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Musser G, Clarke JA. A new Paleogene fossil and a new dataset for waterfowl (Aves: Anseriformes) clarify phylogeny, ecological evolution, and avian evolution at the K-Pg Boundary. PLoS One 2024; 19:e0278737. [PMID: 39078833 PMCID: PMC11288464 DOI: 10.1371/journal.pone.0278737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 05/05/2024] [Indexed: 08/02/2024] Open
Abstract
Despite making up one of the most ecologically diverse groups of living birds, comprising soaring, diving and giant flightless taxa, the evolutionary relationships and ecological evolution of Anseriformes (waterfowl) remain unresolved. Although Anseriformes have a comparatively rich, global Cretaceous and Paleogene fossil record, morphological datasets for this group that include extinct taxa report conflicting relationships for all known extinct taxa. Correct placement of extinct taxa is necessary to understand whether ancestral anseriform feeding ecology was more terrestrial or one of a set of diverse aquatic ecologies and to better understand avian evolution around the K-T boundary. Here, we present a new morphological dataset for Anseriformes that includes more extant and extinct taxa than any previous anseriform-focused dataset and describe a new anseriform species from the early Eocene Green River Formation of North America. The new taxon has a mediolaterally narrow bill which is rarely found in previously described anseriform fossils. The matrix created to assess the placement of this taxon comprises 41 taxa and 719 discrete morphological characters describing skeletal morphology, musculature, syringeal morphology, ecology, and behavior. We additionally combine the morphological dataset with published sequences using Bayesian methods and perform ancestral state reconstruction for select morphological, ecological and behavioral characters. We recover the new Eocene taxon as the sister taxon to (Anseranatidae+Anatidae) across all analyses, and find that the new taxon represents a novel ecology within known Anseriformes and the Green River taxa. Results provide insight into avian evolution during and following the K-Pg mass extinction and indicate that Anseriformes were likely ancestrally aquatic herbivores with rhamphothecal lamellae..
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Affiliation(s)
- Grace Musser
- Department of Vertebrate Zoology, Division of Birds, The Smithsonian National Museum of Natural History, Washington, District of Columbia, United States of America
- Department of Earth and Planetary Sciences, The University of Texas at Austin, Austin, Texas, United States of America
| | - Julia A. Clarke
- Department of Earth and Planetary Sciences, The University of Texas at Austin, Austin, Texas, United States of America
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2
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Kaiho K. Role of volcanism and impact heating in mass extinction climate shifts. Sci Rep 2024; 14:9946. [PMID: 38688982 PMCID: PMC11061309 DOI: 10.1038/s41598-024-60467-y] [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: 07/26/2023] [Accepted: 04/23/2024] [Indexed: 05/02/2024] Open
Abstract
This study investigates the mechanisms underlying the varied climate changes witnessed during mass extinctions in the Phanerozoic Eon. Climate shifts during mass extinctions have manifested as either predominant global cooling or predominant warming, yet the causes behind these occurrences remain unclear. We emphasize the significance of sedimentary rock temperature in comprehending these climate shifts. Our research reveals that low-temperature heating of sulfide leads to global cooling through the release of sulfur dioxide (SO2), while intermediate-temperature heating of hydrocarbons and carbonates releases substantial carbon dioxide (CO2), contributing to global warming. High-temperature heating additionally generates SO2 from sulfate, further contributing to global cooling. Different degrees of contact heating of the host rock can lead to different dominant volatile gas emissions, crucially driving either warming or cooling. Moreover, medium to high-temperature shock-heating resulting from asteroid impacts produces soot from hydrocarbons, also contributing to global cooling. Large-scale volcanic activity and asteroid impacts are both events that heat rocks, emitting the same gases and particles, causing climate changes. The findings elucidate the critical role of heating temperature and heating time in understanding major climate changes during mass extinctions.
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Affiliation(s)
- Kunio Kaiho
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan.
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3
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Pal S, Shrivastava JP, Kalpana MS. Fire activity across Cretaceous/Paleogene transition: Evidence from pyrogenic biomarkers preserved in the Mahadeo-Cherrapunji section, Meghalaya, India. GEOBIOLOGY 2023; 21:612-628. [PMID: 37312289 DOI: 10.1111/gbi.12567] [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: 09/10/2022] [Revised: 04/17/2023] [Accepted: 05/22/2023] [Indexed: 06/15/2023]
Abstract
Previous studies on high concentrations of polycyclic aromatic hydrocarbon (PAHs) present in the shallow-marine Um-Sohryngkew River (USR) Cretaceous/Paleogene Boundary (KPB) section suggested regional fire incidences and biotic stress on life. However, such observations at the USR site have not been confirmed so far anywhere else in the region, we, therefore, do not know whether the signal was local or regional. Thus, to find out charred organic markers associated with the shelf facies KPB outcrop (at a distance of over 5 km) of the Mahadeo-Cherrapunji road (MCR) section, PAHs were analyzed using gas chromatography-mass spectroscopy. Data show a notable rise in the PAHs and exhibit maximum abundance in the shaly KPB transition layer (in biozone P0) and the immediately underlying layer. The PAH excursions match well with the major incidences of the Deccan volcanic episodes and convergence of the Indian plate with the Eurasian and Burmese plates. These events were responsible for seawater disturbances and eustatic and depositional changes, including the retreat of the Tethys. The incidence of high amount of pyogenic PAHs unrelated to the total organic carbon content is suggestive of wind-blown or aquatic system transportation. A down-thrown shallow-marine facies of the Therriaghat block was responsible for an early accumulation of PAHs. However, the spike of perylene in the immediately underlying KPB transition layer is plausibly linked to the Chicxulub impact crater core. Anomalous concentrations of combustion-derived PAHs together with the high fragmentation and dissolution of the planktonic foraminifer shells show marine biodiversity and biotic distress. Significantly, the pyrogenic PAH excursions are restricted to either the KPB layer itself or strictly below or above it, indicating regional fire incidences and attendant KPB transition (66.016 ± 0.050 Ma).
