Articles | Volume 44, issue 1
https://doi.org/10.5194/jm-44-145-2025
© 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/jm-44-145-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
28 May 2025
Research article |
| 28 May 2025
| 28 May 2025
Community guidelines to increase the reusability of marine microfossil assemblage data
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
Montserrat Alonso-Garcia
Área de Paleontología, Departamento de Geología, Universidad de Salamanca, Salamanca, 37008, Spain
Simon D'haenens
Data Science Institute, UHasselt – Hasselt University, Diepenbeek, 3590, Belgium
Directorate Research, Library and Internationalisation, UHasselt – Hasselt University, Hasselt, 3500, Belgium
Robert Huber
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
Michal Kucera
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
Iván Hernández-Almeida
PAGES IPO, University of Bern, Bern, 3012, Switzerland
Chloe L. C. Jones
School of Ocean and Earth Science, University of Southampton, Southampton, SO17 1BJ, United Kingdom
Brett Metcalfe
Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, the Netherlands
Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, 6700 EJ, the Netherlands
Rajeev Saraswat
Micropaleontology Laboratory, Geological Oceanography Division, CSIR – National Institute of Oceanography, Goa, 403004, India
Lóránd Silye
Department of Geology, Babeș-Bolyai University, Cluj-Napoca, 400084, Romania
Sanjay K. Verma
Palaeontology Division, Central Headquarters, Geological Survey of India, Kolkata, 700016, India
Muhamad Naim Abd Malek
Department of Biological Sciences, Faculty of Science, Universiti Tunku Abdul Rahman (UTAR), Kampar 31900, Perak, Malaysia
Gerald Auer
NAWI Graz Geocenter, Department of Earth Sciences, University of Graz, Graz, 8010, Austria
Cátia F. Barbosa
Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, 24020-141, Brazil
Maria A. Barcena
Área de Paleontología, Departamento de Geología, Universidad de Salamanca, Salamanca, 37008, Spain
Karl-Heinz Baumann
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
Department of Geosciences, University of Bremen, Bremen, 28359, Germany
Flavia Boscolo-Galazzo
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
Joeven Austine S. Calvelo
Nannoworks Laboratory, University of the Philippines, Quezon City, 1101, Philippines
Lucilla Capotondi
Instituto di Scienze Marine, Consiglio Nazionale delle Ricerche (CNR-ISMAR), Bologna, 40129, Italy
Martina Caratelli
CONICET – Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, C1040 AAH, Argentina
Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro and CONICET, General Roca, R8332, Argentina
Jorge Cardich
CIDIS-Facultad de Ciencias e Ingeniería, Universidad Peruana Cayetano Heredia, Lima, 15102, Peru
Humberto Carvajal-Chitty
Departamento de Estudios Ambientales, Laboratorio de Bioestratigrafía, Universidad Simón Bolívar, Caracas, 1086, Venezuela
Markéta Chroustová
Czech Geological Survey, Prague, 11821 1, Czech Republic
Helen K. Coxall
Department of Geological Sciences, Bolin Centre for Climate Research, Stockholm University, Stockholm, 106 91, Sweden
Renata M. de Mello
PETROBRAS S.A. Headquarters, Rio de Janeiro, 20231-030, Brazil
Anne de Vernal
Geotop and Department of Earth and Atmospheric Sciences, Université du Québec à Montréal, Montréal, H3C 3P8, Canada
Paula Diz
Centro de Investigación Mariña, XM1, Universidade de Vigo, Vigo, 36310, Spain
Kirsty M. Edgar
School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, United Kingdom
Helena L. Filipsson
Department of Geology, Lund University, Lund, 223 62, Sweden
Ángela Fraguas
Department of Biology, Geology, Physics and Inorganic Chemistry and Research Group in Earth Dynamics and Landscape Evolution (DYNAMICAL), University King Juan Carlos, Móstoles, 28933, Spain
Heather L. Furlong
Department of Earth, Atmosphere and Environment, Northern Illinois University, DeKalb, 60115, USA
Giacomo Galli
Department of Environmental sciences, Informatics and Statistics, Ca' Foscari University of Venice, Venice, 30172, Italy
Department of Earth Sciences, University of Pisa, Pisa, 56126, Italy
Natalia L. García Chapori
IDEAN – Instituto de Estudios Andinos, University of Buenos Aires and CONICET, Buenos Aires, C1428, Argentina
Robyn Granger
Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), Den Burg, 1790 AB, the Netherlands
Jeroen Groeneveld
Institute of Oceanography, National Taiwan University, Taipei City, 10617, Taiwan (R.O.C.)
Adil Imam
Faculty of Sciences Rabat, Mohammed V University in Rabat, Rabat, 1014 RP, Morocco
Rebecca Jackson
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
David Lazarus
Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, 10115, Germany
Julie Meilland
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
Marína Molčan Matejová
Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University Bratislava, Bratislava, 842 15, Slovakia
Raphael Morard
MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, 28359, Germany
Caterina Morigi
Department of Earth Sciences, University of Pisa, Pisa, 56126, Italy
Sven N. Nielsen
Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Valdivia, 5110209, Chile
Diana Ochoa
Área de Paleontología, Departamento de Geología, Universidad de Salamanca, Salamanca, 37008, Spain
Maria Rose Petrizzo
Department of Earth Sciences, University of Milan, Milan, 20133, Italy
Andrés S. Rigual-Hernández
Área de Paleontología, Departamento de Geología, Universidad de Salamanca, Salamanca, 37008, Spain
Marina C. Rillo
Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Wilhelmshaven, 26382, Germany
Matthew L. Staitis
Faculty of Science, University of East Anglia, Norwich, NR4 7TJ, United Kingdom
Gamze Tanık
Department of Geological Engineering, Middle East Technical University, Ankara, 06800, Türkiye
Raúl Tapia
Institute of Oceanography, National Taiwan University, Taipei City, 10617, Taiwan (R.O.C.)
Nishant Vats
Micropaleontology Laboratory, Department of Applied Geology, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, India
Bridget S. Wade
Department of Earth Sciences, University College London, London, WC1E 6BT, United Kingdom
Anna E. Weinmann
Department of Geology and Paleontology, Natural History Museum Vienna, Vienna, 1030, Austria
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Jean-Philippe Baudouin, Nils Weitzel, Maximilian May, Lukas Jonkers, Andrew M. Dolman, and Kira Rehfeld
Clim. Past, 21, 381–403, https://doi.org/10.5194/cp-21-381-2025, https://doi.org/10.5194/cp-21-381-2025, 2025
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Pauline Cornuault, Luc Beaufort, Heiko Pälike, Torsten Bickert, Karl-Heinz Baumann, and Michal Kucera
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This preprint is open for discussion and under review for Biogeosciences (BG).
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Tirza Maria Weitkamp, Mohammad Javad Razmjooei, Paul Nicholas Pearson, and Helen Katherine Coxall
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Kirsty Marie Edgar, Maria Grigoratou, Fanny Monteiro, Ruby Barrett, Rui Ying, and Daniela Schmidt
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Arianna V. Del Gaudio, Aaron Avery, Gerald Auer, Werner E. Piller, and Walter Kurz
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Thibauld M. Béjard, Andrés S. Rigual-Hernández, Javier P. Tarruella, José-Abel Flores, Anna Sanchez-Vidal, Irene Llamas-Cano, and Francisco J. Sierro
Biogeosciences, 21, 4051–4076, https://doi.org/10.5194/bg-21-4051-2024, https://doi.org/10.5194/bg-21-4051-2024, 2024
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The Mediterranean Sea is regarded as a climate change hotspot. Documenting the population of planktonic foraminifera is crucial. In the Sicily Channel, fluxes are higher during winter and positively linked with chlorophyll a concentration and cool temperatures. A comparison with other Mediterranean sites shows the transitional aspect of the studied zone. Finally, modern populations significantly differ from those in the sediment, highlighting a possible effect of environmental change.
Heather Furlong and Reed Paul Scherer
J. Micropalaeontol., 43, 269–282, https://doi.org/10.5194/jm-43-269-2024, https://doi.org/10.5194/jm-43-269-2024, 2024
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Diatom assemblages are vital components of the Antarctic ecosystem and nutrient supply chain, and they are often utilized as paleoclimate proxies to better understand past climatic changes. We demonstrate enhanced diatom production and accumulation in the outer Amundsen Sea during a Mid-Pliocene interglacial that coincides with pulses of ice-rafted terrestrial debris, providing compelling evidence that iceberg calving seeds diatom productivity in the Southern Ocean.
Gabrielle Rodrigues de Faria, David Lazarus, Johan Renaudie, Jessica Stammeier, Volkan Özen, and Ulrich Struck
Clim. Past, 20, 1327–1348, https://doi.org/10.5194/cp-20-1327-2024, https://doi.org/10.5194/cp-20-1327-2024, 2024
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Export productivity is part of the global carbon cycle, influencing the climate system via biological pump. About 34 million years ago, the Earth's climate experienced a climate transition from a greenhouse state to an icehouse state with the onset of ice sheets in Antarctica. Our study shows important productivity events in the Southern Ocean preceding this climatic shift. Our findings strongly indicate that the biological pump potentially played an important role in that past climate change.
Alessio Fabbrini, Maria Rose Petrizzo, Isabella Premoli Silva, Luca M. Foresi, and Bridget S. Wade
J. Micropalaeontol., 43, 121–138, https://doi.org/10.5194/jm-43-121-2024, https://doi.org/10.5194/jm-43-121-2024, 2024
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We report on the rediscovery of Globigerina bollii, a planktonic foraminifer described by Cita and Premoli Silva (1960) in the Mediterranean Basin. We redescribe G. bollii as a valid species belonging to the genus Globoturborotalita. We report and summarise all the recordings of the taxon in the scientific literature. Then we discuss how the taxon might be a palaeogeographical indicator of the intermittent gateways between the Mediterranean Sea, Paratethys, and Indian Ocean.
Yuji Kato, Iván Hernández-Almeida, and Lara F. Pérez
J. Micropalaeontol., 43, 93–119, https://doi.org/10.5194/jm-43-93-2024, https://doi.org/10.5194/jm-43-93-2024, 2024
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In this study, we propose an age framework for an interval of 4.8–3.1 million years ago, using fossil records of marine plankton such as diatoms and radiolarians derived from a sediment core collected in the Southern Ocean. Specifically, a total of 19 bioevents (i.e., extinction/appearance events of selected age marker species) were detected, and their precise ages were calculated. The updated biostratigraphy will contribute to future paleoceanographic work in the Southern Ocean.
Nils Weitzel, Heather Andres, Jean-Philippe Baudouin, Marie-Luise Kapsch, Uwe Mikolajewicz, Lukas Jonkers, Oliver Bothe, Elisa Ziegler, Thomas Kleinen, André Paul, and Kira Rehfeld
Clim. Past, 20, 865–890, https://doi.org/10.5194/cp-20-865-2024, https://doi.org/10.5194/cp-20-865-2024, 2024
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The ability of climate models to faithfully reproduce past warming episodes is a valuable test considering potentially large future warming. We develop a new method to compare simulations of the last deglaciation with temperature reconstructions. We find that reconstructions differ more between regions than simulations, potentially due to deficiencies in the simulation design, models, or reconstructions. Our work is a promising step towards benchmarking simulations of past climate transitions.
Montserrat Alonso-Garcia, Jesus Reolid, Francisco J. Jimenez-Espejo, Or M. Bialik, Carlos A. Alvarez Zarikian, Juan Carlos Laya, Igor Carrasquiera, Luigi Jovane, John J. G. Reijmer, Gregor P. Eberli, and Christian Betzler
Clim. Past, 20, 547–571, https://doi.org/10.5194/cp-20-547-2024, https://doi.org/10.5194/cp-20-547-2024, 2024
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The Maldives Inner Sea (northern Indian Ocean) offers an excellent study site to explore the impact of climate and sea-level changes on carbonate platforms. The sediments from International Ocean Discovery Program (IODP) Site U1467 have been studied to determine the drivers of carbonate production in the atolls over the last 1.3 million years. Even though sea level is important, the intensity of the summer monsoon and the Indian Ocean dipole probably modulated the production at the atolls.
Nico Wunderling, Anna S. von der Heydt, Yevgeny Aksenov, Stephen Barker, Robbin Bastiaansen, Victor Brovkin, Maura Brunetti, Victor Couplet, Thomas Kleinen, Caroline H. Lear, Johannes Lohmann, Rosa Maria Roman-Cuesta, Sacha Sinet, Didier Swingedouw, Ricarda Winkelmann, Pallavi Anand, Jonathan Barichivich, Sebastian Bathiany, Mara Baudena, John T. Bruun, Cristiano M. Chiessi, Helen K. Coxall, David Docquier, Jonathan F. Donges, Swinda K. J. Falkena, Ann Kristin Klose, David Obura, Juan Rocha, Stefanie Rynders, Norman Julius Steinert, and Matteo Willeit
Earth Syst. Dynam., 15, 41–74, https://doi.org/10.5194/esd-15-41-2024, https://doi.org/10.5194/esd-15-41-2024, 2024
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This paper maps out the state-of-the-art literature on interactions between tipping elements relevant for current global warming pathways. We find indications that many of the interactions between tipping elements are destabilizing. This means that tipping cascades cannot be ruled out on centennial to millennial timescales at global warming levels between 1.5 and 2.0 °C or on shorter timescales if global warming surpasses 2.0 °C.
