1
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Sun S, Thompson AF, Yu J, Wu L. Transient overturning changes cause an upper-ocean nutrient decline in a warming climate. Nat Commun 2024; 15:7727. [PMID: 39231975 PMCID: PMC11375078 DOI: 10.1038/s41467-024-52200-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 08/29/2024] [Indexed: 09/06/2024] Open
Abstract
Models and proxy data suggest multi-centennial nutrient reorganization and biological productivity changes under sustained climate warming. These changes have traditionally been attributed to processes in the Southern Ocean. Here we instead show that transient overturning circulation adjustments, associated with changes in the Atlantic Meridional Overturning Circulation (AMOC), dominate the global nutrient reorganization on centennial timescales. Following an AMOC weakening, a typical feature of a warming climate, a transient overturning circulation develops in the Indo-Pacific basins, characterized by enhanced southward transport in the deep ocean. Coupled with the vertical nutrient structure, these transient overturning changes produce a net transport of nutrients from the Indo-Pacific into the Southern Ocean. Meanwhile, isopycnal surfaces deepen and bring nutrient-depleted waters to greater depths, causing nutrient concentrations to decline in much of the global upper ocean. Given the close link between nutrients and carbon, our findings suggest that transient overturning circulation changes across different basins can critically affect the marine carbon cycle.
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Affiliation(s)
- Shantong Sun
- Laoshan Laboratory, Qingdao, China.
- Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, USA.
- Environmental Science and Engineering, California Institute of Technology, Pasadena, CA, USA.
| | - Andrew F Thompson
- Environmental Science and Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Jimin Yu
- Laoshan Laboratory, Qingdao, China
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
- SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Lixin Wu
- Laoshan Laboratory, Qingdao, China
- Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao, China
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2
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Kirtland Turner S, Ridgwell A, Keller AL, Vahlenkamp M, Aleksinski AK, Sexton PF, Penman DE, Hull PM, Norris RD. Sensitivity of ocean circulation to warming during the Early Eocene greenhouse. Proc Natl Acad Sci U S A 2024; 121:e2311980121. [PMID: 38830092 PMCID: PMC11181020 DOI: 10.1073/pnas.2311980121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 04/19/2024] [Indexed: 06/05/2024] Open
Abstract
Multiple abrupt warming events ("hyperthermals") punctuated the Early Eocene and were associated with deep-sea temperature increases of 2 to 4 °C, seafloor carbonate dissolution, and negative carbon isotope (δ13C) excursions. Whether hyperthermals were associated with changes in the global ocean overturning circulation is important for understanding their driving mechanisms and feedbacks and for gaining insight into the circulation's sensitivity to climatic warming. Here, we present high-resolution benthic foraminiferal stable isotope records (δ13C and δ18O) throughout the Early Eocene Climate Optimum (~53.26 to 49.14 Ma) from the deep equatorial and North Atlantic. Combined with existing records from the South Atlantic and Pacific, these indicate consistently amplified δ13C excursion sizes during hyperthermals in the deep equatorial Atlantic. We compare these observations with results from an intermediate complexity Earth system model to demonstrate that this spatial pattern of δ13C excursion size is a predictable consequence of global warming-induced changes in ocean overturning circulation. In our model, transient warming drives the weakening of Southern Ocean-sourced overturning circulation, strengthens Atlantic meridional water mass aging gradients, and amplifies the magnitude of negative δ13C excursions in the equatorial to North Atlantic. Based on model-data consistency, we conclude that Eocene hyperthermals coincided with repeated weakening of the global overturning circulation. Not accounting for ocean circulation impacts on δ13C excursions will lead to incorrect estimates of the magnitude of carbon release driving hyperthermals. Our finding of weakening overturning in response to past transient climatic warming is consistent with predictions of declining Atlantic Ocean overturning strength in our warm future.
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Affiliation(s)
- Sandra Kirtland Turner
- Department of Earth and Planetary Sciences, University of California, Riverside, CA92521
| | - Andy Ridgwell
- Department of Earth and Planetary Sciences, University of California, Riverside, CA92521
| | - Allison L. Keller
- Department of Earth and Planetary Sciences, University of California, Riverside, CA92521
| | - Maximilian Vahlenkamp
- Center for Marine Environmental Sciences (MARUM), University of Bremen, Bremen28359, Germany
| | - Adam K. Aleksinski
- Department of Earth and Planetary Sciences, University of California, Riverside, CA92521
- Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN47906
| | - Philip F. Sexton
- School of Environment, Earth and Ecosystem Sciences, The Open University, Milton KeynesMK7 6AA, United Kingdom
| | - Donald E. Penman
- Department of Geosciences, Utah State University, Logan, UT84322
| | - Pincelli M. Hull
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT06511
| | - Richard D. Norris
- Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA92093
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3
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Srinivasulu A, Zeale MRK, Srinivasulu B, Srinivasulu C, Jones G, González‐Suárez M. Future climatically suitable areas for bats in South Asia. Ecol Evol 2024; 14:e11420. [PMID: 38774139 PMCID: PMC11106050 DOI: 10.1002/ece3.11420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 05/24/2024] Open
Abstract
Climate change majorly impacts biodiversity in diverse regions across the world, including South Asia, a megadiverse area with heterogeneous climatic and vegetation regions. However, climate impacts on bats in this region are not well-studied, and it is unclear whether climate effects will follow patterns predicted in other regions. We address this by assessing projected near-future changes in climatically suitable areas for 110 bat species from South Asia. We used ensemble ecological niche modelling with four algorithms (random forests, artificial neural networks, multivariate adaptive regression splines and maximum entropy) to define climatically suitable areas under current conditions (1970-2000). We then extrapolated near future (2041-2060) suitable areas under four projected scenarios (combining two global climate models and two shared socioeconomic pathways, SSP2: middle-of-the-road and SSP5: fossil-fuelled development). Projected future changes in suitable areas varied across species, with most species predicted to retain most of the current area or lose small amounts. When shifts occurred due to projected climate change, new areas were generally northward of current suitable areas. Suitability hotspots, defined as regions suitable for >30% of species, were generally predicted to become smaller and more fragmented. Overall, climate change in the near future may not lead to dramatic shifts in the distribution of bat species in South Asia, but local hotspots of biodiversity may be lost. Our results offer insight into climate change effects in less studied areas and can inform conservation planning, motivating reappraisals of conservation priorities and strategies for bats in South Asia.
