Articles | Volume 21, issue 11
https://doi.org/10.5194/cp-21-2283-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-21-2283-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
19 Nov 2025
Research article |
| 19 Nov 2025
| 19 Nov 2025
Increasing opal productivity in the Late Eocene Southern Ocean: Evidence for increased carbon export preceding the Eocene-Oligocene glaciation
Volkan Özen
CORRESPONDING AUTHOR
Freie Universität Berlin, Institute for Geological Sciences, Malteserstraße 74–100, 12249 Berlin, Germany
Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany
Johan Renaudie
Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany
David Lazarus
Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany
Gabrielle Rodrigues de Faria
Freie Universität Berlin, Institute for Geological Sciences, Malteserstraße 74–100, 12249 Berlin, Germany
Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, 10115 Berlin, Germany
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Cited articles
Abrantes, F., Cermeno, P., Lopes, C., Romero, O., Matos, L., Van Iperen, J., Rufino, M., and Magalhães, V.: Diatoms Si uptake capacity drives carbon export in coastal upwelling systems, Biogeosciences, 13, 4099–4109, https://doi.org/10.5194/bg-13-4099-2016, 2016.
Anagnostou, E., John, E. H., Babila, T. L., Sexton, P. F., Ridgwell, A., Lunt, D. J., Pearson, P. N., Chalk, T. B., Pancost, R. D., and Foster, G. L.: Proxy evidence for state-dependence of climate sensitivity in the Eocene greenhouse, Nat. Commun., 11, 4436, https://doi.org/10.1038/s41467-020-17887-x, 2020.
Anderson, L. D. and Delaney, M. L.: Middle Eocene to early Oligocene paleoceanography from Agulhas Ridge, Southern Ocean (Ocean Drilling Program Leg 177, Site 1090), Paleoceanography, 20, PA1013, https://doi.org/10.1029/2004PA001043, 2005.
Baldauf, J. G. and Barron, J. A.: Evolution of Biosiliceous Sedimentation Patterns – Eocene Through Quaternary: Paleoceanographic Response to Polar Cooling, in: Geological History of the Polar Oceans: Arctic versus Antarctic, edited by: Bleil, U. and Thiede, J., Springer Netherlands, Dordrecht, 575–607, https://doi.org/10.1007/978-94-009-2029-3_32, 1990.
Barker, P. F.: Scotia Sea regional tectonic evolution: Implications for mantle flow and palaeocirculation, Earth-Sci. Rev., 55, 1–39, https://doi.org/10.1016/s0012-8252(01)00055-1, 2001.
Barker, P. F., Filippelli, G. M., Florindo, F., Martin, E. E., and Scher, H. D.: Onset and role of the Antarctic Circumpolar Current, Deep-Sea Res. Pt. II, 54, 2388–2398, https://doi.org/10.1016/j.dsr2.2007.07.028, 2007.
Barron, J. A., Stickley, C. E., and Bukry, D.: Paleoceanographic, and paleoclimatic constraints on the global Eocene diatom and silicoflagellate record, Palaeogeogr. Palaeocl., 422, 85–100, https://doi.org/10.1016/j.palaeo.2015.01.015, 2015.
Borrelli, C., Cramer, B. S., and Katz, M. E.: Bipolar Atlantic deepwater circulation in the middle-late Eocene: Effects of Southern Ocean gateway openings, Paleoceanography, 29, 308–327, https://doi.org/10.1002/2012PA002444, 2014.
Bryłka, K., Witkowski, J., and Bohaty, S. M.: Biogenic silica accumulation and diatom assemblage variations through the Eocene-Oligocene Transition: A Southern Indian Ocean versus South Atlantic perspective, Palaeogeogr. Palaeocl., 636, 111971, https://doi.org/10.1016/j.palaeo.2023.111971, 2024.
Cabrera-Brufau, M., Arin, L., Sala, M. M., Cermeño, P., and Marrasé, C.: Diatom dominance enhances resistance of phytoplanktonic POM to mesopelagic microbial decomposition, Frontiers in Marine Science, 8, https://doi.org/10.3389/fmars.2021.683354, 2021.
Cortese, G., Gersonde, R., Hillenbrand, C.-D., and Kuhn, G.: Opal sedimentation shifts in the World Ocean over the last 15 Myr, Earth Planet. Sc. Lett., 224, 509–527, https://doi.org/10.1016/j.epsl.2004.05.035, 2004.