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Affiliation(s)
- Sucharita Pal
- Department of Geology, University of Delhi, Delhi, India
- Centre for Earth, Ocean and Atmospheric Sciences (CEOAS), University of Hyderabad, Hyderabad, India
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Zhang G, Hu Y, Huang MZ, Huang WC, Liu DK, Zhang D, Hu H, Downing JL, Liu ZJ, Ma H. Comprehensive phylogenetic analyses of Orchidaceae using nuclear genes and evolutionary insights into epiphytism. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:1204-1225. [PMID: 36738233 DOI: 10.1111/jipb.13462] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 02/03/2023] [Indexed: 05/13/2023]
Abstract
Orchidaceae (with >28,000 orchid species) are one of the two largest plant families, with economically and ecologically important species, and occupy global and diverse niches with primary distribution in rainforests. Among orchids, 70% grow on other plants as epiphytes; epiphytes contribute up to ~50% of the plant diversity in rainforests and provide food and shelter for diverse animals and microbes, thereby contributing to the health of these ecosystems. Orchids account for over two-thirds of vascular epiphytes and provide an excellent model for studying evolution of epiphytism. Extensive phylogenetic studies of Orchidaceae and subgroups have ;been crucial for understanding relationships among many orchid lineages, although some uncertainties remain. For example, in the largest subfamily Epidendroideae with nearly all epiphytic orchids, relationships among some tribes and many subtribes are still controversial, hampering evolutionary analyses of epiphytism. Here we obtained 1,450 low-copy nuclear genes from 610 orchid species, including 431 with newly generated transcriptomes, and used them for the reconstruction of robust Orchidaceae phylogenetic trees with highly supported placements of tribes and subtribes. We also provide generally well-supported phylogenetic placements of 131 genera and 437 species that were not sampled by previous plastid and nuclear phylogenomic studies. Molecular clock analyses estimated the Orchidaceae origin at ~132 million years ago (Ma) and divergences of most subtribes from 52 to 29 Ma. Character reconstruction supports at least 14 parallel origins of epiphytism; one such origin was placed at the most recent common ancestor of ~95% of epiphytic orchids and linked to modern rainforests. Ten occurrences of rapid increase in the diversification rate were detected within Epidendroideae near and after the K-Pg boundary, contributing to ~80% of the Orchidaceae diversity. This study provides a robust and the largest family-wide Orchidaceae nuclear phylogenetic tree thus far and new insights into the evolution of epiphytism in vascular plants.
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Affiliation(s)
- Guojin Zhang
- Department of Biology, 510 Mueller Laboratory, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Yi Hu
- Department of Biology, 510 Mueller Laboratory, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Ming-Zhong Huang
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wei-Chang Huang
- Shanghai Chenshan Botanical Garden, Songjiang, Shanghai, 201602, China
| | - Ding-Kun Liu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Diyang Zhang
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Haihua Hu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Jason L Downing
- Fairchild Tropical Botanic Garden, Coral Gables, Florida, 33156, USA
| | - Zhong-Jian Liu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Hong Ma
- Department of Biology, 510 Mueller Laboratory, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
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Kaiho K. An animal crisis caused by pollution, deforestation, and warming in the late 21st century and exacerbation by nuclear war. Heliyon 2023; 9:e15221. [PMID: 37095985 PMCID: PMC10122020 DOI: 10.1016/j.heliyon.2023.e15221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/20/2023] [Accepted: 03/30/2023] [Indexed: 04/08/2023] Open
Abstract
An environmental-animal crisis is currently ongoing and is becoming increasingly severe due to human activity. However, the magnitude, timing, and processes related to this crisis are unclear. This paper clarifies the likely magnitude and timing of animal extinctions and changes in the contribution rates of select causes (global warming, pollution, deforestation, and two hypothetical nuclear conflicts) of animal extinctions during 2000-2300 CE. This paper demonstrates that an animal crisis marked by a 5-13% terrestrial tetrapod species loss and 2-6% marine animal species loss will occur in the next generation during 2060-2080 CE if humans do not engage in nuclear wars. These variations are due to magnitudes of pollution, deforestation, and global warming. The main causes of this crisis will change from pollution and deforestation to deforestation in 2030 under the low CO2 emission scenarios but will change from pollution and deforestation to deforestation in 2070 and then to deforestation and global warming after 2090 under the medium CO2 emissions. A nuclear conflict will increase animal species loss up to approximately 40-70% for terrestrial tetrapod species and 25-50% for marine animal species, including errors. Therefore, this study shows that the animal species conservation priority is to prevent nuclear war, reduce deforestation rates, decrease pollution, and limit global warming, in this order.