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Affiliation(s)
- Aditya Srinivasulu
- Ecology and Evolutionary Biology, School of Biological SciencesUniversity of ReadingReadingUK
- ZOO Outreach OrganizationCoimbatoreTamil NaduIndia
| | | | - Bhargavi Srinivasulu
- ZOO Outreach OrganizationCoimbatoreTamil NaduIndia
- Centre for Biodiversity and Conservation StudiesOsmania UniversityHyderabadTelangana StateIndia
| | - Chelmala Srinivasulu
- ZOO Outreach OrganizationCoimbatoreTamil NaduIndia
- Centre for Biodiversity and Conservation StudiesOsmania UniversityHyderabadTelangana StateIndia
- Wildlife Biology and Taxonomy Lab, Department of ZoologyOsmania UniversityHyderabadTelangana StateIndia
| | - Gareth Jones
- School of Biological SciencesUniversity of BristolBristolUK
| | - Manuela González‐Suárez
- Ecology and Evolutionary Biology, School of Biological SciencesUniversity of ReadingReadingUK
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4
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Pomowski A, Dell'Acqua S, Wüst A, Pauleta SR, Moura I, Einsle O. Revisiting the metal sites of nitrous oxide reductase in a low-dose structure from Marinobacter nauticus. J Biol Inorg Chem 2024; 29:279-290. [PMID: 38720157 DOI: 10.1007/s00775-024-02056-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 04/10/2024] [Indexed: 05/24/2024]
Abstract
Copper-containing nitrous oxide reductase catalyzes a 2-electron reduction of the green-house gas N2O to yield N2. It contains two metal centers, the binuclear electron transfer site CuA, and the unique, tetranuclear CuZ center that is the site of substrate binding. Different forms of the enzyme were described previously, representing variations in oxidation state and composition of the metal sites. Hypothesizing that many reported discrepancies in the structural data may be due to radiation damage during data collection, we determined the structure of anoxically isolated Marinobacter nauticus N2OR from diffraction data obtained with low-intensity X-rays from an in-house rotating anode generator and an image plate detector. The data set was of exceptional quality and yielded a structure at 1.5 Å resolution in a new crystal form. The CuA site of the enzyme shows two distinct conformations with potential relevance for intramolecular electron transfer, and the CuZ cluster is present in a [4Cu:2S] configuration. In addition, the structure contains three additional types of ions, and an analysis of anomalous scattering contributions confirms them to be Ca2+, K+, and Cl-. The uniformity of the present structure supports the hypothesis that many earlier analyses showed inhomogeneities due to radiation effects. Adding to the earlier description of the same enzyme with a [4Cu:S] CuZ site, a mechanistic model is presented, with a structurally flexible CuZ center that does not require the complete dissociation of a sulfide prior to N2O binding.
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Affiliation(s)
- Anja Pomowski
- Institute for Biochemistry, Albert-Ludwigs-University Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Simone Dell'Acqua
- Dipartimento Di Chimica, Università Di Pavia, Via Taramelli 12, 27100, Pavia, Italy
| | - Anja Wüst
- Institute for Biochemistry, Albert-Ludwigs-University Freiburg, Albertstrasse 21, 79104, Freiburg, Germany
| | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO-Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
- Associate Laboratory i4HB-Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Isabel Moura
- LAQV, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2529-516, Caparica, Portugal
| | - Oliver Einsle
- Institute for Biochemistry, Albert-Ludwigs-University Freiburg, Albertstrasse 21, 79104, Freiburg, Germany.
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5
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Wang Y, Costa KM, Lu W, Hines SKV, Nielsen SG. Global oceanic oxygenation controlled by the Southern Ocean through the last deglaciation. SCIENCE ADVANCES 2024; 10:eadk2506. [PMID: 38241365 PMCID: PMC10798564 DOI: 10.1126/sciadv.adk2506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 12/19/2023] [Indexed: 01/21/2024]
Abstract
Ocean dissolved oxygen (DO) can provide insights on how the marine carbon cycle affects global climate change. However, the net global DO change and the controlling mechanisms remain uncertain through the last deglaciation. Here, we present a globally integrated DO reconstruction using thallium isotopes, corroborating lower global DO during the Last Glacial Maximum [19 to 23 thousand years before the present (ka B.P.)] relative to the Holocene. During the deglaciation, we reveal reoxygenation in the Heinrich Stadial 1 (~14.7 to 18 ka B.P.) and the Younger Dryas (11.7 to 12.9 ka B.P.), with deoxygenation during the Bølling-Allerød (12.9 to 14.7 ka B.P.). The deglacial DO changes were decoupled from North Atlantic Deep Water formation rates and imply that Southern Ocean ventilation controlled ocean oxygen. The coherence between global DO and atmospheric CO2 on millennial timescales highlights the Southern Ocean's role in deglacial atmospheric CO2 rise.
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Affiliation(s)
- Yi Wang
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- NIRVANA Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA 70118, USA
| | - Kassandra M. Costa
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Wanyi Lu
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Sophia K. V. Hines
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Sune G. Nielsen
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- NIRVANA Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Centre de Recherches Pétrographiques et Géochimiques, CNRS, Université de Lorraine, 15 rue Notre Dame des Pauvres, 54501 Vandoeuvre lès Nancy, France
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6
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Liu Z. Evolution of Atlantic Meridional Overturning Circulation since the last glaciation: model simulations and relevance to present and future. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220190. [PMID: 37866385 PMCID: PMC10590670 DOI: 10.1098/rsta.2022.0190] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 05/15/2023] [Indexed: 10/24/2023]
Abstract
The Atlantic Meridional Overturning Circulation (AMOC) and the associated water masses have changed dramatically during the glacial-interglacial cycle. Here, I review some recent progress in the modelling of the AMOC and water masses since the Last Glacial Maximum and discuss the relevance of these past AMOC studies to the present and future AMOC study. Recent studies suggested that Atlantic water masses were constrained by carbon isotopes (δ13C) and neodymium isotopes (εNd), while the strength of the AMOC better was constrained by protactinium/thorium ratio (231Pa/230Th) and the spatial gradient of calcite oxygen isotopes (δ18Oc). In spite of the shallower AMOC at the glacial period, its intensity did not differ substantially from the present because of the cancellation of opposite responses to the rising CO2 and the retreating ice sheet. This article is part of a discussion meeting issue 'Atlantic overturning: new observations and challenges'.
