          <srv:DCP gco:nilReason="unknown"/>
          <srv:connectPoint>
            <gmd:CI_OnlineResource>
              <gmd:linkage>
                <gmd:URL>https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_885506_v2</gmd:URL>
              </gmd:linkage>
              <gmd:protocol>
                <gco:CharacterString>OPeNDAP:OPeNDAP</gco:CharacterString>
              </gmd:protocol>
              <gmd:name>
                <gco:CharacterString>OPeNDAP</gco:CharacterString>
              </gmd:name>
              <gmd:description>
                <gco:CharacterString>An OPeNDAP service for tabular (sequence) data. Add different extensions (e.g., .html, .das, .dds) to the base URL for different purposes.</gco:CharacterString>
              </gmd:description>
              <gmd:function>
                <gmd:CI_OnLineFunctionCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="download">download</gmd:CI_OnLineFunctionCode>
              </gmd:function>
            </gmd:CI_OnlineResource>
          </srv:connectPoint>
        </srv:SV_OperationMetadata>
      </srv:containsOperations>
      <srv:operatesOn xlink:href="#DataIdentification"/>
    </srv:SV_ServiceIdentification>
  </gmd:identificationInfo>
  <gmd:contentInfo>
    <gmi:MI_CoverageDescription>
      <gmd:attributeDescription gco:nilReason="unknown"/>
      <gmd:contentType>
        <gmd:MD_CoverageContentTypeCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:MD_CoverageContentTypeCode" codeListValue="physicalMeasurement">physicalMeasurement</gmd:MD_CoverageContentTypeCode>
      </gmd:contentType>
      <gmd:dimension>
        <gmd:MD_Band>
          <gmd:sequenceIdentifier>
            <gco:MemberName>
              <gco:aName>
                <gco:CharacterString>Station</gco:CharacterString>
              </gco:aName>
              <gco:attributeType>
                <gco:TypeName>
                  <gco:aName>
                    <gco:CharacterString>int</gco:CharacterString>
                  </gco:aName>
                </gco:TypeName>
              </gco:attributeType>
            </gco:MemberName>
          </gmd:sequenceIdentifier>
          <gmd:descriptor>
            <gco:CharacterString>Station</gco:CharacterString>
          </gmd:descriptor>
          <gmd:units xlink:href="https://unitsofmeasure.org/ucum.html#1"/>
        </gmd:MD_Band>
      </gmd:dimension>
      <gmd:dimension>
        <gmd:MD_Band>
          <gmd:sequenceIdentifier>
            <gco:MemberName>
              <gco:aName>
                <gco:CharacterString>Depth_m</gco:CharacterString>
              </gco:aName>
              <gco:attributeType>
                <gco:TypeName>
                  <gco:aName>
                    <gco:CharacterString>int</gco:CharacterString>
                  </gco:aName>
                </gco:TypeName>
              </gco:attributeType>
            </gco:MemberName>
          </gmd:sequenceIdentifier>
          <gmd:descriptor>
            <gco:CharacterString>Depth_m</gco:CharacterString>
          </gmd:descriptor>
          <gmd:units xlink:href="https://unitsofmeasure.org/ucum.html#m"/>
        </gmd:MD_Band>
      </gmd:dimension>
      <gmd:dimension>
        <gmd:MD_Band>
          <gmd:sequenceIdentifier>
            <gco:MemberName>
              <gco:aName>
                <gco:CharacterString>dBa_nmol_kg</gco:CharacterString>
              </gco:aName>
              <gco:attributeType>
                <gco:TypeName>
                  <gco:aName>
                    <gco:CharacterString>float</gco:CharacterString>
                  </gco:aName>
                </gco:TypeName>
              </gco:attributeType>
            </gco:MemberName>
          </gmd:sequenceIdentifier>
          <gmd:descriptor>
            <gco:CharacterString>Dba_nmol_kg</gco:CharacterString>
          </gmd:descriptor>
          <gmd:units xlink:href="https://unitsofmeasure.org/ucum.html#nmol&#x2e;kg&#x2d;1"/>
        </gmd:MD_Band>
      </gmd:dimension>
      <gmd:dimension>
        <gmd:MD_Band>
          <gmd:sequenceIdentifier>
            <gco:MemberName>
              <gco:aName>
                <gco:CharacterString>omega_Ba</gco:CharacterString>
              </gco:aName>
              <gco:attributeType>
                <gco:TypeName>
                  <gco:aName>
                    <gco:CharacterString>float</gco:CharacterString>
                  </gco:aName>
                </gco:TypeName>
              </gco:attributeType>
            </gco:MemberName>
          </gmd:sequenceIdentifier>
          <gmd:descriptor>
            <gco:CharacterString>Omega_ba</gco:CharacterString>
          </gmd:descriptor>
          <gmd:units xlink:href="https://unitsofmeasure.org/ucum.html#1"/>
        </gmd:MD_Band>
      </gmd:dimension>
      <gmd:dimension>
        <gmd:MD_Band>
          <gmd:sequenceIdentifier>
            <gco:MemberName>
              <gco:aName>
                <gco:CharacterString>Ba_star_nmol_kg</gco:CharacterString>
              </gco:aName>
              <gco:attributeType>
                <gco:TypeName>
                  <gco:aName>
                    <gco:CharacterString>float</gco:CharacterString>
                  </gco:aName>
                </gco:TypeName>
              </gco:attributeType>
            </gco:MemberName>
          </gmd:sequenceIdentifier>
          <gmd:descriptor>
            <gco:CharacterString>Ba_star_nmol_kg</gco:CharacterString>
          </gmd:descriptor>
          <gmd:units xlink:href="https://unitsofmeasure.org/ucum.html#nmol&#x2e;kg&#x2d;1"/>
        </gmd:MD_Band>
      </gmd:dimension>
    </gmi:MI_CoverageDescription>
  </gmd:contentInfo>
  <gmd:distributionInfo>