Heather M. Stoll, Leopoldo D. Pena, Ivan Hernandez-Almeida, José Guitián, Thomas Tanner, and Heiko Pälike
Clim. Past, 20, 25–36, https://doi.org/10.5194/cp-20-25-2024, https://doi.org/10.5194/cp-20-25-2024, 2024
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The Oligocene and early Miocene periods featured dynamic glacial cycles on Antarctica. In this paper, we use Sr isotopes in marine carbonate sediments to document a change in the location and intensity of continental weathering during short periods of very intense Antarctic glaciation. Potentially, the weathering intensity of old continental rocks on Antarctica was reduced during glaciation. We also show improved age models for correlation of Southern Ocean and North Atlantic sediments.
Mariem Saavedra-Pellitero, Karl-Heinz Baumann, Nuria Bachiller-Jareno, Harold Lovell, Nele Manon Vollmar, and Elisa Malinverno
EGUsphere, https://doi.org/10.5194/egusphere-2023-2801, https://doi.org/10.5194/egusphere-2023-2801, 2023
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In this manuscript we combine micropalaeontology and remote-sensing. We compare the calcium carbonate produced by tiny marine algae called coccolithophores to satellite-derived particulate organic carbon in the Southern Ocean. They show good agreement north of the polar front, but hugely differ south of it. We argue that those highly reflective values could be due to small opal particles and we highlight the need to improve satellite algorithms in this unexplored part of the ocean.
K. Mareike Paul, Martijn Hermans, Sami A. Jokinen, Inda Brinkmann, Helena L. Filipsson, and Tom Jilbert
Biogeosciences, 20, 5003–5028, https://doi.org/10.5194/bg-20-5003-2023, https://doi.org/10.5194/bg-20-5003-2023, 2023
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Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.
Paul N. Pearson, Jeremy Young, David J. King, and Bridget S. Wade
J. Micropalaeontol., 42, 211–255, https://doi.org/10.5194/jm-42-211-2023, https://doi.org/10.5194/jm-42-211-2023, 2023
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Planktonic foraminifera are marine plankton that have a long and continuous fossil record. They are used for correlating and dating ocean sediments and studying evolution and past climates. This paper presents new information about Pulleniatina, one of the most widespread and abundant groups, from an important site in the Pacific Ocean. It also brings together a very large amount of information on the fossil record from other sites globally.
Gerald Auer, Or M. Bialik, Mary-Elizabeth Antoulas, Noam Vogt-Vincent, and Werner E. Piller
Clim. Past, 19, 2313–2340, https://doi.org/10.5194/cp-19-2313-2023, https://doi.org/10.5194/cp-19-2313-2023, 2023
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We provided novel insights into the behaviour of a major upwelling cell between 15 and 8.5 million years ago. To study changing conditions, we apply a combination of geochemical and paleoecological parameters to characterize the nutrient availability and subsequent utilization by planktonic primary producers. These changes we then juxtapose with established records of contemporary monsoon wind intensification and changing high-latitude processes to explain shifts in the plankton community.
Sabrina Hohmann, Michal Kucera, and Anne de Vernal
Clim. Past, 19, 2027–2051, https://doi.org/10.5194/cp-19-2027-2023, https://doi.org/10.5194/cp-19-2027-2023, 2023
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Drivers for dinocyst assemblage compositions differ regionally and through time. Shifts in the assemblages can sometimes only be interpreted robustly by locally and sometimes globally calibrated transfer functions, questioning the reliability of environmental reconstructions. We suggest the necessity of a thorough evaluation of transfer function performance and significance for downcore applications to disclose the drivers for present and fossil dinocyst assemblages in a studied core location.
Stephen P. Hesselbo, Aisha Al-Suwaidi, Sarah J. Baker, Giorgia Ballabio, Claire M. Belcher, Andrew Bond, Ian Boomer, Remco Bos, Christian J. Bjerrum, Kara Bogus, Richard Boyle, James V. Browning, Alan R. Butcher, Daniel J. Condon, Philip Copestake, Stuart Daines, Christopher Dalby, Magret Damaschke, Susana E. Damborenea, Jean-Francois Deconinck, Alexander J. Dickson, Isabel M. Fendley, Calum P. Fox, Angela Fraguas, Joost Frieling, Thomas A. Gibson, Tianchen He, Kat Hickey, Linda A. Hinnov, Teuntje P. Hollaar, Chunju Huang, Alexander J. L. Hudson, Hugh C. Jenkyns, Erdem Idiz, Mengjie Jiang, Wout Krijgsman, Christoph Korte, Melanie J. Leng, Timothy M. Lenton, Katharina Leu, Crispin T. S. Little, Conall MacNiocaill, Miguel O. Manceñido, Tamsin A. Mather, Emanuela Mattioli, Kenneth G. Miller, Robert J. Newton, Kevin N. Page, József Pálfy, Gregory Pieńkowski, Richard J. Porter, Simon W. Poulton, Alberto C. Riccardi, James B. Riding, Ailsa Roper, Micha Ruhl, Ricardo L. Silva, Marisa S. Storm, Guillaume Suan, Dominika Szűcs, Nicolas Thibault, Alfred Uchman, James N. Stanley, Clemens V. Ullmann, Bas van de Schootbrugge, Madeleine L. Vickers, Sonja Wadas, Jessica H. Whiteside, Paul B. Wignall, Thomas Wonik, Weimu Xu, Christian Zeeden, and Ke Zhao
Sci. Dril., 32, 1–25, https://doi.org/10.5194/sd-32-1-2023, https://doi.org/10.5194/sd-32-1-2023, 2023
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We present initial results from a 650 m long core of Late Triasssic to Early Jurassic (190–202 Myr) sedimentary strata from the Cheshire Basin, UK, which is shown to be an exceptional record of Earth evolution for the time of break-up of the supercontinent Pangaea. Further work will determine periodic changes in depositional environments caused by solar system dynamics and used to reconstruct orbital history.
David De Vleeschouwer, Theresa Nohl, Christian Schulbert, Or M. Bialik, and Gerald Auer
Sci. Dril., 32, 43–54, https://doi.org/10.5194/sd-32-43-2023, https://doi.org/10.5194/sd-32-43-2023, 2023
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Differences exist in International Ocean Discovery Program (IODP) sediment lithification depending on the coring tool used. Advanced piston corers (APCs) display less pronounced lithification compared to extended core barrels (XCBs) of the same formation. The difference stems from the destruction of early cements between sediment grains and an
acoustic compactioncaused by the piston-core pressure wave. XCB cores provide a more accurate picture of the lithification of the original formation.
Giacomo Galli, Caterina Morigi, Romana Melis, Alessio Di Roberto, Tommaso Tesi, Fiorenza Torricella, Leonardo Langone, Patrizia Giordano, Ester Colizza, Lucilla Capotondi, Andrea Gallerani, and Karen Gariboldi
J. Micropalaeontol., 42, 95–115, https://doi.org/10.5194/jm-42-95-2023, https://doi.org/10.5194/jm-42-95-2023, 2023
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A sediment core was analysed, focusing over the 2000 years, in Edisto Inlet. Benthic and planktic foraminifera were picked and used to determine changes in the faunal composition. Using other nearby cores, by comparing different proxies, we were able to identify a succession of three different environmental phases over the studied period: a seasonal-cycle phase (from 2000 to around 1500 years BP), a transitional phase (from 1500 to 700 years BP) and a cold phase (from 700 years to present).
Xiaoxu Shi, Alexandre Cauquoin, Gerrit Lohmann, Lukas Jonkers, Qiang Wang, Hu Yang, Yuchen Sun, and Martin Werner
Geosci. Model Dev., 16, 5153–5178, https://doi.org/10.5194/gmd-16-5153-2023, https://doi.org/10.5194/gmd-16-5153-2023, 2023
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We developed a new climate model with isotopic capabilities and simulated the pre-industrial and mid-Holocene periods. Despite certain regional model biases, the modeled isotope composition is in good agreement with observations and reconstructions. Based on our analyses, the observed isotope–temperature relationship in polar regions may have a summertime bias. Using daily model outputs, we developed a novel isotope-based approach to determine the onset date of the West African summer monsoon.
Marcin Latas, Paul N. Pearson, Christopher R. Poole, Alessio Fabbrini, and Bridget S. Wade
J. Micropalaeontol., 42, 57–81, https://doi.org/10.5194/jm-42-57-2023, https://doi.org/10.5194/jm-42-57-2023, 2023
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Planktonic foraminifera are microscopic single-celled organisms populating world oceans. They have one of the most complete fossil records; thanks to their great abundance, they are widely used to study past marine environments. We analysed and measured series of foraminifera shells from Indo-Pacific sites, which led to the description of a new species of fossil planktonic foraminifera. Part of its population exhibits pink pigmentation, which is only the third such case among known species.
Anna E. Weinmann, Olga Koukousioura, Maria V. Triantaphyllou, and Martin R. Langer
Web Ecol., 23, 71–86, https://doi.org/10.5194/we-23-71-2023, https://doi.org/10.5194/we-23-71-2023, 2023
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This study analyzes the diversity of benthic foraminifera at the range expansion front of the invasive species Amphistegina lobifera in Corfu (central Mediterranean). The species has been suggested to impact local diversity and community structures, and our results confirm these effects as soon as A. lobifera exceeds a specific abundance threshold (> 20 %). Nevertheless, we found that the study area reveals an overall high biodiversity that can be attributed to its unique location.
Michal Kučera and Geert-Jan A. Brummer
J. Micropalaeontol., 42, 33–34, https://doi.org/10.5194/jm-42-33-2023, https://doi.org/10.5194/jm-42-33-2023, 2023
Amanda Gerotto, Hongrui Zhang, Renata Hanae Nagai, Heather M. Stoll, Rubens César Lopes Figueira, Chuanlian Liu, and Iván Hernández-Almeida
Biogeosciences, 20, 1725–1739, https://doi.org/10.5194/bg-20-1725-2023, https://doi.org/10.5194/bg-20-1725-2023, 2023
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Based on the analysis of the response of coccolithophores’ morphological attributes in a laboratory dissolution experiment and surface sediment samples from the South China Sea, we proposed that the thickness shape (ks) factor of fossil coccoliths together with the normalized ks variation, which is the ratio of the standard deviation of ks (σ) over the mean ks (σ/ks), is a robust and novel proxy to reconstruct past changes in deep ocean carbon chemistry.
Thibauld M. Béjard, Andrés S. Rigual-Hernández, José A. Flores, Javier P. Tarruella, Xavier Durrieu de Madron, Isabel Cacho, Neghar Haghipour, Aidan Hunter, and Francisco J. Sierro
Biogeosciences, 20, 1505–1528, https://doi.org/10.5194/bg-20-1505-2023, https://doi.org/10.5194/bg-20-1505-2023, 2023
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The Mediterranean Sea is undergoing a rapid and unprecedented environmental change. Planktic foraminifera calcification is affected on different timescales. On seasonal and interannual scales, calcification trends differ according to the species and are linked mainly to sea surface temperatures and carbonate system parameters, while comparison with pre/post-industrial assemblages shows that all three species have reduced their calcification between 10 % to 35 % according to the species.
Jesse R. Farmer, Katherine J. Keller, Robert K. Poirier, Gary S. Dwyer, Morgan F. Schaller, Helen K. Coxall, Matt O'Regan, and Thomas M. Cronin
Clim. Past, 19, 555–578, https://doi.org/10.5194/cp-19-555-2023, https://doi.org/10.5194/cp-19-555-2023, 2023
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Oxygen isotopes are used to date marine sediments via similar large-scale ocean patterns over glacial cycles. However, the Arctic Ocean exhibits a different isotope pattern, creating uncertainty in the timing of past Arctic climate change. We find that the Arctic Ocean experienced large local oxygen isotope changes over glacial cycles. We attribute this to a breakdown of stratification during ice ages that allowed for a unique low isotope value to characterize the ice age Arctic Ocean.
Paula Diz, Víctor González-Guitián, Rita González-Villanueva, Aida Ovejero, and Iván Hernández-Almeida
Earth Syst. Sci. Data, 15, 697–722, https://doi.org/10.5194/essd-15-697-2023, https://doi.org/10.5194/essd-15-697-2023, 2023
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Benthic foraminifera are key components of the ocean benthos and marine sediments. Determining their geographic distribution is highly relevant for improving our understanding of the recent and past ocean benthic ecosystem and establishing adequate conservation strategies. Here, we contribute to this knowledge by generating an open-access database of previously documented quantitative data of benthic foraminifera species from surface sediments of the eastern Pacific (BENFEP).
Pauline Cornuault, Thomas Westerhold, Heiko Pälike, Torsten Bickert, Karl-Heinz Baumann, and Michal Kucera
Biogeosciences, 20, 597–618, https://doi.org/10.5194/bg-20-597-2023, https://doi.org/10.5194/bg-20-597-2023, 2023
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We generated high-resolution records of carbonate accumulation rate from the Miocene to the Quaternary in the tropical Atlantic Ocean to characterize the variability in pelagic carbonate production during warm climates. It follows orbital cycles, responding to local changes in tropical conditions, as well as to long-term shifts in climate and ocean chemistry. These changes were sufficiently large to play a role in the carbon cycle and global climate evolution.
