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Maloney KM, Halverson GP, Lechte M, Gibson TM, Bui TH, Schiffbauer JD, Laflamme M. The paleoredox context of early eukaryotic evolution: insights from the Tonian Mackenzie Mountains Supergroup, Canada. GEOBIOLOGY 2024; 22:e12598. [PMID: 38700417 DOI: 10.1111/gbi.12598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 05/05/2024]
Abstract
Tonian (ca. 1000-720 Ma) marine environments are hypothesised to have experienced major redox changes coinciding with the evolution and diversification of multicellular eukaryotes. In particular, the earliest Tonian stratigraphic record features the colonisation of benthic habitats by multicellular macroscopic algae, which would have been powerful ecosystem engineers that contributed to the oxygenation of the oceans and the reorganisation of biogeochemical cycles. However, the paleoredox context of this expansion of macroalgal habitats in Tonian nearshore marine environments remains uncertain due to limited well-preserved fossils and stratigraphy. As such, the interdependent relationship between early complex life and ocean redox state is unclear. An assemblage of macrofossils including the chlorophyte macroalga Archaeochaeta guncho was recently discovered in the lower Mackenzie Mountains Supergroup in Yukon (Canada), which archives marine sedimentation from ca. 950-775 Ma, permitting investigation into environmental evolution coincident with eukaryotic ecosystem evolution and expansion. Here we present multi-proxy geochemical data from the lower Mackenzie Mountains Supergroup to constrain the paleoredox environment within which these large benthic macroalgae thrived. Two transects show evidence for basin-wide anoxic (ferruginous) oceanic conditions (i.e., high FeHR/FeT, low Fepy/FeHR), with muted redox-sensitive trace metal enrichments and possible seasonal variability. However, the weathering of sulfide minerals in the studied samples may obscure geochemical signatures of euxinic conditions. These results suggest that macroalgae colonized shallow environments in an ocean that remained dominantly anoxic with limited evidence for oxygenation until ca. 850 Ma. Collectively, these geochemical results provide novel insights into the environmental conditions surrounding the evolution and expansion of benthic macroalgae and the eventual dominance of oxygenated oceanic conditions required for the later emergence of animals.
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Affiliation(s)
- Katie M Maloney
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, Québec, Canada
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Galen P Halverson
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, Québec, Canada
| | - Maxwell Lechte
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, Québec, Canada
| | - Timothy M Gibson
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
| | - Thi Hao Bui
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, Québec, Canada
| | - James D Schiffbauer
- Department of Geological Sciences, University of Missouri, Columbia, Missouri, USA
- X-ray Microanalysis Core, University of Missouri, Columbia, Missouri, USA
| | - Marc Laflamme
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
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2
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Choi SW, Graf L, Choi JW, Jo J, Boo GH, Kawai H, Choi CG, Xiao S, Knoll AH, Andersen RA, Yoon HS. Ordovician origin and subsequent diversification of the brown algae. Curr Biol 2024; 34:740-754.e4. [PMID: 38262417 DOI: 10.1016/j.cub.2023.12.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/08/2023] [Accepted: 12/20/2023] [Indexed: 01/25/2024]
Abstract
Brown algae are the only group of heterokont protists exhibiting complex multicellularity. Since their origin, brown algae have adapted to various marine habitats, evolving diverse thallus morphologies and gamete types. However, the evolutionary processes behind these transitions remain unclear due to a lack of a robust phylogenetic framework and problems with time estimation. To address these issues, we employed plastid genome data from 138 species, including heterokont algae, red algae, and other red-derived algae. Based on a robust phylogeny and new interpretations of algal fossils, we estimated the geological times for brown algal origin and diversification. The results reveal that brown algae first evolved true multicellularity, with plasmodesmata and reproductive cell differentiation, during the late Ordovician Period (ca. 450 Ma), coinciding with a major diversification of marine fauna (the Great Ordovician Biodiversification Event) and a proliferation of multicellular green algae. Despite its early Paleozoic origin, the diversification of major orders within this brown algal clade accelerated only during the Mesozoic Era, coincident with both Pangea rifting and the diversification of other heterokont algae (e.g., diatoms), coccolithophores, and dinoflagellates, with their red algal-derived plastids. The transition from ancestral isogamy to oogamy was followed by three simultaneous reappearances of isogamy during the Cretaceous Period. These are concordant with a positive character correlation between parthenogenesis and isogamy. Our new brown algal timeline, combined with a knowledge of past environmental conditions, shed new light on brown algal diversification and the intertwined evolution of multicellularity and sexual reproduction.
