1
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Wagner I, Smolina I, Koop MEL, Bal T, Lizano AM, Choo LQ, Hofreiter M, Gennari E, de Sabata E, Shivji MS, Noble LR, Jones CS, Hoarau G. Genome analysis reveals three distinct lineages of the cosmopolitan white shark. Curr Biol 2024; 34:3582-3590.e4. [PMID: 39047735 DOI: 10.1016/j.cub.2024.06.076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/22/2024] [Accepted: 06/27/2024] [Indexed: 07/27/2024]
Abstract
The white shark (Carcharodon carcharias) (Linnaeus, 1758), an iconic apex predator occurring in all oceans,1,2 is classified as Vulnerable globally3-with global abundance having dropped to 63% of 1970s estimates,4-and as Critically Endangered in Europe.5 Identification of evolutionary significant units and their management are crucial for conservation,6 especially as the white shark is facing various but often region-specific anthropogenic threats.7,8,9,10,11 Assessing connectivity in a cosmopolitan marine species requires worldwide sampling and high-resolution genetic markers.12 Both are lacking for the white shark, with studies to date typified by numerous but geographically limited sampling, and analyses relying largely on relatively small numbers of nuclear microsatellites,13,14,15,16,17,18,19 which can be plagued by various genotyping artefacts and thus require cautious interpretation.20 Sequencing and computational advances are finally allowing genomes21,22,23 to be leveraged into population studies,24,25,26,27 with datasets comprising thousands of single-nucleotide polymorphisms (SNPs). Here, combining target gene capture (TGC)28 sequencing (89 individuals, 4,000 SNPs) and whole-genome re-sequencing (17 individuals, 391,000 SNPs) with worldwide sampling across most of the distributional range, we identify three genetically distinct allopatric lineages (North Atlantic, Indo-Pacific, and North Pacific). These diverged 100,000-200,000 years ago during the Penultimate Glaciation, when low sea levels, different ocean currents, and water temperatures produced significant biogeographic barriers. Our results show that without high-resolution genomic analyses of samples representative of a species' range,12 the true extent of diversity, presence of past and contemporary barriers to gene flow, subsequent speciation, and local evolutionary events will remain enigmatic.
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Affiliation(s)
- Isabel Wagner
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway
| | - Irina Smolina
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway
| | - Martina E L Koop
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway
| | - Thijs Bal
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway
| | - Apollo M Lizano
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway; Marine Science Institute, University of the Philippines, Diliman Quezon City 1101, Philippines
| | - Le Qin Choo
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway; Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Michael Hofreiter
- Evolutionary Adaptive Genomics, Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Enrico Gennari
- Oceans Research Institute, Mossel Bay 6500, South Africa
| | | | - Mahmood S Shivji
- Save Our Seas Shark Foundation Research Center and Guy Harvey Research Institute, Nova Southeastern University, Dania Beach, FL 33004, USA
| | - Leslie R Noble
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway; School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland AB24 2TZ, UK.
| | - Catherine S Jones
- School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland AB24 2TZ, UK.
| | - Galice Hoarau
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway.
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2
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An Z, Zhou W, Zhang Z, Zhang X, Liu Z, Sun Y, Clemens SC, Wu L, Zhao J, Shi Z, Ma X, Yan H, Li G, Cai Y, Yu J, Sun Y, Li S, Zhang Y, Stepanek C, Lohmann G, Dong G, Cheng H, Liu Y, Jin Z, Li T, Hao Y, Lei J, Cai W. Mid-Pleistocene climate transition triggered by Antarctic Ice Sheet growth. Science 2024; 385:560-565. [PMID: 39088600 DOI: 10.1126/science.abn4861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/06/2023] [Accepted: 06/28/2024] [Indexed: 08/03/2024]
Abstract
Despite extensive investigation, the nature and causes of the Mid-Pleistocene Transition remain enigmatic. In this work, we assess its linkage to asynchronous development of bipolar ice sheets by synthesizing Pleistocene mid- to high-latitude proxy records linked to hemispheric ice sheet evolution. Our results indicate substantial growth of the Antarctic Ice Sheets (AISs) at 2.0 to 1.25 million years ago, preceding the rapid expansion of Northern Hemisphere Ice Sheets after ~1.25 million years ago. Proxy-model comparisons suggest that AIS and associated Southern Ocean sea ice expansion can induce northern high-latitude cooling and enhanced moisture transport to the Northern Hemisphere, thus triggering the Mid-Pleistocene Transition. The dynamic processes involved are crucial for assessing modern global warming that is already inducing asynchronous bipolar melting of ice sheets.