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Affiliation(s)
- Zhengyu Liu
- Department of Geography, The Ohio State University,154 North Oval Mall, Columbus OH 43210, USA
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7
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Festa F, Ancillotto L, Santini L, Pacifici M, Rocha R, Toshkova N, Amorim F, Benítez-López A, Domer A, Hamidović D, Kramer-Schadt S, Mathews F, Radchuk V, Rebelo H, Ruczynski I, Solem E, Tsoar A, Russo D, Razgour O. Bat responses to climate change: a systematic review. Biol Rev Camb Philos Soc 2023; 98:19-33. [PMID: 36054527 PMCID: PMC10087939 DOI: 10.1111/brv.12893] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/27/2022] [Accepted: 08/01/2022] [Indexed: 01/13/2023]
Abstract
Understanding how species respond to climate change is key to informing vulnerability assessments and designing effective conservation strategies, yet research efforts on wildlife responses to climate change fail to deliver a representative overview due to inherent biases. Bats are a species-rich, globally distributed group of organisms that are thought to be particularly sensitive to the effects of climate change because of their high surface-to-volume ratios and low reproductive rates. We systematically reviewed the literature on bat responses to climate change to provide an overview of the current state of knowledge, identify research gaps and biases and highlight future research needs. We found that studies are geographically biased towards Europe, North America and Australia, and temperate and Mediterranean biomes, thus missing a substantial proportion of bat diversity and thermal responses. Less than half of the published studies provide concrete evidence for bat responses to climate change. For over a third of studied bat species, response evidence is only based on predictive species distribution models. Consequently, the most frequently reported responses involve range shifts (57% of species) and changes in patterns of species diversity (26%). Bats showed a variety of responses, including both positive (e.g. range expansion and population increase) and negative responses (range contraction and population decrease), although responses to extreme events were always negative or neutral. Spatial responses varied in their outcome and across families, with almost all taxonomic groups featuring both range expansions and contractions, while demographic responses were strongly biased towards negative outcomes, particularly among Pteropodidae and Molossidae. The commonly used correlative modelling approaches can be applied to many species, but do not provide mechanistic insight into behavioural, physiological, phenological or genetic responses. There was a paucity of experimental studies (26%), and only a small proportion of the 396 bat species covered in the examined studies were studied using long-term and/or experimental approaches (11%), even though they are more informative about the effects of climate change. We emphasise the need for more empirical studies to unravel the multifaceted nature of bats' responses to climate change and the need for standardised study designs that will enable synthesis and meta-analysis of the literature. Finally, we stress the importance of overcoming geographic and taxonomic disparities through strengthening research capacity in the Global South to provide a more comprehensive view of terrestrial biodiversity responses to climate change.
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Affiliation(s)
- Francesca Festa
- Laboratory of Emerging Viral Zoonoses, Research and Innovation Department, Istituto Zooprofilattico Sperimentale delle Venezie, 35020, Legnaro, Italy
| | - Leonardo Ancillotto
- Wildlife Research Unit, Dipartimento di Agraria, Università degli Studi di Napoli Federico II, via Università, 100, 80055, Portici, Napoli, Italy
| | - Luca Santini
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, Viale dell'Università, 32, Rome, 00185, Italy
| | - Michela Pacifici
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, Viale dell'Università, 32, Rome, 00185, Italy
| | - Ricardo Rocha
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, 4485-661, Vairão, Portugal.,CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017, Lisbon, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Nia Toshkova
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000, Sofia, Bulgaria.,National Museum of Natural History at the Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000, Sofia, Bulgaria
| | - Francisco Amorim
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, 4485-661, Vairão, Portugal.,CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017, Lisbon, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Ana Benítez-López
- Integrative Ecology Group, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, Cartuja TA-10, Edificio I, C. Américo Vespucio, s/n, 41092, Sevilla, Spain.,Department of Zoology, Faculty of Sciences, University of Granada, Campus Universitario de Cartuja, Calle Prof. Vicente Callao, 3, 18011, Granada, Spain
| | - Adi Domer
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 8410501, Israel
| | - Daniela Hamidović
- Ministry of Economy and Sustainable Development, Institute for Environment and Nature, Radnička cesta 80, HR-10000, Zagreb, Croatia.,Croatian Biospelological Society, Rooseveltov trg 6, HR-10000, Zagreb, Croatia
| | - Stephanie Kramer-Schadt
- Department of Ecological Dynamics, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315, Berlin, Germany.,Institute of Ecology, Technische Universität Berlin, Rothenburgstr. 12, 12165, Berlin, Germany
| | - Fiona Mathews
- University of Sussex, John Maynard Smith Building, Falmer, Brighton, BN1 9RH, UK
| | - Viktoriia Radchuk
- Department of Ecological Dynamics, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315, Berlin, Germany
| | - Hugo Rebelo
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, 4485-661, Vairão, Portugal.,CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017, Lisbon, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Ireneusz Ruczynski
- Mammal Research Institute Polish Academy of Sciences, Stoczek 1, 17-230, Białowieża, Poland
| | - Estelle Solem
- Department of Ecological Dynamics, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315, Berlin, Germany
| | - Asaf Tsoar
- Israel Nature and Parks Authority, Southern District Omer Industrial Park, P.O. Box 302, Omer, Israel
| | - Danilo Russo
- Wildlife Research Unit, Dipartimento di Agraria, Università degli Studi di Napoli Federico II, via Università, 100, 80055, Portici, Napoli, Italy
| | - Orly Razgour
- Biosciences, University of Exeter, Streatham Campus, Hatherly Laboratories, Prince of Wales Road, Exeter, EX4 4PS, UK
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8
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Rafter PA, Gray WR, Hines SK, Burke A, Costa KM, Gottschalk J, Hain MP, Rae JW, Southon JR, Walczak MH, Yu J, Adkins JF, DeVries T. Global reorganization of deep-sea circulation and carbon storage after the last ice age. SCIENCE ADVANCES 2022; 8:eabq5434. [PMID: 36383653 PMCID: PMC9668286 DOI: 10.1126/sciadv.abq5434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Using new and published marine fossil radiocarbon (14C/C) measurements, a tracer uniquely sensitive to circulation and air-sea gas exchange, we establish several benchmarks for Atlantic, Southern, and Pacific deep-sea circulation and ventilation since the last ice age. We find the most 14C-depleted water in glacial Pacific bottom depths, rather than the mid-depths as they are today, which is best explained by a slowdown in glacial deep-sea overturning in addition to a "flipped" glacial Pacific overturning configuration. These observations cannot be produced by changes in air-sea gas exchange alone, and they underscore the major role for changes in the overturning circulation for glacial deep-sea carbon storage in the vast Pacific abyss and the concomitant drawdown of atmospheric CO2.