Kasia K. Śliwińska, Helen K. Coxall, David K. Hutchinson, Diederik Liebrand, Stefan Schouten, and Agatha M. de Boer
Clim. Past, 19, 123–140, https://doi.org/10.5194/cp-19-123-2023, https://doi.org/10.5194/cp-19-123-2023, 2023
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We provide a sea surface temperature record from the Labrador Sea (ODP Site 647) based on organic geochemical proxies across the late Eocene and early Oligocene. Our study reveals heterogenic cooling of the Atlantic. The cooling of the North Atlantic is difficult to reconcile with the active Atlantic Meridional Overturning Circulation (AMOC). We discuss possible explanations like uncertainty in the data, paleogeography and atmospheric CO2 boundary conditions, model weaknesses, and AMOC activity.
Rajeev Saraswat, Thejasino Suokhrie, Dinesh K. Naik, Dharmendra P. Singh, Syed M. Saalim, Mohd Salman, Gavendra Kumar, Sudhira R. Bhadra, Mahyar Mohtadi, Sujata R. Kurtarkar, and Abhayanand S. Maurya
Earth Syst. Sci. Data, 15, 171–187, https://doi.org/10.5194/essd-15-171-2023, https://doi.org/10.5194/essd-15-171-2023, 2023
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Much effort is made to project monsoon changes by reconstructing the past. The stable oxygen isotopic ratio of marine calcareous organisms is frequently used to reconstruct past monsoons. Here, we use the published and new stable oxygen isotopic data to demonstrate a diagenetic effect and a strong salinity influence on the oxygen isotopic ratio of foraminifera in the northern Indian Ocean. We also provide updated calibration equations to deduce monsoons from the oxygen isotopic ratio.
Jessica G. M. Crumpton-Banks, Thomas Tanner, Ivan Hernández Almeida, James W. B. Rae, and Heather Stoll
Biogeosciences, 19, 5633–5644, https://doi.org/10.5194/bg-19-5633-2022, https://doi.org/10.5194/bg-19-5633-2022, 2022
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Past ocean carbon is reconstructed using proxies, but it is unknown whether preparing ocean sediment for one proxy might damage the data given by another. We have tested whether the extraction of an organic proxy archive from sediment samples impacts the geochemistry of tiny shells also within the sediment. We find no difference in shell geochemistry between samples which come from treated and untreated sediment. This will help us to maximize scientific return from valuable sediment samples.
Daniel François, Adina Paytan, Olga Maria Oliveira de Araújo, Ricardo Tadeu Lopes, and Cátia Fernandes Barbosa
Biogeosciences, 19, 5269–5285, https://doi.org/10.5194/bg-19-5269-2022, https://doi.org/10.5194/bg-19-5269-2022, 2022
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Our analysis revealed that under the two most conservative acidification projections foraminifera assemblages did not display considerable changes. However, a significant decrease in species richness was observed when pH decreases to 7.7 pH units, indicating adverse effects under high-acidification scenarios. A micro-CT analysis revealed that calcified tests of Archaias angulatus were of lower density in low pH, suggesting no acclimation capacity for this species.
José Guitián, Miguel Ángel Fuertes, José-Abel Flores, Iván Hernández-Almeida, and Heather Stoll
Biogeosciences, 19, 5007–5019, https://doi.org/10.5194/bg-19-5007-2022, https://doi.org/10.5194/bg-19-5007-2022, 2022
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The effect of environmental conditions on the degree of calcification of marine phytoplankton remains unclear. This study implements a new microscopic approach to quantify the calcification of ancient coccolithophores, using North Atlantic sediments. Results show significant differences in the thickness and shape factor of coccoliths for samples with minimum dissolution, providing the first evaluation of phytoplankton physiology adaptation to million-year-scale variable environmental conditions.
Franziska Tell, Lukas Jonkers, Julie Meilland, and Michal Kucera
Biogeosciences, 19, 4903–4927, https://doi.org/10.5194/bg-19-4903-2022, https://doi.org/10.5194/bg-19-4903-2022, 2022
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This study analyses the production of calcite shells formed by one of the main Arctic pelagic calcifiers, the foraminifera N. pachyderma. Using vertically resolved profiles of shell concentration, size and weight, we show that calcification occurs throughout the upper 300 m with an average production flux below the calcification zone of 8 mg CaCO3 m−2 d−1 representing 23 % of the total pelagic biogenic carbonate production. The production flux is attenuated in the twilight zone by dissolution.
Paul N. Pearson, Eleanor John, Bridget S. Wade, Simon D'haenens, and Caroline H. Lear
J. Micropalaeontol., 41, 107–127, https://doi.org/10.5194/jm-41-107-2022, https://doi.org/10.5194/jm-41-107-2022, 2022
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The microscopic shells of planktonic foraminifera accumulate on the sea floor over millions of years, providing a rich archive for understanding the history of the oceans. We examined an extinct group that flourished between about 63 and 32 million years ago using scanning electron microscopy and show that they were covered with needle-like spines in life. This has implications for analytical methods that we use to determine past seawater temperature and acidity.
Raúl Tapia, Sze Ling Ho, Hui-Yu Wang, Jeroen Groeneveld, and Mahyar Mohtadi
Biogeosciences, 19, 3185–3208, https://doi.org/10.5194/bg-19-3185-2022, https://doi.org/10.5194/bg-19-3185-2022, 2022
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We report census counts of planktic foraminifera in depth-stratified plankton net samples off Indonesia. Our results show that the vertical distribution of foraminifera species routinely used in paleoceanographic reconstructions varies in hydrographically distinct regions, likely in response to food availability. Consequently, the thermal gradient based on mixed layer and thermocline dwellers also differs for these regions, suggesting potential implications for paleoceanographic reconstructions.
Stefan Mulitza, Torsten Bickert, Helen C. Bostock, Cristiano M. Chiessi, Barbara Donner, Aline Govin, Naomi Harada, Enqing Huang, Heather Johnstone, Henning Kuhnert, Michael Langner, Frank Lamy, Lester Lembke-Jene, Lorraine Lisiecki, Jean Lynch-Stieglitz, Lars Max, Mahyar Mohtadi, Gesine Mollenhauer, Juan Muglia, Dirk Nürnberg, André Paul, Carsten Rühlemann, Janne Repschläger, Rajeev Saraswat, Andreas Schmittner, Elisabeth L. Sikes, Robert F. Spielhagen, and Ralf Tiedemann
Earth Syst. Sci. Data, 14, 2553–2611, https://doi.org/10.5194/essd-14-2553-2022, https://doi.org/10.5194/essd-14-2553-2022, 2022
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Stable isotope ratios of foraminiferal shells from deep-sea sediments preserve key information on the variability of ocean circulation and ice volume. We present the first global atlas of harmonized raw downcore oxygen and carbon isotope ratios of various planktonic and benthic foraminiferal species. The atlas is a foundation for the analyses of the history of Earth system components, for finding future coring sites, and for teaching marine stratigraphy and paleoceanography.
David De Vleeschouwer, Marion Peral, Marta Marchegiano, Angelina Füllberg, Niklas Meinicke, Heiko Pälike, Gerald Auer, Benjamin Petrick, Christophe Snoeck, Steven Goderis, and Philippe Claeys
Clim. Past, 18, 1231–1253, https://doi.org/10.5194/cp-18-1231-2022, https://doi.org/10.5194/cp-18-1231-2022, 2022
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The Leeuwin Current transports warm water along the western coast of Australia: from the tropics to the Southern Hemisphere midlatitudes. Therewith, the current influences climate in two ways: first, as a moisture source for precipitation in southwestern Australia; second, as a vehicle for Equator-to-pole heat transport. In this study, we study sediment cores along the Leeuwin Current pathway to understand its ocean–climate interactions between 4 and 2 Ma.
Inda Brinkmann, Christine Barras, Tom Jilbert, Tomas Næraa, K. Mareike Paul, Magali Schweizer, and Helena L. Filipsson
Biogeosciences, 19, 2523–2535, https://doi.org/10.5194/bg-19-2523-2022, https://doi.org/10.5194/bg-19-2523-2022, 2022
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The concentration of the trace metal barium (Ba) in coastal seawater is a function of continental input, such as riverine discharge. Our geochemical records of the severely hot and dry year 2018, and following wet year 2019, reveal that prolonged drought imprints with exceptionally low Ba concentrations in benthic foraminiferal calcium carbonates of coastal sediments. This highlights the potential of benthic Ba / Ca to trace past climate extremes and variability in coastal marine records.
Geert-Jan A. Brummer and Michal Kučera
J. Micropalaeontol., 41, 29–74, https://doi.org/10.5194/jm-41-29-2022, https://doi.org/10.5194/jm-41-29-2022, 2022
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To aid researchers working with living planktonic foraminifera, we provide a comprehensive review of names that we consider appropriate for extant species. We discuss the reasons for the decisions we made and provide a list of species and genus-level names as well as other names that have been used in the past but are considered inappropriate for living taxa, stating the reasons.
Bryan C. Lougheed and Brett Metcalfe
Biogeosciences, 19, 1195–1209, https://doi.org/10.5194/bg-19-1195-2022, https://doi.org/10.5194/bg-19-1195-2022, 2022
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Measurements on sea-dwelling shelled organisms called foraminifera retrieved from deep-sea sediment cores have been used to reconstruct sea surface temperature (SST) variation. To evaluate the method, we use a computer model to simulate millions of single foraminifera and how they become mixed in the sediment after being deposited on the seafloor. We compare the SST inferred from the single foraminifera in the sediment core to the true SST in the water, thus quantifying method uncertainties.
Flavia Boscolo-Galazzo, Amy Jones, Tom Dunkley Jones, Katherine A. Crichton, Bridget S. Wade, and Paul N. Pearson
Biogeosciences, 19, 743–762, https://doi.org/10.5194/bg-19-743-2022, https://doi.org/10.5194/bg-19-743-2022, 2022
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Deep-living organisms are a major yet poorly known component of ocean biomass. Here we reconstruct the evolution of deep-living zooplankton and phytoplankton. Deep-dwelling zooplankton and phytoplankton did not occur 15 Myr ago, when the ocean was several degrees warmer than today. Deep-dwelling species first evolve around 7.5 Myr ago, following global climate cooling. Their evolution was driven by colder ocean temperatures allowing more food, oxygen, and light at depth.
Nele Manon Vollmar, Karl-Heinz Baumann, Mariem Saavedra-Pellitero, and Iván Hernández-Almeida
Biogeosciences, 19, 585–612, https://doi.org/10.5194/bg-19-585-2022, https://doi.org/10.5194/bg-19-585-2022, 2022
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We studied recent (sub-)fossil remains of a type of algae (coccolithophores) off southernmost Chile and across the Drake Passage, adding to the scarce knowledge that exists in the Southern Ocean, a rapidly changing environment. We found that those can be used to reconstruct the surface ocean conditions in the north but not in the south. We also found variations in shape in the dominant species Emiliania huxleyi depending on the location, indicating subtle adaptations to environmental conditions.
Lukas Jonkers, Geert-Jan A. Brummer, Julie Meilland, Jeroen Groeneveld, and Michal Kucera
Clim. Past, 18, 89–101, https://doi.org/10.5194/cp-18-89-2022, https://doi.org/10.5194/cp-18-89-2022, 2022
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The variability in the geochemistry among individual foraminifera is used to reconstruct seasonal to interannual climate variability. This method requires that each foraminifera shell accurately records environmental conditions, which we test here using a sediment trap time series. Even in the absence of environmental variability, planktonic foraminifera display variability in their stable isotope ratios that needs to be considered in the interpretation of individual foraminifera data.
Gerhard Fischer, Oscar E. Romero, Johannes Karstensen, Karl-Heinz Baumann, Nasrollah Moradi, Morten Iversen, Götz Ruhland, Marco Klann, and Arne Körtzinger
Biogeosciences, 18, 6479–6500, https://doi.org/10.5194/bg-18-6479-2021, https://doi.org/10.5194/bg-18-6479-2021, 2021
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Low-oxygen eddies in the eastern subtropical North Atlantic can form an oasis for phytoplankton growth. Here we report on particle flux dynamics at the oligotrophic Cape Verde Ocean Observatory. We observed consistent flux patterns during the passages of low-oxygen eddies. We found distinct flux peaks in late winter, clearly exceeding background fluxes. Our findings suggest that the low-oxygen eddies sequester higher organic carbon than expected for oligotrophic settings.
Lukas Jonkers, Oliver Bothe, and Michal Kucera
Clim. Past, 17, 2577–2581, https://doi.org/10.5194/cp-17-2577-2021, https://doi.org/10.5194/cp-17-2577-2021, 2021
Julie Meilland, Michael Siccha, Maike Kaffenberger, Jelle Bijma, and Michal Kucera
Biogeosciences, 18, 5789–5809, https://doi.org/10.5194/bg-18-5789-2021, https://doi.org/10.5194/bg-18-5789-2021, 2021
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Planktonic foraminifera population dynamics has long been assumed to be controlled by synchronous reproduction and ontogenetic vertical migration (OVM). Due to contradictory observations, this concept became controversial. We here test it in the Atlantic ocean for four species of foraminifera representing the main clades. Our observations support the existence of synchronised reproduction and OVM but show that more than half of the population does not follow the canonical trajectory.