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Kaiho K. Extinction magnitude of animals in the near future. Sci Rep 2022; 12:19593. [PMID: 36418340 PMCID: PMC9684554 DOI: 10.1038/s41598-022-23369-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/31/2022] [Indexed: 11/24/2022] Open
Abstract
There have been five major mass extinctions and some minor mass extinctions of animals since early animal diversification 540-520 Myr ago. It is said that a sixth mass extinction is already underway. However, the future extinction magnitude has not been quantitatively estimated. Here, I show that the sixth major mass extinction (defined as > 60% species loss) will be avoided, but a minor mass extinction, 20-50% animal species loss (1% now), will occur when humans cause nuclear war and/or fail to stop increasing greenhouse gas (GHG) emissions, pollution, and deforestation until 2060-2080 CE. When humans decrease GHG emissions, pollution, and deforestation in 40 years and prevent nuclear war in the future, 10-15% animal species loss will occur. Humans should stop not only industrial GHG emissions but also deforestation, environmental pollution, and nuclear war to prevent this mass extinction. When humans fail to stop these processes, significant decreases in biodiversity and the human population and a collapse of ecological balance will occur on Earth.
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Affiliation(s)
- Kunio Kaiho
- grid.69566.3a0000 0001 2248 6943Department of Earth Science, Tohoku University, Aoba-Aza, Aramaki, Aoba-Ku, Sendai, 980-8578 Japan
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7
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Likhoshvai VA, Khlebodarova TM. Evolution and extinction can occur rapidly: a modeling approach. PeerJ 2021; 9:e11130. [PMID: 33954033 PMCID: PMC8051336 DOI: 10.7717/peerj.11130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 02/27/2021] [Indexed: 11/25/2022] Open
Abstract
Fossil record of Earth describing the last 500 million years is characterized by evolution discontinuity as well as recurring global extinctions of some species and their replacement by new types, the causes of which are still debate. We developed a model of evolutionary self-development of a large ecosystem. This model of biota evolution based on the universal laws of living systems functioning: reproduction, dependence of reproduction efficiency and mortality on biota density, mutational variability in the process of reproduction and selection of the most adapted individuals. We have shown that global extinctions and phases of rapid growth and biodiversity stasis can be a reflection of the emergence of bistability in a self-organizing system, which is the Earth’s biota. Bistability was found to be characteristic only for ecosystems with predominant sexual reproduction. The reason for the transition from one state to another is the selection of the most adapted individuals. That is, we explain the characteristics of the Earth’s fossil record during the last 500 million years by the internal laws of Earth’s ecosystem functioning, which appeared at a certain stage of evolution as a result of the emergence of life forms with an increased adaptive diversification associated with sexual dimorphism.
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Affiliation(s)
- Vitaly A Likhoshvai
- Department of Systems Biology, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
| | - Tamara M Khlebodarova
- Department of Systems Biology, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation.,Kurchatov Genomics Center, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation
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8
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Bonsor JA, Barrett PM, Raven TJ, Cooper N. Dinosaur diversification rates were not in decline prior to the K-Pg boundary. ROYAL SOCIETY OPEN SCIENCE 2020; 7:201195. [PMID: 33391800 PMCID: PMC7735361 DOI: 10.1098/rsos.201195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/29/2020] [Indexed: 05/29/2023]
Abstract
Determining the tempo and mode of non-avian dinosaur extinction is one of the most contentious issues in palaeobiology. Extensive disagreements remain over whether their extinction was catastrophic and geologically instantaneous or the culmination of long-term evolutionary trends. These conflicts have arisen due to numerous hierarchical sampling biases in the fossil record and differences in analytical methodology, with some studies identifying long-term declines in dinosaur richness prior to the Cretaceous-Palaeogene (K-Pg) boundary and others proposing continued diversification. Here, we use Bayesian phylogenetic generalized linear mixed models to assess the fit of 12 dinosaur phylogenies to three speciation models (null, slowdown to asymptote, downturn). We do not find strong support for the downturn model in our analyses, which suggests that dinosaur speciation rates were not in terminal decline prior to the K-Pg boundary and that the clade was still capable of generating new taxa. Nevertheless, we advocate caution in interpreting the results of such models, as they may not accurately reflect the complexities of the underlying data. Indeed, current phylogenetic methods may not provide the best test for hypotheses of dinosaur extinction; the collection of more dinosaur occurrence data will be essential to test these ideas further.
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Affiliation(s)
- Joseph A. Bonsor
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Paul M. Barrett
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Thomas J. Raven
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
- School of Environment and Technology, University of Brighton, Lewes Road, Brighton BN2 4GA, UK
| | - Natalie Cooper
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
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Organic matter from the Chicxulub crater exacerbated the K-Pg impact winter. Proc Natl Acad Sci U S A 2020; 117:25327-25334. [PMID: 32989138 DOI: 10.1073/pnas.2004596117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An asteroid impact in the Yucatán Peninsula set off a sequence of events that led to the Cretaceous-Paleogene (K-Pg) mass extinction of 76% species, including the nonavian dinosaurs. The impact hit a carbonate platform and released sulfate aerosols and dust into Earth's upper atmosphere, which cooled and darkened the planet-a scenario known as an impact winter. Organic burn markers are observed in K-Pg boundary records globally, but their source is debated. If some were derived from sedimentary carbon, and not solely wildfires, it implies soot from the target rock also contributed to the impact winter. Characteristics of polycyclic aromatic hydrocarbons (PAHs) in the Chicxulub crater sediments and at two deep ocean sites indicate a fossil carbon source that experienced rapid heating, consistent with organic matter ejected during the formation of the crater. Furthermore, PAH size distributions proximal and distal to the crater indicate the ejected carbon was dispersed globally by atmospheric processes. Molecular and charcoal evidence indicates wildfires were also present but more delayed and protracted and likely played a less acute role in biotic extinctions than previously suggested. Based on stratigraphy near the crater, between 7.5 × 1014 and 2.5 × 1015 g of black carbon was released from the target and ejected into the atmosphere, where it circulated the globe within a few hours. This carbon, together with sulfate aerosols and dust, initiated an impact winter and global darkening that curtailed photosynthesis and is widely considered to have caused the K-Pg mass extinction.