    <gmd:MD_Distribution>
      <gmd:distributor>
        <gmd:MD_Distributor>
          <gmd:distributorContact>
            <gmd:CI_ResponsibleParty>
              <gmd:individualName>
                <gco:CharacterString>Adam Shepherd</gco:CharacterString>
              </gmd:individualName>
              <gmd:organisationName>
                <gco:CharacterString>BCO-DMO</gco:CharacterString>
              </gmd:organisationName>
              <gmd:contactInfo>
                <gmd:CI_Contact>
                  <gmd:phone>
                    <gmd:CI_Telephone>
                      <gmd:voice>
                        <gco:CharacterString>508-289-2772</gco:CharacterString>
                      </gmd:voice>
                    </gmd:CI_Telephone>
                  </gmd:phone>
                  <gmd:address>
                    <gmd:CI_Address>
                      <gmd:deliveryPoint>
                        <gco:CharacterString>266 Woods Hole Rd. MS#36</gco:CharacterString>
                      </gmd:deliveryPoint>
                      <gmd:city>
                        <gco:CharacterString>Woods Hole</gco:CharacterString>
                      </gmd:city>
                      <gmd:administrativeArea>
                        <gco:CharacterString>MA</gco:CharacterString>
                      </gmd:administrativeArea>
                      <gmd:postalCode>
                        <gco:CharacterString>02543</gco:CharacterString>
                      </gmd:postalCode>
                      <gmd:country>
                        <gco:CharacterString>USA</gco:CharacterString>
                      </gmd:country>
                      <gmd:electronicMailAddress>
                        <gco:CharacterString>erddap@bco-dmo.org</gco:CharacterString>
                      </gmd:electronicMailAddress>
                    </gmd:CI_Address>
                  </gmd:address>
                </gmd:CI_Contact>
              </gmd:contactInfo>
              <gmd:role>
                <gmd:CI_RoleCode codeList="https://data.noaa.gov/resources/iso19139/schema/resources/Codelist/gmxCodelists.xml#gmd:CI_RoleCode" codeListValue="distributor">distributor</gmd:CI_RoleCode>
              </gmd:role>
            </gmd:CI_ResponsibleParty>
          </gmd:distributorContact>
          <gmd:distributorFormat>
            <gmd:MD_Format>
              <gmd:name>
                <gco:CharacterString>OPeNDAP</gco:CharacterString>
              </gmd:name>
              <gmd:version>
                <gco:CharacterString>DAP/2.0</gco:CharacterString>
              </gmd:version>
            </gmd:MD_Format>
          </gmd:distributorFormat>
          <gmd:distributorTransferOptions>
            <gmd:MD_DigitalTransferOptions>
              <gmd:onLine>
                <gmd:CI_OnlineResource>
                  <gmd:linkage>
                    <gmd:URL>https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_885506_v2.html</gmd:URL>
                  </gmd:linkage>
                  <gmd:protocol>
                    <gco:CharacterString>order</gco:CharacterString>
                  </gmd:protocol>
                  <gmd:name>
                    <gco:CharacterString>Data Subset Form</gco:CharacterString>
                  </gmd:name>
                  <gmd:description>
                    <gco:CharacterString>ERDDAP's version of the OPeNDAP .html web page for this dataset. Specify a subset of the dataset and download the data via OPeNDAP or in many different file types.</gco:CharacterString>
                  </gmd:description>
                  <gmd:function>
                    <gmd:CI_OnLineFunctionCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="download">download</gmd:CI_OnLineFunctionCode>
                  </gmd:function>
                </gmd:CI_OnlineResource>
              </gmd:onLine>
            </gmd:MD_DigitalTransferOptions>
          </gmd:distributorTransferOptions>
          <gmd:distributorTransferOptions>
            <gmd:MD_DigitalTransferOptions>
              <gmd:onLine>
                <gmd:CI_OnlineResource>
                  <gmd:linkage>
                    <gmd:URL>https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_885506_v2.graph</gmd:URL>
                  </gmd:linkage>
                  <gmd:protocol>
                    <gco:CharacterString>order</gco:CharacterString>
                  </gmd:protocol>
                  <gmd:name>
                    <gco:CharacterString>Make-A-Graph Form</gco:CharacterString>
                  </gmd:name>
                  <gmd:description>
                    <gco:CharacterString>ERDDAP's Make-A-Graph .html web page for this dataset. Create an image with a map or graph of a subset of the data.</gco:CharacterString>
                  </gmd:description>
                  <gmd:function>
                    <gmd:CI_OnLineFunctionCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#CI_OnLineFunctionCode" codeListValue="mapDigital">mapDigital</gmd:CI_OnLineFunctionCode>
                  </gmd:function>
                </gmd:CI_OnlineResource>
              </gmd:onLine>
            </gmd:MD_DigitalTransferOptions>
          </gmd:distributorTransferOptions>
        </gmd:MD_Distributor>
      </gmd:distributor>
    </gmd:MD_Distribution>
  </gmd:distributionInfo>
  <gmd:metadataMaintenance>
    <gmd:MD_MaintenanceInformation>
      <gmd:maintenanceAndUpdateFrequency gco:nilReason="unknown"/>
      <gmd:maintenanceNote>
        <gco:CharacterString>This record was created from dataset metadata by ERDDAP Version 2.22</gco:CharacterString>
      </gmd:maintenanceNote>
    </gmd:MD_MaintenanceInformation>
  </gmd:metadataMaintenance>
</gmi:MI_Metadata>
