10.1594/PANGAEA.986846Jacobel, Allison WAllison WJacobel0000-0002-1036-9026Middlebury CollegeUniversity of Colorado, BoulderCosta, Kassandra MKassandra MCosta0000-0001-8715-638XWoods Hole Oceanographic InstitutionLynch-Stieglitz, JeanJeanLynch-Stieglitz0000-0002-9353-1972Georgia Institute of TechnologyMarchitto, Thomas MThomas MMarchitto0000-0003-2397-8768University of Colorado, BoulderPANGAEA2026B/Cacarbonate preservationEquatorial pacific oceanLGMtrace metalsDepth, sediment/rock, top/minimumDepth, sediment/rock, bottom/maximumDEPTH, sediment/rockAge modelAge, uncertaintyCibicidoides wuellerstorfi, Boron/Calcium ratioCibicidoides wuellerstorfi, Boron/Calcium ratio, uncertaintyCibicidoides wuellerstorfi, carbonate saturation stateCibicidoides wuellerstorfi, carbonate saturation state, uncertaintyCibicidoides wuellerstorfi, Manganese/Calcium ratioCibicidoides wuellerstorfi, Aluminium/Calcium ratioCibicidoides wuellerstorfi, Iron/Calcium ratioGravity corersee commentInductively coupled plasma - mass spectrometry (ICP-MS), Thermo Finnigan, Element 2 followed by Marchitto (2006)Calculated according to Yu and Elderfield (2007)MGL2408Marcus G. LangsethDataset10.1016/j.quascirev.2025.10965610.1093/climsys/dzx00210.5194/gchron-7-123-202510.5194/cp-19-1993-202310.1029/2005GC00101810.1016/j.epsl.2007.03.025374 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalQuantitative constraints on deep ocean carbonate chemistry are critical for understanding the processes responsible for glacial-interglacial changes in atmospheric pCO2 and the ocean feedbacks that amplify carbon cycle change. Here, we present a new, millennially-resolved, B/Ca-based record of carbonate ion concentration (∆[CO32-]), measured on C. wullerstorfi, from central equatorial Pacific site ML1208-16BB spanning the last 35 ka. This site, bathed by Pacific Deep Water, reveals a ~24 ± 7 µmol/kg rise in deep ocean [CO32-] between ~20 and 10 ka, a larger change than previously reconstructed from sites in the western equatorial Pacific and those in the central equatorial Pacific bathed by Lower Circumpolar Deep Water.-156.270.48Central equatorial PacificNational Science Foundationhttps://doi.org/10.13039/100000001OCE-1502927National Science Foundationhttps://doi.org/10.13039/100000001OCE-210300National Science Foundationhttps://doi.org/10.13039/100000001OCE-2103031