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10
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Gibbs SJ, Bown PR, Ward BA, Alvarez SA, Kim H, Archontikis OA, Sauterey B, Poulton AJ, Wilson J, Ridgwell A. Algal plankton turn to hunting to survive and recover from end-Cretaceous impact darkness. SCIENCE ADVANCES 2020; 6:6/44/eabc9123. [PMID: 33127682 PMCID: PMC7608818 DOI: 10.1126/sciadv.abc9123] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/16/2020] [Indexed: 05/26/2023]
Abstract
The end-Cretaceous bolide impact triggered the devastation of marine ecosystems. However, the specific kill mechanism(s) are still debated, and how primary production subsequently recovered remains elusive. We used marine plankton microfossils and eco-evolutionary modeling to determine strategies for survival and recovery, finding that widespread phagotrophy (prey ingestion) was fundamental to plankton surviving the impact and also for the subsequent reestablishment of primary production. Ecological selectivity points to extreme post-impact light inhibition as the principal kill mechanism, with the marine food chain temporarily reset to a bacteria-dominated state. Subsequently, in a sunlit ocean inhabited by only rare survivor grazers but abundant small prey, it was mixotrophic nutrition (autotrophy and heterotrophy) and increasing cell sizes that enabled the eventual reestablishment of marine food webs some 2 million years later.
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Affiliation(s)
- Samantha J Gibbs
- Ocean and Earth Science, National Oceanography Centre, Southampton, University of Southampton, Southampton SO14 3ZH, UK.
| | - Paul R Bown
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Ben A Ward
- Ocean and Earth Science, National Oceanography Centre, Southampton, University of Southampton, Southampton SO14 3ZH, UK
| | - Sarah A Alvarez
- University of Gibraltar, Europa Point Campus, Gibraltar GX11 1AA, Gibraltar
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Hojung Kim
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Odysseas A Archontikis
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Boris Sauterey
- Ecole Normale Supérieure, PSL Research University, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 8197, Institut National de la Santé et de la Recherche Médicale (INSERM) U1024, 46 rue d'Ulm, F-75005 Paris, France
| | - Alex J Poulton
- The Lyell Centre for Earth and Marine Science and Technology, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Jamie Wilson
- School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
| | - Andy Ridgwell
- Earth and Planetary Sciences, University of California at Riverside, Riverside, CA 92521, USA
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11
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Khlebodarova TM, Likhoshvai VA. Causes of global extinctions in the history of life: facts and hypotheses. Vavilovskii Zhurnal Genet Selektsii 2020; 24:407-419. [PMID: 33659824 PMCID: PMC7716527 DOI: 10.18699/vj20.633] [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] [Indexed: 11/19/2022] Open
Abstract
Paleontologists define global extinctions on Earth as a loss of about three-quarters of plant and animal species over a relatively short period of time. At least five global extinctions are documented in the Phanerozoic fossil record (~500-million-year period): ~65, 200, 260, 380, and 440 million years ago. In addition, there is evidence of global extinctions in earlier periods of life on Earth - during the Late Cambrian (~500 million years ago) and Ediacaran periods (more than 540 million years ago). There is still no common opinion on the causes of their occurrence. The current study is a systematized review of the data on recorded extinctions of complex life forms on Earth from the moment of their occurrence during the Ediacaran period to the modern period. The review discusses possible causes for mass extinctions in the light of the influence of abiogenic factors, planetary or astronomical, and the consequences of their actions. We evaluate the pros and cons of the hypothesis on the presence of periodicity in the extinction of Phanerozoic marine biota. Strong evidence that allows us to hypothesize that additional mechanisms associated with various internal biotic factors are responsible for the emergence of extinctions in the evolution of complex life forms is discussed. Developing the idea of the internal causes of periodicity and discontinuity in evolution, we propose our own original hypothesis, according to which the bistability phenomenon underlies the complex dynamics of the biota development, which is manifested in the form of global extinctions. The bistability phenomenon arises only in ecosystems with predominant sexual reproduction. Our hypothesis suggests that even in the absence of global abiotic catastrophes, extinctions of biota would occur anyway. However, our hypothesis does not exclude the possibility that in different periods of the Earth's history the biota was subjected to powerful external influences that had a significant impact on its further development, which is reflected in the Earth's fossil record.
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Affiliation(s)
- T M Khlebodarova
- Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - V A Likhoshvai
- Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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12
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Abstract
We present a quantitative test of end-Cretaceous extinction scenarios and how these would have affected dinosaur habitats. Combining climate and ecological modeling tools, we demonstrate a substantial detrimental effect on dinosaur habitats caused by an impact winter scenario triggered by the Chicxulub asteroid. We were not able to obtain such an extinction state with several modeling scenarios of Deccan volcanism. We further show that the concomitant prolonged eruption of the Deccan traps might have acted as an ameliorating agent, buffering the negative effects on climate and global ecosystems that the asteroid impact produced at the Cretaceous–Paleogene boundary. The Cretaceous/Paleogene mass extinction, 66 Ma, included the demise of non-avian dinosaurs. Intense debate has focused on the relative roles of Deccan volcanism and the Chicxulub asteroid impact as kill mechanisms for this event. Here, we combine fossil-occurrence data with paleoclimate and habitat suitability models to evaluate dinosaur habitability in the wake of various asteroid impact and Deccan volcanism scenarios. Asteroid impact models generate a prolonged cold winter that suppresses potential global dinosaur habitats. Conversely, long-term forcing from Deccan volcanism (carbon dioxide [CO2]-induced warming) leads to increased habitat suitability. Short-term (aerosol cooling) volcanism still allows equatorial habitability. These results support the asteroid impact as the main driver of the non-avian dinosaur extinction. By contrast, induced warming from volcanism mitigated the most extreme effects of asteroid impact, potentially reducing the extinction severity.