Jakub Witkowski, Karolina Bryłka, Steven M. Bohaty, Elżbieta Mydłowska, Donald E. Penman, and Bridget S. Wade
Clim. Past, 17, 1937–1954, https://doi.org/10.5194/cp-17-1937-2021, https://doi.org/10.5194/cp-17-1937-2021, 2021
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We reconstruct the history of biogenic opal accumulation through the early to middle Paleogene in the western North Atlantic. Biogenic opal accumulation was controlled by deepwater temperatures, atmospheric greenhouse gas levels, and continental weathering intensity. Overturning circulation in the Atlantic was established at the end of the extreme early Eocene greenhouse warmth period. We also show that the strength of the link between climate and continental weathering varies through time.
Bridget S. Wade, Mohammed H. Aljahdali, Yahya A. Mufrreh, Abdullah M. Memesh, Salih A. AlSoubhi, and Iyad S. Zalmout
J. Micropalaeontol., 40, 145–161, https://doi.org/10.5194/jm-40-145-2021, https://doi.org/10.5194/jm-40-145-2021, 2021
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We examined the planktonic foraminifera (calcareous zooplankton) from a section in northern Saudi Arabia. We found the assemblages to be diverse, well-preserved and of late Eocene age. Our study provides new insights into the stratigraphic ranges of many species and indicates that the late Eocene had a higher tropical/subtropical diversity of planktonic foraminifera than previously reported.
Andrew M. Dolman, Torben Kunz, Jeroen Groeneveld, and Thomas Laepple
Clim. Past, 17, 825–841, https://doi.org/10.5194/cp-17-825-2021, https://doi.org/10.5194/cp-17-825-2021, 2021
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Uncertainties in climate proxy records are temporally autocorrelated. By deriving expressions for the power spectra of errors in proxy records, we can estimate appropriate uncertainties for any timescale, for example, for temporally smoothed records or for time slices. Here we outline and demonstrate this approach for climate proxies recovered from marine sediment cores.
Markus Raitzsch, Jelle Bijma, Torsten Bickert, Michael Schulz, Ann Holbourn, and Michal Kučera
Clim. Past, 17, 703–719, https://doi.org/10.5194/cp-17-703-2021, https://doi.org/10.5194/cp-17-703-2021, 2021
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At approximately 14 Ma, the East Antarctic Ice Sheet expanded to almost its current extent, but the role of CO2 in this major climate transition is not entirely known. We show that atmospheric CO2 might have varied on 400 kyr cycles linked to the eccentricity of the Earth’s orbit. The resulting change in weathering and ocean carbon cycle affected atmospheric CO2 in a way that CO2 rose after Antarctica glaciated, helping to stabilize the climate system on its way to the “ice-house” world.
Romana Melis, Lucilla Capotondi, Fiorenza Torricella, Patrizia Ferretti, Andrea Geniram, Jong Kuk Hong, Gerhard Kuhn, Boo-Keun Khim, Sookwan Kim, Elisa Malinverno, Kyu Cheul Yoo, and Ester Colizza
J. Micropalaeontol., 40, 15–35, https://doi.org/10.5194/jm-40-15-2021, https://doi.org/10.5194/jm-40-15-2021, 2021
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Integrated micropaleontological (planktic and benthic foraminifera, diatoms, and silicoflagellates) analysis, together with textural and geochemical results of a deep-sea core from the Hallett Ridge (northwestern Ross Sea), provides new data for late Quaternary (23–2 ka) paleoenvironmental and paleoceanographic reconstructions of this region. Results allow us to identify three time intervals: the glacial–deglacial transition, the deglacial period, and the interglacial period.
Annette Hahn, Enno Schefuß, Jeroen Groeneveld, Charlotte Miller, and Matthias Zabel
Clim. Past, 17, 345–360, https://doi.org/10.5194/cp-17-345-2021, https://doi.org/10.5194/cp-17-345-2021, 2021
David K. Hutchinson, Helen K. Coxall, Daniel J. Lunt, Margret Steinthorsdottir, Agatha M. de Boer, Michiel Baatsen, Anna von der Heydt, Matthew Huber, Alan T. Kennedy-Asser, Lutz Kunzmann, Jean-Baptiste Ladant, Caroline H. Lear, Karolin Moraweck, Paul N. Pearson, Emanuela Piga, Matthew J. Pound, Ulrich Salzmann, Howie D. Scher, Willem P. Sijp, Kasia K. Śliwińska, Paul A. Wilson, and Zhongshi Zhang
Clim. Past, 17, 269–315, https://doi.org/10.5194/cp-17-269-2021, https://doi.org/10.5194/cp-17-269-2021, 2021
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The Eocene–Oligocene transition was a major climate cooling event from a largely ice-free world to the first major glaciation of Antarctica, approximately 34 million years ago. This paper reviews observed changes in temperature, CO2 and ice sheets from marine and land-based records at this time. We present a new model–data comparison of this transition and find that CO2-forced cooling provides the best explanation of the observed global temperature changes.
Daniel J. Lunt, Fran Bragg, Wing-Le Chan, David K. Hutchinson, Jean-Baptiste Ladant, Polina Morozova, Igor Niezgodzki, Sebastian Steinig, Zhongshi Zhang, Jiang Zhu, Ayako Abe-Ouchi, Eleni Anagnostou, Agatha M. de Boer, Helen K. Coxall, Yannick Donnadieu, Gavin Foster, Gordon N. Inglis, Gregor Knorr, Petra M. Langebroek, Caroline H. Lear, Gerrit Lohmann, Christopher J. Poulsen, Pierre Sepulchre, Jessica E. Tierney, Paul J. Valdes, Evgeny M. Volodin, Tom Dunkley Jones, Christopher J. Hollis, Matthew Huber, and Bette L. Otto-Bliesner
Clim. Past, 17, 203–227, https://doi.org/10.5194/cp-17-203-2021, https://doi.org/10.5194/cp-17-203-2021, 2021
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This paper presents the first modelling results from the Deep-Time Model Intercomparison Project (DeepMIP), in which we focus on the early Eocene climatic optimum (EECO, 50 million years ago). We show that, in contrast to previous work, at least three models (CESM, GFDL, and NorESM) produce climate states that are consistent with proxy indicators of global mean temperature and polar amplification, and they achieve this at a CO2 concentration that is consistent with the CO2 proxy record.
Constance Choquel, Emmanuelle Geslin, Edouard Metzger, Helena L. Filipsson, Nils Risgaard-Petersen, Patrick Launeau, Manuel Giraud, Thierry Jauffrais, Bruno Jesus, and Aurélia Mouret
Biogeosciences, 18, 327–341, https://doi.org/10.5194/bg-18-327-2021, https://doi.org/10.5194/bg-18-327-2021, 2021
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Marine microorganisms such as foraminifera are able to live temporarily without oxygen in sediments. In a Swedish fjord subjected to seasonal oxygen scarcity, a change in fauna linked to the decrease in oxygen and the increase in an invasive species was shown. The invasive species respire nitrate until 100 % of the nitrate porewater in the sediment and could be a major contributor to nitrogen balance in oxic coastal ecosystems. But prolonged hypoxia creates unfavorable conditions to survive.
Masa Kageyama, Louise C. Sime, Marie Sicard, Maria-Vittoria Guarino, Anne de Vernal, Ruediger Stein, David Schroeder, Irene Malmierca-Vallet, Ayako Abe-Ouchi, Cecilia Bitz, Pascale Braconnot, Esther C. Brady, Jian Cao, Matthew A. Chamberlain, Danny Feltham, Chuncheng Guo, Allegra N. LeGrande, Gerrit Lohmann, Katrin J. Meissner, Laurie Menviel, Polina Morozova, Kerim H. Nisancioglu, Bette L. Otto-Bliesner, Ryouta O'ishi, Silvana Ramos Buarque, David Salas y Melia, Sam Sherriff-Tadano, Julienne Stroeve, Xiaoxu Shi, Bo Sun, Robert A. Tomas, Evgeny Volodin, Nicholas K. H. Yeung, Qiong Zhang, Zhongshi Zhang, Weipeng Zheng, and Tilo Ziehn
Clim. Past, 17, 37–62, https://doi.org/10.5194/cp-17-37-2021, https://doi.org/10.5194/cp-17-37-2021, 2021
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The Last interglacial (ca. 127 000 years ago) is a period with increased summer insolation at high northern latitudes, resulting in a strong reduction in Arctic sea ice. The latest PMIP4-CMIP6 models all simulate this decrease, consistent with reconstructions. However, neither the models nor the reconstructions agree on the possibility of a seasonally ice-free Arctic. Work to clarify the reasons for this model divergence and the conflicting interpretations of the records will thus be needed.
Bette L. Otto-Bliesner, Esther C. Brady, Anni Zhao, Chris M. Brierley, Yarrow Axford, Emilie Capron, Aline Govin, Jeremy S. Hoffman, Elizabeth Isaacs, Masa Kageyama, Paolo Scussolini, Polychronis C. Tzedakis, Charles J. R. Williams, Eric Wolff, Ayako Abe-Ouchi, Pascale Braconnot, Silvana Ramos Buarque, Jian Cao, Anne de Vernal, Maria Vittoria Guarino, Chuncheng Guo, Allegra N. LeGrande, Gerrit Lohmann, Katrin J. Meissner, Laurie Menviel, Polina A. Morozova, Kerim H. Nisancioglu, Ryouta O'ishi, David Salas y Mélia, Xiaoxu Shi, Marie Sicard, Louise Sime, Christian Stepanek, Robert Tomas, Evgeny Volodin, Nicholas K. H. Yeung, Qiong Zhang, Zhongshi Zhang, and Weipeng Zheng
Clim. Past, 17, 63–94, https://doi.org/10.5194/cp-17-63-2021, https://doi.org/10.5194/cp-17-63-2021, 2021
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The CMIP6–PMIP4 Tier 1 lig127k experiment was designed to address the climate responses to strong orbital forcing. We present a multi-model ensemble of 17 climate models, most of which have also completed the CMIP6 DECK experiments and are thus important for assessing future projections. The lig127ksimulations show strong summer warming over the NH continents. More than half of the models simulate a retreat of the Arctic minimum summer ice edge similar to the average for 2000–2018.
Tom Dunkley Jones, Yvette L. Eley, William Thomson, Sarah E. Greene, Ilya Mandel, Kirsty Edgar, and James A. Bendle
Clim. Past, 16, 2599–2617, https://doi.org/10.5194/cp-16-2599-2020, https://doi.org/10.5194/cp-16-2599-2020, 2020
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We explore the utiliity of the composition of fossil lipid biomarkers, which are commonly preserved in ancient marine sediments, in providing estimates of past ocean temperatures. The group of lipids concerned show compositional changes across the modern oceans that are correlated, to some extent, with local surface ocean temperatures. Here we present new machine learning approaches to improve our understanding of this temperature sensitivity and its application to reconstructing past climates.
Catarina Cavaleiro, Antje H. L. Voelker, Heather Stoll, Karl-Heinz Baumann, and Michal Kucera
Clim. Past, 16, 2017–2037, https://doi.org/10.5194/cp-16-2017-2020, https://doi.org/10.5194/cp-16-2017-2020, 2020
Gordon N. Inglis, Fran Bragg, Natalie J. Burls, Marlow Julius Cramwinckel, David Evans, Gavin L. Foster, Matthew Huber, Daniel J. Lunt, Nicholas Siler, Sebastian Steinig, Jessica E. Tierney, Richard Wilkinson, Eleni Anagnostou, Agatha M. de Boer, Tom Dunkley Jones, Kirsty M. Edgar, Christopher J. Hollis, David K. Hutchinson, and Richard D. Pancost
Clim. Past, 16, 1953–1968, https://doi.org/10.5194/cp-16-1953-2020, https://doi.org/10.5194/cp-16-1953-2020, 2020
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This paper presents estimates of global mean surface temperatures and climate sensitivity during the early Paleogene (∼57–48 Ma). We employ a multi-method experimental approach and show that i) global mean surface temperatures range between 27 and 32°C and that ii) estimates of
bulkequilibrium climate sensitivity (∼3 to 4.5°C) fall within the range predicted by the IPCC AR5 Report. This work improves our understanding of two key climate metrics during the early Paleogene.
Bronwen L. Konecky, Nicholas P. McKay, Olga V. Churakova (Sidorova), Laia Comas-Bru, Emilie P. Dassié, Kristine L. DeLong, Georgina M. Falster, Matt J. Fischer, Matthew D. Jones, Lukas Jonkers, Darrell S. Kaufman, Guillaume Leduc, Shreyas R. Managave, Belen Martrat, Thomas Opel, Anais J. Orsi, Judson W. Partin, Hussein R. Sayani, Elizabeth K. Thomas, Diane M. Thompson, Jonathan J. Tyler, Nerilie J. Abram, Alyssa R. Atwood, Olivier Cartapanis, Jessica L. Conroy, Mark A. Curran, Sylvia G. Dee, Michael Deininger, Dmitry V. Divine, Zoltán Kern, Trevor J. Porter, Samantha L. Stevenson, Lucien von Gunten, and Iso2k Project Members
Earth Syst. Sci. Data, 12, 2261–2288, https://doi.org/10.5194/essd-12-2261-2020, https://doi.org/10.5194/essd-12-2261-2020, 2020
Douglas Lessa, Raphaël Morard, Lukas Jonkers, Igor M. Venancio, Runa Reuter, Adrian Baumeister, Ana Luiza Albuquerque, and Michal Kucera
Biogeosciences, 17, 4313–4342, https://doi.org/10.5194/bg-17-4313-2020, https://doi.org/10.5194/bg-17-4313-2020, 2020
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We observed that living planktonic foraminifera had distinct vertically distributed communities across the Subtropical South Atlantic. In addition, a hierarchic alternation of environmental parameters was measured to control the distribution of planktonic foraminifer's species depending on the water depth. This implies that not only temperature but also productivity and subsurface processes are signed in fossil assemblages, which could be used to perform paleoceanographic reconstructions.
