M. P. Badger, C. H. Lear, R. D. Pancost, G. L. Foster, T. R. Bailey et al., , p.498

H. A. , CO 2 drawdown following the middle Miocene expansion of the Antarctic 499 Ice Sheet, Paleoceanography, vol.28, pp.42-53, 2013.

C. Beltran, M. De-rafélis, A. Person, F. Stalport, and M. Renard, Multiproxy approach 501 for determination of nature and origin of carbonate micro-particles so-called "micarb" in 502 pelagic sediments, Sediment. Geol, vol.213, pp.64-76, 2009.

K. Billups and D. P. Schrag, Paleotemperatures and ice volume of the past 27 Myr 504 revisited with paired Mg/Ca and 18 O/ 16 O measurements on benthic foraminifera, 505 Paleoceanography, vol.17, p.1003, 2002.

C. T. Bolton, M. T. Hernández-sánchez, M. Fuertes, S. González-lemos, and L. Abrevaya, , p.507

A. Mendez-vicente, J. Flores, I. Probert, L. Giosan, J. Johnson et al., 508 Decrease in coccolithophore calcification and CO 2 since the middle Miocene, 2016.

, Commun, vol.7, p.10284

C. T. Bolton and H. M. Stoll, Late Miocene threshold response of marine algae to carbon 511 dioxide limitation, Nature, vol.500, pp.558-562, 2013.

C. T. Bolton, H. M. Stoll, and A. Mendez-vicente, Vital effects in coccolith calcite: 513 climate evolution during the middle Miocene 'Monterey' carbon-isotope excursion, 564 Earth Planet. Sci. Lett, vol.261, pp.534-550, 2012.

C. J. Hollis, The DeepMIP contribution to PMIP4: methodologies for selection, 566 compilation and analysis of latest Paleocene and early Eocene climate proxy data, 567 incorporating version 0.1 of the DeepMIP database, Geosci. Model Dev, vol.12, pp.3149-3206, 2019.

L. Holtz, D. Wolf-gladrow, and S. Thoms, Numerical cell model investigating 569 cellular carbon fluxes in Emiliania huxleyi, J. Theor. Biol, vol.364, pp.305-315, 2015.

J. P. Kennett, Miocene to Early Pliocene Oxygen and Carbon Isotope Stratigraohy in 571 the Southwest Pacific, Deep Sea Drilling Project Leg 90, 1986.

J. P. Kennett, C. Borch, P. A. Baker, C. E. Barton, A. Boersma et al., , p.574

W. C. Dudley, J. V. Gardner, D. G. Jenkins, W. H. Lohman, E. Martini et al., , p.575

R. Morin, C. S. Nelson, C. Robert, M. S. Srinivasan, R. Stein et al., , p.576

M. G. , Palaeotectonic implications of increased late Eocene-early Oligocene 577 volcanism from South Pacific DSDP sites, Nature, vol.316, pp.507-511, 1985.

S. Kim and J. R. O'neil, Equilibrium and nonequilibrium oxygen isotope effects in 579 synthetic carbonates, Geochim. Cosmochim. Acta, vol.61, pp.3461-3475, 1997.

W. M. Kürschner, Z. Kva?ek, and D. L. Dilcher, The impact of Miocene atmospheric 581 carbon dioxide fluctuations on climate and the evolution of terrestrial ecosystems, Proc. 582 Natl. Acad. Sci. 105, pp.449-453, 2008.

C. H. Lear, H. Elderfield, and P. A. Wilson, Cenozoic Deep-Sea Temperatures and Global 584 Ice Volumes from Mg/Ca in Benthic Foraminiferal Calcite, Science, vol.287, pp.269-272, 2000.

C. H. Lear, E. M. Mawbey, and Y. Rosenthal, Cenozoic benthic foraminiferal Mg/Ca and 586, 2010.

L. Records, Toward unlocking temperatures and saturation states, Paleoceanography, vol.587, pp.1-11

H. L. Mcclelland, N. Barbarin, L. Beaufort, M. Hermoso, P. Ferretti et al., , p.589

R. E. Rickaby, Calcification response of a key phytoplankton family to 590 millennial-scale environmental change, Sci. Rep, vol.6, p.34263, 2016.