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Hull PM, Bornemann A, Penman DE, Henehan MJ, Norris RD, Wilson PA, Blum P, Alegret L, Batenburg SJ, Bown PR, Bralower TJ, Cournede C, Deutsch A, Donner B, Friedrich O, Jehle S, Kim H, Kroon D, Lippert PC, Loroch D, Moebius I, Moriya K, Peppe DJ, Ravizza GE, Röhl U, Schueth JD, Sepúlveda J, Sexton PF, Sibert EC, Śliwińska KK, Summons RE, Thomas E, Westerhold T, Whiteside JH, Yamaguchi T, Zachos JC. On impact and volcanism across the Cretaceous-Paleogene boundary. Science 2020; 367:266-272. [PMID: 31949074 DOI: 10.1126/science.aay5055] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 12/05/2019] [Indexed: 11/02/2022]
Abstract
The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction. We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic outgassing. We found support for major outgassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change. Our models show that these extinction-related carbon cycle changes would have allowed the ocean to absorb massive amounts of carbon dioxide, thus limiting the global warming otherwise expected from postextinction volcanism.
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Affiliation(s)
- Pincelli M Hull
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA.
| | - André Bornemann
- Bundesanstalt für Geowissenschaften und Rohstoffe, 30655 Hannover, Germany
| | - Donald E Penman
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
| | - Michael J Henehan
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA.,GFZ German Research Centre for Geosciences, 14473 Potsdam, Germany
| | - Richard D Norris
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Paul A Wilson
- National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, UK
| | - Peter Blum
- International Ocean Discovery Program, Texas A&M University, College Station, TX 77845, USA
| | - Laia Alegret
- Departamento de Ciencias de la Tierra and Instituto Universitario de Ciencias Ambientales, Universidad Zaragoza, 50009 Zaragoza, Spain
| | | | - Paul R Bown
- Department of Earth Sciences, University College London, London WC1E 6BT, UK
| | - Timothy J Bralower
- Department of Geosciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Cecile Cournede
- CEREGE, Université Aix-Marseille, 13545 Aix en Provence, France.,Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alexander Deutsch
- Institut für Planetologie, Universität Münster, 48149 Münster, Germany
| | - Barbara Donner
- MARUM - Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Oliver Friedrich
- Institute of Earth Sciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Sofie Jehle
- Institut für Geophysik und Geologie, Universität Leipzig, 04103 Leipzig, Germany
| | - Hojung Kim
- Department of Earth Sciences, University College London, London WC1E 6BT, UK
| | - Dick Kroon
- School of Geosciences, University of Edinburgh, Edinburgh EH8 9XP, UK
| | - Peter C Lippert
- Department of Geology & Geophysics, The University of Utah, Salt Lake City, UT 84112, USA
| | - Dominik Loroch
- Institut für Planetologie, Universität Münster, 48149 Münster, Germany
| | - Iris Moebius
- Institute of Earth Sciences, Heidelberg University, 69120 Heidelberg, Germany.,Department of Biogeochemical Systems, Max Planck Institute for Biogeochemistry, 07745 Jena, Germany
| | - Kazuyoshi Moriya
- Department of Earth Sciences, Waseda University, Shinjyuku-ku, Tokyo 169-8050, Japan
| | - Daniel J Peppe
- Department of Geosciences, Baylor University, Waco, TX 76798, USA
| | - Gregory E Ravizza
- Department of Earth Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Ursula Röhl
- MARUM - Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | | | - Julio Sepúlveda
- Department of Geological Sciences and Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Philip F Sexton
- School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes MK7 6AA, UK
| | - Elizabeth C Sibert
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA.,Harvard Society of Fellows, Harvard University, Cambridge, MA 02138, USA.,Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Kasia K Śliwińska
- Department of Stratigraphy, Geological Survey of Denmark and Greenland (GEUS), DK-1350 Copenhagen K, Denmark
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ellen Thomas
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA.,Department of Earth and Environmental Sciences, Wesleyan University, Middletown, CT 06459, USA
| | - Thomas Westerhold
- MARUM - Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Jessica H Whiteside
- National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, UK
| | | | - James C Zachos
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, USA
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14
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Liao YY, Liu Y, Liu X, Lü TF, Mbichi RW, Wan T, Liu F. The complete chloroplast genome of Myriophyllum spicatum reveals a 4-kb inversion and new insights regarding plastome evolution in Haloragaceae. Ecol Evol 2020; 10:3090-3102. [PMID: 32211179 PMCID: PMC7083656 DOI: 10.1002/ece3.6125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 09/11/2019] [Accepted: 02/05/2020] [Indexed: 12/13/2022] Open
Abstract
Myriophyllum, among the most species-rich genera of aquatic angiosperms with ca. 68 species, is an extensively distributed hydrophyte lineage in the cosmopolitan family Haloragaceae. The chloroplast (cp) genome is useful in the study of genetic evolution, phylogenetic analysis, and molecular dating of controversial taxa. Here, we sequenced and assembled the whole chloroplast genome of Myriophyllum spicatum L. and compared it to other species in the order Saxifragales. The complete chloroplast genome sequence of M. spicatum is 158,858 bp long and displays a quadripartite structure with two inverted repeats (IR) separating the large single copy (LSC) region from the small single copy (SSC) region. Based on sequence identification and the phylogenetic analysis, a 4-kb phylogenetically informative inversion between trnE-trnC in Myriophyllum was determined, and we have placed this inversion on a lineage specific to Myriophyllum and its close relatives. The divergence time estimation suggested that the trnE-trnC inversion possibly occurred between the upper Cretaceous (72.54 MYA) and middle Eocene (47.28 MYA) before the divergence of Myriophyllum from its most recent common ancestor. The unique 4-kb inversion might be caused by an occurrence of nonrandom recombination associated with climate changes around the K-Pg boundary, making it interesting for future evolutionary investigations.