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Affiliation(s)
- Seok-Wan Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Louis Graf
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea; Institut de Biologie de l'École Normale Supérieure, Université Paris Sciences et Lettres, Paris 75005, France
| | - Ji Won Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jihoon Jo
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea; Honam National Institute of Biological Resources, Mokpo 58762, Republic of Korea
| | - Ga Hun Boo
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hiroshi Kawai
- Kobe University Research Center for Inland Seas, Rokkodai, Nadaku, Kobe 657-8501, Japan
| | - Chang Geun Choi
- Department of Ecological Engineering, College of Environmental and Marine Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Shuhai Xiao
- Department of Geosciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Andrew H Knoll
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Robert A Andersen
- Friday Harbor Laboratories, University of Washington, Seattle, WA 98250, USA
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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3
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De Clerck O, LoDuca ST. Algal evolution: A touch of brown in a Paleozoic sea of greens and reds. Curr Biol 2024; 34:R150-R152. [PMID: 38412826 DOI: 10.1016/j.cub.2024.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Previous molecular clock studies indicated a Mesozoic origin for the brown algae (Phaeophyceae). New research based on phylogenetic evidence challenges this notion and provides novel insights into the origin and diversification of brown algae, which includes multiple transitions within the group from isogamy to oogamy (and back again!).
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Affiliation(s)
- Olivier De Clerck
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent 9000, Belgium.
| | - Steven T LoDuca
- Department of Geography and Geology, Eastern Michigan University, Ypsilanti, MI 48197, USA.
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Niklas KJ, Tiffney BH. Viridiplantae Body Plans Viewed Through the Lens of the Fossil Record and Molecular Biology. Integr Comp Biol 2023; 63:1316-1330. [PMID: 36316013 PMCID: PMC10755189 DOI: 10.1093/icb/icac150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/19/2022] [Accepted: 10/27/2022] [Indexed: 12/30/2023] Open
Abstract
A review of the fossil record coupled with insights gained from molecular and developmental biology reveal a series of body plan transformations that gave rise to the first land plants. Across diverse algal clades, including the green algae and their descendants, the plant body plan underwent a unicellular $\to $ colonial $\to $ simple multicellular → complex multicellular transformation series. The colonization of land involved increasing body size and associated cell specialization, including cells capable of hydraulic transport. The evolution of the life-cycle that characterizes all known land plant species involved a divergence in body plan phenotypes between the haploid and diploid generations, one adapted to facilitate sexual reproduction (a free-water dependent gametophyte) and another adapted to the dissemination of spores (a more water-independent sporophyte). The amplification of this phenotypic divergence, combined with indeterminate growth in body size, resulted in a desiccation-adapted branched sporophyte with a cuticularized epidermis, stomates, and vascular tissues. Throughout the evolution of the land plants, the body plans of the sporophyte generation involved "axiation," i.e., the acquisition of a cylindrical geometry and subsequent organographic specializations.
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Affiliation(s)
- Karl J Niklas
- The School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Bruce H Tiffney
- Department of Earth Science and College of Creative Studies, University of California, Santa Barbara, CA 93106, USA
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5
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Kimmig J, LaVine RJ, Schiffbauer JD, Egenhoff SO, Shelton KL, Leibach WW. Annelids from the Cambrian (Wuliuan Stage, Miaolingian) Spence Shale Lagerstätte of northern Utah, USA. HISTORICAL BIOLOGY 2023; 36:934-943. [PMID: 38800616 PMCID: PMC11114447 DOI: 10.1080/08912963.2023.2196685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/22/2023] [Indexed: 05/29/2024]
Abstract
The Spence Shale Member of the Langston Formation in northern Utah and southern Idaho preserves generally non-biomineralized fossil assemblages referred to as the Spence Shale Lagerstätte. The biota of this Lagerstätte is dominated by panarthropods, both biomineralized and soft-bodied examples, but also preserves diverse infaunal organisms, including species of scalidophorans, echinoderms, lobopodians, stalked filter feeders, and various problematic taxa. To date, however, only a single annelid fossil, originally assigned to Canadia sp., has been described from the Spence Shale. This lone specimen and another recently collected specimen were analyzed in this study using scanning electron microscopy and energy dispersive X-ray spectrometry. The previous occurrence is reassigned to Burgessochaeta cf. B. setigera Walcott, 1911. The new fossil, however, is identified as a novel polychaete taxon, Shaihuludia shurikeni gen. et sp. nov., characterized by the presence of fused, bladed chaetae and a wide body. The occurrence of Burgessochaeta is the first outside the Burgess Shale and its vicinity, whereas Shaihuludia shurikeni gen. et sp. nov. adds to the diversity of annelids in the middle Cambrian and highlights the diversity of the Spence Shale Lagerstätte.