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Affiliation(s)
- Zhisheng An
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
- Interdisciplinary Research Center of Earth Science Frontier, Beijing Normal University, Beijing 100875, China
| | - Weijian Zhou
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
- Interdisciplinary Research Center of Earth Science Frontier, Beijing Normal University, Beijing 100875, China
| | - Zeke Zhang
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing 210023, China
| | - Xu Zhang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
- British Antarctic Survey, Cambridge CB3 0ET, UK
| | - Zhonghui Liu
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Department of Earth Sciences, The University of Hong Kong, Hong Kong, China
| | - Youbin Sun
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Steven C Clemens
- Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA
| | - Lixin Wu
- Laoshan Laboratory, Qingdao 266000, China
- Key Laboratory of Physical Oceanography/Institute for Advanced Ocean Studies, Ocean University of China, Qingdao 266100, China
| | - Jiaju Zhao
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhengguo Shi
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xiaolin Ma
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Hong Yan
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Gaojun Li
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing 210023, China
| | - Yanjun Cai
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jimin Yu
- Laoshan Laboratory, Qingdao 266000, China
- Research School of Earth Sciences, Australian National University, Canberra, ACT 2601, Australia
| | - Yuchen Sun
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Siqi Li
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Yu'ao Zhang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Christian Stepanek
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Gerrit Lohmann
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, 27570 Bremerhaven, Germany
| | - Guocheng Dong
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Hai Cheng
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yu Liu
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Zhangdong Jin
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China
| | - Tao Li
- Key Laboratory of Palaeobiology and Petroleum Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yifei Hao
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Jing Lei
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Xi'an Institute for Innovative Earth Environment Research, Xi'an 710061, China
| | - Wenju Cai
- State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
- Laoshan Laboratory, Qingdao 266000, China
- Key Laboratory of Physical Oceanography/Institute for Advanced Ocean Studies, Ocean University of China, Qingdao 266100, China
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3
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Le Houedec S, Tremblin M, Champion A, Samankassou E. Modulation of the northward penetration of Antarctica intermediate waters into the eastern equatorial Indian Ocean under glacial and interglacial conditions. Sci Rep 2024; 14:6673. [PMID: 38509205 PMCID: PMC11349886 DOI: 10.1038/s41598-024-57411-5] [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: 05/26/2023] [Accepted: 03/18/2024] [Indexed: 03/22/2024] Open
Abstract
The Indo-Pacific warm pool is the warmest and most dynamic ocean-atmosphere-climate system on Earth and was subject to significant climate changes during the Pleistocene glacial-interglacial transitions. This has been shown to significantly affected the strength of surface waters that redistribute heat from the tropics to the southern part of the Indian Ocean. Here we investigate the response of the oceanic circulation at intermediate depth (1200 m) of the eastern equatorial Indian Ocean (EEIO) with neodymium (Nd) isotopes in the context of the climatic oscillation of the last 500 ka. The most striking feature of our new dataset is the seesaw Nd record that mimics glacial-interglacial cycles. While the interglacial periods are characterized by a higher contribution of the less radiogenic neodymium (~ - 7εNd) Antarctic Intermediate Water (AAIW), the glacial periods are characterized by more radiogenic water mass of Pacific origin (~ - 5εNd). To explain the increase in the εNd signature toward a more radiogenic signature as the Indo-Pacific connection is reduced under the low sea level of the glacial periods, we show that under global cooling, the AAIW advances northward into the tropics, which is a consequence of the general slowdown of the thermohaline circulation. Therefore, oceanic mixing at intermediate depth in the eastern tropical Indian intermediate water is modulated by the production rate of the AAIW in the Southern Ocean. Our study provides new evidence for the role that changes in the deep oceanic conditions play in amplifying externally forced climate changes that ultimately lead to drier/moister atmospheric conditions and weaker/stronger monsoons during glacial/interglacial periods over eastern tropical Indian Ocean.
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Affiliation(s)
- Sandrine Le Houedec
- Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland.
