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Pu JP, Macdonald FA, Schmitz MD, Rainbird RH, Bleeker W, Peak BA, Flowers RM, Hoffman PF, Rioux M, Hamilton MA. Emplacement of the Franklin large igneous province and initiation of the Sturtian Snowball Earth. SCIENCE ADVANCES 2022; 8:eadc9430. [PMID: 36417531 PMCID: PMC9683727 DOI: 10.1126/sciadv.adc9430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
During the Cryogenian (720 to 635 Ma ago) Snowball Earth glaciations, ice extended to sea level near the equator. The cause of this catastrophic failure of Earth's thermostat has been unclear, but previous geochronology has suggested a rough coincidence of glacial onset with one of the largest magmatic episodes in the geological record, the Franklin large igneous province. U-Pb geochronology on zircon and baddeleyite from sills associated with the paleo-equatorial Franklin large igneous province in Arctic Canada record rapid emplacement between 719.86 ± 0.21 and 718.61 ± 0.30 Ma ago, 0.9 to 1.6 Ma before the onset of widespread glaciation. Geologic observations and (U-Th)/He dates on Franklin sills are compatible with major post-Franklin exhumation, possibly due to development of mafic volcanic highlands on windward equatorial Laurentia and increased global weatherability. After a transient magmatic CO2 flux, long-term carbon sequestration associated with increased weatherability could have nudged Earth over the threshold for runaway ice-albedo feedback.
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Affiliation(s)
- Judy P. Pu
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Francis A. Macdonald
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Mark D. Schmitz
- Department of Geosciences, Boise State University, Boise, ID, USA
| | | | | | - Barra A. Peak
- Department of Geological Sciences, University of Colorado, Boulder, CO, USA
| | - Rebecca M. Flowers
- Department of Geological Sciences, University of Colorado, Boulder, CO, USA
| | - Paul F. Hoffman
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
- School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - Matthew Rioux
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Michael A. Hamilton
- Department of Earth Sciences, University of Toronto, Toronto, Ontario, Canada
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Silva MDS, Funch LS, da Silva LB, Cardoso D. A phylogenetic and functional perspective on the origin and evolutionary shifts of growth ring anatomical markers in seed plants. Biol Rev Camb Philos Soc 2021; 96:842-876. [PMID: 33385187 DOI: 10.1111/brv.12681] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 11/29/2022]
Abstract
We reconstruct the evolutionary changes in different anatomical markers in order to understand the evolution and functional aspects of growth rings during the diversification of seed plants (spermatophytes), one of the largest and most diverse lineages of the tree of life. We carried out a wide revision of the anatomy of secondary xylem in spermatophytes and reconstructed the evolution of the different anatomical markers in a time-calibrated phylogeny. By embodying a functionally and evolutionarily significant concept in growth rings we reveal a new panorama for their frequency and show how common they are in diverse lineages of tropical plants. In this context, the principal anatomical markers of growth rings are identified in the evolutionary history of plants and their association with climate-related ecological characteristics. We discuss the function of these anatomical markers, especially for thick-walled and/or radially flattened latewood fibres, fibre zone and dilated rays. Despite the high evolutionary lability of the anatomical markers evidenced by our analyses, they appear to represent deep homologies.