Coxall, H. K. and Pearson, P. N.: The Eocene–Oligocene Transition, in: Deep-time perspectives on climate change: Marrying the signal from computer models and biological proxies, The Geological Society of London on behalf of The Micropalaeontological Society, 351–387, https://doi.org/10.1144/tms002.16, 2007.
Coxall, H. K., Wilson, P. A., Pälike, H., Lear, C. H., and Backman, J.: Rapid stepwise onset of Antarctic glaciation and deeper calcite compensation in the Pacific Ocean, Nature, 433, 53–57, https://doi.org/10.1038/nature03135, 2005.
DeConto, R. M. and Pollard, D.: Rapid Cenozoic glaciation of antarctica induced by declining atmospheric CO2, Nature, 421, 245–249, https://doi.org/10.1038/nature01290, 2003.
Diekmann, B., Kuhn, G., Gersonde, R., and Mackensen, A.: Middle Eocene to early Miocene environmental changes in the sub-Antarctic Southern Ocean: Evidence from biogenic and terrigenous depositional patterns at ODP site 1090, Global Planet. Change, 40, 295–313, https://doi.org/10.1016/j.gloplacha.2003.09.001, 2004.
Diester-Haass, L. and Zahn, R.: Eocene-Oligocene transition in the Southern Ocean: History of water mass circulation and biological productivity, Geology, 24, 163–166, https://doi.org/10.1130/0091-7613(1996)024<0163:EOTITS>2.3.CO;2, 1996.
Douglas, P. M. J., Affek, H. P., Ivany, L. C., Houben, A. J. P., Sijp, W. P., Sluijs, A., Schouten, S., and Pagani, M.: Pronounced zonal heterogeneity in Eocene southern high-latitude sea surface temperatures, P. Natl. Acad. Sci. USA, 111, 6582–6587, https://doi.org/10.1073/pnas.1321441111, 2014.
Egan, K. E., Rickaby, R. E. M., Hendry, K. R., and Halliday, A. N.: Opening the gateways for diatoms primes earth for Antarctic glaciation, Earth Planet. Sc. Lett., 375, 34–43, https://doi.org/10.1016/j.epsl.2013.04.030, 2013.
Ehrmann, W. U.: Implications of sediment composition on the southern Kerguelen Plateau for paleoclimate and depositional environment, in: Proceedings of the ocean drilling program, Proceedings of the Ocean Drilling Program, Scientific Results, 119, https://doi.org/10.2973/odp.proc.sr.119.121.1991, 1991.
Ehrmann, W. U. and Mackensen, A.: Sedimentological evidence for the formation of an east Antarctic ice sheet in Eocene/Oligocene time, Palaeogeogr. Palaeocl., 93, 85–112, https://doi.org/10.1016/0031-0182(92)90185-8, 1992.
Elsworth, G., Galbraith, E., Halverson, G., and Yang, S.: Enhanced weathering and CO2 drawdown caused by latest Eocene strengthening of the Atlantic meridional overturning circulation, Nat. Geosci., 10, 213–216, https://doi.org/10.1038/ngeo2888, 2017.
Evangelinos, D., Escutia, C., Flierdt, T. van de, Valero, L., Flores, J.-A., Harwood, D. M., Hoem, F. S., Bijl, P., Etourneau, J., Kreissig, K., Nilsson-Kerr, K., Holder, L., López-Quirós, A., and Salabarnada, A.: Absence of a strong, deep-reaching antarctic circumpolar current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene, Global Planet. Change, 208, 103718, https://doi.org/10.1016/j.gloplacha.2021.103718, 2022.
Evangelinos, D., Etourneau, J., Van De Flierdt, T., Crosta, X., Jeandel, C., Flores, J.-A., Harwood, D. M., Valero, L., Ducassou, E., Sauermilch, I., Klocker, A., Cacho, I., Pena, L. D., Kreissig, K., Benoit, M., Belhadj, M., Paredes, E., Garcia-Solsona, E., López-Quirós, A., Salabarnada, A., and Escutia, C.: Late Miocene onset of the modern Antarctic Circumpolar Current, Nat. Geosci., 17, 165–170, https://doi.org/10.1038/s41561-023-01356-3, 2024.
Farmer, J. R., Hertzberg, J. E., Cardinal, D., Fietz, S., Hendry, K., Jaccard, S. L., Paytan, A., Rafter, P. A., Ren, H., Somes, C. J., Sutton, J. N., and GEOTRACES-PAGES Biological Productivity Working Group Members: Assessment of C, N and Si isotopes as tracers of past ocean nutrient and carbon cycling, Global Biogeochem. Cy., 35, e2020GB006775, https://doi.org/10.1029/2020GB006775, 2021.