Robert Huber, Robert Darga, and Hans Lauterbach
E&G Quaternary Sci. J., 69, 93–120, https://doi.org/10.5194/egqsj-69-93-2020, https://doi.org/10.5194/egqsj-69-93-2020, 2020
Erin L. McClymont, Heather L. Ford, Sze Ling Ho, Julia C. Tindall, Alan M. Haywood, Montserrat Alonso-Garcia, Ian Bailey, Melissa A. Berke, Kate Littler, Molly O. Patterson, Benjamin Petrick, Francien Peterse, A. Christina Ravelo, Bjørg Risebrobakken, Stijn De Schepper, George E. A. Swann, Kaustubh Thirumalai, Jessica E. Tierney, Carolien van der Weijst, Sarah White, Ayako Abe-Ouchi, Michiel L. J. Baatsen, Esther C. Brady, Wing-Le Chan, Deepak Chandan, Ran Feng, Chuncheng Guo, Anna S. von der Heydt, Stephen Hunter, Xiangyi Li, Gerrit Lohmann, Kerim H. Nisancioglu, Bette L. Otto-Bliesner, W. Richard Peltier, Christian Stepanek, and Zhongshi Zhang
Clim. Past, 16, 1599–1615, https://doi.org/10.5194/cp-16-1599-2020, https://doi.org/10.5194/cp-16-1599-2020, 2020
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We examine the sea-surface temperature response to an interval of climate ~ 3.2 million years ago, when CO2 concentrations were similar to today and the near future. Our geological data and climate models show that global mean sea-surface temperatures were 2.3 to 3.2 ºC warmer than pre-industrial climate, that the mid-latitudes and high latitudes warmed more than the tropics, and that the warming was particularly enhanced in the North Atlantic Ocean.
Kirsty M. Edgar, Steven M. Bohaty, Helen K. Coxall, Paul R. Bown, Sietske J. Batenburg, Caroline H. Lear, and Paul N. Pearson
J. Micropalaeontol., 39, 117–138, https://doi.org/10.5194/jm-39-117-2020, https://doi.org/10.5194/jm-39-117-2020, 2020
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We identify the first continuous carbonate-bearing sediment record from the tropical ocean that spans the entirety of the global warming event, the Middle Eocene Climatic Optimum, ca. 40 Ma. We determine significant mismatches between middle Eocene calcareous microfossil datums from the tropical Pacific Ocean and established low-latitude zonation schemes. We highlight the potential of ODP Site 865 for future investigations into environmental and biotic changes throughout the early Paleogene.
Zeynep Erdem, Joachim Schönfeld, Anthony E. Rathburn, Maria-Elena Pérez, Jorge Cardich, and Nicolaas Glock
Biogeosciences, 17, 3165–3182, https://doi.org/10.5194/bg-17-3165-2020, https://doi.org/10.5194/bg-17-3165-2020, 2020
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Recent observations from today’s oceans revealed that oxygen concentrations are decreasing, and oxygen minimum zones are expanding together with current climate change. With the aim of understanding past climatic events and their relationship with oxygen content, we looked at the fossils, called benthic foraminifera, preserved in the sediment archives from the Peruvian margin and quantified the bottom-water oxygen content for the last 22 000 years.
Brett Metcalfe, Bryan C. Lougheed, Claire Waelbroeck, and Didier M. Roche
Clim. Past, 16, 885–910, https://doi.org/10.5194/cp-16-885-2020, https://doi.org/10.5194/cp-16-885-2020, 2020
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Planktonic foraminifera construct a shell that, post mortem, settles to the seafloor, prior to collection by Palaeoclimatologists for use as proxies. Such organisms in life are sensitive to the ambient conditions (e.g. temperature, salinity), which therefore means our proxies maybe skewed toward the ecology of organisms. Using a proxy system model, Foraminifera as Modelled Entities (FAME), we assess the potential of extracting ENSO signal from tropical Pacific planktonic foraminifera.
Lukas Jonkers, Olivier Cartapanis, Michael Langner, Nick McKay, Stefan Mulitza, Anne Strack, and Michal Kucera
Earth Syst. Sci. Data, 12, 1053–1081, https://doi.org/10.5194/essd-12-1053-2020, https://doi.org/10.5194/essd-12-1053-2020, 2020
Bryan C. Lougheed, Philippa Ascough, Andrew M. Dolman, Ludvig Löwemark, and Brett Metcalfe
Geochronology, 2, 17–31, https://doi.org/10.5194/gchron-2-17-2020, https://doi.org/10.5194/gchron-2-17-2020, 2020
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The current geochronological state of the art for applying the radiocarbon (14C) method to deep-sea sediment archives lacks key information on sediment bioturbation, which could affect palaeoclimate interpretations made from deep-sea sediment. We use a computer model that simulates the 14C activity and bioturbation history of millions of single foraminifera at the sea floor, allowing us to evaluate the current state of the art at the most fundamental level.
Julie Meilland, Hélène Howa, Vivien Hulot, Isaline Demangel, Joëlle Salaün, and Thierry Garlan
Biogeosciences, 17, 1437–1450, https://doi.org/10.5194/bg-17-1437-2020, https://doi.org/10.5194/bg-17-1437-2020, 2020
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This study reports on planktonic foraminifera (PF) diversity and distribution in the Barents Sea. The species Globigerinita uvula and Turborotalita quinqueloba dominate the water column while surface sediments are dominated by Neogloboquadrina pachyderma. We hypothesize the unusual dominance of G. uvula in the water to be a seasonal signal or a result of climate forcing. Size-normalized-protein concentrations of PF show a northward decrease, suggesting biomass to vary with the environment.
Aurélie Marcelle Renée Aubry, Stijn De Schepper, and Anne de Vernal
J. Micropalaeontol., 39, 41–60, https://doi.org/10.5194/jm-39-41-2020, https://doi.org/10.5194/jm-39-41-2020, 2020
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We used organic-walled microfossils to better define the Plio–Pleistocene transition (2.56 Ma) that is associated with the intensification of the Northern Hemisphere glaciation. The disappearance of species around 2.75 Ma reflects an ecological response accompanying the Greenland ice sheet growth.
A strong regionalism marks the Labrador Sea and suggests cooler conditions than elsewhere in the North Atlantic, although our zone boundaries are contemporaneous with the eastern North Atlantic.
Geert-Jan A. Brummer, Brett Metcalfe, Wouter Feldmeijer, Maarten A. Prins, Jasmijn van 't Hoff, and Gerald M. Ganssen
Clim. Past, 16, 265–282, https://doi.org/10.5194/cp-16-265-2020, https://doi.org/10.5194/cp-16-265-2020, 2020
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Here, mid-ocean seasonality is resolved through time, using differences in the oxygen isotope composition between individual shells of the commonly used (sub)polar planktonic foraminifera species in ocean-climate reconstruction, N. pachyderma and G. bulloides. Single-specimen isotope measurements during the deglacial period revealed a surprising bimodality, the cause of which was investigated.
Oscar E. Romero, Karl-Heinz Baumann, Karin A. F. Zonneveld, Barbara Donner, Jens Hefter, Bambaye Hamady, Vera Pospelova, and Gerhard Fischer
Biogeosciences, 17, 187–214, https://doi.org/10.5194/bg-17-187-2020, https://doi.org/10.5194/bg-17-187-2020, 2020
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Monitoring of the multiannual evolution of populations representing different trophic levels allows for obtaining insights into the impact of climate variability in marine coastal upwelling ecosystems. By using a multiyear, continuous (1,900 d) sediment trap record, we assess the dynamics and fluxes of calcareous, organic and siliceous microorganisms off Mauritania (NW Africa). The experiment allowed for the recognition of a general sequence of seasonal variations of the main populations.
Andrés S. Rigual Hernández, Thomas W. Trull, Scott D. Nodder, José A. Flores, Helen Bostock, Fátima Abrantes, Ruth S. Eriksen, Francisco J. Sierro, Diana M. Davies, Anne-Marie Ballegeer, Miguel A. Fuertes, and Lisa C. Northcote
Biogeosciences, 17, 245–263, https://doi.org/10.5194/bg-17-245-2020, https://doi.org/10.5194/bg-17-245-2020, 2020
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Coccolithophores account for a major fraction of the carbonate produced in the world's oceans. However, their contribution in the subantarctic Southern Ocean remains undocumented. We quantitatively partition calcium carbonate fluxes amongst coccolithophore species in the Australian–New Zealand sector of the Southern Ocean. We provide new insights into the importance of species other than Emiliania huxleyi in the carbon cycle and assess their possible response to projected environmental change.
Anna Jentzen, Joachim Schönfeld, Agnes K. M. Weiner, Manuel F. G. Weinkauf, Dirk Nürnberg, and Michal Kučera
J. Micropalaeontol., 38, 231–247, https://doi.org/10.5194/jm-38-231-2019, https://doi.org/10.5194/jm-38-231-2019, 2019
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The study assessed the population dynamics of living planktic foraminifers on a weekly, seasonal, and interannual timescale off the coast of Puerto Rico to improve our understanding of short- and long-term variations. The results indicate a seasonal change of the faunal composition, and over the last decades. Lower standing stocks and lower stable carbon isotope values of foraminifers in shallow waters can be linked to the hurricane Sandy, which passed the Greater Antilles during autumn 2012.
Dana Ridha, Ian Boomer, and Kirsty M. Edgar
J. Micropalaeontol., 38, 189–229, https://doi.org/10.5194/jm-38-189-2019, https://doi.org/10.5194/jm-38-189-2019, 2019
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This paper records the spatial and temporal distribution of deep-sea benthic microfossils (Foraminifera, single-celled organisms) from the latest Oligocene to earliest Pliocene (about 28 to 4 million years ago) from Ocean Drilling Program cores in the southern Indian Ocean. Key taxa are illustrated and their stratigraphic distribution is presented as they respond to a period of marked global climatic changes, with a pronounced warm period in the mid-Miocene followed by subsequent cooling.
Christian Berndt, Sverre Planke, Damon Teagle, Ritske Huismans, Trond Torsvik, Joost Frieling, Morgan T. Jones, Dougal A. Jerram, Christian Tegner, Jan Inge Faleide, Helen Coxall, and Wei-Li Hong
Sci. Dril., 26, 69–85, https://doi.org/10.5194/sd-26-69-2019, https://doi.org/10.5194/sd-26-69-2019, 2019
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The northeast Atlantic encompasses archetypal examples of volcanic rifted margins. Twenty-five years after the last ODP leg on these volcanic margins, the reasons for excess melting are still disputed with at least three competing hypotheses being discussed. We are proposing a new drilling campaign that will constrain the timing, rates of volcanism, and vertical movements of rifted margins.
Laurie M. Charrieau, Karl Ljung, Frederik Schenk, Ute Daewel, Emma Kritzberg, and Helena L. Filipsson
Biogeosciences, 16, 3835–3852, https://doi.org/10.5194/bg-16-3835-2019, https://doi.org/10.5194/bg-16-3835-2019, 2019
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We reconstructed environmental changes in the Öresund during the last 200 years, using foraminifera (microfossils), sediment, and climate data. Five zones were identified, reflecting oxygen, salinity, food content, and pollution levels for each period. The largest changes occurred ~ 1950, towards stronger currents. The foraminifera responded quickly (< 10 years) to the changes. Moreover, they did not rebound when the system returned to the previous pattern, but displayed a new equilibrium state.
Mariem Saavedra-Pellitero, Karl-Heinz Baumann, Miguel Ángel Fuertes, Hartmut Schulz, Yann Marcon, Nele Manon Vollmar, José-Abel Flores, and Frank Lamy
Biogeosciences, 16, 3679–3702, https://doi.org/10.5194/bg-16-3679-2019, https://doi.org/10.5194/bg-16-3679-2019, 2019
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Open ocean phytoplankton include coccolithophore algae, a key element in carbon cycle regulation with important feedbacks to the climate system. We document latitudinal variability in both coccolithophore assemblage and the mass variation in one particular species, Emiliania huxleyi, for a transect across the Drake Passage (in the Southern Ocean). Coccolithophore abundance, diversity and maximum depth habitat decrease southwards, coinciding with changes in the predominant E. huxleyi morphotypes.
Mattia Greco, Lukas Jonkers, Kerstin Kretschmer, Jelle Bijma, and Michal Kucera
Biogeosciences, 16, 3425–3437, https://doi.org/10.5194/bg-16-3425-2019, https://doi.org/10.5194/bg-16-3425-2019, 2019
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To be able to interpret the paleoecological signal contained in N. pachyderma's shells, its habitat depth must be known. Our investigation on 104 density profiles of this species from the Arctic and North Atlantic shows that specimens reside closer to the surface when sea-ice and/or surface chlorophyll concentrations are high. This is in contrast with previous investigations that pointed at the position of the deep chlorophyll maximum as the main driver of N. pachyderma vertical distribution.
