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Rule JP, Duncan RJ, Marx FG, Pollock TI, Evans AR, Fitzgerald EM. Giant baleen whales emerged from a cold southern cradle. Proc Biol Sci 2023; 290:20232177. [PMID: 38113937 PMCID: PMC10730287 DOI: 10.1098/rspb.2023.2177] [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: 02/03/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023] Open
Abstract
Baleen whales (mysticetes) include the largest animals on the Earth. How they achieved such gigantic sizes remains debated, with previous research focusing primarily on when mysticetes became large, rather than where. Here, we describe an edentulous baleen whale fossil (21.12-16.39 mega annum (Ma)) from South Australia. With an estimated body length of 9 m, it is the largest mysticete from the Early Miocene. Analysing body size through time shows that ancient baleen whales from the Southern Hemisphere were larger than their northern counterparts. This pattern seemingly persists for much of the Cenozoic, even though southern specimens contribute only 19% to the global mysticete fossil record. Our findings contrast with previous ideas of a single abrupt shift towards larger size during the Plio-Pleistocene, which we here interpret as a glacially driven Northern Hemisphere phenomenon. Our results highlight the importance of incorporating Southern Hemisphere fossils into macroevolutionary patterns, especially in light of the high productivity of Southern Ocean environments.
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Affiliation(s)
- James P. Rule
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
- Sciences, Museums Victoria Research Institute, Museums Victoria, Melbourne, Victoria 3001, Australia
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
| | - Ruairidh J. Duncan
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
- Sciences, Museums Victoria Research Institute, Museums Victoria, Melbourne, Victoria 3001, Australia
| | - Felix G. Marx
- Museum of New Zealand Te Papa Tongarewa, Wellington 6011, New Zealand
- Department of Geology, University of Otago, Dunedin 9016, New Zealand
| | - Tahlia I. Pollock
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
- Department of Anatomy and Developmental Biology, Monash University, Victoria, Australia
| | - Alistair R. Evans
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
- Sciences, Museums Victoria Research Institute, Museums Victoria, Melbourne, Victoria 3001, Australia
| | - Erich M.G. Fitzgerald
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
- Sciences, Museums Victoria Research Institute, Museums Victoria, Melbourne, Victoria 3001, Australia
- Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
- National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA
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2
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De Lira Mota MA, Dunkley Jones T, Sulaiman N, Edgar KM, Yamaguchi T, Leng MJ, Adloff M, Greene SE, Norris R, Warren B, Duffy G, Farrant J, Murayama M, Hall J, Bendle J. Multi-proxy evidence for sea level fall at the onset of the Eocene-Oligocene transition. Nat Commun 2023; 14:4748. [PMID: 37553323 PMCID: PMC10409788 DOI: 10.1038/s41467-023-39806-6] [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: 12/22/2021] [Accepted: 06/27/2023] [Indexed: 08/10/2023] Open
Abstract
Continental-scale expansion of the East Antarctic Ice Sheet during the Eocene-Oligocene Transition (EOT) is one of the largest non-linear events in Earth's climate history. Declining atmospheric carbon dioxide concentrations and orbital variability triggered glacial expansion and strong feedbacks in the climate system. Prominent among these feedbacks was the repartitioning of biogeochemical cycles between the continental shelves and the deep ocean with falling sea level. Here we present multiple proxies from a shallow shelf location that identify a marked regression and an elevated flux of continental-derived organic matter at the earliest stage of the EOT, a time of deep ocean carbonate dissolution and the extinction of oligotrophic phytoplankton groups. We link these observations using an Earth System model, whereby this first regression delivers a pulse of organic carbon to the oceans that could drive the observed patterns of deep ocean dissolution and acts as a transient negative feedback to climate cooling.