Faul, K. L. and Delaney, M. L.: A comparison of early Paleogene export productivity and organic carbon burial flux for Maud Rise, Weddell Sea, and Kerguelen Plateau, south Indian Ocean, Paleoceanography, 25, https://doi.org/10.1029/2009PA001916, 2010.
Funakawa, S. and Nishi, H.: Radiolarian faunal changes during the Eocene-Oligocene transition in the Southern Ocean (maud rise, ODP leg 113, site 689) and its significance in paleoceanographic change, Micropaleontology, 54, 15–26, https://doi.org/10.47894/mpal.54.1.03, 2008.
Gasson, E., Lunt, D. J., DeConto, R., Goldner, A., Heinemann, M., Huber, M., LeGrande, A. N., Pollard, D., Sagoo, N., Siddall, M., Winguth, A., and Valdes, P. J.: Uncertainties in the modelled CO2 threshold for Antarctic glaciation, Clim. Past, 10, 451–466, https://doi.org/10.5194/cp-10-451-2014, 2014.
Hatton, I. A., Mazzarisi, O., Altieri, A., and Smerlak, M.: Diversity begets stability: Sublinear growth and competitive coexistence across ecosystems, Science, 383, https://doi.org/10.1126/science.adg8488, 2024.
Hodel, F., Grespan, R., De Rafélis, M., Dera, G., Lezin, C., Nardin, E., Rouby, D., Aretz, M., Steinnman, M., Buatier, M., Lacan, F., Jeandel, C., and Chavagnac, V.: Drake Passage gateway opening and Antarctic Circumpolar Current onset 31 Ma ago: The message of foraminifera and reconsideration of the Neodymium isotope record, Chem. Geol., 570, 120171, https://doi.org/10.1016/j.chemgeo.2021.120171, 2021.
Hodel, F., Fériot, C., Dera, G., De Rafélis, M., Lezin, C., Nardin, E., Rouby, D., Aretz, M., Antonio, P., Buatier, M., Steinmann, M., Lacan, F., Jeandel, C., and Chavagnac, V.: Eocene-Oligocene southwest Pacific Ocean paleoceanography new insights from foraminifera chemistry (DSDP site 277, Campbell Plateau), Front. Earth Sci., 10, 998237, https://doi.org/10.3389/feart.2022.998237, 2022.
Houben, A. J. P., Bijl, P. K., Sluijs, A., Schouten, S., and Brinkhuis, H.: Late Eocene Southern Ocean Cooling and Invigoration of Circulation Preconditioned Antarctica for Full-Scale Glaciation, Geochem. Geophy. Geosy., 20, 2214–2234, https://doi.org/10.1029/2019GC008182, 2019.
Hutchinson, D. K., Coxall, H. K., Lunt, D. J., Steinthorsdottir, M., de Boer, A. M., Baatsen, M., von der Heydt, A., Huber, M., Kennedy-Asser, A. T., Kunzmann, L., Ladant, J.-B., Lear, C. H., Moraweck, K., Pearson, P. N., Piga, E., Pound, M. J., Salzmann, U., Scher, H. D., Sijp, W. P., Śliwińska, K. K., Wilson, P. A., and Zhang, Z.: The Eocene–Oligocene transition: a review of marine and terrestrial proxy data, models and model–data comparisons, Clim. Past, 17, 269–315, https://doi.org/10.5194/cp-17-269-2021, 2021.
Kennett, J. P.: Cenozoic evolution of Antarctic glaciation, the circum-Antarctic Ocean, and their impact on global paleoceanography, J. Geophys. Res., 82, 3843–3860, https://doi.org/10.1029/JC082i027p03843, 1977.
Klages, J. P., Hillenbrand, C.-D., Bohaty, S. M., Salzmann, U., Bickert, T., Lohmann, G., Knahl, H. S., Gierz, P., Niu, L., Titschack, J., Kuhn, G., Frederichs, T., Müller, J., Bauersachs, T., Larter, R. D., Hochmuth, K., Ehrmann, W., Nehrke, G., Rodríguez-Tovar, F. J., Schmiedl, G., Spezzaferri, S., Läufer, A., Lisker, F., Van De Flierdt, T., Eisenhauer, A., Uenzelmann-Neben, G., Esper, O., Smith, J. A., Pälike, H., Spiegel, C., Dziadek, R., Ronge, T. A., Freudenthal, T., and Gohl, K.: Ice sheet–free West Antarctica during peak early Oligocene glaciation, Science, 385, 322–327, https://doi.org/10.1126/science.adj3931, 2024.