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Affiliation(s)
| | - William R. Gray
- Laboratoire des Science du Climat et de l’Environnement (LSCE/IPSL), Université-Paris-Saclay, Gif-sur-Yvette, France
| | | | - Andrea Burke
- University of St. Andrews, St. Andrews, Scotland, UK
| | | | | | - Mathis P. Hain
- University of California, Santa Cruz, Santa Cruz, CA, USA
| | | | | | | | - Jimin Yu
- Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
- Australia National University, Canberra, Australia
| | | | - Timothy DeVries
- Department of Geography and Earth Research Institute, University of California, Santa Barbara, CA, USA
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9
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Barker S, Knorr G. Millennial scale feedbacks determine the shape and rapidity of glacial termination. Nat Commun 2021; 12:2273. [PMID: 33859188 PMCID: PMC8050095 DOI: 10.1038/s41467-021-22388-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 03/11/2021] [Indexed: 11/08/2022] Open
Abstract
Within the Late Pleistocene, terminations describe the major transitions marking the end of glacial cycles. While it is established that abrupt shifts in the ocean/atmosphere system are a ubiquitous component of deglaciation, significant uncertainties remain concerning their specific role and the likelihood that terminations may be interrupted by large-amplitude abrupt oscillations. In this perspective we address these uncertainties in the light of recent developments in the understanding of glacial terminations as the ultimate interaction between millennial and orbital timescale variability. Innovations in numerical climate simulation and new geologic records allow us to highlight new avenues of research and identify key remaining uncertainties such as sea-level variability.
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Affiliation(s)
- Stephen Barker
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK.
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10
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Gottschalk J, Michel E, Thöle LM, Studer AS, Hasenfratz AP, Schmid N, Butzin M, Mazaud A, Martínez-García A, Szidat S, Jaccard SL. Glacial heterogeneity in Southern Ocean carbon storage abated by fast South Indian deglacial carbon release. Nat Commun 2020; 11:6192. [PMID: 33273459 PMCID: PMC7712879 DOI: 10.1038/s41467-020-20034-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 11/05/2020] [Indexed: 11/24/2022] Open
Abstract
Past changes in ocean 14C disequilibria have been suggested to reflect the Southern Ocean control on global exogenic carbon cycling. Yet, the volumetric extent of the glacial carbon pool and the deglacial mechanisms contributing to release remineralized carbon, particularly from regions with enhanced mixing today, remain insufficiently constrained. Here, we reconstruct the deglacial ventilation history of the South Indian upwelling hotspot near Kerguelen Island, using high-resolution 14C-dating of smaller-than-conventional foraminiferal samples and multi-proxy deep-ocean oxygen estimates. We find marked regional differences in Southern Ocean overturning with distinct South Indian fingerprints on (early de-)glacial atmospheric CO2 change. The dissipation of this heterogeneity commenced 14.6 kyr ago, signaling the onset of modern-like, strong South Indian Ocean upwelling, likely promoted by rejuvenated Atlantic overturning. Our findings highlight the South Indian Ocean’s capacity to influence atmospheric CO2 levels and amplify the impacts of inter-hemispheric climate variability on global carbon cycling within centuries and millennia. A Southern Ocean influences on the carbon cycle is considered a key component of deglacial changes. Here, the authors show spatial differences in glacial Southern Ocean carbon storage that dissipated rapidly 14.6 kyr ago, revealing a South Indian Ocean contribution to rapid deglacial atmospheric CO2 increases.
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Affiliation(s)
- Julia Gottschalk
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland. .,Lamont-Doherty Earth Observatory, Columbia University of the City of New York, Palisades, NY, USA.
| | - Elisabeth Michel
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CNRS-CEA-UVSQ, Université de Paris-Saclay, Gif-sur-Yvette, France
| | - Lena M Thöle
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland.,Department of Earth Sciences, Marine Palynology and Paleoceanography, Utrecht University, Utrecht, Netherlands
| | - Anja S Studer
- Max Planck Institute for Chemistry, Climate Geochemistry Department, Mainz, Germany.,Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Adam P Hasenfratz
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland.,Geological Institute, Department of Earth Sciences, ETH Zurich, Zurich, Switzerland
| | - Nicole Schmid
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland
| | - Martin Butzin
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung, Bremerhaven, Germany
| | - Alain Mazaud
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CNRS-CEA-UVSQ, Université de Paris-Saclay, Gif-sur-Yvette, France
| | | | - Sönke Szidat
- Department of Chemistry and Biochemistry and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Samuel L Jaccard
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland.,Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland
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11
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Nehrbass-Ahles C, Shin J, Schmitt J, Bereiter B, Joos F, Schilt A, Schmidely L, Silva L, Teste G, Grilli R, Chappellaz J, Hodell D, Fischer H, Stocker TF. Abrupt CO 2 release to the atmosphere under glacial and early interglacial climate conditions. Science 2020; 369:1000-1005. [PMID: 32820127 DOI: 10.1126/science.aay8178] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 07/09/2020] [Indexed: 11/02/2022]
Abstract
Pulse-like carbon dioxide release to the atmosphere on centennial time scales has only been identified for the most recent glacial and deglacial periods and is thought to be absent during warmer climate conditions. Here, we present a high-resolution carbon dioxide record from 330,000 to 450,000 years before present, revealing pronounced carbon dioxide jumps (CDJ) under cold and warm climate conditions. CDJ come in two varieties that we attribute to invigoration or weakening of the Atlantic meridional overturning circulation (AMOC) and associated northward and southward shifts of the intertropical convergence zone, respectively. We find that CDJ are pervasive features of the carbon cycle that can occur during interglacial climate conditions if land ice masses are sufficiently extended to be able to disturb the AMOC by freshwater input.
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Affiliation(s)
- C Nehrbass-Ahles
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland. .,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland.,Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - J Shin
- Institute of Environmental Geosciences (IGE), Grenoble INP, IRD, CNRS, Université Grenoble Alpes, Grenoble, France
| | - J Schmitt
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - B Bereiter
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland.,Laboratory for Air Pollution/Environmental Technology, Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - F Joos
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - A Schilt
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - L Schmidely
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - L Silva
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - G Teste
- Institute of Environmental Geosciences (IGE), Grenoble INP, IRD, CNRS, Université Grenoble Alpes, Grenoble, France
| | - R Grilli
- Institute of Environmental Geosciences (IGE), Grenoble INP, IRD, CNRS, Université Grenoble Alpes, Grenoble, France
| | - J Chappellaz
- Institute of Environmental Geosciences (IGE), Grenoble INP, IRD, CNRS, Université Grenoble Alpes, Grenoble, France
| | - D Hodell
- Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - H Fischer
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - T F Stocker
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
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12
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Muschitiello F, D'Andrea WJ, Schmittner A, Heaton TJ, Balascio NL, deRoberts N, Caffee MW, Woodruff TE, Welten KC, Skinner LC, Simon MH, Dokken TM. Deep-water circulation changes lead North Atlantic climate during deglaciation. Nat Commun 2019; 10:1272. [PMID: 30894523 PMCID: PMC6426850 DOI: 10.1038/s41467-019-09237-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 02/26/2019] [Indexed: 11/21/2022] Open
Abstract
Constraining the response time of the climate system to changes in North Atlantic Deep Water (NADW) formation is fundamental to improving climate and Atlantic Meridional Overturning Circulation predictability. Here we report a new synchronization of terrestrial, marine, and ice-core records, which allows the first quantitative determination of the response time of North Atlantic climate to changes in high-latitude NADW formation rate during the last deglaciation. Using a continuous record of deep water ventilation from the Nordic Seas, we identify a ∼400-year lead of changes in high-latitude NADW formation ahead of abrupt climate changes recorded in Greenland ice cores at the onset and end of the Younger Dryas stadial, which likely occurred in response to gradual changes in temperature- and wind-driven freshwater transport. We suggest that variations in Nordic Seas deep-water circulation are precursors to abrupt climate changes and that future model studies should address this phasing. The response time of North Atlantic climate to changes in high-latitude deep-water formation during the last deglaciation is still unclear. Here the authors show that gradual changes in Nordic Seas deep-water circulation systematically lead ahead of abrupt regional climate shifts by ~400 years.