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Affiliation(s)
- Yi-Ying Liao
- Key Laboratory of Southern Subtropical Plant Diversity Fairy Lake Botanical Garden Shenzhen China
| | - Yu Liu
- Key Laboratory of Southern Subtropical Plant Diversity Fairy Lake Botanical Garden Shenzhen China
| | - Xing Liu
- Laboratory of Plant Systematics and Evolutionary Biology College of Life Science Wuhan University Wuhan China
| | - Tian-Feng Lü
- Laboratory of Plant Systematics and Evolutionary Biology College of Life Science Wuhan University Wuhan China
| | - Ruth Wambui Mbichi
- Sino-Africa Joint Research Centre Chinese Academy of Science Wuhan China
| | - Tao Wan
- Key Laboratory of Southern Subtropical Plant Diversity Fairy Lake Botanical Garden Shenzhen China
| | - Fan Liu
- Key Laboratory of Aquatic Botany and Watershed Ecology Wuhan Botanical Garden Chinese Academy of Sciences Wuhan China
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15
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Chamber volume development, metabolic rates, and selective extinction in cephalopods. Sci Rep 2020; 10:2950. [PMID: 32076034 PMCID: PMC7031508 DOI: 10.1038/s41598-020-59748-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/03/2020] [Indexed: 11/08/2022] Open
Abstract
Reconstructing the physiology of extinct organisms is key to understanding mechanisms of selective extinction during biotic crises. Soft tissues of extinct organisms are rarely preserved and, therefore, a proxy for physiological aspects is needed. Here, we examine whether cephalopod conchs yield information about their physiology by assessing how the formation of chambers respond to external stimuli such as environmental changes. We measured chamber volume through ontogeny to detect differences in the pattern of chamber volume development in nautilids, coleoids, and ammonoids. Results reveal that the differences between ontogenetic trajectories of these cephalopods involve the presence or absence of abrupt decreases of chamber volume. Accepting the link between metabolic rate and growth, we assume that this difference is rooted in metabolic rates that differ between cephalopod clades. High metabolic rates combined with small hatching size in ammonoids as opposed to lower metabolic rates and much larger hatchlings in most nautilids may explain the selective extinction of ammonoids as a consequence of low food availability at the end of the Cretaceous.
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16
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The efficiency paradox: How wasteful competitors forge thrifty ecosystems. Proc Natl Acad Sci U S A 2019; 116:17619-17623. [PMID: 31420512 DOI: 10.1073/pnas.1901785116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Organic waste, an inevitable byproduct of metabolism, increases in amount as metabolic rates (per capita power) of animals and plants rise. Most of it is recycled within aerobic ecosystems, but some is lost to the system and is sequestered in the crust for millions of years. Here, I identify and resolve a previously overlooked paradox concerning the long-term loss of organic matter. In this efficiency paradox, high-powered species are inefficient in that they release copious waste, but the ecosystems they inhabit lose almost no organic matter. Systems occupied by more efficient low-powered species suffer greater losses because of less efficient recycling. Over Phanerozoic time, ecosystems have become more productive and increasingly efficient at retaining and redistributing organic matter even as opportunistic and highly competitive producers and consumers gained power and became less efficient. These patterns and trends are driven by natural selection at the level of individuals and coherent groups, which favors winners that are more powerful, active, and wasteful. The activities of these competitors collectively create conditions that are increasingly conducive to more efficient recycling and retention of organic matter in the ecosystem.
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17
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Why did the dinosaurs become extinct? Could cholecalciferol (vitamin D 3) deficiency be the answer? J Nutr Sci 2019; 8:e9. [PMID: 30911383 PMCID: PMC6425225 DOI: 10.1017/jns.2019.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 02/19/2019] [Accepted: 02/21/2019] [Indexed: 11/07/2022] Open
Abstract
Palaeontological deductions from the fossil remnants of extinct dinosaurs tell us much about their classification into species as well as about their physiological and behavioural characteristics. Geological evidence indicates that dinosaurs became extinct at the boundary between the Cretaceous and Paleogene eras, about 66 million years ago, at a time when there was worldwide environmental change resulting from the impact of a large celestial object with the Earth and/or from vast volcanic eruptions. However, apart from the presumption that climate change and interference with food supply contributed to their extinction, no biological mechanism has been suggested to explain why such a diverse range of terrestrial vertebrates ceased to exist. One of perhaps several contributing mechanisms comes by extrapolating from the physiology of the avian descendants of dinosaurs. This raises the possibility that cholecalciferol (vitamin D3) deficiency of developing embryos in dinosaur eggs could have caused their death before hatching, thus extinguishing the entire family of dinosaurs through failure to reproduce.