Haruka Takagi, Katsunori Kimoto, Tetsuichi Fujiki, Hiroaki Saito, Christiane Schmidt, Michal Kucera, and Kazuyoshi Moriya
Biogeosciences, 16, 3377–3396, https://doi.org/10.5194/bg-16-3377-2019, https://doi.org/10.5194/bg-16-3377-2019, 2019
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Photosymbiosis (endosymbiosis with algae) is an evolutionary important ecology for many marine organisms but has poorly been identified among planktonic foraminifera. In this study, we identified and characterized photosymbiosis of various species of planktonic foraminifera by focusing on their photosynthesis–related features. We finally proposed a new framework showing a potential strength of photosymbiosis, which will serve as a basis for future ecological studies of planktonic foraminifera.
Anna Mikis, Katharine R. Hendry, Jennifer Pike, Daniela N. Schmidt, Kirsty M. Edgar, Victoria Peck, Frank J. C. Peeters, Melanie J. Leng, Michael P. Meredith, Chloe L. C. Jones, Sharon Stammerjohn, and Hugh Ducklow
Biogeosciences, 16, 3267–3282, https://doi.org/10.5194/bg-16-3267-2019, https://doi.org/10.5194/bg-16-3267-2019, 2019
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Antarctic marine calcifying organisms are threatened by regional climate change and ocean acidification. Future projections of regional carbonate production are challenging due to the lack of historical data combined with complex climate variability. We present a 6-year record of flux, morphology and geochemistry of an Antarctic planktonic foraminifera, which shows that their growth is most sensitive to sea ice dynamics and is linked with the El Niño–Southern Oscillation.
Christopher J. Hollis, Tom Dunkley Jones, Eleni Anagnostou, Peter K. Bijl, Marlow Julius Cramwinckel, Ying Cui, Gerald R. Dickens, Kirsty M. Edgar, Yvette Eley, David Evans, Gavin L. Foster, Joost Frieling, Gordon N. Inglis, Elizabeth M. Kennedy, Reinhard Kozdon, Vittoria Lauretano, Caroline H. Lear, Kate Littler, Lucas Lourens, A. Nele Meckler, B. David A. Naafs, Heiko Pälike, Richard D. Pancost, Paul N. Pearson, Ursula Röhl, Dana L. Royer, Ulrich Salzmann, Brian A. Schubert, Hannu Seebeck, Appy Sluijs, Robert P. Speijer, Peter Stassen, Jessica Tierney, Aradhna Tripati, Bridget Wade, Thomas Westerhold, Caitlyn Witkowski, James C. Zachos, Yi Ge Zhang, Matthew Huber, and Daniel J. Lunt
Geosci. Model Dev., 12, 3149–3206, https://doi.org/10.5194/gmd-12-3149-2019, https://doi.org/10.5194/gmd-12-3149-2019, 2019
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The Deep-Time Model Intercomparison Project (DeepMIP) is a model–data intercomparison of the early Eocene (around 55 million years ago), the last time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Previously, we outlined the experimental design for climate model simulations. Here, we outline the methods used for compilation and analysis of climate proxy data. The resulting climate
atlaswill provide insights into the mechanisms that control past warm climate states.
Anna Paula Soares Cruz, Cátia Fernandes Barbosa, Angélica Maria Blanco, Camila Areias de Oliveira, Cleverson Guizan Silva, and José Carlos Sícoli Seoane
Clim. Past, 15, 1363–1373, https://doi.org/10.5194/cp-15-1363-2019, https://doi.org/10.5194/cp-15-1363-2019, 2019
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Salgada Lagoon is a hypersaline lake investigated for its sedimentation history in order to interpret past climatic events. We studied the geochemistry of sediments from 5800 years ago until the present and found sea level oscillations, different climatic conditions, and proxies for vegetation cover and productivity, which highlight a dry event 4200 years ago that matches a global event of the same age, marking changes to favorable conditions for carbonates microbial mats and stromatolites.
Andreia Rebotim, Antje Helga Luise Voelker, Lukas Jonkers, Joanna J. Waniek, Michael Schulz, and Michal Kucera
J. Micropalaeontol., 38, 113–131, https://doi.org/10.5194/jm-38-113-2019, https://doi.org/10.5194/jm-38-113-2019, 2019
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To reconstruct subsurface water conditions using deep-dwelling planktonic foraminifera, we must fully understand how the oxygen isotope signal incorporates into their shell. We report δ18O in four species sampled in the eastern North Atlantic with plankton tows. We assess the size and crust effect on the isotopic δ18O and compared them with predictions from two equations. We reveal different patterns of calcite addition with depth, highlighting the need to perform species-specific calibrations.
Flor Vermassen, Nanna Andreasen, David J. Wangner, Nicolas Thibault, Marit-Solveig Seidenkrantz, Rebecca Jackson, Sabine Schmidt, Kurt H. Kjær, and Camilla S. Andresen
Clim. Past, 15, 1171–1186, https://doi.org/10.5194/cp-15-1171-2019, https://doi.org/10.5194/cp-15-1171-2019, 2019
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By studying microfossils from sediments in Upernavik Fjord we investigate the role of ocean warming on the retreat of Upernavik Isstrøm during the past ~90 years. The reconstruction of Atlantic-derived waters shows a pattern similar to that of the Atlantic Multidecadal Oscillation, corroborating previous studies. The response of Upernavik Isstrøm to ocean forcing has been variable in the past, but the current retreat may be temporarily tempered by cooling bottom waters in the coming decade.
Rodrigo da Costa Portilho-Ramos, Tainã Marcos Lima Pinho, Cristiano Mazur Chiessi, and Cátia Fernandes Barbosa
Clim. Past, 15, 943–955, https://doi.org/10.5194/cp-15-943-2019, https://doi.org/10.5194/cp-15-943-2019, 2019
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Fossil microorganisms from the last glacial found in marine sediments collected off southern Brazil suggest that more productive austral summer upwelling and more frequent austral winter incursions of nutrient-rich waters from the Plata River boosted regional productivity year-round. While upwelling was more productive due to the higher silicon content from the Southern Ocean, more frequent riverine incursions were modulated by stronger alongshore southwesterly winds.
Lukas Jonkers and Michal Kučera
Clim. Past, 15, 881–891, https://doi.org/10.5194/cp-15-881-2019, https://doi.org/10.5194/cp-15-881-2019, 2019
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Fossil plankton assemblages have been widely used to reconstruct SST. In such approaches, full taxonomic resolution is often used. We assess whether this is required for reliable reconstructions as some species may not respond to SST. We find that only a few species are needed for low reconstruction errors but that species selection has a pronounced effect on reconstructions. We suggest that the sensitivity of a reconstruction to species pruning can be used as a measure of its robustness.
Hilde Pracht, Brett Metcalfe, and Frank J. C. Peeters
Biogeosciences, 16, 643–661, https://doi.org/10.5194/bg-16-643-2019, https://doi.org/10.5194/bg-16-643-2019, 2019
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In palaeoceanography the shells of single-celled foraminifera are routinely used as proxies to reconstruct the temperature, salinity and circulation of the ocean in the past. Traditionally a number of specimens were pooled for a single stable isotope measurement; however, technical advances now mean that a single shell or chamber of a shell can be measured individually. Three different hypotheses regarding foraminiferal biology and ecology were tested using this approach.
Nadia Al-Sabouni, Isabel S. Fenton, Richard J. Telford, and Michal Kučera
J. Micropalaeontol., 37, 519–534, https://doi.org/10.5194/jm-37-519-2018, https://doi.org/10.5194/jm-37-519-2018, 2018
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In this study we investigate consistency in species-level identifications and whether disagreements are predictable. Overall, 21 researchers from across the globe identified sets of 300 specimens or digital images of planktonic foraminifera. Digital identifications tended to be more disparate. Participants trained by the same person often had more similar identifications. Disagreements hardly affected transfer-function temperature estimates but produced larger differences in diversity metrics.
Isabel S. Fenton, Ulrike Baranowski, Flavia Boscolo-Galazzo, Hannah Cheales, Lyndsey Fox, David J. King, Christina Larkin, Marcin Latas, Diederik Liebrand, C. Giles Miller, Katrina Nilsson-Kerr, Emanuela Piga, Hazel Pugh, Serginio Remmelzwaal, Zoe A. Roseby, Yvonne M. Smith, Stephen Stukins, Ben Taylor, Adam Woodhouse, Savannah Worne, Paul N. Pearson, Christopher R. Poole, Bridget S. Wade, and Andy Purvis
J. Micropalaeontol., 37, 431–443, https://doi.org/10.5194/jm-37-431-2018, https://doi.org/10.5194/jm-37-431-2018, 2018
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In this study we investigate consistency in species-level identifications and whether disagreements are predictable. Twenty-three scientists identified a set of 100 planktonic foraminifera, noting their confidence in each identification. The median accuracy of students was 57 %; 79 % for experienced researchers. Where they were confident in the identifications, the values are 75 % and 93 %, respectively. Accuracy was significantly higher if the students had been taught how to identify species.
Jeroen Groeneveld, Helena L. Filipsson, William E. N. Austin, Kate Darling, David McCarthy, Nadine B. Quintana Krupinski, Clare Bird, and Magali Schweizer
J. Micropalaeontol., 37, 403–429, https://doi.org/10.5194/jm-37-403-2018, https://doi.org/10.5194/jm-37-403-2018, 2018
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Current climate and environmental changes strongly affect shallow marine and coastal areas like the Baltic Sea. The combination of foraminiferal geochemistry and environmental parameters demonstrates that in a highly variable setting like the Baltic Sea, it is possible to separate different environmental impacts on the foraminiferal assemblages and therefore use chemical factors to reconstruct how seawater temperature, salinity, and oxygen varied in the past and may vary in the future.
Didier M. Roche, Claire Waelbroeck, Brett Metcalfe, and Thibaut Caley
Geosci. Model Dev., 11, 3587–3603, https://doi.org/10.5194/gmd-11-3587-2018, https://doi.org/10.5194/gmd-11-3587-2018, 2018
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The oxygen-18 signal recorded in fossil planktonic foraminifers has been used for over 50 years in many geoscience applications. However, different planktonic foraminifer species from the same sediment core generally yield distinct oxygen-18 signals, as a consequence of their specific living habitat in the water column and along the year. To explicitly take into account this variability for five common planktonic species, we developed the portable module FAME (Foraminifers As Modeled Entities).
Irina Polovodova Asteman, Helena L. Filipsson, and Kjell Nordberg
Clim. Past, 14, 1097–1118, https://doi.org/10.5194/cp-14-1097-2018, https://doi.org/10.5194/cp-14-1097-2018, 2018
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We present 2500 years of winter temperatures, using a sediment record from Gullmar Fjord analyzed for stable oxygen isotopes in benthic foraminifera. Reconstructed temperatures are within the annual temperature variability recorded in the fjord since the 1890s. Results show the warm Roman and Medieval periods and the cold Little Ice Age. The record also shows the recent warming, which does not stand out in the 2500-year perspective and is comparable to the Roman and Medieval climate anomalies.
Kerstin Kretschmer, Lukas Jonkers, Michal Kucera, and Michael Schulz
Biogeosciences, 15, 4405–4429, https://doi.org/10.5194/bg-15-4405-2018, https://doi.org/10.5194/bg-15-4405-2018, 2018
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The fossil shells of planktonic foraminifera are widely used to reconstruct past climate conditions. To do so, information about their seasonal and vertical habitat is needed. Here we present an updated version of a planktonic foraminifera model to better understand species-specific habitat dynamics under climate change. This model produces spatially and temporally coherent distribution patterns, which agree well with available observations, and can thus aid the interpretation of proxy records.
David K. Hutchinson, Agatha M. de Boer, Helen K. Coxall, Rodrigo Caballero, Johan Nilsson, and Michiel Baatsen
Clim. Past, 14, 789–810, https://doi.org/10.5194/cp-14-789-2018, https://doi.org/10.5194/cp-14-789-2018, 2018
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The Eocene--Oligocene transition was a major cooling event 34 million years ago. Climate model studies of this transition have used low ocean resolution or topography that roughly approximates the time period. We present a new climate model simulation of the late Eocene, with higher ocean resolution and topography which is accurately designed for this time period. These features improve the ocean circulation and gateways which are thought to be important for this climate transition.
Bryan C. Lougheed, Brett Metcalfe, Ulysses S. Ninnemann, and Lukas Wacker
Clim. Past, 14, 515–526, https://doi.org/10.5194/cp-14-515-2018, https://doi.org/10.5194/cp-14-515-2018, 2018
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Palaeoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid climate change, but only a small proportion of the ocean is suitable for such reconstructions using the existing state of the art, i.e. the age–depth approach. We use dual radiocarbon (14C) and stable isotope analysis on single foraminifera to bypass the long-standing age–depth approach, thus facilitating past ocean chemistry reconstructions from vast, previously untapped ocean areas.
Andrés S. Rigual Hernández, José A. Flores, Francisco J. Sierro, Miguel A. Fuertes, Lluïsa Cros, and Thomas W. Trull
Biogeosciences, 15, 1843–1862, https://doi.org/10.5194/bg-15-1843-2018, https://doi.org/10.5194/bg-15-1843-2018, 2018
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Long-term and annual field observations on key organisms are a critical basis for predicting changes in Southern Ocean ecosystems. Coccolithophores are the most abundant calcium-carbonate-producing phytoplankton and play an important role in Southern Ocean biogeochemical cycles. In this study we document the composition, degree of calcification and annual cycle of coccolithophore communities in one of the largest unexplored regions of the world oceans: the Antarctic zone.