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Affiliation(s)
- Francesco Muschitiello
- Department of Geography, University of Cambridge, Cambridge, CB2 3EN, UK. .,Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA. .,NORCE Norwegian Research Centre and Bjerknes Centre for Climate Research, 5007, Bergen, Norway.
| | - William J D'Andrea
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA
| | - Andreas Schmittner
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, 97331-5503, USA
| | - Timothy J Heaton
- School of Mathematics and Statistics, University of Sheffield, Sheffield, S3 7RH, UK
| | - Nicholas L Balascio
- Department of Geology, College of William and Mary, Williamsburg, VA, 23187, USA
| | - Nicole deRoberts
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA
| | - Marc W Caffee
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA.,Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Thomas E Woodruff
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
| | - Kees C Welten
- Space Sciences Laboratory, University of California, Berkeley, CA, 94720, USA
| | - Luke C Skinner
- Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, UK
| | - Margit H Simon
- NORCE Norwegian Research Centre and Bjerknes Centre for Climate Research, 5007, Bergen, Norway
| | - Trond M Dokken
- NORCE Norwegian Research Centre and Bjerknes Centre for Climate Research, 5007, Bergen, Norway
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13
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Gong X, Lembke-Jene L, Lohmann G, Knorr G, Tiedemann R, Zou JJ, Shi XF. Enhanced North Pacific deep-ocean stratification by stronger intermediate water formation during Heinrich Stadial 1. Nat Commun 2019; 10:656. [PMID: 30737377 PMCID: PMC6368553 DOI: 10.1038/s41467-019-08606-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 01/22/2019] [Indexed: 11/09/2022] Open
Abstract
The deglacial history of CO2 release from the deep North Pacific remains unresolved. This is due to conflicting indications about subarctic Pacific ventilation changes based on various marine proxies, especially for Heinrich Stadial 1 (HS-1) when a rapid atmospheric CO2 rise occurs. Here, we use a complex Earth System Model to investigate the deglacial North Pacific overturning and its control on ocean stratification. Our results show an enhanced intermediate-to-deep ocean stratification coeval with intensified North Pacific Intermediate Water (NPIW) formation during HS-1, compared to the Last Glacial Maximum. The stronger NPIW formation causes lower salinities and higher temperatures at intermediate depths. By lowering NPIW densities, this enlarges vertical density gradient and thus enhances intermediate-to-deep ocean stratification during HS-1. Physically, this process prevents the North Pacific deep waters from a better communication with the upper oceans, thus prolongs the existing isolation of glacial Pacific abyssal carbons during HS-1.
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Affiliation(s)
- X Gong
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bussestr. 24, 27570, Bremerhaven, Germany.
| | - L Lembke-Jene
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bussestr. 24, 27570, Bremerhaven, Germany
| | - G Lohmann
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bussestr. 24, 27570, Bremerhaven, Germany.,MARUM-Center for Marine Environmental Sciences, University Bremen, Leobener Strasse, 28359, Bremen, Germany
| | - G Knorr
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bussestr. 24, 27570, Bremerhaven, Germany
| | - R Tiedemann
- Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bussestr. 24, 27570, Bremerhaven, Germany
| | - J J Zou
- Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, China
| | - X F Shi
- Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China.,Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, China
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14
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Deglacial mobilization of pre-aged terrestrial carbon from degrading permafrost. Nat Commun 2018; 9:3666. [PMID: 30201999 PMCID: PMC6131488 DOI: 10.1038/s41467-018-06080-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 08/13/2018] [Indexed: 11/16/2022] Open
Abstract
The mobilization of glacial permafrost carbon during the last glacial–interglacial transition has been suggested by indirect evidence to be an additional and significant source of greenhouse gases to the atmosphere, especially at times of rapid sea-level rise. Here we present the first direct evidence for the release of ancient carbon from degrading permafrost in East Asia during the last 17 kyrs, using biomarkers and radiocarbon dating of terrigenous material found in two sediment cores from the Okhotsk Sea. Upscaling our results to the whole Arctic shelf area, we show by carbon cycle simulations that deglacial permafrost-carbon release through sea-level rise likely contributed significantly to the changes in atmospheric CO2 around 14.6 and 11.5 kyrs BP. Permafrost-derived carbon (C) may have been an additional source of greenhouse gases during the last glacial-interglacial transition. Here the authors show that ancient C from degrading permafrost was mobilised during phases of rapid sea-level rise, partially explaining changes in atmospheric CO2 and ∆14C.
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15
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Antarctic and global climate history viewed from ice cores. Nature 2018; 558:200-208. [DOI: 10.1038/s41586-018-0172-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 03/19/2018] [Indexed: 11/08/2022]
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16
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Hibbert F, Williams F, Fallon S, Rohling E. A database of biological and geomorphological sea-level markers from the Last Glacial Maximum to present. Sci Data 2018; 5:180088. [PMID: 29809175 PMCID: PMC5972710 DOI: 10.1038/sdata.2018.88] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 03/13/2018] [Indexed: 11/09/2022] Open
Abstract
The last deglacial was an interval of rapid climate and sea-level change, including the collapse of large continental ice sheets. This database collates carefully assessed sea-level data from peer-reviewed sources for the interval 0 to 25 thousand years ago (ka), from the Last Glacial Maximum to the present interglacial. In addition to facilitating site-specific reconstructions of past sea levels, the database provides a suite of data beyond the range of modern/instrumental variability that may help hone future sea-level projections. The database is global in scope, internally consistent, and contains U-series and radiocarbon dated indicators from both biological and geomorpohological archives. We focus on far-field data (i.e., away from the sites of the former continental ice sheets), but some key intermediate (i.e., from the Caribbean) data are also included. All primary fields (i.e., sample location, elevation, age and context) possess quantified uncertainties, which-in conjunction with available metadata-allows the reconstructed sea levels to be interpreted within both their uncertainties and geological context.