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18
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Field DJ, Bercovici A, Berv JS, Dunn R, Fastovsky DE, Lyson TR, Vajda V, Gauthier JA. Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction. Curr Biol 2018; 28:1825-1831.e2. [PMID: 29804807 DOI: 10.1016/j.cub.2018.04.062] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/19/2018] [Accepted: 04/18/2018] [Indexed: 10/16/2022]
Abstract
The fossil record and recent molecular phylogenies support an extraordinary early-Cenozoic radiation of crown birds (Neornithes) after the Cretaceous-Paleogene (K-Pg) mass extinction [1-3]. However, questions remain regarding the mechanisms underlying the survival of the deepest lineages within crown birds across the K-Pg boundary, particularly since this global catastrophe eliminated even the closest stem-group relatives of Neornithes [4]. Here, ancestral state reconstructions of neornithine ecology reveal a strong bias toward taxa exhibiting predominantly non-arboreal lifestyles across the K-Pg, with multiple convergent transitions toward predominantly arboreal ecologies later in the Paleocene and Eocene. By contrast, ecomorphological inferences indicate predominantly arboreal lifestyles among enantiornithines, the most diverse and widespread Mesozoic avialans [5-7]. Global paleobotanical and palynological data show that the K-Pg Chicxulub impact triggered widespread destruction of forests [8, 9]. We suggest that ecological filtering due to the temporary loss of significant plant cover across the K-Pg boundary selected against any flying dinosaurs (Avialae [10]) committed to arboreal ecologies, resulting in a predominantly non-arboreal post-extinction neornithine avifauna composed of total-clade Palaeognathae, Galloanserae, and terrestrial total-clade Neoaves that rapidly diversified into the broad range of avian ecologies familiar today. The explanation proposed here provides a unifying hypothesis for the K-Pg-associated mass extinction of arboreal stem birds, as well as for the post-K-Pg radiation of arboreal crown birds. It also provides a baseline hypothesis to be further refined pending the discovery of additional neornithine fossils from the Latest Cretaceous and earliest Paleogene.
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Affiliation(s)
- Daniel J Field
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK.
| | - Antoine Bercovici
- Department of Paleobiology MRC-121, National Museum of Natural History, Smithsonian Institution, 10(th) Street and Constitution Avenue NW, Washington, DC 20560-0121, USA
| | - Jacob S Berv
- Department of Ecology & Evolutionary Biology, Cornell University, 215 Tower Road, Ithaca, NY 14853, USA
| | - Regan Dunn
- Integrated Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, USA
| | - David E Fastovsky
- Department of Geosciences, University of Rhode Island, 9 East Alumni Avenue, Kingston, RI 02881, USA
| | - Tyler R Lyson
- Department of Earth Sciences, Denver Museum of Nature and Science, 2001 Colorado Boulevard, Denver, CO 80205, USA
| | - Vivi Vajda
- Department of Palaeobiology, Swedish Museum of Natural History, Svante Arrhenius Väg 9, 104 05 Stockholm, Sweden
| | - Jacques A Gauthier
- Department of Geology & Geophysics, Yale University 210 Whitney Avenue, New Haven, CT 06511, USA
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19
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Kaiho K, Oshima N. Site of asteroid impact changed the history of life on Earth: the low probability of mass extinction. Sci Rep 2017; 7:14855. [PMID: 29123110 PMCID: PMC5680197 DOI: 10.1038/s41598-017-14199-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 10/06/2017] [Indexed: 12/02/2022] Open
Abstract
Sixty-six million years ago, an asteroid approximately 9 km in diameter hit the hydrocarbon- and sulfur-rich sedimentary rocks in what is now Mexico. Recent studies have shown that this impact at the Yucatan Peninsula heated the hydrocarbon and sulfur in these rocks, forming stratospheric soot and sulfate aerosols and causing extreme global cooling and drought. These events triggered a mass extinction, including dinosaurs, and led to the subsequent macroevolution of mammals. The amount of hydrocarbon and sulfur in rocks varies widely, depending on location, which suggests that cooling and extinction levels were dependent on impact site. Here we show that the probability of significant global cooling, mass extinction, and the subsequent appearance of mammals was quite low after an asteroid impact on the Earth’s surface. This significant event could have occurred if the asteroid hit the hydrocarbon-rich areas occupying approximately 13% of the Earth’s surface. The site of asteroid impact, therefore, changed the history of life on Earth.
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Affiliation(s)
- Kunio Kaiho
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan.
| | - Naga Oshima
- Meteorological Research Institute, Tsukuba, 305-0052, Japan
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20
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Characterizing particulate polycyclic aromatic hydrocarbon emissions from diesel vehicles using a portable emissions measurement system. Sci Rep 2017; 7:10058. [PMID: 28855647 PMCID: PMC5577249 DOI: 10.1038/s41598-017-09822-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/31/2017] [Indexed: 11/30/2022] Open
Abstract
Particulate polycyclic aromatic hydrocarbons (p-PAHs) emitted from diesel vehicles are of concern because of their significant health impacts. Laboratory tests, road tunnel and roadside experiments have been conducted to measure p-PAH emissions. While providing valuable information, these methods have limited capabilities of characterizing p-PAH emissions either from individual vehicles or under real-world conditions. We employed a portable emissions measurement (PEMS) to measure real-world emission factors of priority p-PAHs for diesel vehicles representative of an array of emission control technologies. The results indicated over 80% reduction in p-PAH emission factors comparing the China V and China II emission standard groups (113 μg kg−1 vs. 733 μg kg−1). The toxicity abatement in terms of Benzo[a]pyrene equivalent emissions was substantial because of the large reductions in highly toxic components. By assessing real traffic conditions, the p-PAH emission factors on freeways were lower than on local roads by 52% ± 24%. A significant correlation (R2~0.85) between the p-PAH and black carbon emissions was identified with a mass ratio of approximately 1/2000. A literature review indicated that diesel p-PAH emission factors varied widely by engine technology, measurement methods and conditions, and the molecular diagnostic ratio method for source apportionment should be used with great caution.