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Affiliation(s)
- Marcelo A De Lira Mota
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
- Institute of Geosciences, University of São Paulo, Rua do Lago, 562 - Butantã, São Paulo, SP, 05508-080, Brazil.
| | - Tom Dunkley Jones
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Nursufiah Sulaiman
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- Faculty of Earth Science, Universiti Malaysia Kelantan Jeli Campus, Locked Bag No 100, 17600, Jeli, Kelantan, Malaysia
| | - Kirsty M Edgar
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Tatsuhiko Yamaguchi
- National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, 305-0005, Japan
- Center for Advanced Marine Core Research, Kochi University, 200 Monobe Otsu, Nankoku, Kochi, 783-8502, Japan
| | - Melanie J Leng
- British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
- Centre for Environmental Geochemistry, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Markus Adloff
- School of Geographical Sciences, University of Bristol, University Road, Bristol, BS81SS, UK
- Oeschger Centre, University of Bern, Hochschulstrasse 6, 3012, Bern, Switzerland
| | - Sarah E Greene
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Richard Norris
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA
| | - Bridget Warren
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Grace Duffy
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jennifer Farrant
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Masafumi Murayama
- Center for Advanced Marine Core Research, Kochi University, 200 Monobe Otsu, Nankoku, Kochi, 783-8502, Japan
- Faculty of Agriculture and Marine Science, Kochi University, B200 Monobe, Nankoku, Kochi, 783-8502, Japan
| | - Jonathan Hall
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - James Bendle
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
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3
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Hochmuth K, Whittaker JM, Sauermilch I, Klocker A, Gohl K, LaCasce JH. Southern Ocean biogenic blooms freezing-in Oligocene colder climates. Nat Commun 2022; 13:6785. [PMID: 36351905 PMCID: PMC9646741 DOI: 10.1038/s41467-022-34623-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/01/2022] [Indexed: 11/10/2022] Open
Abstract
Crossing a key atmospheric CO2 threshold triggered a fundamental global climate reorganisation ~34 million years ago (Ma) establishing permanent Antarctic ice sheets. Curiously, a more dramatic CO2 decline (~800-400 ppm by the Early Oligocene(~27 Ma)), postdates initial ice sheet expansion but the mechanisms driving this later, rapid drop in atmospheric carbon during the early Oligocene remains elusive and controversial. Here we use marine seismic reflection and borehole data to reveal an unprecedented accumulation of early Oligocene strata (up to 2.2 km thick over 1500 × 500 km) with a major biogenic component in the Australian Southern Ocean. High-resolution ocean simulations demonstrate that a tectonically-driven, one-off reorganisation of ocean currents, caused a unique period where current instability coincided with high nutrient input from the Antarctic continent. This unrepeated and short-lived environment favoured extreme bioproductivity and enhanced sediment burial. The size and rapid accumulation of this sediment package potentially holds ~1.067 × 1015 kg of the 'missing carbon' sequestered during the decline from an Eocene high CO2-world to a mid-Oligocene medium CO2-world, highlighting the exceptional role of the Southern Ocean in modulating long-term climate.
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Affiliation(s)
- Katharina Hochmuth
- grid.9918.90000 0004 1936 8411School of Geography, Geology and the Environment, University of Leicester, Leicester, UK ,grid.1009.80000 0004 1936 826XInstitute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS Australia ,grid.1009.80000 0004 1936 826XAustralian Center for Excellence in Antarctic Sciences, University of Tasmania, Hobart, TAS Australia
| | - Joanne M. Whittaker
- grid.1009.80000 0004 1936 826XInstitute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS Australia ,grid.1009.80000 0004 1936 826XAustralian Center for Excellence in Antarctic Sciences, University of Tasmania, Hobart, TAS Australia
| | - Isabel Sauermilch
- grid.5477.10000000120346234Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Andreas Klocker
- grid.5510.10000 0004 1936 8921Department of Geosciences, University of Oslo, Oslo, Norway ,Present Address: NORCE Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen, Norway
| | - Karsten Gohl
- grid.10894.340000 0001 1033 7684Alfred Wegener Institute Helmholtz-Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Joseph H. LaCasce
- grid.5510.10000 0004 1936 8921Department of Geosciences, University of Oslo, Oslo, Norway
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4
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Xie L, Liu J, Bao X, Chen J, Zheng X, He Y, Zhang W, Zeng J, Wang Y, Kong B. Interfacial Assembly of Nanowire Arrays toward Carbonaceous Mesoporous Nanorods and Superstructures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2104477. [PMID: 34738718 DOI: 10.1002/smll.202104477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/07/2021] [Indexed: 06/13/2023]