H. L. Mcclelland, J. Bruggeman, M. Hermoso, and R. E. Rickaby, The origin of 592 carbon isotope vital effects in coccolith calcite, Nat. Commun, vol.8, p.14511, 2017.

F. Minoletti, M. Hermoso, Y. Candelier, and I. Probert, Calibration of stable isotope 594 composition of Thoracosphaera heimii (dinoflagellate) calcite for reconstructing 595 paleotemperatures in the intermediate photic zone, Paleoceanography, vol.29, pp.1111-1126, 2014.

F. Minoletti, M. Hermoso, and V. Gressier, Separation of sedimentary micron-sized 597 particles for palaeoceanography and calcareous nannoplankton biogeochemistry, 2009.

. Protoc, , vol.4, pp.14-24

H. Niebler, H. Hubberten, and R. Gersonde, Oxygen Isotope Values of Planktic 600 Foraminifera: A Tool for the Reconstruction of Surface Water Stratification, in: Use of 601 Proxies in Paleoceanography, p.189, 1999.

M. Pagani, A. Arthur, and H. Freeman, Variations in Miocene phytoplankton growth 604 rates in the southwest Atlantic: Evidence for changes in ocean circulation, 605 Paleoceanography, vol.15, pp.486-496, 2000.

M. Pagani, M. A. Arthur, and K. H. Freeman, Miocene evolution of atmospheric carbon 607 dioxide, Paleoceanography, vol.14, pp.273-292, 1999.

P. N. Pearson, N. J. Shackleton, and M. A. Hall, Stable isotopic evidence for the sympatric 609 divergence of Globigerinoides trilobus and Orbulina universa, 1997.

, J. Geol. Soc. London, vol.154, pp.295-302

D. Reghellin, H. K. Coxall, G. R. Dickens, and J. Backman, Carbon and oxygen isotopes 612 of bulk carbonate in sediment deposited beneath the eastern equatorial Pacific over the 613 last 8 million years, Paleoceanography, vol.30, pp.1-26, 2015.

R. E. Rickaby, E. Bard, C. Sonzogni, F. Rostek, L. Beaufort et al., , p.615

D. P. Schrag, Coccolith chemistry reveals secular variations in the global ocean 616 carbon cycle?, Earth Planet. Sci. Lett, vol.253, pp.83-95, 2007.

R. E. Rickaby, J. Henderiks, and J. N. Young, Perturbing phytoplankton: response and 618 isotopic fractionation with changing carbonate chemistry in two coccolithophore 619 species, Clim. Past, vol.6, pp.771-785, 2010.

G. Rousselle, C. Beltran, M. Sicre, I. Raffi, and M. De-rafélis, Changes in sea-621 surface conditions in the Equatorial Pacific during the middle Miocene-Pliocene as 622 inferred from coccolith geochemistry, Earth Planet. Sci. Lett, vol.361, pp.412-421, 2013.

R. Schlitzer, Ocean Data View Package, 2017.

A. E. Shevenell, J. P. Kennett, and D. W. Lea, Middle Miocene ice sheet dynamics, deep-625 sea temperatures, and carbon cycling: A Southern Ocean perspective, Geochemistry, p.626, 2008.

, Geophys. Geosystems, vol.9, p.2006

A. E. Shevenell, J. P. Kennett, and D. W. Lea, Middle Miocene Southern Ocean cooling 628 and Antarctic cryosphere expansion, Science, vol.305, pp.1766-1770, 2004.

H. J. Spero, K. M. Mielke, E. M. Kalve, D. W. Lea, and D. K. Pak, Multispecies approach 630 to reconstructing eastern equatorial Pacific thermocline hydrography during the past 360 631 kyr, Paleoceanography, vol.18, 2003.

J. R. Super, E. Thomas, M. Pagani, M. Huber, C. O. Brien et al., , p.633

P. M. , North Atlantic temperature and pCO 2 coupling in the early-middle Miocene, 634 Geology, vol.46, pp.519-522, 2018.

J. C. Tindall and A. M. Haywood, Modeling oxygen isotopes in the Pliocene: Large-scale 636 features over the land and ocean, Paleoceanography, vol.30, pp.1183-1201, 2015.

M. Tomczak and S. Godfrey, Regional Oceanography: An Introduction, 2003.

M. Tremblin, M. Hermoso, and F. Minoletti, Equatorial heat accumulation as a long-term 640 trigger of permanent Antarctic ice-sheets during the Cenozoic, Proc. Natl. Acad. Sci. 641 USA, vol.113, pp.11782-11787, 2016.