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21
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On transient climate change at the Cretaceous-Paleogene boundary due to atmospheric soot injections. Proc Natl Acad Sci U S A 2017; 114:E7415-E7424. [PMID: 28827324 DOI: 10.1073/pnas.1708980114] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Climate simulations that consider injection into the atmosphere of 15,000 Tg of soot, the amount estimated to be present at the Cretaceous-Paleogene boundary, produce what might have been one of the largest episodes of transient climate change in Earth history. The observed soot is believed to originate from global wildfires ignited after the impact of a 10-km-diameter asteroid on the Yucatán Peninsula 66 million y ago. Following injection into the atmosphere, the soot is heated by sunlight and lofted to great heights, resulting in a worldwide soot aerosol layer that lasts several years. As a result, little or no sunlight reaches the surface for over a year, such that photosynthesis is impossible and continents and oceans cool by as much as 28 °C and 11 °C, respectively. The absorption of light by the soot heats the upper atmosphere by hundreds of degrees. These high temperatures, together with a massive injection of water, which is a source of odd-hydrogen radicals, destroy the stratospheric ozone layer, such that Earth's surface receives high doses of UV radiation for about a year once the soot clears, five years after the impact. Temperatures remain above freezing in the oceans, coastal areas, and parts of the Tropics, but photosynthesis is severely inhibited for the first 1 y to 2 y, and freezing temperatures persist at middle latitudes for 3 y to 4 y. Refugia from these effects would have been very limited. The transient climate perturbation ends abruptly as the stratosphere cools and becomes supersaturated, causing rapid dehydration that removes all remaining soot via wet deposition.
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22
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Kaiho K, Saito R, Ito K, Miyaji T, Biswas R, Tian L, Sano H, Shi Z, Takahashi S, Tong J, Liang L, Oba M, Nara FW, Tsuchiya N, Chen ZQ. Effects of soil erosion and anoxic-euxinic ocean in the Permian-Triassic marine crisis. Heliyon 2016; 2:e00137. [PMID: 27547833 PMCID: PMC4983274 DOI: 10.1016/j.heliyon.2016.e00137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 05/11/2016] [Accepted: 07/27/2016] [Indexed: 11/05/2022] Open
Abstract
The largest mass extinction of biota in the Earth’s history occurred during the Permian–Triassic transition and included two extinctions, one each at the latest Permian (first phase) and earliest Triassic (second phase). High seawater temperature in the surface water accompanied by euxinic deep-intermediate water, intrusion of the euxinic water to the surface water, a decrease in pH, and hypercapnia have been proposed as direct causes of the marine crisis. For the first-phase extinction, we here add a causal mechanism beginning from massive soil and rock erosion and leading to algal blooms, release of toxic components, asphyxiation, and oxygen-depleted nearshore bottom water that created environmental stress for nearshore marine animals. For the second-phase extinction, we show that a soil and rock erosion/algal bloom event did not occur, but culmination of anoxia–euxinia in intermediate waters did occur, spanning the second-phase extinction. We investigated sedimentary organic molecules, and the results indicated a peak of a massive soil erosion proxy followed by peaks of marine productivity proxy. Anoxic proxies of surface sediments and water occurred in the shallow nearshore sea at the eastern and western margins of the Paleotethys at the first-phase extinction horizon, but not at the second-phase extinction horizon. Our reconstruction of ocean redox structure at low latitudes indicates that a gradual increase in temperature spanning the two extinctions could have induced a gradual change from a well-mixed oxic to a stratified euxinic ocean beginning immediately prior to the first-phase extinction, followed by culmination of anoxia in nearshore surface waters and of anoxia and euxinia in the shallow-intermediate waters at the second-phase extinction over a period of approximately one million years or more. Enhanced global warming, ocean acidification, and hypercapnia could have caused the second-phase extinction approximately 60 kyr after the first-phase extinction. The causes of the first-phase extinction were not only those environmental stresses but also environmental stresses caused by the soil and rock erosion/algal bloom event.
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Affiliation(s)
- Kunio Kaiho
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Ryosuke Saito
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Kosuke Ito
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Takashi Miyaji
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Raman Biswas
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Li Tian
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Hiroyoshi Sano
- Department of Earth and Planetary Sciences, Kyushu University, Fukuoka, Japan
| | - Zhiqiang Shi
- Chengdu University of Technology, Chengdu, China
| | - Satoshi Takahashi
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Jinnan Tong
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Lei Liang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Masahiro Oba
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Japan
| | - Fumiko W Nara
- Graduate School of Environmental Studies, Tohoku University, Sendai, Japan
| | - Noriyoshi Tsuchiya
- Graduate School of Environmental Studies, Tohoku University, Sendai, Japan
| | - Zhong-Qiang Chen
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
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