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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Katherine Keller</dc:contributor>
  <dc:contributor>Robert Poirier</dc:contributor>
  <dc:contributor>Gary S. Dwyer</dc:contributor>
  <dc:contributor>Morgan Schaller</dc:contributor>
  <dc:contributor>Helen K Coxall</dc:contributor>
  <dc:contributor>Matt O’Regan</dc:contributor>
  <dc:contributor>Thomas M. Cronin</dc:contributor>
  <dc:creator>Jesse Farmer</dc:creator>
  <dc:date>2023</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;The oxygen isotopic composition of benthic foraminiferal tests&amp;nbsp;(&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;b&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;) is one of the pre-eminent tools for correlating marine sediments and interpreting past terrestrial ice volume and deep-ocean temperatures. Despite the prevalence of&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;&lt;/span&gt;&lt;span&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;b&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;applications to marine sediment cores over the Quaternary, its use is limited in the Arctic Ocean because of low benthic foraminiferal abundances, challenges with constructing independent sediment core age models, and an apparent muted amplitude of Arctic&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;b&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;variability compared to open-ocean records. Here we evaluate the controls on Arctic&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;b&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;by using ostracode&amp;nbsp;&lt;/span&gt;&lt;span id="MathJax-Element-1-Frame" class="MathJax" data-mathml="&lt;math xmlns=&amp;quot;http://www.w3.org/1998/Math/MathML&amp;quot; id=&amp;quot;M14&amp;quot; display=&amp;quot;inline&amp;quot; overflow=&amp;quot;scroll&amp;quot; dspmath=&amp;quot;mathml&amp;quot;&gt;&lt;mrow&gt;&lt;mrow class=&amp;quot;chem&amp;quot;&gt;&lt;mi mathvariant=&amp;quot;normal&amp;quot;&gt;Mg&lt;/mi&gt;&lt;/mrow&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;mrow class=&amp;quot;chem&amp;quot;&gt;&lt;mi mathvariant=&amp;quot;normal&amp;quot;&gt;Ca&lt;/mi&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;"&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;paleothermometry to generate a composite record of the&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span&gt;&amp;nbsp;of seawater (&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;sw&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;) from 12&amp;nbsp;sediment cores in the intermediate to deep Arctic Ocean (700–2700 m) that covers the last 600 kyr based on biostratigraphy and orbitally tuned age models. Results show that Arctic&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;b&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;was generally higher than open-ocean&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;&lt;/span&gt;&lt;span&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;b&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;during interglacials but was generally equivalent to global reference records during glacial periods. The reduced glacial–interglacial Arctic&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;b&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;range resulted in part from the opposing effect of temperature, with intermediate to deep Arctic warming during glacials counteracting the whole-ocean&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;sw&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;increase from expanded terrestrial ice sheets. After removing the temperature effect from&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;b&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;, we find that the intermediate to deep Arctic experienced large (&lt;/span&gt;&lt;span class="inline-formula"&gt;≥1&lt;/span&gt;&lt;span&gt; ‰) variations in local&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;sw&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;, with generally higher local&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;sw&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;during interglacials and lower&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;sw&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;during glacials. Both the magnitude and timing of low local&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;sw&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;intervals are inconsistent with the recent proposal of freshwater intervals in the Arctic Ocean during past glaciations. Instead, we suggest that lower local&amp;nbsp;&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;sw&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;in the intermediate to deep Arctic Ocean during glaciations reflected weaker upper-ocean stratification and more efficient transport of low-&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O&lt;/span&gt;&lt;span class="inline-formula"&gt;&lt;sub&gt;sw&lt;/sub&gt;&lt;/span&gt;&lt;span&gt;&amp;nbsp;Arctic surface waters to depth by mixing and/or brine rejection.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.5194/cp-19-555-2023</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>European Geophysical Union</dc:publisher>
  <dc:title>A 600-kyr reconstruction of deep Arctic seawater δ18O from benthic foraminiferal oxygen isotopes and ostracode Mg/Ca paleothermometry</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>