Ladant, J.-B., Donnadieu, Y., and Dumas, C.: Links between CO2, glaciation and water flow: reconciling the Cenozoic history of the Antarctic Circumpolar Current, Clim. Past, 10, 1957–1966, https://doi.org//10.5194/cp-10-1957-2014, 2014.
Lauretano, V., Kennedy-Asser, A. T., Korasidis, V. A., Wallace, M. W., Valdes, P. J., Lunt, D. J., Pancost, R. D., and Naafs, B. D. A.: Eocene to Oligocene terrestrial southern hemisphere cooling caused by declining pCO2, Nat. Geosci., 14, 659–664, https://doi.org/10.1038/s41561-021-00788-z, 2021.
Lazarus, D.: An improved cover-slip holder for preparing microslides of randomly distributed particles, J. Sediment. Res., 64, p. 686, https://doi.org/10.2110/jsr.64.686, 1994.
Lazarus, D., Hollis, C. J., and Apel, M.: Patterns of opal and radiolarian change in the Antarctic mid-Paleogene: Clues to the origin of the Southern Ocean, Micropaleontology, 54, 41–48, https://doi.org/10.47894/mpal.54.1.05, 2008.
Lazarus, D., Barron, J., Renaudie, J., Diver, P., and Türke, A.: Cenozoic planktonic marine diatom diversity and correlation to climate change, PLoS ONE, 9, e84857, https://doi.org/10.1371/journal.pone.0084857, 2014.
Lear, C. H., Bailey, T. R., Pearson, P. N., Coxall, H. K., and Rosenthal, Y.: Cooling and ice growth across the Eocene-Oligocene transition, Geology, 36, 251–254, https://doi.org/10.1130/G24584A.1, 2008.
Liu, Z., Pagani, M., Zinniker, D., DeConto, R., Huber, M., Brinkhuis, H., Shah, S. R., Leckie, R. M., and Pearson, A.: Global Cooling During the Eocene-Oligocene Climate Transition, Science, 323, 1187–1190, https://doi.org/10.1126/science.1166368, 2009.
Livermore, R., Hillenbrand, C., Meredith, M., and Eagles, G.: Drake passage and Cenozoic climate: An open and shut case?, Geochem. Geophy. Geosy., 8, https://doi.org/10.1029/2005gc001224, 2007.
Mackensen, A.: Changing Southern Ocean palaeocirculation and effects on global climate, Antarctic Science, 16, 369–386, https://doi.org/10.1017/s0954102004002202, 2004.
Malviya, S., Scalco, E., Audic, S., Vincent, F., Veluchamy, A., Poulain, J., Wincker, P., Iudicone, D., De Vargas, C., Bittner, L., Zingone, A., and Bowler, C.: Insights into global diatom distribution and diversity in the world's ocean, P. Natl. Acad. Sci. USA, 113, https://doi.org/10.1073/pnas.1509523113, 2016.
Mittelbach, G. G., Scheiner, S. M., and Steiner, C. F.: What Is the Observed Relationship Between Species Richness and Productivity? Reply, Ecology, 84, 3390–3395, https://doi.org/10.1890/03-3077, 2003.
Moore, T. C.: Method of randomly distributing grains for microscopic examination, J. Sediment. Res., 43, https://doi.org/10.1306/74d728ba-2b21-11d7-8648000102c1865d, 1973.
Müller, R. D., Cannon, J., Qin, X., Watson, R. J., Gurnis, M., Williams, S., Pfaffelmoser, T., Seton, M., Russell, S. H. J., and Zahirovic, S.: GPlates: Building a Virtual Earth Through Deep Time, Geochem. Geophy. Geosy., 19, 2243–2261, https://doi.org/10.1029/2018GC007584, 2018.
Nilsen, E. B., Anderson, L. D., and Delaney, M. L.: Paleoproductivity, nutrient burial, climate change and the carbon cycle in the western equatorial Atlantic across the Eocene/Oligocene boundary, Paleoceanography, 18, https://doi.org/10.1029/2002PA000804, 2003.
