Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 Middlebury College https://ror.org/0217hb928 University of Colorado, Boulder https://ror.org/02ttsq026 Costa Kassandra M kassandra.costa@whoi.edu 0000-0001-8715-638X Woods Hole Oceanographic Institution WHOI https://ror.org/03zbnzt98 Lynch-Stieglitz Jean jean@eas.gatech.edu 0000-0002-9353-1972 Georgia Institute of Technology https://ror.org/01zkghx44 Marchitto Thomas M thomas.marchitto@colorado.edu 0000-0003-2397-8768 University of Colorado, Boulder https://ror.org/02ttsq026 2026 Trace Elements of sediment core ML1208-16BB from central equatorial Pacific dataset https://doi.org/10.1594/PANGAEA.986846 2026-01-23T12:05:52 Quantitative 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. Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 Costa Kassandra M kassandra.costa@whoi.edu 0000-0001-8715-638X Lynch-Stieglitz Jean jean@eas.gatech.edu 0000-0002-9353-1972 Marchitto Thomas M thomas.marchitto@colorado.edu 0000-0003-2397-8768 2025 Deep Pacific carbonate chemistry since the Last Glacial Maximum journal article Quaternary Science Reviews 370 https://doi.org/10.1016/j.quascirev.2025.109656 109656 Ahn Seonmin Khider D 0000-0001-7501-8430 Lisiecki Lorraine E lelisi@ucsb.edu http://lorraine-lisiecki.com/ 0000-0001-7859-0096 Lawrence Charles E charles_lawrence@brown.edu 2017 A probabilistic Pliocene–Pleistocene stack of benthic δ18O using a profile hidden Markov model journal article Dynamics and Statistics of the Climate System 2(1) https://doi.org/10.1093/climsys/dzx002 Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 Costa Kassandra M kassandra.costa@whoi.edu 0000-0001-8715-638X Applebaum Lily M Conde Serena 2025 New controls on sedimentation and climate in the central equatorial Pacific Ocean journal article Geochronology (GChron) 7(1) https://doi.org/10.5194/gchron-7-123-2025 123-138 Lee T 0000-0002-5936-762X Rand Devin S drand@ucsb.edu 0000-0002-1860-2582 Lisiecki Lorraine E lelisi@ucsb.edu http://lorraine-lisiecki.com/ 0000-0001-7859-0096 Gebbie Geoffrey ggebbie@whoi.edu Lawrence Charles E charles_lawrence@brown.edu 2023 Bayesian age models and stacks: combining age inferences from radiocarbon and benthic δ 18 O stratigraphic alignment journal article Climate of the Past 19(10) https://doi.org/10.5194/cp-19-1993-2023 1993-2012 Marchitto Thomas M thomas.marchitto@colorado.edu 0000-0003-2397-8768 2006 Precise multielemental ratios in small foraminiferal samples determined by sector field ICP-MS journal article Geochemistry, Geophysics, Geosystems 7(5) https://doi.org/10.1029/2005GC001018 2005GC001018 Yu Jimin jimin.yu@anu.edu.au 0000-0002-3896-1777 Elderfield Henry he101@esc.cam.ac.uk http://www.esc.cam.ac.uk/people/academic-staff/harry-elderfield 2007 Benthic foraminiferal B/Ca ratios reflect deep water carbonate saturation state journal article Earth and Planetary Science Letters 258(1-2) https://doi.org/10.1016/j.epsl.2007.03.025 73-86 -156.27 -156.27 0.48 0.48 -156.27 0.48 0.025 0.765 National Science Foundation NSF https://doi.org/10.13039/100000001 OCE-1502927 National Science Foundation NSF https://doi.org/10.13039/100000001 OCE-210300 National Science Foundation NSF https://doi.org/10.13039/100000001 OCE-2103031 ML1208-16BB 0.48 -156.27 Central equatorial Pacific -2926.0 MGL2408 MGL2408 https://www.rvdata.us/search/cruise/MGL2408 2024-08-04T00:00:00 2024-08-04 2024-09-09T00:00:00 2024-09-09 Marcus G. Langseth Jones, Stephen Jones, Stephen Marcus G. Langseth Gravity corer GC 374 CC-BY-4.0 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ Depth, sediment/rock, top/minimum Depth sed top m depth http://purl.obolibrary.org/obo/PATO_0001595 sediment http://purl.obolibrary.org/obo/ENVO_00002007 rock http://purl.obolibrary.org/obo/ENVO_00001995 minimum Length L http://dbpedia.org/resource/Length Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 Depth sed top [m] Depth, sediment/rock, bottom/maximum Depth sed bot m depth http://purl.obolibrary.org/obo/PATO_0001595 sediment http://purl.obolibrary.org/obo/ENVO_00002007 rock http://purl.obolibrary.org/obo/ENVO_00001995 maximum Length L http://dbpedia.org/resource/Length Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 Depth sed bot [m] DEPTH, sediment/rock Depth sed m depth http://purl.obolibrary.org/obo/PATO_0001595 sediment http://purl.obolibrary.org/obo/ENVO_00002007 rock Length L http://dbpedia.org/resource/Length Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 Depth sed [m] Age model Age model ka Time T http://dbpedia.org/resource/Time see