| | - Maxime Tremblin
- Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland
| | - Amaury Champion
- Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland
| | - Elias Samankassou
- Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205, Geneva, Switzerland
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4
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Weij R, Sniderman JMK, Woodhead JD, Hellstrom JC, Brown JR, Drysdale RN, Reed E, Bourne S, Gordon J. Elevated Southern Hemisphere moisture availability during glacial periods. Nature 2024; 626:319-326. [PMID: 38326596 DOI: 10.1038/s41586-023-06989-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 12/15/2023] [Indexed: 02/09/2024]
Abstract
Late Pleistocene ice-age climates are routinely characterized as having imposed moisture stress on low- to mid-latitude ecosystems1-5. This idea is largely based on fossil pollen evidence for widespread, low-biomass glacial vegetation, interpreted as indicating climatic dryness6. However, woody plant growth is inhibited under low atmospheric CO2 (refs. 7,8), so understanding glacial environments requires the development of new palaeoclimate indicators that are independent of vegetation9. Here we show that, contrary to expectations, during the past 350 kyr, peaks in southern Australian climatic moisture availability were largely confined to glacial periods, including the Last Glacial Maximum, whereas warm interglacials were relatively dry. By measuring the timing of speleothem growth in the Southern Hemisphere subtropics, which today has a predominantly negative annual moisture balance, we developed a record of climatic moisture availability that is independent of vegetation and extends through multiple glacial-interglacial cycles. Our results demonstrate that a cool-moist response is consistent across the austral subtropics and, in part, may result from reduced evaporation under cool glacial temperatures. Insofar as cold glacial environments in the Southern Hemisphere subtropics have been portrayed as uniformly arid3,10,11, our findings suggest that their characterization as evolutionary or physiological obstacles to movement and expansion of animal, plant and, potentially, human populations10 should be reconsidered.
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Affiliation(s)
- Rieneke Weij
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia.
- Department of Geological Sciences and the Human Evolution Research Institute, University of Cape Town, Rondebosch, Western Cape, South Africa.
| | - J M Kale Sniderman
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia.
| | - Jon D Woodhead
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - John C Hellstrom
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Josephine R Brown
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Russell N Drysdale
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
- Environnements, Dynamiques et Territoires de la Montagne, UMR CNRS, Université de Savoie-Mont, Chambéry, France
| | - Elizabeth Reed
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Museum, Adelaide, South Australia, Australia
| | - Steven Bourne
- Limestone Coast Landscape Board, Mount Gambier, South Australia, Australia
| | - Jay Gordon
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
- IEEFA, Melbourne, Victoria, Australia
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5
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Fang X, Dong D, Yang M, Li X. Phylogenetics and Population Genetics of the Petrolisthes lamarckii-P. haswelli Complex in China: Old Lineage and New Species. Int J Mol Sci 2023; 24:15843. [PMID: 37958829 PMCID: PMC10648172 DOI: 10.3390/ijms242115843] [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: 10/01/2023] [Revised: 10/27/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
Petrolisthes lamarckii (Leach, 1821) and P. haswelli Miers, 1884 are a pair of sister species of porcelain crabs, both of which are common in the intertidal zone of southern China, typically found under rocks and in the crevices of coral reefs. However, the distribution, genetic relationship and diversity of the two species in China have not been rigorously studied. Meanwhile, P. lamarckii is considered as a complex of cryptic species due to their diverse morphological features. In this study, we identified 127 specimens of the P. lamarckii-P. haswelli complex (LH complex) and recognised a new species through morphological and molecular analysis. Furthermore, we constructed a time-calibrated phylogeny of the LH complex using three mitochondrial and two nuclear genes from all three species, finding that the divergence of the LH complex can be traced back to the Miocene epoch, and that the genetic diversity increased during the Mid-Pleistocene transition period. Glacial refugia formed during the Pleistocene climatic oscillations has been regarded as one of the contributing factors to the diversification of marine organisms in the north-western Pacific. Petrolisthes haswelli demonstrates a wide distribution along the southern coast of China, while other lineages display more restricted distributions. The research on the demographic history and gene flow of P. haswelli revealed that the Chinese coastal populations experienced an expansion event approximately 12.5 thousand years ago (Kya) and the asymmetrical gene flows were observed between the two sides of the Taiwan Strait and Qiongzhou Strait, respectively, which is likely influenced by the restriction of ocean currents.
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Affiliation(s)
- Xuefeng Fang
- Department of Marine Organism Taxonomy & Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (X.F.); (M.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong Dong
- Department of Marine Organism Taxonomy & Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (X.F.); (M.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mei Yang
- Department of Marine Organism Taxonomy & Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (X.F.); (M.Y.)
| | - Xinzheng Li
- Department of Marine Organism Taxonomy & Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (X.F.); (M.Y.)