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Affiliation(s)
- Julien Kimmig
- Abteilung Geowissenschaften, Staatliches Museum für Naturkunde Karlsruhe, Karlsruhe, 76133, Germany
- The Harold Hamm School of Geology & Geological Engineering, University of North Dakota, Grand Forks, ND 58202, USA
| | - Rhiannon J. LaVine
- Biodiversity Institute, University of Kansas, Lawrence, Kansas 66045, USA
| | - James D. Schiffbauer
- Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA
- X-ray Microanalysis Laboratory, University of Missouri, Columbia, MO 65211, USA
| | - Sven O. Egenhoff
- The Harold Hamm School of Geology & Geological Engineering, University of North Dakota, Grand Forks, ND 58202, USA
| | - Kevin L. Shelton
- Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Wade W. Leibach
- Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA
- Jacobs Solutions, St. Louis, MO 63102, USA
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6
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Maloney KM, Schiffbauer JD, Halverson GP, Xiao S, Laflamme M. Preservation of early Tonian macroalgal fossils from the Dolores Creek Formation, Yukon. Sci Rep 2022; 12:6222. [PMID: 35418588 PMCID: PMC9007953 DOI: 10.1038/s41598-022-10223-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 04/04/2022] [Indexed: 11/30/2022] Open
Abstract
The rise of eukaryotic macroalgae in the late Mesoproterozoic to early Neoproterozoic was a critical development in Earth’s history that triggered dramatic changes in biogeochemical cycles and benthic habitats, ultimately resulting in ecosystems habitable to animals. However, evidence of the diversification and expansion of macroalgae is limited by a biased fossil record. Non-mineralizing organisms are rarely preserved, occurring only in exceptional environments that favor fossilization. Investigating the taphonomy of well-preserved macroalgae will aid in identifying these target environments, allowing ecological trends to be disentangled from taphonomic overprints. Here we describe the taphonomy of macroalgal fossils from the Tonian Dolores Creek Formation (ca. 950 Ma) of northwestern Canada (Yukon Territory) that preserves cm-scale macroalgae. Analytical microscopy, including scanning electron microscopy and tomographic x-ray microscopy, was used to investigate fossil preservation, which was the result of a combination of pyritization and aluminosilicification, similar to accessory mineralization observed in Paleozoic Burgess Shale-type fossils. These new Neoproterozoic fossils help to bridge a gap in the fossil record of early algae, offer a link between the fossil and molecular record, and provide new insights into evolution during the Tonian Period, when many eukaryotic lineages are predicted to have diversified.
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Affiliation(s)
- Katie M Maloney
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.
| | - James D Schiffbauer
- Department of Geological Sciences, University of Missouri, Columbia, MO, 65211, USA.,X-Ray Microanalysis Core, University of Missouri, Columbia, MO, 65211, USA
| | - Galen P Halverson
- Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montréal, QC, H3A 0E8, Canada
| | - Shuhai Xiao
- Department of Geosciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Marc Laflamme
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
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7
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Hou Z, Ma X, Shi X, Li X, Yang L, Xiao S, De Clerck O, Leliaert F, Zhong B. Phylotranscriptomic insights into a Mesoproterozoic-Neoproterozoic origin and early radiation of green seaweeds (Ulvophyceae). Nat Commun 2022; 13:1610. [PMID: 35318329 PMCID: PMC8941102 DOI: 10.1038/s41467-022-29282-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 03/09/2022] [Indexed: 01/09/2023] Open
Abstract
The Ulvophyceae, a major group of green algae, is of particular evolutionary interest because of its remarkable morphological and ecological diversity. Its phylogenetic relationships and diversification timeline, however, are still not fully resolved. In this study, using an extensive nuclear gene dataset, we apply coalescent- and concatenation-based approaches to reconstruct the phylogeny of the Ulvophyceae and to explore the sources of conflict in previous phylogenomic studies. The Ulvophyceae is recovered as a paraphyletic group, with the Bryopsidales being a sister group to the Chlorophyceae, and the remaining taxa forming a clade (Ulvophyceae sensu stricto). Molecular clock analyses with different calibration strategies emphasize the large impact of fossil calibrations, and indicate a Meso-Neoproterozoic origin of the Ulvophyceae (sensu stricto), earlier than previous estimates. The results imply that ulvophyceans may have had a profound influence on oceanic redox structures and global biogeochemical cycles at the Mesoproterozoic-Neoproterozoic transition. “Ulvophyceae is a remarkably morphologically and ecologically diverse clade of green algae. Here, the authors reconstruct the Ulvophyceae phylogeny, showing that these algae originated earlier than expected and may have influenced biogeochemical cycles at the Mesoproterozoic-Neoproterozoic transition.”
