Deglacial carbon cycle changes observed in a compilation of 127 benthic <i>δ</i><sup>13</sup>C time series (20–6 ka)

Abstract

<p><strong>Abstract.</strong> We present a compilation of 127 time series <span class="inline-formula"><i>δ</i>¹³C</span> records from <i>Cibicides wuellerstorfi</i> spanning the last deglaciation (20–6<span class="thinspace"></span>ka) which is well-suited for reconstructing large-scale carbon cycle changes, especially for comparison with isotope-enabled carbon cycle models. The age models for the <span class="inline-formula"><i>δ</i>¹³C</span> records are derived from regional planktic radiocarbon compilations (<span class="cit" id="xref_altparen.1"><a href="#bib1.bibx195">Stern and Lisiecki</a>, <a href="#bib1.bibx195">2014</a></span>). The <span class="inline-formula"><i>δ</i>¹³C</span> records were stacked in nine different regions and then combined using volume-weighted averages to create intermediate, deep, and global <span class="inline-formula"><i>δ</i>¹³C</span> stacks. These benthic <span class="inline-formula"><i>δ</i>¹³C</span> stacks are used to reconstruct changes in the size of the terrestrial biosphere and deep ocean carbon storage. The timing of change in global mean <span class="inline-formula"><i>δ</i>¹³C</span> is interpreted to indicate terrestrial biosphere expansion from 19–6<span class="thinspace"></span>ka. The <span class="inline-formula"><i>δ</i>¹³C</span> gradient between the intermediate and deep ocean, which we interpret as a proxy for deep ocean carbon storage, matches the pattern of atmospheric <span class="inline-formula">CO₂</span> change observed in ice core records. The presence of signals associated with the terrestrial biosphere and atmospheric <span class="inline-formula">CO₂</span> indicates that the compiled <span class="inline-formula"><i>δ</i>¹³C</span> records have sufficient spatial coverage and time resolution to accurately reconstruct large-scale carbon cycle changes during the glacial termination.</p>