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Affiliation(s)
- Marcelo Dos S Silva
- Laboratório de Anatomia Vegetal e Identificação de Madeiras - LAVIM, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, Campus de Ondina, 147, Salvador, BA, 40.170-290, Brazil.,Programa de Pós-Graduação em Botânica, Departamento de Ciências Biológicas, Universidade Estadual de Feira de Santana, Av. Universitária, s/n, Feira de Santana, BA, 44.031-460, Brazil
| | - Ligia S Funch
- Programa de Pós-Graduação em Botânica, Departamento de Ciências Biológicas, Universidade Estadual de Feira de Santana, Av. Universitária, s/n, Feira de Santana, BA, 44.031-460, Brazil
| | - Lazaro B da Silva
- Laboratório de Anatomia Vegetal e Identificação de Madeiras - LAVIM, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, Campus de Ondina, 147, Salvador, BA, 40.170-290, Brazil.,Programa de Pós-Graduação em Ecologia Aplicada à Gestão Ambiental, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, Campus de Ondina, 147, Salvador, BA, 40.170-290, Brazil
| | - Domingos Cardoso
- Programa de Pós-Graduação em Botânica, Departamento de Ciências Biológicas, Universidade Estadual de Feira de Santana, Av. Universitária, s/n, Feira de Santana, BA, 44.031-460, Brazil.,National Institute of Science and Technology in Interdisciplinary and Transdisciplinary Studies in Ecology and Evolution (INCT IN-TREE), Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, Campus de Ondina, 147, Salvador, BA, 40.170-290, Brazil
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Whitney MR, Sidor CA. Evidence of torpor in the tusks of Lystrosaurus from the Early Triassic of Antarctica. Commun Biol 2020; 3:471. [PMID: 32855434 PMCID: PMC7453012 DOI: 10.1038/s42003-020-01207-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 08/01/2020] [Indexed: 11/16/2022] Open
Abstract
Antarctica has hosted a wide range of ecosystems over the past 500-million years. Early in the Mesozoic, the Antarctic portion of southern Pangaea had a more habitable climate, but its position within the polar circle imposed extreme photoperiod seasonality on its resident flora and fauna. It remains unclear to what degree physiological adaptations underpinned the ability of tetrapods to establish the terrestrial communities captured in the fossil record. Here we use regular and stressful growth marks preserved in the dentine of ever-growing tusks of the Early Triassic mammalian predecessor, Lystrosaurus, to test for adaptations specific to this polar inhabitant. We find evidence of prolonged stress indicative of torpor when compared to tusk samples from non-polar populations of Lystrosaurus. These preliminary findings are to our knowledge the oldest instance of torpor yet reported in the fossil record and demonstrate unexpected physiological flexibility in Lystrosaurus that may have contributed its survivorship through the Permo-Triassic mass extinction. Whitney and Sidor examine the growth marks on Lystrosaurus tusks from the Early Triassic, and demonstrate evidence of torpor in polar specimens. These preliminary findings give insight into physiological adaptations that could have aided in survival and recovery from the Permo-Triassic mass extinction.
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Affiliation(s)
- Megan R Whitney
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, 02138, USA.
| | - Christian A Sidor
- Department of Biology and Burke Museum, University of Washington, Seattle, WA, 98195, USA
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Gaston KJ, Bennie J, Davies TW, Hopkins J. The ecological impacts of nighttime light pollution: a mechanistic appraisal. Biol Rev Camb Philos Soc 2013; 88:912-27. [PMID: 23565807 DOI: 10.1111/brv.12036] [Citation(s) in RCA: 430] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 02/16/2013] [Accepted: 02/27/2013] [Indexed: 11/28/2022]
Abstract
The ecological impacts of nighttime light pollution have been a longstanding source of concern, accentuated by realized and projected growth in electrical lighting. As human communities and lighting technologies develop, artificial light increasingly modifies natural light regimes by encroaching on dark refuges in space, in time, and across wavelengths. A wide variety of ecological implications of artificial light have been identified. However, the primary research to date is largely focused on the disruptive influence of nighttime light on higher vertebrates, and while comprehensive reviews have been compiled along taxonomic lines and within specific research domains, the subject is in need of synthesis within a common mechanistic framework. Here we propose such a framework that focuses on the cross-factoring of the ways in which artificial lighting alters natural light regimes (spatially, temporally, and spectrally), and the ways in which light influences biological systems, particularly the distinction between light as a resource and light as an information source. We review the evidence for each of the combinations of this cross-factoring. As artificial lighting alters natural patterns of light in space, time and across wavelengths, natural patterns of resource use and information flows may be disrupted, with downstream effects to the structure and function of ecosystems. This review highlights: (i) the potential influence of nighttime lighting at all levels of biological organisation (from cell to ecosystem); (ii) the significant impact that even low levels of nighttime light pollution can have; and (iii) the existence of major research gaps, particularly in terms of the impacts of light at population and ecosystem levels, identification of intensity thresholds, and the spatial extent of impacts in the vicinity of artificial lights.