Helen M. Beddow, Diederik Liebrand, Douglas S. Wilson, Frits J. Hilgen, Appy Sluijs, Bridget S. Wade, and Lucas J. Lourens
Clim. Past, 14, 255–270, https://doi.org/10.5194/cp-14-255-2018, https://doi.org/10.5194/cp-14-255-2018, 2018
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We present two astronomy-based timescales for climate records from the Pacific Ocean. These records range from 24 to 22 million years ago, a time period when Earth was warmer than today and the only land ice was located on Antarctica. We use tectonic plate-pair spreading rates to test the two timescales, which shows that the carbonate record yields the best timescale. In turn, this implies that Earth’s climate system and carbon cycle responded slowly to changes in incoming solar radiation.
Marie Nicolle, Maxime Debret, Nicolas Massei, Christophe Colin, Anne deVernal, Dmitry Divine, Johannes P. Werner, Anne Hormes, Atte Korhola, and Hans W. Linderholm
Clim. Past, 14, 101–116, https://doi.org/10.5194/cp-14-101-2018, https://doi.org/10.5194/cp-14-101-2018, 2018
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Arctic climate variability for the last 2 millennia has been investigated using statistical and signal analyses from North Atlantic, Siberia and Alaska regionally averaged records. A focus on the last 2 centuries shows a climate variability linked to anthropogenic forcing but also a multidecadal variability likely due to regional natural processes acting on the internal climate system. It is an important issue to understand multidecadal variabilities occurring in the instrumental data.
Laurie M. Charrieau, Lene Bryngemark, Ingemar Hansson, and Helena L. Filipsson
J. Micropalaeontol., 37, 191–194, https://doi.org/10.5194/jm-37-191-2018, https://doi.org/10.5194/jm-37-191-2018, 2018
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Splitting samples into smaller subsamples is often necessary in micropalaeontological studies. Indeed, the general high abundance of microfossils – which makes them excellent tools to reconstruct past environments – also results in very time-consuming faunal analyses. Here we present an improved and cost-effective wet splitter for micropalaeontological samples aimed to reduce picking time, while keeping information loss to a minimum.
Ulrich Kotthoff, Jeroen Groeneveld, Jeanine L. Ash, Anne-Sophie Fanget, Nadine Quintana Krupinski, Odile Peyron, Anna Stepanova, Jonathan Warnock, Niels A. G. M. Van Helmond, Benjamin H. Passey, Ole Rønø Clausen, Ole Bennike, Elinor Andrén, Wojciech Granoszewski, Thomas Andrén, Helena L. Filipsson, Marit-Solveig Seidenkrantz, Caroline P. Slomp, and Thorsten Bauersachs
Biogeosciences, 14, 5607–5632, https://doi.org/10.5194/bg-14-5607-2017, https://doi.org/10.5194/bg-14-5607-2017, 2017
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We present reconstructions of paleotemperature, paleosalinity, and paleoecology from the Little Belt (Site M0059) over the past ~ 8000 years and evaluate the applicability of numerous proxies. Conditions were lacustrine until ~ 7400 cal yr BP. A transition to brackish–marine conditions then occurred within ~ 200 years. Salinity proxies rarely allowed quantitative estimates but revealed congruent results, while quantitative temperature reconstructions differed depending on the proxies used.
Catarina V. Guerreiro, Karl-Heinz Baumann, Geert-Jan A. Brummer, Gerhard Fischer, Laura F. Korte, Ute Merkel, Carolina Sá, Henko de Stigter, and Jan-Berend W. Stuut
Biogeosciences, 14, 4577–4599, https://doi.org/10.5194/bg-14-4577-2017, https://doi.org/10.5194/bg-14-4577-2017, 2017
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Our study provides insights into the factors governing the spatio-temporal variability of coccolithophores in the equatorial North Atlantic and illustrates how this supposedly oligotrophic and stable open-ocean region actually reveals significant ecological variability. We provide evidence for Saharan dust and the Amazon River acting as fertilizers for phytoplankton and highlight the the importance of the thermocline depth for coccolithophore productivity in the lower photic zone.
Martin Jakobsson, Christof Pearce, Thomas M. Cronin, Jan Backman, Leif G. Anderson, Natalia Barrientos, Göran Björk, Helen Coxall, Agatha de Boer, Larry A. Mayer, Carl-Magnus Mörth, Johan Nilsson, Jayne E. Rattray, Christian Stranne, Igor Semiletov, and Matt O'Regan
Clim. Past, 13, 991–1005, https://doi.org/10.5194/cp-13-991-2017, https://doi.org/10.5194/cp-13-991-2017, 2017
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The Arctic and Pacific oceans are connected by the presently ~53 m deep Bering Strait. During the last glacial period when the sea level was lower than today, the Bering Strait was exposed. Humans and animals could then migrate between Asia and North America across the formed land bridge. From analyses of sediment cores and geophysical mapping data from Herald Canyon north of the Bering Strait, we show that the land bridge was flooded about 11 000 years ago.
Raphaël Morard, Franck Lejzerowicz, Kate F. Darling, Béatrice Lecroq-Bennet, Mikkel Winther Pedersen, Ludovic Orlando, Jan Pawlowski, Stefan Mulitza, Colomban de Vargas, and Michal Kucera
Biogeosciences, 14, 2741–2754, https://doi.org/10.5194/bg-14-2741-2017, https://doi.org/10.5194/bg-14-2741-2017, 2017
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The exploitation of deep-sea sedimentary archive relies on the recovery of mineralized skeletons of pelagic organisms. Planktonic groups leaving preserved remains represent only a fraction of the total marine diversity. Environmental DNA left by non-fossil organisms is a promising source of information for paleo-reconstructions. Here we show how planktonic-derived environmental DNA preserves ecological structure of planktonic communities. We use planktonic foraminifera as a case study.
Lukas Jonkers and Michal Kučera
Clim. Past, 13, 573–586, https://doi.org/10.5194/cp-13-573-2017, https://doi.org/10.5194/cp-13-573-2017, 2017
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Planktonic foraminifera – the most important proxy carriers in palaeoceanography – adjust their seasonal and vertical habitat. They are thought to do so in a way that minimises the change in their environment, implying that proxy records based on these organisms may not capture the full amplitude of past climate change. Here we demonstrate that they indeed track a particular thermal habitat and suggest that this could lead to a 40 % underestimation of reconstructed temperature change.
Philipp M. Munz, Stephan Steinke, Anna Böll, Andreas Lückge, Jeroen Groeneveld, Michal Kucera, and Hartmut Schulz
Clim. Past, 13, 491–509, https://doi.org/10.5194/cp-13-491-2017, https://doi.org/10.5194/cp-13-491-2017, 2017
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We present the results of several independent proxies of summer SST and upwelling SST from the Oman margin indicative of monsoon strength during the early Holocene. In combination with indices of carbonate preservation and bottom water redox conditions, we demonstrate that a persistent solar influence was modulating summer monsoon intensity. Furthermore, bottom water conditions are linked to atmospheric forcing, rather than changes of intermediate water masses.
Montserrat Alonso-Garcia, Helga (Kikki) F. Kleiven, Jerry F. McManus, Paola Moffa-Sanchez, Wallace S. Broecker, and Benjamin P. Flower
Clim. Past, 13, 317–331, https://doi.org/10.5194/cp-13-317-2017, https://doi.org/10.5194/cp-13-317-2017, 2017
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This study focuses on understanding climatic and oceanographic variations that took place during the last 1000 years. We studied sediment samples from the Labrador Sea, looking for evidence of events of freshwater and iceberg discharges to this region. The importance of this study is to evaluate when these events happened and their consequences. The freshening of the Labrador Sea region may have played a major role in promoting cooling during the 15th to 19th centuries.
Andreia Rebotim, Antje H. L. Voelker, Lukas Jonkers, Joanna J. Waniek, Helge Meggers, Ralf Schiebel, Igaratza Fraile, Michael Schulz, and Michal Kucera
Biogeosciences, 14, 827–859, https://doi.org/10.5194/bg-14-827-2017, https://doi.org/10.5194/bg-14-827-2017, 2017
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Planktonic foraminifera species depth habitat remains poorly constrained and the existing conceptual models are not sufficiently tested by observational data. Here we present a synthesis of living planktonic foraminifera abundance data in the subtropical eastern North Atlantic from vertical plankton tows. We also test potential environmental factors influencing the species depth habitat and investigate yearly or lunar migration cycles. These findings may impact paleoceanographic studies.
Daniel J. Lunt, Matthew Huber, Eleni Anagnostou, Michiel L. J. Baatsen, Rodrigo Caballero, Rob DeConto, Henk A. Dijkstra, Yannick Donnadieu, David Evans, Ran Feng, Gavin L. Foster, Ed Gasson, Anna S. von der Heydt, Chris J. Hollis, Gordon N. Inglis, Stephen M. Jones, Jeff Kiehl, Sandy Kirtland Turner, Robert L. Korty, Reinhardt Kozdon, Srinath Krishnan, Jean-Baptiste Ladant, Petra Langebroek, Caroline H. Lear, Allegra N. LeGrande, Kate Littler, Paul Markwick, Bette Otto-Bliesner, Paul Pearson, Christopher J. Poulsen, Ulrich Salzmann, Christine Shields, Kathryn Snell, Michael Stärz, James Super, Clay Tabor, Jessica E. Tierney, Gregory J. L. Tourte, Aradhna Tripati, Garland R. Upchurch, Bridget S. Wade, Scott L. Wing, Arne M. E. Winguth, Nicky M. Wright, James C. Zachos, and Richard E. Zeebe
Geosci. Model Dev., 10, 889–901, https://doi.org/10.5194/gmd-10-889-2017, https://doi.org/10.5194/gmd-10-889-2017, 2017
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In this paper we describe the experimental design for a set of simulations which will be carried out by a range of climate models, all investigating the climate of the Eocene, about 50 million years ago. The intercomparison of model results is called 'DeepMIP', and we anticipate that we will contribute to the next IPCC report through an analysis of these simulations and the geological data to which we will compare them.
Wenxin Ning, Jing Tang, and Helena L. Filipsson
Earth Surf. Dynam., 4, 773–780, https://doi.org/10.5194/esurf-4-773-2016, https://doi.org/10.5194/esurf-4-773-2016, 2016
Gerhard Fischer, Johannes Karstensen, Oscar Romero, Karl-Heinz Baumann, Barbara Donner, Jens Hefter, Gesine Mollenhauer, Morten Iversen, Björn Fiedler, Ivanice Monteiro, and Arne Körtzinger
Biogeosciences, 13, 3203–3223, https://doi.org/10.5194/bg-13-3203-2016, https://doi.org/10.5194/bg-13-3203-2016, 2016
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Particle fluxes at the Cape Verde Ocean Observatory in the eastern tropical North Atlantic for the period December 2009 until May 2011 are discussed based on deep sediment trap time-series data collected at 1290 and 3439 m water depths. The typically open-ocean flux pattern with weak seasonality is modified by the appearance of a highly productive and low oxygen eddy in winter 2010. The eddy passage was accompanied by high biogenic and lithogenic fluxes, lasting from December 2009 to May 2010.
David Evans, Bridget S. Wade, Michael Henehan, Jonathan Erez, and Wolfgang Müller
Clim. Past, 12, 819–835, https://doi.org/10.5194/cp-12-819-2016, https://doi.org/10.5194/cp-12-819-2016, 2016
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We show that seawater pH exerts a substantial control on planktic foraminifera Mg / Ca, a widely applied palaeothermometer. As a result, temperature reconstructions based on this proxy are likely inaccurate over climatic events associated with a significant change in pH. We examine the implications of our findings for hydrological and temperature shifts over the Paleocene-Eocene Thermal Maximum and for the degree of surface ocean precursor cooling before the Eocene-Oligocene transition.
Francisco Javier Briceño-Zuluaga, Abdelfettah Sifeddine, Sandrine Caquineau, Jorge Cardich, Renato Salvatteci, Dimitri Gutierrez, Luc Ortlieb, Federico Velazco, Hugues Boucher, and Carine Machado
Clim. Past, 12, 787–798, https://doi.org/10.5194/cp-12-787-2016, https://doi.org/10.5194/cp-12-787-2016, 2016
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Comparison between records reveals a coherent match between the meridional displacement of the ITCZ-SPSH system and the regional fluvial and aeolian terrigenous input variability. The aeolian input intensity and the anoxic conditions recorded by marine sediments showed a close link that suggests a common mechanism associated with SPSH displacement. Changes in sediment discharge to the continental shelf are linked to the southward displacement of the ITCZ-SPSH and Walker circulation.