- University of Chinese Academy of Sciences, Beijing 100049, China
- Laoshan Laboratory, Qingdao 266237, China
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6
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Nuber S, Rae JWB, Zhang X, Andersen MB, Dumont MD, Mithan HT, Sun Y, de Boer B, Hall IR, Barker S. Indian Ocean salinity build-up primes deglacial ocean circulation recovery. Nature 2023; 617:306-311. [PMID: 37165236 DOI: 10.1038/s41586-023-05866-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 02/17/2023] [Indexed: 05/12/2023]
Abstract
The Indian Ocean provides a source of salt for North Atlantic deep-water convection sites, via the Agulhas Leakage, and may thus drive changes in the ocean's overturning circulation1-3. However, little is known about the salt content variability of Indian Ocean and Agulhas Leakage waters during past glacial cycles and how this may influence circulation. Here we show that the glacial Indian Ocean surface salt budget was notably different from the modern, responding dynamically to changes in sea level. Indian Ocean surface salinity increased during glacial intensification, peaking in glacial maxima. We find that this is due to rapid land exposure in the Indonesian archipelago induced by glacial sea-level lowering, and we suggest a mechanistic link via reduced input of relatively fresh Indonesian Throughflow waters into the Indian Ocean. Using climate model results, we show that the release of this glacial Indian Ocean salinity via the Agulhas Leakage during deglaciation can directly impact the Atlantic Meridional Overturning Circulation and global climate.
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Affiliation(s)
- Sophie Nuber
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK.
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK.
- Department of Geosciences, National Taiwan University, Taipei City, Taiwan.
| | - James W B Rae
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - Xu Zhang
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Morten B Andersen
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
| | - Matthew D Dumont
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - Huw T Mithan
- Department of Geosciences, National Taiwan University, Taipei City, Taiwan
| | - Yuchen Sun
- Alfred Wegener Institute, Bremerhaven, Germany
| | - Bas de Boer
- Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Ian R Hall
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
| | - Stephen Barker
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
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7
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Auderset A, Moretti S, Taphorn B, Ebner PR, Kast E, Wang XT, Schiebel R, Sigman DM, Haug GH, Martínez-García A. Enhanced ocean oxygenation during Cenozoic warm periods. Nature 2022; 609:77-82. [PMID: 36045236 PMCID: PMC9433325 DOI: 10.1038/s41586-022-05017-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/09/2022] [Indexed: 11/09/2022]
Abstract
Dissolved oxygen (O2) is essential for most ocean ecosystems, fuelling organisms’ respiration and facilitating the cycling of carbon and nutrients. Oxygen measurements have been interpreted to indicate that the ocean’s oxygen-deficient zones (ODZs) are expanding under global warming1,2. However, models provide an unclear picture of future ODZ change in both the near term and the long term3–6. The paleoclimate record can help explore the possible range of ODZ changes in warmer-than-modern periods. Here we use foraminifera-bound nitrogen (N) isotopes to show that water-column denitrification in the eastern tropical North Pacific was greatly reduced during the Middle Miocene Climatic Optimum (MMCO) and the Early Eocene Climatic Optimum (EECO). Because denitrification is restricted to oxygen-poor waters, our results indicate that, in these two Cenozoic periods of sustained warmth, ODZs were contracted, not expanded. ODZ contraction may have arisen from a decrease in upwelling-fuelled biological productivity in the tropical Pacific, which would have reduced oxygen demand in the subsurface. Alternatively, invigoration of deep-water ventilation by the Southern Ocean may have weakened the ocean’s ‘biological carbon pump’, which would have increased deep-ocean oxygen. The mechanism at play would have determined whether the ODZ contractions occurred in step with the warming or took centuries or millennia to develop. Thus, although our results from the Cenozoic do not necessarily apply to the near-term future, they might imply that global warming may eventually cause ODZ contraction. By using foraminifera-bound nitrogen isotopes, it is shown that, during two warm periods of the Cenozoic, oxygen-deficient zones contracted rather than expanded, suggesting that global warming may not necessarily lead to increased oceanic anoxia.
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Affiliation(s)
- Alexandra Auderset
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany. .,Department of Earth Sciences, ETH Zurich, Zurich, Switzerland.