O'Brien, C. L., Huber, M., Thomas, E., Pagani, M., Super, J. R., Elder, L. E., and Hull, P. M.: The enigma of Oligocene climate and global surface temperature evolution, Proc. Natl. Acad. Sci. U.S.A., 117, 25302–25309, https://doi.org/10.1073/pnas.2003914117, 2020.
Özen, V., Lazarus, D., Renaudie, J., and Faria, G.: Increasing opal productivity in the Late Eocene Southern Ocean: Evidence for increased carbon export preceding the Eocene-Oligocene glaciation, Zenodo [data set], https://doi.org/10.5281/zenodo.14826336, 2025a.
Özen, V., Renaudie, J., and Lazarus, D.: Unraveling Southern Ocean Diatom Diversity Across the Eocene-Oligocene Transition, EarthArxiv [preprint], https://doi.org/10.31223/X50N1B, 2025b.
Pascher, K. M., Hollis, C. J., Bohaty, S. M., Cortese, G., McKay, R. M., Seebeck, H., Suzuki, N., and Chiba, K.: Expansion and diversification of high-latitude radiolarian assemblages in the late Eocene linked to a cooling event in the southwest Pacific, Clim. Past, 11, 1599–1620, https://doi.org/10.5194/cp-11-1599-2015, 2015.
Paxman, G. J. G., Jamieson, S. S. R., Hochmuth, K., Gohl, K., Bentley, M. J., Leitchenkov, G., and Ferraccioli, F.: Reconstructions of Antarctic topography since the Eocene–Oligocene boundary, Palaeogeogr. Palaeocl., 535, 109346, https://doi.org/10.1016/j.palaeo.2019.109346, 2019.
Plancq, J., Mattioli, E., Pittet, B., Simon, L., and Grossi, V.: Productivity and sea-surface temperature changes recorded during the late Eocene early Oligocene at DSDP Site 511 (South Atlantic), Palaeogeogr. Palaeocl., 407, 34–44, https://doi.org/10.1016/j.palaeo.2014.04.016, 2014.
Rabosky, D. L. and Sorhannus, U.: Diversity dynamics of marine planktonic diatoms across the Cenozoic, Nature, 457, 183–186, https://doi.org/10.1038/nature07435, 2009.
Ragueneau, O., Tréguer, P., Leynaert, A., Anderson, R. F., Brzezinski, M. A., DeMaster, D. J., Dugdale, R. C., Dymond, J., Fischer, G., François, R., Heinze, C., Maier-Reimer, E., Martin-Jézéquel, V., Nelson, D. M., and Quéguiner, B.: A review of the Si cycle in the modern ocean: Recent progress and missing gaps in the application of biogenic opal as a paleoproductivity proxy, Global Planet. Change, 26, 317–365, https://doi.org/10.1016/S0921-8181(00)00052-7, 2000.
Ragueneau, O., Schultes, S., Bidle, K., Claquin, P., and Moriceau, B.: Si and C interactions in the world ocean: Importance of ecological processes and implications for the role of diatoms in the biological pump: Si AND C INTERACTIONS IN THE OCEAN, Global Biogeochem. Cy., 20, https://doi.org/10.1029/2006GB002688, 2006.
Renaudie, J.: Quantifying the Cenozoic marine diatom deposition history: links to the C and Si cycles, Biogeosciences, 13, 6003–6014, https://doi.org/10.5194/bg-13-6003-2016, 2016.
Renaudie, J., Lazarus, D., and Diver, P.: NSB (Neptune Sandbox Berlin): An expanded and improved database of marine planktonic microfossil data and deep-sea stratigraphy, Palaeontologia Electronica, 23, a11, https://doi.org/10.26879/1032, 2020.
Renaudie, J., Lazarus, D., and Diver, P.: Archive of Neptune (NSB) database backups, Version 2023-06-05, Zenod [data set], https://doi.org/10.5281/zenodo.10063218, 2023.
Rigual-Hernández, A. S., Pilskaln, C. H., Cortina, A., Abrantes, F., and Armand, L. K.: Diatom species fluxes in the seasonally ice-covered Antarctic Zone: New data from offshore Prydz Bay and comparison with other regions from the eastern Antarctic and western Pacific sectors of the Southern Ocean, Deep-Sea Res. Pt. II, 161, 92–104, https://doi.org/10.1016/j.dsr2.2018.06.005, 2019.
Rintoul, R. S., W. Hughes, C., and Olbers, D.: Chapter 4.6 The antarctic circumpolar current system, International Geophysics, 77, 271–302, https://doi.org/10.1016/S0074-6142(01)80124-8, 2001.