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Affiliation(s)
- Zheng Hou
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaoya Ma
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xuan Shi
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xi Li
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Lingxiao Yang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shuhai Xiao
- Department of Geosciences and Global Change Center, Virginia Tech, Blacksburg, VA, USA
| | - Olivier De Clerck
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium
| | - Frederik Leliaert
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium.,Meise Botanic Garden, Meise, Belgium
| | - Bojian Zhong
- College of Life Sciences, Nanjing Normal University, Nanjing, China.
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8
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9
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Del Cortona A, Jackson CJ, Bucchini F, Van Bel M, D'hondt S, Škaloud P, Delwiche CF, Knoll AH, Raven JA, Verbruggen H, Vandepoele K, De Clerck O, Leliaert F. Neoproterozoic origin and multiple transitions to macroscopic growth in green seaweeds. Proc Natl Acad Sci U S A 2020; 117:2551-2559. [PMID: 31911467 PMCID: PMC7007542 DOI: 10.1073/pnas.1910060117] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Neoproterozoic Era records the transition from a largely bacterial to a predominantly eukaryotic phototrophic world, creating the foundation for the complex benthic ecosystems that have sustained Metazoa from the Ediacaran Period onward. This study focuses on the evolutionary origins of green seaweeds, which play an important ecological role in the benthos of modern sunlit oceans and likely played a crucial part in the evolution of early animals by structuring benthic habitats and providing novel niches. By applying a phylogenomic approach, we resolve deep relationships of the core Chlorophyta (Ulvophyceae or green seaweeds, and freshwater or terrestrial Chlorophyceae and Trebouxiophyceae) and unveil a rapid radiation of Chlorophyceae and the principal lineages of the Ulvophyceae late in the Neoproterozoic Era. Our time-calibrated tree points to an origin and early diversification of green seaweeds in the late Tonian and Cryogenian periods, an interval marked by two global glaciations with strong consequent changes in the amount of available marine benthic habitat. We hypothesize that unicellular and simple multicellular ancestors of green seaweeds survived these extreme climate events in isolated refugia, and diversified in benthic environments that became increasingly available as ice retreated. An increased supply of nutrients and biotic interactions, such as grazing pressure, likely triggered the independent evolution of macroscopic growth via different strategies, including true multicellularity, and multiple types of giant-celled forms.
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Affiliation(s)
- Andrea Del Cortona
- Department of Biology, Phycology Research Group, Ghent University, 9000 Ghent, Belgium;
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Zwijnaarde, Belgium
- Vlaams Instituut voor Biotechnologie Center for Plant Systems Biology, 9052 Zwijnaarde, Belgium
- Bioinformatics Institute Ghent, Ghent University, 9052 Zwijnaarde, Belgium
| | | | - François Bucchini
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Zwijnaarde, Belgium
- Vlaams Instituut voor Biotechnologie Center for Plant Systems Biology, 9052 Zwijnaarde, Belgium
| | - Michiel Van Bel
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Zwijnaarde, Belgium
- Vlaams Instituut voor Biotechnologie Center for Plant Systems Biology, 9052 Zwijnaarde, Belgium
| | - Sofie D'hondt
- Department of Biology, Phycology Research Group, Ghent University, 9000 Ghent, Belgium
| | - Pavel Škaloud
- Department of Botany, Faculty of Science, Charles University, CZ-12800 Prague 2, Czech Republic
| | - Charles F Delwiche
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Andrew H Knoll
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138
| | - John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Dundee DD2 5DA, United Kingdom
- School of Biological Sciences, University of Western Australia, WA 6009, Australia
- Climate Change Cluster, University of Technology, Ultimo, NSW 2006, Australia
| | - Heroen Verbruggen
- School of Biosciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Klaas Vandepoele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Zwijnaarde, Belgium;
- Vlaams Instituut voor Biotechnologie Center for Plant Systems Biology, 9052 Zwijnaarde, Belgium
- Bioinformatics Institute Ghent, Ghent University, 9052 Zwijnaarde, Belgium
| | - Olivier De Clerck
- Department of Biology, Phycology Research Group, Ghent University, 9000 Ghent, Belgium;
| | - Frederik Leliaert