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Affiliation(s)
- F.D. Hibbert
- Research School of Earth Sciences, The Australian National University, Canberra, ACT 2601, Australia
| | - F.H. Williams
- Research School of Earth Sciences, The Australian National University, Canberra, ACT 2601, Australia
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton SO14 3ZH, UK
| | - S.J. Fallon
- Research School of Earth Sciences, The Australian National University, Canberra, ACT 2601, Australia
| | - E.J. Rohling
- Research School of Earth Sciences, The Australian National University, Canberra, ACT 2601, Australia
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton SO14 3ZH, UK
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17
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Deaney EL, Barker S, van de Flierdt T. Timing and nature of AMOC recovery across Termination 2 and magnitude of deglacial CO 2 change. Nat Commun 2017; 8:14595. [PMID: 28239149 PMCID: PMC5333367 DOI: 10.1038/ncomms14595] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 01/17/2017] [Indexed: 11/09/2022] Open
Abstract
Large amplitude variations in atmospheric CO2 were associated with glacial terminations of the Late Pleistocene. Here we provide multiple lines of evidence suggesting that the ∼20 p.p.m.v. overshoot in CO2 at the end of Termination 2 (T2) ∼129 ka was associated with an abrupt (≤400 year) deepening of Atlantic Meridional Overturning Circulation (AMOC). In contrast to Termination 1 (T1), which was interrupted by the Bølling-Allerød (B-A), AMOC recovery did not occur until the very end of T2, and was characterized by pronounced formation of deep waters in the NW Atlantic. Considering the variable influences of ocean circulation change on atmospheric CO2, we suggest that the net change in CO2 across the last 2 terminations was approximately equal if the transient effects of deglacial oscillations in ocean circulation are taken into account. Differences in the sequence and timing of ocean circulation changes across glacial terminations could affect the magnitude of deglacial atmospheric CO2 rise. Here, the authors argue that late ocean circulation recovery during the penultimate deglaciation (T2) led to a larger rise in CO2 compared with T1.
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Affiliation(s)
- Emily L Deaney
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
| | - Stephen Barker
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
| | - Tina van de Flierdt
- Department of Earth Science and Engineering, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
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18
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Henry LG, McManus JF, Curry WB, Roberts NL, Piotrowski AM, Keigwin LD. North Atlantic ocean circulation and abrupt climate change during the last glaciation. Science 2016; 353:470-4. [DOI: 10.1126/science.aaf5529] [Citation(s) in RCA: 202] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/20/2016] [Indexed: 11/02/2022]
Affiliation(s)
- L. G. Henry
- Lamont-Doherty Earth Observatory (LDEO), Columbia University, Palisades, NY 10964, USA
| | - J. F. McManus
- Lamont-Doherty Earth Observatory (LDEO), Columbia University, Palisades, NY 10964, USA
| | - W. B. Curry
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
| | - N. L. Roberts
- University of Cambridge, Department of Earth Sciences, Cambridge CB2 3EQ, UK
| | - A. M. Piotrowski
- University of Cambridge, Department of Earth Sciences, Cambridge CB2 3EQ, UK
| | - L. D. Keigwin
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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19
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Gottschalk J, Skinner LC, Lippold J, Vogel H, Frank N, Jaccard SL, Waelbroeck C. Biological and physical controls in the Southern Ocean on past millennial-scale atmospheric CO2 changes. Nat Commun 2016; 7:11539. [PMID: 27187527 PMCID: PMC4873644 DOI: 10.1038/ncomms11539] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 04/06/2016] [Indexed: 11/09/2022] Open
Abstract
Millennial-scale climate changes during the last glacial period and deglaciation were accompanied by rapid changes in atmospheric CO2 that remain unexplained. While the role of the Southern Ocean as a 'control valve' on ocean-atmosphere CO2 exchange has been emphasized, the exact nature of this role, in particular the relative contributions of physical (for example, ocean dynamics and air-sea gas exchange) versus biological processes (for example, export productivity), remains poorly constrained. Here we combine reconstructions of bottom-water [O2], export production and (14)C ventilation ages in the sub-Antarctic Atlantic, and show that atmospheric CO2 pulses during the last glacial- and deglacial periods were consistently accompanied by decreases in the biological export of carbon and increases in deep-ocean ventilation via southern-sourced water masses. These findings demonstrate how the Southern Ocean's 'organic carbon pump' has exerted a tight control on atmospheric CO2, and thus global climate, specifically via a synergy of both physical and biological processes.
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Affiliation(s)
- Julia Gottschalk
- Godwin Laboratory for Palaeoclimate Research, Earth Sciences Department, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
| | - Luke C Skinner
- Godwin Laboratory for Palaeoclimate Research, Earth Sciences Department, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
| | - Jörg Lippold
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Baltzerstr. 1-3, Bern 3012, Switzerland
| | - Hendrik Vogel
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Baltzerstr. 1-3, Bern 3012, Switzerland
| | - Norbert Frank
- Institute of Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 229, Heidelberg 69120, Germany
| | - Samuel L Jaccard
- Institute of Geological Sciences and Oeschger Center for Climate Change Research, University of Bern, Baltzerstr. 1-3, Bern 3012, Switzerland
| | - Claire Waelbroeck
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CNRS-CEA-UVSQ, Université de Paris-Saclay, Domaine du CNRS, bât. 12, Gif-sur-Yvette 91198, France
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20
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Carbon isotopes characterize rapid changes in atmospheric carbon dioxide during the last deglaciation. Proc Natl Acad Sci U S A 2016; 113:3465-70. [PMID: 26976561 DOI: 10.1073/pnas.1513868113] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An understanding of the mechanisms that control CO2 change during glacial-interglacial cycles remains elusive. Here we help to constrain changing sources with a high-precision, high-resolution deglacial record of the stable isotopic composition of carbon in CO2(δ(13)C-CO2) in air extracted from ice samples from Taylor Glacier, Antarctica. During the initial rise in atmospheric CO2 from 17.6 to 15.5 ka, these data demarcate a decrease in δ(13)C-CO2, likely due to a weakened oceanic biological pump. From 15.5 to 11.5 ka, the continued atmospheric CO2 rise of 40 ppm is associated with small changes in δ(13)C-CO2, consistent with a nearly equal contribution from a further weakening of the biological pump and rising ocean temperature. These two trends, related to marine sources, are punctuated at 16.3 and 12.9 ka with abrupt, century-scale perturbations in δ(13)C-CO2 that suggest rapid oxidation of organic land carbon or enhanced air-sea gas exchange in the Southern Ocean. Additional century-scale increases in atmospheric CO2 coincident with increases in atmospheric CH4 and Northern Hemisphere temperature at the onset of the Bølling (14.6-14.3 ka) and Holocene (11.6-11.4 ka) intervals are associated with small changes in δ(13)C-CO2, suggesting a combination of sources that included rising surface ocean temperature.