Robert, C., Diester-Haass, L., and Chamley, H.: Late Eocene–Oligocene oceanographic development at southern high latitudes, from terrigenous and biogenic particles: A comparison of Kerguelen Plateau and Maud Rise, ODP Sites 744 and 689, Mar. Geol., 191, 37–54, https://doi.org/10.1016/S0025-3227(02)00508-X, 2002.
Rodrigues de Faria, G., Lazarus, D., Renaudie, J., Stammeier, J., Özen, V., and Struck, U.: Late Eocene to early Oligocene productivity events in the proto-Southern Ocean and correlation to climate change, Clim. Past, 20, 1327–1348, https://doi.org/10.5194/cp-20-1327-2024, 2024.
Salamy, K. A. and Zachos, J. C.: Latest Eocene-Early Oligocene climate change and Southern Ocean fertility: Inferences from sediment accumulation and stable isotope data, Palaeogeogr. Palaeocl., 145, 61–77, https://doi.org/10.1016/S0031-0182(98)00093-5, 1999.
Sarkar, S., Basak, C., Frank, M., Berndt, C., Huuse, M., Badhani, S., and Bialas, J.: Late Eocene onset of the Proto-Antarctic Circumpolar Current, Sci. Rep., 9, 10125, https://doi.org/10.1038/s41598-019-46253-1, 2019.
Sauermilch, I., Whittaker, J. M., Klocker, A., Munday, D. R., Hochmuth, K., Bijl, P. K., and LaCasce, J. H.: Gateway-driven weakening of ocean gyres leads to Southern Ocean cooling, Nat. Commun., 12, https://doi.org/10.1038/s41467-021-26658-1, 2021.
Scher, H. D. and Martin, E. E.: Circulation in the Southern Ocean during the Paleogene inferred from neodymium isotopes, Earth and Planetary Science Letters, 228, 391–405, https://doi.org/10.1016/j.epsl.2004.10.016, 2004.
Scher, H. D. and Martin, E. E.: Timing and Climatic Consequences of the Opening of Drake Passage, Science, 312, 428–430, https://doi.org/10.1126/science.1120044, 2006.
Scher, H. D., Bohaty, S. M., Zachos, J. C., and Delaney, M. L.: Two-stepping into the icehouse: East Antarctic weathering during progressive ice-sheet expansion at the Eocene-Oligocene transition, Geology, 39, 383–386, https://doi.org/10.1130/G31726.1, 2011.
Scher, H. D., Bohaty, S. M., Smith, B. W., and Munn, G. H.: Isotopic interrogation of a suspected late Eocene glaciation: Hidden glaciation revealed in the Eocene, Paleoceanography, 29, 628–644, https://doi.org/10.1002/2014pa002648, 2014.
Schumacher, S. and Lazarus, D.: Regional differences in pelagic productivity in the late Eocene to early Oligocene comparison of southern high latitudes and lower latitudes, Palaeogeogr. Palaeocl., 214, 243–263, https://doi.org/10.1016/S0031-0182(04)00424-9, 2004.
Shackleton, N. J. and Kennett, J. P.: Paleotemperature history of the Cenozoic and the initiation of Antarctic glaciation: Oxygen and carbon isotope analyses in DSDP sites 277, 279 and 281, in: Initial reports of the deep-sea drilling project, 29, U.S. Government Printing Office, https://doi.org/10.2973/dsdp.proc.29.117.1975, 1975.
Shipboard Scientific Party: Site 511, in: Initial Reports of the Deep-Sea Drilling Project, edited by: Ludwig, W. J., Krasheninnikov, V. A., Basov, I. A., Bayer, U., Bloemendal, J., Bornhold, B., Ciesielski, P. F., Goldstein, E. H., Robert, C., Salloway, J., Usher, J. L., von der Dick, H., Weaver, F. M., and Wise, S. W., U.S. Govt. Printing Office, Washington, 71, https://doi.org/10.2973/dsdp.proc.71.102.1983, 1983.
Shipboard Scientific Party: Site 689, in: Proceedings of the Ocean Drilling Program, Initial Reports, edited by: Barker, P. R, Kennett, J. P., O’Connell, S., Berkowitz, S., Bryant, W. R., Burckle, L. H., Egeberg, P. K., Fütterer, D. K., Gersonde, R. E., Golovchenko, X., Hamilton, N., Lawver, L., Lazarus, D. B., Lonsdale, M., Mohr, B., Nagao, T., Pereira, C. P. G., Pudsey, C. J., Robert, C. M., Schandl, E., Spiess, V., Stott, L. D., Thomas, E., Thompson, K. F. M., and Wise, S. W., 113: College Station, TX (Ocean Drilling Program), https://doi.org/10.2973/odp.proc.ir.113.106.1988, 1988.