Abstract
Synthesis of anisotropic carbonaceous nano- and micro-materials with well-ordered mesoporous structures has attracted increasing attention for a broad scope of applications. Although hard-templating method has been widely employed, overcoming the viscous forces to prepare anisotropic mesoporous materials is particularly challenging via the universal soft-templating method, especially from sustainable biomass as a carbon resource. Herein, the synthesis of biomass-derived nanowire-arrays based mesoporous nanorods and teeth-like superstructures is reported, through a simple and straightforward polyelectrolyte assisted soft-templating hydrothermal carbonization (HTC) approach. A surface energy induced interfacial assembly mechanism with the synergetic interactions between micelles, nanowire, nanorods, and polyelectrolyte is proposed. The polyelectrolyte acts not only as a stabilizer to decrease the surface energy of cylindrical micelles, nanowires and nanorods, but also as a structure-directing agent to regulate the oriented attachment and anisotropic assembly of micelles, nanowires, and nanorods. After a calcination treatment, the carbon nanorod and teeth-like superstructure are successfully coupled with Ru to directly produce supported catalysts for the hydrogen evolution reaction, exhibiting much better performance than the isotropic nanospheres based catalyst. This HTC approach will open up new avenues for the synthesis of anisotropic materials with various morphologies and dimensions, expanding the palette of materials selection for many applications.
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Affiliation(s)
- Lei Xie
- Advanced Materials and Catalysis Group, Institute of Catalysis, Department of Chemistry, Zhejiang University, Hangzhou, 310028, P. R. China
- Department of Chemistry, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai, 200438, P. R. China
| | - Jinrong Liu
- Advanced Materials and Catalysis Group, Institute of Catalysis, Department of Chemistry, Zhejiang University, Hangzhou, 310028, P. R. China
| | - Xiaobing Bao
- Advanced Materials and Catalysis Group, Institute of Catalysis, Department of Chemistry, Zhejiang University, Hangzhou, 310028, P. R. China
| | - Jiadong Chen
- Advanced Materials and Catalysis Group, Institute of Catalysis, Department of Chemistry, Zhejiang University, Hangzhou, 310028, P. R. China
| | - Xiaozhong Zheng
- Advanced Materials and Catalysis Group, Institute of Catalysis, Department of Chemistry, Zhejiang University, Hangzhou, 310028, P. R. China
| | - Yanjun He
- Department of Chemistry, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai, 200438, P. R. China
| | - Wei Zhang
- Department of Chemistry, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai, 200438, P. R. China
| | - Jie Zeng
- Department of Chemistry, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai, 200438, P. R. China
| | - Yong Wang
- Advanced Materials and Catalysis Group, Institute of Catalysis, Department of Chemistry, Zhejiang University, Hangzhou, 310028, P. R. China
| | - Biao Kong
- Department of Chemistry, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Fudan University, Shanghai, 200438, P. R. China
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5
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Sauermilch I, Whittaker JM, Klocker A, Munday DR, Hochmuth K, Bijl PK, LaCasce JH. Gateway-driven weakening of ocean gyres leads to Southern Ocean cooling. Nat Commun 2021; 12:6465. [PMID: 34753912 PMCID: PMC8578591 DOI: 10.1038/s41467-021-26658-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/08/2021] [Indexed: 11/09/2022] Open
Abstract
Declining atmospheric CO2 concentrations are considered the primary driver for the Cenozoic Greenhouse-Icehouse transition, ~34 million years ago. A role for tectonically opening Southern Ocean gateways, initiating the onset of a thermally isolating Antarctic Circumpolar Current, has been disputed as ocean models have not reproduced expected heat transport to the Antarctic coast. Here we use high-resolution ocean simulations with detailed paleobathymetry to demonstrate that tectonics did play a fundamental role in reorganising Southern Ocean circulation patterns and heat transport, consistent with available proxy data. When at least one gateway (Tasmanian or Drake) is shallow (300 m), gyres transport warm waters towards Antarctica. When the second gateway subsides below 300 m, these gyres weaken and cause a dramatic cooling (average of 2–4 °C, up to 5 °C) of Antarctic surface waters whilst the ACC remains weak. Our results demonstrate that tectonic changes are crucial for Southern Ocean climate change and should be carefully considered in constraining long-term climate sensitivity to CO2. The role of Southern Ocean gateways contributing to the Eocene-Oligocene climate transition is still debated. Here, the authors present high-resolution ocean simulations to show that gateways opening led to a reorganization of ocean circulation, heat transport and Antarctic surface water cooling.