comment Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 Average. Statistically constrained with 14C and 18O via tuning to the Ahn et al. (2017, doi:10.1093/climsys/dzx002) stack using BIGMACS (Lee at al. (2023, doi:10.1093/climsys/dzx002)); age model published by Jacobel et al. (2025, doi:10.5194/gchron-7-123-2025). Age model [ka] Age, uncertainty Age unc ± age http://purl.obolibrary.org/obo/PATO_0000011 Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 1 sigma Age unc [±] Cibicidoides wuellerstorfi, Boron/Calcium ratio C. wuellerstorfi B/Ca µmol/mol Cibicidoides wuellerstorfi https://www.marinespecies.org/aphia.php?p=taxdetails&id=112890 calcium Ca https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:22984 ratio Inductively coupled plasma - mass spectrometry (ICP-MS), Thermo Finnigan, Element 2 followed by Marchitto (2006) Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 C. wuellerstorfi B/Ca [µmol/mol] Cibicidoides wuellerstorfi, Boron/Calcium ratio, uncertainty C. wuellerstorfi B/Ca unc ± calcium Ca https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:22984 ratio Inductively coupled plasma - mass spectrometry (ICP-MS), Thermo Finnigan, Element 2 followed by Marchitto (2006) Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 1 sigma C. wuellerstorfi B/Ca unc [±] Cibicidoides wuellerstorfi, carbonate saturation state C. wuellerstorfi, ∆[CO3]2- Cibicidoides wuellerstorfi https://www.marinespecies.org/aphia.php?p=taxdetails&id=112890 Calculated according to Yu and Elderfield (2007) https://doi.org/10.1016/j.epsl.2007.03.025 Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 C. wuellerstorfi, ∆[CO3]2- Cibicidoides wuellerstorfi, carbonate saturation state, uncertainty C. wuellerstorfi ∆[CO3]2- unc ± Calculated according to Yu and Elderfield (2007) https://doi.org/10.1016/j.epsl.2007.03.025 Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 1 sigma (using the analytical uncertainty and uncertainty in the calibration constants). C. wuellerstorfi ∆[CO3]2- unc [±] Cibicidoides wuellerstorfi, Manganese/Calcium ratio C. wuellerstorfi Mn/Ca µmol/mol Cibicidoides wuellerstorfi https://www.marinespecies.org/aphia.php?p=taxdetails&id=112890 manganese Mn https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:18291 calcium Ca https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:22984 ratio Inductively coupled plasma - mass spectrometry (ICP-MS), Thermo Finnigan, Element 2 followed by Marchitto (2006) Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 C. wuellerstorfi Mn/Ca [µmol/mol] Cibicidoides wuellerstorfi, Aluminium/Calcium ratio C. wuellerstorfi Al/Ca µmol/mol Cibicidoides wuellerstorfi https://www.marinespecies.org/aphia.php?p=taxdetails&id=112890 aluminium Al calcium Ca https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:22984 ratio Inductively coupled plasma - mass spectrometry (ICP-MS), Thermo Finnigan, Element 2 followed by Marchitto (2006) Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 C. wuellerstorfi Al/Ca [µmol/mol] Cibicidoides wuellerstorfi, Iron/Calcium ratio C. wuellerstorfi Fe/Ca µmol/mol Cibicidoides wuellerstorfi https://www.marinespecies.org/aphia.php?p=taxdetails&id=112890 Iron https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=100628 calcium Ca https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:22984 ratio Inductively coupled plasma - mass spectrometry (ICP-MS), Thermo Finnigan, Element 2 followed by Marchitto (2006) Jacobel Allison W Ajacobel@middlebury.edu 0000-0002-1036-9026 C. wuellerstorfi Fe/Ca [µmol/mol] citable B/Ca carbonate preservation Equatorial pacific ocean LGM trace metals author10780 author113096 author113097 author28492 author29622 author31433 author42643 author51083 author66169 author67807 author75429 author77018 author86116 author87937 author896 award4018 award4019 award4421 basis5006 campaign3395063 campaign52708 event3302621 funder20211 geocode1 geocode1599 geocode1600 geocode1601 geocode8128 inst20185 inst20582 inst21732 inst22141 journal13626 journal16991 journal17054 journal3567 journal4644 journal6006 license21 method11107 method18349 method18351 method195 param101831 param130845 param518755 param518756 param533830 param533831 param550684 param550685 param550692 param550693 param6 pi66169 ref105186 ref135750 ref135751 ref135752 ref135754 ref64472 term1045260 term1073130 term1073131 term1073132 term1073135 term2022952 term2663825 term38263 term38492 term38520 term38521 term40136 term41019 term41056 term43863 term43975 term47246 term52136 term627 term68811 term71508 term76749