Shipboard Scientific Party: Site 748, in: Proceedings of the Ocean Drilling Program, Initial Reports, edited by: Schlich, R., Wise Jr., S. W., Jr., Palmer Julson, A. A., Aubry, M.-P., Berggren, W. A., Bitschene, P. R., Blackburn, N. A., Breza, J., Coffin, M. F., Harwood, D. M., Heider, F., Holmes, M. A., Howard, W. R., Inokuchi, H., Kelts, K., Lazarus, D. B., Mackensen, A., Maruyama, T., Munschy, M., Pratson, E., Quilty, P. Q., Rack, F., Salters, V. J. M., Sevigny, J. H., Storey, M., Takemura, A., Watkins, D. K., Whitechurch, H., and Zachos, J., 120: College Station, TX (Ocean Drilling Program), https://doi.org/10.2973/odp.proc.ir.120.110.1989, 1989.
Shipboard Scientific Party: Site 1090, in: Proceedings of the Ocean Drilling Program, Initial Reports, edited by: Gersonde, R., Hodell, D. A., Blum, P., Andersson, C., Austin, W. E. N., Billups, K., Channell, J. E. T., Charles, C. D., Diekmann, B., Filippelli, G. M., Flores, J.-A., Hewitt, A. T., Howard, W. R., Ikehara, M., Janecek, T. R., Kanfoush, S. L., Kemp, A. E. S., King, S. L., Kleiven, H. F., Kuhn, G., Marino, M., Ninnemann, U. S., O’Connell, S., Ortiz, J. D., Stoner, J. S., Sugiyama, K., Warnke, D. A., and Zielinski, U., 177: College Station, TX (Ocean Drilling Program), https://doi.org/10.2973/odp.proc.ir.177.105.1999, 1999.
Stickley, C. E., Brinkhuis, H., Schellenberg, S. A., Sluijs, A., Röhl, U., Fuller, M., Grauert, M., Huber, M., Warnaar, J., and Williams, G. L.: Timing and nature of the deepening of the Tasmanian Gateway, Paleoceanography, 19, 2004PA001022, https://doi.org/10.1029/2004PA001022, 2004.
Straume, E. O., Nummelin, A., Gaina, C., and Nisancioglu, K. H.: Climate transition at the Eocene Oligocene influenced by bathymetric changes to the Atlantic Arctic oceanic gateways, P. Natl. Acad. Sci. USA, 119, e2115346119, https://doi.org/10.1073/pnas.2115346119, 2022.
Toumoulin, A., Donnadieu, Y., Ladant, J.-B., Batenburg, S. J., Poblete, F., and Dupont-Nivet, G.: Quantifying the Effect of the Drake Passage Opening on the Eocene Ocean, Paleoceanogr. Paleocl., 35, e2020PA003889, https://doi.org/10.1029/2020PA003889, 2020.
Tréguer, P., Nelson, D. M., Van Bennekom, A. J., DeMaster, D. J., Leynaert, A., and Quéguiner, B.: The silica balance in the world ocean: A reestimate, Science, 268, 375–379, https://doi.org/10.1126/science.268.5209.375, 1995.
Tréguer, P., Bowler, C., Moriceau, B., Dutkiewicz, S., Gehlen, M., Aumont, O., Bittner, L., Dugdale, R., Finkel, Z., Iudicone, D., Jahn, O., Guidi, L., Lasbleiz, M., Leblanc, K., Levy, M., and Pondaven, P.: Influence of diatom diversity on the ocean biological carbon pump, Nat. Geosci., 11, 27–37, https://doi.org/10.1038/s41561-017-0028-x, 2018.
Villa, G., Fioroni, C., Persico, D., Roberts, A. P., and Florindo, F.: Middle Eocene to Late Oligocene Antarctic glaciation/deglaciation and Southern Ocean productivity, Paleoceanography, 29, 223–237, https://doi.org/10.1002/2013PA002518, 2014.
Virta, L., Gammal, J., Järnström, M., Bernard, G., Soininen, J., Norkko, J., and Norkko, A.: The diversity of benthic diatoms affects ecosystem productivity in heterogeneous coastal environments, Ecology, 100, e02765, https://doi.org/10.1002/ecy.2765, 2019.