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Affiliation(s)
- Isabel Sauermilch
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia. .,Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands.
| | - Joanne M Whittaker
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
| | - Andreas Klocker
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia.,Australian Research Council Centre of Excellence for Climate Extremes, University of Tasmania, Hobart, Australia
| | | | - Katharina Hochmuth
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany.,School of Geography, Geology and the Environment, University of Leicester, Leicester, UK
| | - Peter K Bijl
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
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6
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López-Quirós A, Escutia C, Sánchez-Navas A, Nieto F, Garcia-Casco A, Martín-Algarra A, Evangelinos D, Salabarnada A. Glaucony authigenesis, maturity and alteration in the Weddell Sea: An indicator of paleoenvironmental conditions before the onset of Antarctic glaciation. Sci Rep 2019; 9:13580. [PMID: 31537907 PMCID: PMC6753099 DOI: 10.1038/s41598-019-50107-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 09/06/2019] [Indexed: 11/09/2022] Open
Abstract
Three types of glaucony grains were identified in the late Eocene (~35.5-34.1 Ma) sediments from Ocean Drilling Program (ODP) Hole 696B in the northwestern Weddell Sea (Antarctica). The grains are K2O-rich (~7 wt%) and formed by smectite-poor interstratified ~10 Å glauconite-smectite with flaky/rosette-shaped surface nanostructures. Two glaucony types reflect an evolved (types 1 and 2 glaucony; less mature to mature) stage and long term glauconitization, attesting to the glaucony grains being formed in situ, whereas the third type (type 3 glaucony) shows evidences of alteration and reworking from nearby areas. Conditions for the glaucony authigenesis occurred in an open-shelf environment deeper than 50 m, under sub-oxic conditions near the sediment-water interface. These environmental conditions were triggered by low sedimentation rates and recurrent winnowing action by bottom-currents, leading to stratigraphic condensation. The condensed glaucony-bearing section provides an overview of continuous sea-level rise conditions pre-dating the onset of Antarctic glaciation during the Eocene-Oligocene transition. Sediment burial, drop of O2 levels, and ongoing reducing (postoxic to sulphidic) conditions at Hole 696B, resulting in iron-sulphide precipitation, were a key limiting factor for the glauconitization by sequestration of Fe2+.
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Affiliation(s)
- Adrián López-Quirós
- Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Avda. las Palmeras 4, 18100, Armilla, Granada, Spain.
| | - Carlota Escutia
- Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Avda. las Palmeras 4, 18100, Armilla, Granada, Spain
| | - Antonio Sánchez-Navas
- Department of Mineralogy and Petrology, University of Granada, 18071, Granada, Spain
| | - Fernando Nieto
- Department of Mineralogy and Petrology, University of Granada, 18071, Granada, Spain
| | - Antonio Garcia-Casco
- Department of Mineralogy and Petrology, University of Granada, 18071, Granada, Spain
| | - Agustín Martín-Algarra
- Department of Stratigraphy and Paleontology, University of Granada, 18071, Granada, Spain
| | - Dimitris Evangelinos
- Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Avda. las Palmeras 4, 18100, Armilla, Granada, Spain
| | - Ariadna Salabarnada
- Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Avda. las Palmeras 4, 18100, Armilla, Granada, Spain
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7
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Southern Ocean warming and Wilkes Land ice sheet retreat during the mid-Miocene. Nat Commun 2018; 9:317. [PMID: 29358604 PMCID: PMC5778126 DOI: 10.1038/s41467-017-02609-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 12/13/2017] [Indexed: 01/20/2023] Open
Abstract
Observations and model experiments highlight the importance of ocean heat in forcing ice sheet retreat during the present and geological past, but past ocean temperature data are virtually missing in ice sheet proximal locations. Here we document paleoceanographic conditions and the (in)stability of the Wilkes Land subglacial basin (East Antarctica) during the mid-Miocene (~17-13.4 million years ago) by studying sediment cores from offshore Adélie Coast. Inland retreat of the ice sheet, temperate vegetation, and warm oligotrophic waters characterise the mid-Miocene Climatic Optimum (MCO; 17-14.8 Ma). After the MCO, expansion of a marine-based ice sheet occurs, but remains sensitive to melting upon episodic warm water incursions. Our results suggest that the mid-Miocene latitudinal temperature gradient across the Southern Ocean never resembled that of the present day. We demonstrate that a strong coupling of oceanic climate and Antarctic continental conditions existed and that the East Antarctic subglacial basins were highly sensitive to ocean warming.