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Affiliation(s)
- Kevin J Gaston
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, U.K
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Gulbranson EL, Isbell JL, Taylor EL, Ryberg PE, Taylor TN, Flaig PP. Permian polar forests: deciduousness and environmental variation. GEOBIOLOGY 2012; 10:479-495. [PMID: 22845834 DOI: 10.1111/j.1472-4669.2012.00338.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 07/02/2012] [Indexed: 06/01/2023]
Abstract
Forests are expected to expand into northern polar latitudes in the next century. However, the impact of forests at high latitudes on climate and terrestrial biogeochemical cycling is poorly understood because such forests cannot be studied in the modern. This study presents forestry and geochemical analyses of three in situ fossil forests from Late Permian strata of Antarctica, which grew at polar latitudes. Stem size measurements and stump spacing measurements indicate significant differences in forest density and canopy structure that are related to the local depositional setting. For forests closest to fluvial systems, tree density appears to decrease as the forests mature, which is the opposite trend of self-thinning observed in modern forests. We speculate that a combination of tree mortality and high disturbance created low-density mature forests without understory vegetation near Late Permian river systems. Stable carbon isotopes measured from permineralized wood in these forests demonstrate two important points: (i) recently developed techniques of high-resolution carbon isotope studies of wood and mummified wood can be applied to permineralized wood, for which much of the original organic matter has been lost and (ii) that the fossil trees maintained a deciduous habit at polar latitudes during the Late Permian. The combination of paleobotanical, sedimentologic, and paleoforestry techniques provides an unrivaled examination of the function of polar forests in deep time; and the carbon isotope geochemistry supplements this work with subannual records of carbon fixation that allows for the quantitative analysis of deciduous versus evergreen habits and environmental parameters, for example, relative humidity.
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Affiliation(s)
- E L Gulbranson
- Department of Geosciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
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Ryberg PE, Taylor EL, Taylor TN. Antarctic glossopterid diversity on a local scale: the presence of multiple megasporophyll genera, Upper Permian, Mt. Achernar, Transantarctic Mountains, Antarctica. AMERICAN JOURNAL OF BOTANY 2012; 99:1531-1540. [PMID: 22922397 DOI: 10.3732/ajb.1200142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PREMISE OF THE STUDY The glossopterids are a group of plants that thrived during a time of global warming similar to what is happening on the Earth today as well as the transition from archaic plant groups to the ancestors of modern groups. The diversity of the glossopterid clade is based on the megasporangiate structures assigned to the group, because the vegetative and pollen-bearing structures vary little. The presence of numerous reproductive genera from a single Upper Permian locality in the central Transantarctic Mountains provides important data on local glossopterid diversity in Antarctica. METHODS Impression/compression fossils were imaged with a Leica 5000C digital camera on a dissecting microscope or a Fujifilm FinePix S1pro digital camera. KEY RESULTS Two megasporangiate taxa are described: Scutum leiophyllum, which represents the first confirmed record of the genus in Antarctica, and Lidgettoniopsis ramulus, a new morphology consisting of a pinnate structure with oppositely attached megasporophylls. Plumsteadia ovata specimens indicate that this genus can be larger than previously recorded and illustrate the vegetative surface with a distinct midrib. CONCLUSIONS The presence of a laminar, multiovulate structure and a pinnate structure at the same site indicates that local-level glossopterid diversity in Antarctica is greater than previously hypothesized. The discovery of a new megasporophyll morphology in Antarctica (confirming the presence of three distinctive morphologies on the continent) shows that Antarctic glossopterid heterogeneity is on a par with other Gondwanan continents. The diversity of the Antarctic landscape reveals that high polar latitudes can sustain a diverse ecosystem during times of global warming.
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Affiliation(s)
- Patricia E Ryberg
- Department of Ecology and Evolutionary Biology, Natural History Museum and Biodiversity Institute, University of Kansas, Lawrence, Kansas 66045, USA.