| | - Simone Moretti
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany.,Department of Earth Sciences, ETH Zurich, Zurich, Switzerland
| | - Björn Taphorn
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Pia-Rebecca Ebner
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Emma Kast
- Department of Geosciences, Princeton University, Princeton, NJ, USA.,Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Xingchen T Wang
- Department of Earth and Environmental Sciences, Boston College, Chestnut Hill, MA, USA
| | - Ralf Schiebel
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Daniel M Sigman
- Department of Geosciences, Princeton University, Princeton, NJ, USA
| | - Gerald H Haug
- Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz, Germany.,Department of Earth Sciences, ETH Zurich, Zurich, Switzerland
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8
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Struve T, Wilson DJ, Hines SKV, Adkins JF, van de Flierdt T. A deep Tasman outflow of Pacific waters during the last glacial period. Nat Commun 2022; 13:3763. [PMID: 35773248 PMCID: PMC9246942 DOI: 10.1038/s41467-022-31116-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 06/06/2022] [Indexed: 11/09/2022] Open
Abstract
The interoceanic exchange of water masses is modulated by flow through key oceanic choke points in the Drake Passage, the Indonesian Seas, south of Africa, and south of Tasmania. Here, we use the neodymium isotope signature (εNd) of cold-water coral skeletons from intermediate depths (1460‒1689 m) to trace circulation changes south of Tasmania during the last glacial period. The key feature of our dataset is a long-term trend towards radiogenic εNd values of ~−4.6 during the Last Glacial Maximum and Heinrich Stadial 1, which are clearly distinct from contemporaneous Southern Ocean εNd of ~−7. When combined with previously published radiocarbon data from the same corals, our results indicate that a unique radiogenic and young water mass was present during this time. This scenario can be explained by a more vigorous Pacific overturning circulation that supported a deeper outflow of Pacific waters, including North Pacific Intermediate Water, through the Tasman Sea. Using cold-water corals, this work identifies a deep outflow of Pacific waters via the Tasman Sea during the last ice age, thus highlighting the role of this area for the interoceanic exchange of water masses on climatic time scales.
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Affiliation(s)
- Torben Struve
- Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, London, UK. .,The Grantham Institute for Climate Change and the Environment, Imperial College London, SW7 2AZ, London, UK. .,Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, 26129, Oldenburg, Germany.
| | - David J Wilson
- Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, London, UK.,Institute of Earth and Planetary Sciences, University College London and Birkbeck, University of London, WC1E 6BT, London, UK
| | - Sophia K V Hines
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.,Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA.,Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Jess F Adkins
- Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Tina van de Flierdt
- Department of Earth Science and Engineering, Imperial College London, SW7 2AZ, London, UK
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9
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van der Lubbe HJL, Hall IR, Barker S, Hemming SR, Baars TF, Starr A, Just J, Backeberg BC, Joordens JCA. Indo-Pacific Walker circulation drove Pleistocene African aridification. Nature 2021; 598:618-623. [PMID: 34707316 DOI: 10.1038/s41586-021-03896-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/11/2021] [Indexed: 11/09/2022]
Abstract
Today, the eastern African hydroclimate is tightly linked to fluctuations in the zonal atmospheric Walker circulation1,2. A growing body of evidence indicates that this circulation shaped hydroclimatic conditions in the Indian Ocean region also on much longer, glacial-interglacial timescales3-5, following the development of Pacific Walker circulation around 2.2-2.0 million years ago (Ma)6,7. However, continuous long-term records to determine the timing and mechanisms of Pacific-influenced climate transitions in the Indian Ocean have been unavailable. Here we present a seven-million-year-long record of wind-driven circulation of the tropical Indian Ocean, as recorded in Mozambique Channel Throughflow (MCT) flow-speed variations. We show that the MCT flow speed was relatively weak and steady until 2.1 ± 0.1 Ma, when it began to increase, coincident with the intensification of the Pacific Walker circulation6,7. Strong increases during glacial periods, which reached maxima after the Mid-Pleistocene Transition (0.9-0.64 Ma; ref. 8), were punctuated by weak flow speeds during interglacial periods. We provide a mechanism explaining that increasing MCT flow speeds reflect synchronous development of the Indo-Pacific Walker cells that promote aridification in Africa. Our results suggest that after about 2.1 Ma, the increasing aridification is punctuated by pronounced humid interglacial periods. This record will facilitate testing of hypotheses of climate-environmental drivers for hominin evolution and dispersal.
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Affiliation(s)
- H J L van der Lubbe
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK. .,Department of Earth Sciences, Faculty of Science, Vrije Universiteit (VU), Amsterdam, the Netherlands.
| | - I R Hall
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK.
| | - S Barker
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
| | - S R Hemming
- Earth and Environmental Sciences, Lamont-Doherty Earth Observatory, Palisades, NY, USA
| | - T F Baars
- Department of Geosciences and Engineering, Delft University of Technology, TU Delft, the Netherlands
| | - A Starr
- School of Earth and Environmental Sciences, Cardiff University, Cardiff, UK
| | - J Just
- Department of Geosciences, Universität Bremen, Bremen, Germany
| | - B C Backeberg
- Deltares, Delft, the Netherlands.,Nansen Environmental and Remote Sensing Center, Bergen, Norway.,Nansen-Tutu Centre for Marine Environmental Research, Cape Town, South Africa
| | - J C A Joordens
- Naturalis Biodiversity Center, Leiden, the Netherlands.,Faculty of Science and Engineering, Maastricht University, Maastricht, the Netherlands.,Faculty of Archaeology, Leiden University, Leiden, the Netherlands
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