. Van-hinsbergen, J. J. Douwe, L. V. De-groot, S. J. Van-schaik, W. Spakman et al., , p.643

A. Sluijs, C. G. Langereis, and H. Brinkhuis, A Paleolatitude Calculator for 644, 2015.

, Paleoclimate Studies (model version 1.2), PLoS One, vol.10, pp.1-21

E. Vincent and W. H. Berger, The Carbon Cycle and 647 Atmospheric CO 2 : Natural Variations Archean to Present, pp.455-468, 1985.

A. Winter, B. Rost, H. Hilbrecht, and M. Elbrächter, Vertical and horizontal distribution 650 of coccolithophores in the Caribbean Sea, Geo-Marine Lett, vol.22, pp.150-161, 2002.

F. Woodruff and S. Savin, Mid-Miocene isotope stratigraphy in the deep sea: High-652 resolution correlations, paleoclimatic cycles, and sediment preservation, 1991.

, Paleoceanography, vol.6, pp.755-806

J. Zachos, M. Pagani, L. Sloan, E. Thomas, and K. Billups, Trends, rhythms, and 655 aberrations in global climate 65 Ma to present, Science, vol.292, pp.686-693, 2001.

Y. G. Zhang, M. Pagani, Z. Liu, S. M. Bohaty, and R. Deconto, A 40-million-year history 657 of atmospheric CO 2, Philos. Trans. R. Soc. A, vol.371, 2013.

P. Ziveri, H. Stoll, I. Probert, C. Klaas, M. Geisen et al., Stable 659 isotope 'vital effects' in coccolith calcite, Earth Planet. Sci. Lett, vol.210, pp.137-149, 2003.

P. Ziveri, S. Thoms, I. Probert, M. Geisen, and G. Langer, A universal carbonate effect 661 on stable oxygen isotope ratios in unicellular planktonic calcifying organisms, 2012.

, Biogeosciences, vol.9, pp.1025-1032

, Raw oxygen and carbon isotopic composition of calcite biominerals (coccoliths and 691 planktonic foraminifera). Panel a shows the evolution of oxygen isotope composition of planktonic 692

, The grey vertical area 694 represents the interval of the middle Miocene Climatic Transition. Data source for the foraminifera 695 measurements is inset. Panel b shows a reconstruction of ? 18 O sw across the study interval accounting 696 from paired Mg/Ca and foraminifera ? 18 O values. The correction of data accounts for changing CO 3 2-697 concentrations on the Mg/Ca calibration (data from Lear et al, foraminifera G. quadrilobatus (white and black dots) and the coccoliths of this study concentrated in 693 narrow size microfractions throughout the studied interval (red and blue dots), 2007.

, Both SST curved 707 derived from Eq. 2 using the seawater ? 18 O compositions shown in Fig. 3b. The coccolith 708 (Reticulofenestrid) ? 18 O-derived SSTs at DSDP site 588 accounting for the culture-derived oxygen 709 isotope vital effect for coccolith of this size range (0.8?, see text) is in good agreement with the 710 foraminiferal reference. Error bars on coccolith dots correspond to the uncertainties in the oxygen 711 isotope vital effect (here taken at ±0.1?). The pink area denotes a sensitivity test of the presence of, Comparison of sea surface temperature estimates derived from the oxygen isotope 706 composition of foraminifera and coccoliths in the 3-5 µm microfractions, vol.712

, We observe enhanced negative carbon isotope 719 vital effects at 12.5 Ma in the coccolith record. Asterisks denote levels that have require interpolation 720 of foraminifera data. Panel b shows isotopic offset between coccolith fractions, comparable to the 721 approach by Bolton & Stoll (2013) introducing "small-large" differences in the context of pCO 2 722 values (raw data). To first order, Figure 5. Expression of the carbon isotopic offsets between foraminifera and coccolith 717 assemblages. Panel a compares ? 13 C values of foraminifera

. Mcclelland, The data suggest that the vital effects affecting both carbon and 730 oxygen isotopic systems are under a common environmental control, although the intracellular 731 mechanisms at play differ, Figure 6. Scatter plot of the carbon and oxygen isotope compositions between relatively small 729 and large coccolith assemblages, 2017.