- Department of Biology, Phycology Research Group, Ghent University, 9000 Ghent, Belgium;
- Meise Botanic Garden, 1860 Meise, Belgium
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Raven J. Blue carbon: past, present and future, with emphasis on macroalgae. Biol Lett 2018; 14:rsbl.2018.0336. [PMID: 30282745 DOI: 10.1098/rsbl.2018.0336] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 09/04/2018] [Indexed: 11/12/2022] Open
Abstract
Blue carbon did not originally include macroalgal ecosystems; however evidence is mounting that macroalgal ecosystems function in marine carbon sequestration. The great majority of present day marine macroalgal net primary productivity (NPP) involves haptophytic algae on eroding shores. For these organisms the long-term storage of particulate organic carbon involves export from the site of production of biomass that has evaded parasites and grazers, and that some of the exported biomass is sedimented and stored rather than being mineralized en route by detritivores (microbes and fauna). Export from eroding shores, and subsequent storage, of haptophytic marine macroalgal particulate organic carbon could have started by 1.6 Ga. Storage on depositing shores close to the site of NPP by rhizophytic macroalgae and then by rhizophytic coastal seagrasses, tidal marshes and mangroves began not less than 209 Ma ago. Future increases in surface ocean temperatures may bring tropical marine macroalgae to their upper temperature limit, while temperate marine macroalgae will migrate poleward, in both cases assuming that temperature increases faster than genetic adaptation to higher temperature. Increased CO2 in the surface ocean will generally favour uncalcified over calcified marine macroalgae. This results in decreased CO2 release from decreased calcification, as well as decreased ballasting by CaCO3 of exported particulate organic carbon resulting in decreasing sedimentation. While much more work is needed, the available information suggests that macroalgae play a significant role in marine organic carbon storage.
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Affiliation(s)
- John Raven
- Division of Plant Science, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DQ, UK .,Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
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11
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After the boring billion and before the freezing millions: evolutionary patterns and innovations in the Tonian Period. Emerg Top Life Sci 2018; 2:161-171. [DOI: 10.1042/etls20170165] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/07/2018] [Accepted: 05/15/2018] [Indexed: 11/17/2022]
Abstract
The Tonian Period (ca. 1000–720 Ma) follows the ‘boring billion' in the Mesoproterozoic Era and precedes ‘snowball Earth' glaciations in the Cryogenian Period. It represents a critical transition in Earth history. Geochemical data indicate that the Tonian Period may have witnessed a significant increase in atmospheric pO2 levels and a major transition from predominantly sulfidic to ferruginous mid-depth seawaters. Molecular clock estimates suggest that early animals may have diverged in the Tonian Period, raising the intriguing possibility of coupled environmental changes and evolutionary innovations. The co-evolution of life and its environment during the Tonian Period can be tested against the fossil record by examining diversity trends in the Proterozoic and evolutionary innovations in the Tonian. Compilations of Proterozoic microfossils and macrofossils apparently support a Tonian increase in global taxonomic diversity and morphological range relative to the Mesoproterozoic Era, although this is not reflected in assemblage-level diversity patterns. The fossil record suggests that major eukaryote groups (including Opisthokonta, Amoebozoa, Plantae, and SAR) may have diverged and important evolutionary innovations (e.g. multicellularity and cell differentiation in several groups, eukaryovory, eukaryote biomineralization, and heterocystous cyanobacteria) may have arisen by the Tonian Period, but thus far no convincing animal fossils have been found in the Tonian. Tonian paleontology is still in its nascent stage, and it offers many opportunities to explore Earth-life evolution in this critical geological period.
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12
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Parry LA, Boggiani PC, Condon DJ, Garwood RJ, Leme JDM, McIlroy D, Brasier MD, Trindade R, Campanha GAC, Pacheco MLAF, Diniz CQC, Liu AG. Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil. Nat Ecol Evol 2017; 1:1455-1464. [DOI: 10.1038/s41559-017-0301-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 07/28/2017] [Indexed: 11/09/2022]
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