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Williams CJ. High-latitude Forest Structure: Methodological Considerations and Insights on Reconstructing High-latitude Fossil Forests. BULLETIN OF THE PEABODY MUSEUM OF NATURAL HISTORY 2007. [DOI: 10.3374/0079-032x(2007)48[339:hfsmca]2.0.co;2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Terry AC, Quick WP, Beerling DJ. Long-term growth of Ginkgo with CO(2) enrichment increases leaf ice nucleation temperatures and limits recovery of the photosynthetic system from freezing. PLANT PHYSIOLOGY 2000; 124:183-90. [PMID: 10982433 PMCID: PMC59133 DOI: 10.1104/pp.124.1.183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2000] [Accepted: 05/15/2000] [Indexed: 05/23/2023]
Abstract
The importance of subzero temperature interactions with elevated CO(2) on plant carbon metabolism has received rather little attention, despite their likely role in influencing future vegetation productivity and dynamics. Here we focused on the critical issues of CO(2)-enrichment effects on leaf-freezing temperatures, subsequent membrane damage, and recovery of the photosynthetic system. We show that growth in elevated CO(2) (70 Pa) results in a substantial and significant (P<0.01) increase (up to 4 degrees C) in the ice nucleation temperature of leaves of Maidenhair tree (Ginkgo biloba), which was observed consistently throughout the 1999 growing season relative to their ambient CO(2) (35 Pa) counterparts. We suggest that increased sensitivity of leaves to ice damage after growth in elevated CO(2) provides an explanation for increased photoinhibition observed in the field early and late in the growing season when low nighttime temperatures are experienced. This new mechanism is proposed in addition to the earlier postulated explanation for this phenomenon involving a reduction in the rate of triose-P utilization owing to a decrease in the rate of carbohydrate export from the leaf.
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Affiliation(s)
- A C Terry
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
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Pigg KB, Taylor TN. ANATOMICALLY PRESERVED GLOSSOPTERIS STEMS WITH ATTACHED LEAVES FROM THE CENTRAL TRANSANTARCTIC MOUNTAINS, ANTARCTICA. AMERICAN JOURNAL OF BOTANY 1993; 80:500-516. [PMID: 30139146 DOI: 10.1002/j.1537-2197.1993.tb13833.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/1992] [Accepted: 01/14/1993] [Indexed: 06/08/2023]
Abstract
Stems and buds of Glossopteris skaarensis Pigg and buds of G. schopfii Pigg from the Permian Skaar Ridge locality in the central Transantarctic Mountains, Antarctica demonstrate the first anatomically preserved glossopterids known with stem/leaf attachment. Stems of G. skaarensis are 1-12 mm in diameter ( = 3.1 mm) with a broad pith, poorly defined primary xylem, and a zone of secondary xylem up to 6 mm thick. Pycnoxylic wood conforming to Araucarioxylon Kraus is composed of tracheids with uni- to biseriate oval to hexagonal bordered pits on radial walls, uniseriate rays one to a few cells high, and cupressoid to taxodioid cross-field pitting. Stems have a narrow zone of secondary phloem, aerenchymatous cortex with scattered sclereids, and sometimes a narrow periderm. Two wedge-shaped leaf traces each bifurcate to form four strands in the base of each petiole. Small axillary branches are vascularized by double branch traces that fuse at the margin of the main axis. Buds of G. skaarensis have leaves with narrow lateral laminae and a thickened midrib containing a wide lacuna, delicate vascular strands, and a prominent hypodermis. In contrast, buds of G. schopfii have uniformly thick leaves with prominent, circular vascular bundle sheaths. These anatomical details are used to reconstruct individual types of glossopterid plants, providing new information toward understanding the ecology and evolution of this important group of Permian seed plants.
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Affiliation(s)
- Kathleen B Pigg
- Department of Botany, Arizona State University, Tempe, Arizona, 85287-1601
| | - Thomas N Taylor
- Department of Plant Biology and Byrd Polar Research Center, The Ohio State University, 1735 Neil Avenue, Columbus, Ohio, 43210
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Yemane K. Contribution of Late Permian palaeogeography in maintaining a temperate climate in Gondwana. Nature 1993. [DOI: 10.1038/361051a0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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