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21
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Schilt A, Brook EJ, Bauska TK, Baggenstos D, Fischer H, Joos F, Petrenko VV, Schaefer H, Schmitt J, Severinghaus JP, Spahni R, Stocker TF. Isotopic constraints on marine and terrestrial N2O emissions during the last deglaciation. Nature 2015; 516:234-7. [PMID: 25503236 DOI: 10.1038/nature13971] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 10/13/2014] [Indexed: 11/09/2022]
Abstract
Nitrous oxide (N2O) is an important greenhouse gas and ozone-depleting substance that has anthropogenic as well as natural marine and terrestrial sources. The tropospheric N2O concentrations have varied substantially in the past in concert with changing climate on glacial-interglacial and millennial timescales. It is not well understood, however, how N2O emissions from marine and terrestrial sources change in response to varying environmental conditions. The distinct isotopic compositions of marine and terrestrial N2O sources can help disentangle the relative changes in marine and terrestrial N2O emissions during past climate variations. Here we present N2O concentration and isotopic data for the last deglaciation, from 16,000 to 10,000 years before present, retrieved from air bubbles trapped in polar ice at Taylor Glacier, Antarctica. With the help of our data and a box model of the N2O cycle, we find a 30 per cent increase in total N2O emissions from the late glacial to the interglacial, with terrestrial and marine emissions contributing equally to the overall increase and generally evolving in parallel over the last deglaciation, even though there is no a priori connection between the drivers of the two sources. However, we find that terrestrial emissions dominated on centennial timescales, consistent with a state-of-the-art dynamic global vegetation and land surface process model that suggests that during the last deglaciation emission changes were strongly influenced by temperature and precipitation patterns over land surfaces. The results improve our understanding of the drivers of natural N2O emissions and are consistent with the idea that natural N2O emissions will probably increase in response to anthropogenic warming.
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Affiliation(s)
- Adrian Schilt
- 1] College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA [2] Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Edward J Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Thomas K Bauska
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Daniel Baggenstos
- Scripps Institution of Oceanography, University of California, San Diego, California 92037, USA
| | - Hubertus Fischer
- Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Fortunat Joos
- Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Vasilii V Petrenko
- Department of Earth and Environmental Sciences, University of Rochester, Rochester, New York 14627, USA
| | - Hinrich Schaefer
- National Institute of Water and Atmospheric Research, Wellington 6021, New Zealand
| | - Jochen Schmitt
- Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Jeffrey P Severinghaus
- Scripps Institution of Oceanography, University of California, San Diego, California 92037, USA
| | - Renato Spahni
- Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Thomas F Stocker
- Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
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22
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Marcott SA, Bauska TK, Buizert C, Steig EJ, Rosen JL, Cuffey KM, Fudge TJ, Severinghaus JP, Ahn J, Kalk ML, McConnell JR, Sowers T, Taylor KC, White JWC, Brook EJ. Centennial-scale changes in the global carbon cycle during the last deglaciation. Nature 2014; 514:616-9. [PMID: 25355363 DOI: 10.1038/nature13799] [Citation(s) in RCA: 319] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 08/27/2014] [Indexed: 11/09/2022]
Abstract
Global climate and the concentration of atmospheric carbon dioxide (CO2) are correlated over recent glacial cycles. The combination of processes responsible for a rise in atmospheric CO2 at the last glacial termination (23,000 to 9,000 years ago), however, remains uncertain. Establishing the timing and rate of CO2 changes in the past provides critical insight into the mechanisms that influence the carbon cycle and helps put present and future anthropogenic emissions in context. Here we present CO2 and methane (CH4) records of the last deglaciation from a new high-accumulation West Antarctic ice core with unprecedented temporal resolution and precise chronology. We show that although low-frequency CO2 variations parallel changes in Antarctic temperature, abrupt CO2 changes occur that have a clear relationship with abrupt climate changes in the Northern Hemisphere. A significant proportion of the direct radiative forcing associated with the rise in atmospheric CO2 occurred in three sudden steps, each of 10 to 15 parts per million. Every step took place in less than two centuries and was followed by no notable change in atmospheric CO2 for about 1,000 to 1,500 years. Slow, millennial-scale ventilation of Southern Ocean CO2-rich, deep-ocean water masses is thought to have been fundamental to the rise in atmospheric CO2 associated with the glacial termination, given the strong covariance of CO2 levels and Antarctic temperatures. Our data establish a contribution from an abrupt, centennial-scale mode of CO2 variability that is not directly related to Antarctic temperature. We suggest that processes operating on centennial timescales, probably involving the Atlantic meridional overturning circulation, seem to be influencing global carbon-cycle dynamics and are at present not widely considered in Earth system models.
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Affiliation(s)
- Shaun A Marcott
- 1] College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA [2] Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Thomas K Bauska
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Christo Buizert
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Eric J Steig
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Julia L Rosen
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Kurt M Cuffey
- Department of Geography, University of California, Berkeley, California 94720, USA
| | - T J Fudge
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington 98195, USA
| | - Jeffery P Severinghaus
- Scripps Institution of Oceanography, University of California, San Diego, California 92037, USA
| | - Jinho Ahn
- School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, South Korea
| | - Michael L Kalk
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
| | - Joseph R McConnell
- Desert Research Institute, Nevada System of Higher Education, Reno, Nevada 89512, USA
| | - Todd Sowers
- Earth and Environmental Systems Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Kendrick C Taylor
- Desert Research Institute, Nevada System of Higher Education, Reno, Nevada 89512, USA
| | - James W C White
- INSTAAR, University of Colorado, Boulder, Colorado 80309, USA
| | - Edward J Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA
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Zhang X, Lohmann G, Knorr G, Purcell C. Abrupt glacial climate shifts controlled by ice sheet changes. Nature 2014; 512:290-4. [DOI: 10.1038/nature13592] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 06/10/2014] [Indexed: 11/09/2022]
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Siple Dome ice reveals two modes of millennial CO2 change during the last ice age. Nat Commun 2014; 5:3723. [PMID: 24781344 PMCID: PMC4015316 DOI: 10.1038/ncomms4723] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 03/26/2014] [Indexed: 11/08/2022] Open
Abstract
Reconstruction of atmospheric CO2 during times of past abrupt climate change may help us better understand climate-carbon cycle feedbacks. Previous ice core studies reveal simultaneous increases in atmospheric CO2 and Antarctic temperature during times when Greenland and the northern hemisphere experienced very long, cold stadial conditions during the last ice age. Whether this relationship extends to all of the numerous stadial events in the Greenland ice core record has not been clear. Here we present a high-resolution record of atmospheric CO2 from the Siple Dome ice core, Antarctica for part of the last ice age. We find that CO2 does not significantly change during the short Greenlandic stadial events, implying that the climate system perturbation that produced the short stadials was not strong enough to substantially alter the carbon cycle. Whether all rapid climate events during the last ice age impacted the global carbon cycle is not clearly understood. Ahn and Brook present a high-resolution record of atmospheric CO2 from Antarctica and suggest that only Greenland stadials associated with massive iceberg discharge influenced atmospheric CO2.