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8
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Park T, Fitzgerald EMG, Gallagher SJ, Tomkins E, Allan T. New Miocene Fossils and the History of Penguins in Australia. PLoS One 2016; 11:e0153915. [PMID: 27115739 PMCID: PMC4845988 DOI: 10.1371/journal.pone.0153915] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 04/06/2016] [Indexed: 11/18/2022] Open
Abstract
Australia has a fossil record of penguins reaching back to the Eocene, yet today is inhabited by just one breeding species, the little penguin Eudyptula minor. The description of recently collected penguin fossils from the re-dated upper Miocene Port Campbell Limestone of Portland (Victoria), in addition to reanalysis of previously described material, has allowed the Cenozoic history of penguins in Australia to be placed into a global context for the first time. Australian pre-Quaternary fossil penguins represent stem taxa phylogenetically disparate from each other and E. minor, implying multiple dispersals and extinctions. Late Eocene penguins from Australia are closest to contemporaneous taxa in Antarctica, New Zealand and South America. Given current material, the Miocene Australian fossil penguin fauna is apparently unique in harbouring 'giant penguins' after they went extinct elsewhere; and including stem taxa until at least 6 Ma, by which time crown penguins dominated elsewhere in the southern hemisphere. Separation of Australia from Antarctica during the Palaeogene, and its subsequent drift north, appears to have been a major event in Australian penguin biogeography. Increasing isolation through the Cenozoic may have limited penguin dispersal to Australia from outside the Australasian region, until intensification of the eastwards-flowing Antarctic Circumpolar Current in the mid-Miocene established a potential new dispersal vector to Australia.
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Affiliation(s)
- Travis Park
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Palaeontology, Museum Victoria, Melbourne, Victoria, Australia
- * E-mail:
| | | | | | - Ellyn Tomkins
- Palaeontology, Museum Victoria, Melbourne, Victoria, Australia
- School of Earth Sciences, University of Melbourne, Victoria, Australia
| | - Tony Allan
- CSIRO Radiogenic Isotope Facility, North Ryde, Sydney, New South Wales, Australia
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9
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Häder DP, Villafañe VE, Helbling EW. Productivity of aquatic primary producers under global climate change. Photochem Photobiol Sci 2015; 13:1370-92. [PMID: 25191675 DOI: 10.1039/c3pp50418b] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The productivity of aquatic primary producers depends on a number of biotic and abiotic factors, such as pH, CO2 concentration, temperature, nutrient availability, solar UV and PAR irradiances, mixing frequency as well as herbivore pressure and the presence of viruses, among others. The effects of these factors, within a climate change context, may be additive, synergistic or antagonistic. Since some of them, e.g. solar radiation and temperature, vary along a latitudinal gradient, this perspective about the effects of global climate change on primary producers will consider ecosystems individually, separated into polar (Arctic and Antarctic), temperate and tropical waters. As coastal waters are characterized by lower light penetration and higher DOM and nutrient concentrations, they are considered in a separate section. Freshwater systems are also governed by different conditions and therefore also treated in their own section. Overall, we show that although there are general common trends of changes in variables associated with global change (e.g. the impact of UVR on photosynthesis tends to decrease with increasing temperature and nutrient input), the responses of aquatic primary producers have great variability in the different ecosystems across latitudes. This is mainly due to direct or indirect effects associated with physico-chemical changes that occur within water bodies. Therefore we stress the need for regional predictions on the responses of primary producers to climate change as it is not warranted to extrapolate from one system to another.