B. A. A. Hoogakker, R. S. Smith, J. S. Singarayer, R. Marchant, I. C. Prentice, J. R. M. Allen, R. S. Anderson, S. A. Bhagwat, H. Behling, O. Borisova, M. Bush, A. Correa-Metrio, A. de Vernal, J. M. Finch, B. Fréchette, S. Lozano-Garcia, W. D. Gosling, W. Granoszewski, E. C. Grimm, E. Grüger, J. Hanselman, S. P. Harrison, T. R. Hill, B. Huntley, G. Jiménez-Moreno, P. Kershaw, M.-P. Ledru, D. Magri, M. McKenzie, U. Müller, T. Nakagawa, E. Novenko, D. Penny, L. Sadori, L. Scott, J. Stevenson, P. J. Valdes, M. Vandergoes, A. Velichko, C. Whitlock, and C. Tzedakis
Clim. Past, 12, 51–73, https://doi.org/10.5194/cp-12-51-2016, https://doi.org/10.5194/cp-12-51-2016, 2016
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In this paper we use two climate models to test how Earth’s vegetation responded to changes in climate over the last 120 000 years, looking at warm interglacial climates like today, cold ice-age glacial climates, and intermediate climates. The models agree well with observations from pollen, showing smaller forested areas and larger desert areas during cold periods. Forests store most terrestrial carbon; the terrestrial carbon lost during cold climates was most likely relocated to the oceans.
B. Ausín, I. Hernández-Almeida, J.-A. Flores, F.-J. Sierro, M. Grosjean, G. Francés, and B. Alonso
Clim. Past, 11, 1635–1651, https://doi.org/10.5194/cp-11-1635-2015, https://doi.org/10.5194/cp-11-1635-2015, 2015
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Coccolithophore distribution in 88 surface sediment samples in the Atlantic Ocean and western Mediterranean was mainly influenced by salinity at 10m depth. A quantitative coccolithophore-based transfer function was developed and applied to a fossil sediment core to estimate sea surface salinity (SSS). The quality of this function and the reliability of the SSS reconstruction were assessed by statistical analyses and discussed. Several centennial SSS changes are identified for the last 15.5 ka.
J. M. Bernhard, W. G. Phalen, A. McIntyre-Wressnig, F. Mezzo, J. C. Wit, M. Jeglinski, and H. L. Filipsson
Biogeosciences, 12, 5515–5522, https://doi.org/10.5194/bg-12-5515-2015, https://doi.org/10.5194/bg-12-5515-2015, 2015
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We present an innovative method using osmotic pumps and the fluorescent marker calcein to help identify where and when calcareous bottom-dwelling organisms mineralize in sediments. These organisms, and their geochemical signatures in their carbonate, are the ocean’s storytellers helping us understand past marine conditions. For many species, the timing and location of their calcite growth is not known. Knowing this will enable us to reconstruct past marine environments with greater accuracy.
C. L. McKay, J. Groeneveld, H. L. Filipsson, D. Gallego-Torres, M. J. Whitehouse, T. Toyofuku, and O.E. Romero
Biogeosciences, 12, 5415–5428, https://doi.org/10.5194/bg-12-5415-2015, https://doi.org/10.5194/bg-12-5415-2015, 2015
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We highlight the proxy potential of foraminiferal Mn/Ca determined by secondary ion mass spectrometry and flow-through inductively coupled plasma optical emission spectroscopy for recording changes in bottom-water oxygen conditions. Comparisons with Mn sediment bulk measurements from the same sediment core largely agree with the results. High foraminiferal Mn/Ca occurs in samples from times of high productivity export and corresponds with the benthic foraminiferal faunal composition.
A. S. Rigual-Hernández, T. W. Trull, S. G. Bray, A. Cortina, and L. K. Armand
Biogeosciences, 12, 5309–5337, https://doi.org/10.5194/bg-12-5309-2015, https://doi.org/10.5194/bg-12-5309-2015, 2015
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Diatom and major components of the flux collected by two sediment traps in subantarctic and polar frontal zones were studied. Despite significant differences in the composition and magnitude of the flux, POC flux was similar between sites. The development of a group of bloom-forming diatoms during summer led to the formation of aggregates and enhanced POC export. Our results suggest that high biogenic silica accumulation rates should be interpreted as a proxy for iron-limited diatom assemblages.
B. Metcalfe, W. Feldmeijer, M. de Vringer-Picon, G.-J. A. Brummer, F. J. C. Peeters, and G. M. Ganssen
Biogeosciences, 12, 4781–4807, https://doi.org/10.5194/bg-12-4781-2015, https://doi.org/10.5194/bg-12-4781-2015, 2015
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Iron biogeochemical budgets during the natural ocean fertilisation experiment KEOPS-2 showed that complex circulation and transport pathways were responsible for differences in the mode and strength of iron supply, with vertical supply dominant on the plateau and lateral supply dominant in the plume. The exchange of iron between dissolved, biogenic and lithogenic pools was highly dynamic, resulting in a decoupling of iron supply and carbon export and controlling the efficiency of fertilisation.
L. Jonkers, C. E. Reynolds, J. Richey, and I. R. Hall
Biogeosciences, 12, 3061–3070, https://doi.org/10.5194/bg-12-3061-2015, https://doi.org/10.5194/bg-12-3061-2015, 2015
I. Hernández-Almeida, F.-J. Sierro, I. Cacho, and J.-A. Flores
Clim. Past, 11, 687–696, https://doi.org/10.5194/cp-11-687-2015, https://doi.org/10.5194/cp-11-687-2015, 2015
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This manuscript presents new Mg/Ca and previously published δ18O measurements of Neogloboquadrina pachyderma sinistral for MIS 31-19, from a sediment core from the subpolar North Atlantic. The mechanism proposed here involves northward subsurface transport of warm and salty subtropical waters during periods of weaker AMOC, leading to ice-sheet instability and IRD discharge. This is the first time that these rapid climate oscillations are described for the early Pleistocene.
L. Jonkers and M. Kučera
Biogeosciences, 12, 2207–2226, https://doi.org/10.5194/bg-12-2207-2015, https://doi.org/10.5194/bg-12-2207-2015, 2015
G. Auer, W. E. Piller, and M. Harzhauser
Clim. Past, 11, 283–303, https://doi.org/10.5194/cp-11-283-2015, https://doi.org/10.5194/cp-11-283-2015, 2015
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High-resolution analyses of paleoecological and geochemical proxies give insight into environmental processes and climate variations in the past on a timescale that is relevant for humans. This study, as the first of its kind, aims to resolve cyclic variations of nannofossil assemblages on a decadal to centennial scale in a highly sensitive Early Miocene (~17Ma) shallow marine setting. Our results indicate that solar variation played a major role in shaping short-term climate variability.
I. Hessler, S. P. Harrison, M. Kucera, C. Waelbroeck, M.-T. Chen, C. Anderson, A. de Vernal, B. Fréchette, A. Cloke-Hayes, G. Leduc, and L. Londeix
Clim. Past, 10, 2237–2252, https://doi.org/10.5194/cp-10-2237-2014, https://doi.org/10.5194/cp-10-2237-2014, 2014
H. S. Sundqvist, D. S. Kaufman, N. P. McKay, N. L. Balascio, J. P. Briner, L. C. Cwynar, H. P. Sejrup, H. Seppä, D. A. Subetto, J. T. Andrews, Y. Axford, J. Bakke, H. J. B. Birks, S. J. Brooks, A. de Vernal, A. E. Jennings, F. C. Ljungqvist, K. M. Rühland, C. Saenger, J. P. Smol, and A. E. Viau
Clim. Past, 10, 1605–1631, https://doi.org/10.5194/cp-10-1605-2014, https://doi.org/10.5194/cp-10-1605-2014, 2014
M. P. Nardelli, C. Barras, E. Metzger, A. Mouret, H. L. Filipsson, F. Jorissen, and E. Geslin
Biogeosciences, 11, 4029–4038, https://doi.org/10.5194/bg-11-4029-2014, https://doi.org/10.5194/bg-11-4029-2014, 2014
F. Klein, H. Goosse, A. Mairesse, and A. de Vernal
Clim. Past, 10, 1145–1163, https://doi.org/10.5194/cp-10-1145-2014, https://doi.org/10.5194/cp-10-1145-2014, 2014
M. T. Horigome, P. Ziveri, M. Grelaud, K.-H. Baumann, G. Marino, and P. G. Mortyn
Biogeosciences, 11, 2295–2308, https://doi.org/10.5194/bg-11-2295-2014, https://doi.org/10.5194/bg-11-2295-2014, 2014
D. K. Naik, R. Saraswat, N. Khare, A. C. Pandey, and R. Nigam
Clim. Past, 10, 745–758, https://doi.org/10.5194/cp-10-745-2014, https://doi.org/10.5194/cp-10-745-2014, 2014
A. J. Enge, U. Witte, M. Kucera, and P. Heinz
Biogeosciences, 11, 2017–2026, https://doi.org/10.5194/bg-11-2017-2014, https://doi.org/10.5194/bg-11-2017-2014, 2014
C. Berger, K. J. S. Meier, H. Kinkel, and K.-H. Baumann
Biogeosciences, 11, 929–944, https://doi.org/10.5194/bg-11-929-2014, https://doi.org/10.5194/bg-11-929-2014, 2014
M. F. G. Weinkauf, T. Moller, M. C. Koch, and M. Kučera
Biogeosciences, 10, 6639–6655, https://doi.org/10.5194/bg-10-6639-2013, https://doi.org/10.5194/bg-10-6639-2013, 2013
Y. Milker, R. Rachmayani, M. F. G. Weinkauf, M. Prange, M. Raitzsch, M. Schulz, and M. Kučera
Clim. Past, 9, 2231–2252, https://doi.org/10.5194/cp-9-2231-2013, https://doi.org/10.5194/cp-9-2231-2013, 2013
J. Groeneveld and H. L. Filipsson
Biogeosciences, 10, 5125–5138, https://doi.org/10.5194/bg-10-5125-2013, https://doi.org/10.5194/bg-10-5125-2013, 2013
C. V. Dylmer, J. Giraudeau, F. Eynaud, K. Husum, and A. De Vernal
Clim. Past, 9, 1505–1518, https://doi.org/10.5194/cp-9-1505-2013, https://doi.org/10.5194/cp-9-1505-2013, 2013
Karl-Heinz Baumann and Babette Boeckel
J. Micropalaeontol., 32, 123–133, https://doi.org/10.1144/jmpaleo2011-007, https://doi.org/10.1144/jmpaleo2011-007, 2013
B. C. Lougheed, H. L. Filipsson, and I. Snowball
Clim. Past, 9, 1015–1028, https://doi.org/10.5194/cp-9-1015-2013, https://doi.org/10.5194/cp-9-1015-2013, 2013
R. J. Telford, C. Li, and M. Kucera
Clim. Past, 9, 859–870, https://doi.org/10.5194/cp-9-859-2013, https://doi.org/10.5194/cp-9-859-2013, 2013
I. Polovodova Asteman, K. Nordberg, and H. L. Filipsson
Biogeosciences, 10, 1275–1290, https://doi.org/10.5194/bg-10-1275-2013, https://doi.org/10.5194/bg-10-1275-2013, 2013
Related subject area
Taxonomy
Ten recommendations for scanning foraminifera by X-ray computed tomography
Semantic segmentation of vertebrate microfossils from computed tomography data using a deep learning approach
Novel heterococcolithophores, holococcolithophores and life cycle combinations from the families Syracosphaeraceae and Papposphaeraceae and the genus Florisphaera
Alex Searle-Barnes, Anieke Brombacher, Orestis Katsamenis, Kathryn Rankin, Mark Mavrogordato, and Thomas Ezard
J. Micropalaeontol., 44, 107–117, https://doi.org/10.5194/jm-44-107-2025, https://doi.org/10.5194/jm-44-107-2025, 2025
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We present an operating procedure that is advantageous for the high-throughput analysis of specimens, yielding consistency between scan data, and a method of sample preparation that does not include glue, gel, or solvents, all of which cause artefacts within the radiographs. We demonstrate how to balance beam power, exposure time, and detector settings with obtainable resolution to ensure the analytical protocols deliver optimal data and scan speed.
Yemao Hou, Mario Canul-Ku, Xindong Cui, Rogelio Hasimoto-Beltran, and Min Zhu
J. Micropalaeontol., 40, 163–173, https://doi.org/10.5194/jm-40-163-2021, https://doi.org/10.5194/jm-40-163-2021, 2021
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In this study, we constructed an open dataset, which contains computed tomography (CT) data on nearly 500 vertebrate microfossils. We propose a semantic segmentation method for CT fish microfossil data based on deep learning (DL). We expect that our proposed method could be applied to CT data on other fossils with good performance. We also believe the fast-accumulating CT data on vertebrate microfossils might become a source of information-rich datasets for deep learning.
Sabine Keuter, Jeremy R. Young, Gil Koplovitz, Adriana Zingone, and Miguel J. Frada
J. Micropalaeontol., 40, 75–99, https://doi.org/10.5194/jm-40-75-2021, https://doi.org/10.5194/jm-40-75-2021, 2021
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Coccolithophores are an important group of phytoplankton that produce intricate skeletons of calcium carbonate. They contribute to the base of the marine food web and are important drivers of the global carbon cycle. Here, we describe novel coccolithophores and novel life cycle combinations detected by electron microscopy in samples collected in the Red Sea and the western Mediterranean. Our study advances our understanding of coccolithophore diversity and life cycle complexity.
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Short summary
Our study provides guidelines improving the reuse of marine microfossil assemblage data, which are valuable for understanding past ecosystems and environmental change. Based on a survey of 113 researchers, we identified key data attributes required for effective reuse. Analysis of a selection of datasets available online reveals a gap between the attributes scientists consider essential and the data currently available, highlighting the need for clearer data documentation and sharing practices.
Our study provides guidelines improving the reuse of marine microfossil assemblage data, which...