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Radiocarbon evidence for alternating northern and southern sources of ventilation of the deep Atlantic carbon pool during the last deglaciation. Proc Natl Acad Sci U S A 2014; 111:5480-4. [PMID: 24706801 DOI: 10.1073/pnas.1400668111] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent theories for glacial-interglacial climate transitions call on millennial climate perturbations that purged the deep sea of sequestered carbon dioxide via a "bipolar ventilation seesaw." However, the viability of this hypothesis has been contested, and robust evidence in its support is lacking. Here we present a record of North Atlantic deep-water radiocarbon ventilation, which we compare with similar data from the Southern Ocean. A striking coherence in ventilation changes is found, with extremely high ventilation ages prevailing across the deep Atlantic during the last glacial period. The data also reveal two reversals in the ventilation gradient between the deep North Atlantic and Southern Ocean during Heinrich Stadial 1 and the Younger Dryas. These coincided with periods of sustained atmospheric CO2 rise and appear to have been driven by enhanced ocean-atmosphere exchange, primarily in the Southern Ocean. These results confirm the operation of a bipolar ventilation seesaw during deglaciation and underline the contribution of abrupt regional climate anomalies to longer-term global climate transitions.
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Robinson LF, Siddall M. Palaeoceanography: motivations and challenges for the future. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2012; 370:5540-5566. [PMID: 23129712 DOI: 10.1098/rsta.2012.0396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The ocean interacts with the atmosphere, biosphere and cryosphere in a complex way, modulating climate through the storage and transport of heat, nutrients and carbon. As such, it is important that we understand the ways in which the ocean behaves and the factors that can lead to change. In order to gain this understanding, we need to look back into the past, on time scales from recent decadal-scale change, through the abrupt changes of the Pleistocene and back to times when the Earth's climate was significantly different than the Holocene. A key challenge facing the field of palaeoceanography is to combine data and modelling in a common framework. Coupling palaeo-data and models should improve our knowledge of how the Earth works, and perhaps of more direct societal relevance, might enable us to provide better predictive capabilities in climate modelling. In this discussion paper, we examine the motivations, past successes and challenges facing palaeoceanographic studies. We then suggest a number of areas and approaches that we believe will allow palaeoceanography to continue to provide new insights into processes that affect future climate change.
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Mode change of millennial CO2 variability during the last glacial cycle associated with a bipolar marine carbon seesaw. Proc Natl Acad Sci U S A 2012; 109:9755-60. [PMID: 22675123 DOI: 10.1073/pnas.1204069109] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Important elements of natural climate variations during the last ice age are abrupt temperature increases over Greenland and related warming and cooling periods over Antarctica. Records from Antarctic ice cores have shown that the global carbon cycle also plays a role in these changes. The available data shows that atmospheric CO(2) follows closely temperatures reconstructed from Antarctic ice cores during these variations. Here, we present new high-resolution CO(2) data from Antarctic ice cores, which cover the period between 115,000 and 38,000 y before present. Our measurements show that also smaller Antarctic warming events have an imprint in CO(2) concentrations. Moreover, they indicate that during Marine Isotope Stage (MIS) 5, the peak of millennial CO(2) variations lags the onset of Dansgaard/Oeschger warmings by 250 ± 190 y. During MIS 3, this lag increases significantly to 870 ± 90 y. Considerations of the ocean circulation suggest that the millennial variability associated with the Atlantic Meridional Overturning Circulation (AMOC) undergoes a mode change from MIS 5 to MIS 4 and 3. Ocean carbon inventory estimates imply that during MIS 3 additional carbon is derived from an extended mass of carbon-enriched Antarctic Bottom Water. The absence of such a carbon-enriched water mass in the North Atlantic during MIS 5 can explain the smaller amount of carbon released to the atmosphere after the Antarctic temperature maximum and, hence, the shorter lag. Our new data provides further constraints for transient coupled carbon cycle-climate simulations during the entire last glacial cycle.
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Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation. Nature 2012; 484:49-54. [PMID: 22481357 DOI: 10.1038/nature10915] [Citation(s) in RCA: 303] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 02/01/2012] [Indexed: 12/13/2022]
Abstract
The covariation of carbon dioxide (CO(2)) concentration and temperature in Antarctic ice-core records suggests a close link between CO(2) and climate during the Pleistocene ice ages. The role and relative importance of CO(2) in producing these climate changes remains unclear, however, in part because the ice-core deuterium record reflects local rather than global temperature. Here we construct a record of global surface temperature from 80 proxy records and show that temperature is correlated with and generally lags CO(2) during the last (that is, the most recent) deglaciation. Differences between the respective temperature changes of the Northern Hemisphere and Southern Hemisphere parallel variations in the strength of the Atlantic meridional overturning circulation recorded in marine sediments. These observations, together with transient global climate model simulations, support the conclusion that an antiphased hemispheric temperature response to ocean circulation changes superimposed on globally in-phase warming driven by increasing CO(2) concentrations is an explanation for much of the temperature change at the end of the most recent ice age.
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Pomowski A, Zumft WG, Kroneck PMH, Einsle O. N2O binding at a [4Cu:2S] copper–sulphur cluster in nitrous oxide reductase. Nature 2011; 477:234-7. [DOI: 10.1038/nature10332] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 06/23/2011] [Indexed: 12/21/2022]
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Cheng J, Liu Z, He F, Otto-Bliesner BL, Brady EC, Wehrenberg M. Simulated Two-Stage Recovery of Atlantic Meridional Overturning Circulation During the Last Deglaciation. ABRUPT CLIMATE CHANGE: MECHANISMS, PATTERNS, AND IMPACTS 2011. [DOI: 10.1029/2010gm001014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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Orbital- and millennial-scale variability of the Asian monsoon during MIS8 from Sanbao Cave at Mount Shennongjia, central China. CHINESE SCIENCE BULLETIN-CHINESE 2009. [DOI: 10.1007/s11434-009-0542-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Brierley AS, Kingsford MJ. Impacts of Climate Change on Marine Organisms and Ecosystems. Curr Biol 2009; 19:R602-14. [DOI: 10.1016/j.cub.2009.05.046] [Citation(s) in RCA: 361] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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