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10
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11
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Sun J, Ni X, Bi S, Wu W, Ye J, Meng J, Windley BF. Synchronous turnover of flora, fauna, and climate at the Eocene-Oligocene Boundary in Asia. Sci Rep 2014; 4:7463. [PMID: 25501388 PMCID: PMC4264005 DOI: 10.1038/srep07463] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 11/25/2014] [Indexed: 01/31/2023] Open
Abstract
The Eocene–Oligocene Boundary (~34 million years ago) marks one of the largest extinctions of marine invertebrates in the world oceans and of mammalian fauna in Europe and Asia in the Cenozoic era. A shift to a cooler climate across this boundary has been suggested as the cause of this extinction in the marine environment, but there is no manifold evidence for a synchronous turnover of flora, fauna and climate at the Eocene–Oligocene Boundary in a single terrestrial site in Asia to support this hypothesis. Here we report new data of magnetostratigraphy, pollen and climatic proxies in the Asian interior across the Eocene–Oligocene Boundary; our results show that climate change forced a turnover of flora and fauna, suggesting there was a change from large-size perissodactyl-dominant fauna in forests under a warm-temperate climate to small rodent/lagomorph-dominant fauna in forest-steppe in a dry-temperate climate across the Eocene–Oligocene Boundary. These data provide a new terrestrial record for this significant Cenozoic environmental event.
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Affiliation(s)
- Jimin Sun
- 1] Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China [2] CAS Center for Excellence in Tibetan Plateau Earth Sciences
| | - Xijun Ni
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Shundong Bi
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Wenyu Wu
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Jie Ye
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Jin Meng
- 1] Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China [2] American Museum of Natural History, New York, New York 10024, USA
| | - Brian F Windley
- Department of Geology, University of Leicester, Leicester LEI 7RH, UK
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12
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Goldner A, Herold N, Huber M. Antarctic glaciation caused ocean circulation changes at the Eocene-Oligocene transition. Nature 2014; 511:574-7. [PMID: 25079555 DOI: 10.1038/nature13597] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/19/2014] [Indexed: 02/01/2023]
Abstract
Two main hypotheses compete to explain global cooling and the abrupt growth of the Antarctic ice sheet across the Eocene-Oligocene transition about 34 million years ago: thermal isolation of Antarctica due to southern ocean gateway opening, and declining atmospheric CO2 (refs 5, 6). Increases in ocean thermal stratification and circulation in proxies across the Eocene-Oligocene transition have been interpreted as a unique signature of gateway opening, but at present both mechanisms remain possible. Here, using a coupled ocean-atmosphere model, we show that the rise of Antarctic glaciation, rather than altered palaeogeography, is best able to explain the observed oceanographic changes. We find that growth of the Antarctic ice sheet caused enhanced northward transport of Antarctic intermediate water and invigorated the formation of Antarctic bottom water, fundamentally reorganizing ocean circulation. Conversely, gateway openings had much less impact on ocean thermal stratification and circulation. Our results support available evidence that CO2 drawdown--not gateway opening--caused Antarctic ice sheet growth, and further show that these feedbacks in turn altered ocean circulation. The precise timing and rate of glaciation, and thus its impacts on ocean circulation, reflect the balance between potentially positive feedbacks (increases in sea ice extent and enhanced primary productivity) and negative feedbacks (stronger southward heat transport and localized high-latitude warming). The Antarctic ice sheet had a complex, dynamic role in ocean circulation and heat fluxes during its initiation, and these processes are likely to operate in the future.
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Affiliation(s)
- A Goldner
- 1] Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, USA [2] American Geophysical Union, Washington DC 20009, USA
| | - N Herold
- Department of Earth Sciences, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - M Huber
- 1] Department of Earth Sciences, University of New Hampshire, Durham, New Hampshire 03824, USA [2] Earth Systems Research Center, Institute for Earth, Ocean and Space Sciences, University of New Hampshire, Durham, New Hampshire 03824, USA
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Norris RD, Turner SK, Hull PM, Ridgwell A. Marine Ecosystem Responses to Cenozoic Global Change. Science 2013; 341:492-8. [DOI: 10.1126/science.1240543] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- R. D. Norris
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - S. Kirtland Turner
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - P. M. Hull
- Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA
| | - A. Ridgwell
- School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK
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