Wade, B. S., O'Neill, J. F., Phujareanchaiwon, C., Ali, I., Lyle, M., and Witkowski, J.: Evolution of deep-sea sediments across the Paleocene-Eocene and Eocene-Oligocene boundaries, Earth-Sci. Rev., 211, 103403, https://doi.org/10.1016/j.earscirev.2020.103403, 2020.
Westacott, S., Planavsky, N. J., Zhao, M.-Y., and Hull, P. M.: Revisiting the sedimentary record of the rise of diatoms, P. Natl. Acad. Sci. USA, 118, https://doi.org/10.1073/pnas.2103517118, 2021.
Westerhold, T., Marwan, N., Drury, A. J., Liebrand, D., Agnini, C., Anagnostou, E., Barnet, J. S. K., Bohaty, S. M., De Vleeschouwer, D., Florindo, F., Frederichs, T., Hodell, D. A., Holbourn, A. E., Kroon, D., Lauretano, V., Littler, K., Lourens, L. J., Lyle, M., Pälike, H., Röhl, U., Tian, J., Wilkens, R. H., Wilson, P. A., and Zachos, J. C.: An astronomically dated record of Earth's climate and its predictability over the last 66 million years, Science, 369, 1383–1387, https://doi.org/10.1126/science.aba6853, 2020.
Wilson, D. S. and Luyendyk, B. P.: West Antarctic paleotopography estimated at the Eocene-Oligocene climate transition, Geophys. Res. Lett., 36, https://doi.org/10.1029/2009gl039297, 2009.
Wilson, D. S., Pollard, D., DeConto, R. M., Jamieson, S. S. R., and Luyendyk, B. P.: Initiation of the West Antarctic Ice Sheet and estimates of total Antarctic ice volume in the earliest Oligocene, Geophys. Res. Lett., 40, 4305–4309, https://doi.org/10.1002/grl.50797, 2013.
Witkowski, J., Bohaty, S. M., McCartney, K., and Harwood, D. M.: Enhanced siliceous plankton productivity in response to middle Eocene warming at Southern Ocean ODP Sites 748 and 749, Palaeogeogr. Palaeocl., 326–328, 78–94, https://doi.org/10.1016/j.palaeo.2012.02.006, 2012.
Witkowski, J., Bryłka, K., Bohaty, S. M., Mydłowska, E., Penman, D. E., and Wade, B. S.: North Atlantic marine biogenic silica accumulation through the early to middle Paleogene: implications for ocean circulation and silicate weathering feedback, Clim. Past, 17, 1937–1954, https://doi.org/10.5194/cp-17-1937-2021, 2021.
Wright, N. M., Scher, H. D., Seton, M., Huck, C. E., and Duggan, B. D.: No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene, Paleoceanography and Paleoclimatolology, 33, 152–167, https://doi.org/10.1002/2017PA003238, 2018.
Zachos, J. and Kump, L.: Carbon cycle feedbacks and the initiation of Antarctic glaciation in the earliest Oligocene, Global Planet. Change, 47, 51–66, https://doi.org/10.1016/j.gloplacha.2005.01.001, 2005.
Zachos, J., Pagani, M., Sloan, L., Thomas, E., and Billups, K.: Trends, rhythms, and aberrations in global climate 65 Ma to present, Science, 292, 686–693, https://doi.org/10.1126/science.1059412, 2001.
Zachos, J. C., Quinn, T. M., and Salamy, K. A.: High-resolution (104 years) deep-sea foraminiferal stable isotope records of the Eocene-Oligocene climate transition, Paleoceanography, 11, 251–266, https://doi.org/10.1029/96pa00571, 1996.
Zhang, Y. G., Pagani, M., Liu, Z., Bohaty, S. M., and DeConto, R.: A 40-million-year history of atmospheric CO2, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 371, 20130096, https://doi.org/10.1098/rsta.2013.0096, 2013.
Short summary
We studied diatom fossils from the Southern Ocean to understand how ocean productivity changed ~40–30 million years ago during a major climate shift marked by the onset of permanent Antarctic glaciation and global cooling. We found striking shifts in diatom productivity, revealing critical changes in ocean circulation and nutrient supply. Our results show how these microscopic organisms may have influenced climate, acting as a geological force that shaped global climate over time.
We studied diatom fossils from the Southern Ocean to understand how ocean productivity changed...
