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Gutarra S, Mitchell EG, Dunn FS, Gibson BM, Racicot RA, Darroch SAF, Rahman IA. Ediacaran marine animal forests and the ventilation of the oceans. Curr Biol 2024; 34:2528-2534.e3. [PMID: 38761801 DOI: 10.1016/j.cub.2024.04.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/18/2024] [Accepted: 04/25/2024] [Indexed: 05/20/2024]
Abstract
The rise of animals across the Ediacaran-Cambrian transition marked a step-change in the history of life, from a microbially dominated world to the complex macroscopic biosphere we see today.1,2,3 While the importance of bioturbation and swimming in altering the structure and function of Earth systems is well established,4,5,6 the influence of epifaunal animals on the hydrodynamics of marine environments is not well understood. Of particular interest are the oldest "marine animal forests,"7 which comprise a diversity of sessile soft-bodied organisms dominated by the fractally branching rangeomorphs.8,9 Typified by fossil assemblages from the Ediacaran of Mistaken Point, Newfoundland,8,10,11 these ancient communities might have played a pivotal role in structuring marine environments, similar to modern ecosystems,7,12,13 but our understanding of how they impacted fluid flow in the water column is limited. Here, we use ecological modeling and computational flow simulations to explore how Ediacaran marine animal forests influenced their surrounding environment. Our results reveal how organism morphology and community structure and composition combined to impact vertical mixing of the surrounding water. We find that Mistaken Point communities were capable of generating high-mixing conditions, thereby likely promoting gas and nutrient transport within the "canopy." This mixing could have served to enhance local-scale oxygen concentrations and redistribute resources like dissolved organic carbon. Our work suggests that Ediacaran marine animal forests may have contributed to the ventilation of the oceans over 560 million years ago, well before the Cambrian explosion of animals.
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Affiliation(s)
| | - Emily G Mitchell
- Department of Zoology, University Museum of Zoology Cambridge, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Frances S Dunn
- Oxford University Museum of Natural History, University of Oxford, Oxford OX1 3PW, UK
| | - Brandt M Gibson
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | | | | | - Imran A Rahman
- The Natural History Museum, London SW7 5BD, UK; Oxford University Museum of Natural History, University of Oxford, Oxford OX1 3PW, UK.
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2
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Gong Z, Wei GY, Fakhraee M, Alcott LJ, Jiang L, Zhao M, Planavsky NJ. Revisiting marine redox conditions during the Ediacaran Shuram carbon isotope excursion. GEOBIOLOGY 2023; 21:407-420. [PMID: 36755479 DOI: 10.1111/gbi.12547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/18/2022] [Accepted: 01/27/2023] [Indexed: 06/13/2023]
Abstract
The Neoproterozoic carbonate record contains multiple carbon isotope anomalies, which are the subject of intense debate. The largest of these anomalies, the Shuram excursion (SE), occurred in the mid-Ediacaran (~574-567 Ma). Accurately reconstructing marine redox landscape is a clear path toward making sense of the mechanism that drives this δ13 C anomaly. Here, we report new uranium isotopic data from the shallow-marine carbonates of the Wonoka Formation, Flinders Ranges, South Australia, where the SE is well preserved. Our data indicate that the δ238 U trend during the SE is highly reproducible across globally disparate sections from different depositional settings. Previously, it was proposed that the positive shift of δ238 U values during the SE suggests an extensive, near-modern level of marine oxygenation. However, recent publications suggest that the fractionation of uranium isotopes in ferruginous and anoxic conditions is comparable, opening up the possibility of non-unique interpretations of the carbonate uranium isotopic record. Here, we build on this idea by investigating the SE in conjunction with additional geochemical proxies. Using a revised uranium isotope mass balance model and an inverse stochastic carbon cycle model, we reevaluate models for δ13 C and δ238 U trends during the SE. We suggest that global seawater δ238 U values during the SE could be explained by an expansion of ferruginous conditions and do not require a near-modern level of oxygenation during the mid-Ediacaran.
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Affiliation(s)
- Zheng Gong
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
| | - Guang-Yi Wei
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
- School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
| | - Mojtaba Fakhraee
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
| | - Lewis J Alcott
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
| | - Lei Jiang
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
- Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Mingyu Zhao
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Noah J Planavsky
- Department of Earth and Planetary Sciences, Yale University, New Haven, Connecticut, USA
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3
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Zhuravlev AY, Wood RA, Bowyer FT. Cambrian radiation speciation events driven by sea level and redoxcline changes on the Siberian Craton. SCIENCE ADVANCES 2023; 9:eadh2558. [PMID: 37327332 DOI: 10.1126/sciadv.adh2558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 05/10/2023] [Indexed: 06/18/2023]
Abstract
The evolutionary processes of speciation during the Cambrian radiation and their potential extrinsic drivers, such as episodic oceanic oxygenation events, remain unconfirmed. High-resolution temporal and spatial distribution of reef-associated archaeocyath sponge species on the Siberian Craton during the early Cambrian [ca. 528 to 510 million years ago] shows that speciation was driven by increased endemism particularly ca. 521 million years (59.7% endemic species) and 514.5 million years (65.25% endemic species) ago. These mark rapid speciation events after dispersal of ancestors from the Aldan-Lena center of origin to other regions. These speciation events coincided with major sea-level lowstands, which we hypothesize were intervals when relative deepening of the shallow redoxcline permitted extensive oxygenation of shallow waters over the entire craton. This provided oxic corridors for dispersal and allowed the formation of new founder communities. Thus, shallow marine oxygen expansion driven by sea-level oscillations provides an evolutionary driver for sucessive speciation events during the Cambrian radiation.
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Affiliation(s)
- Andrey Yu Zhuravlev
- Department of Biological Evolution, Faculty of Biology, Lomonosov Moscow State University Leninskie Gory 1(12), Moscow 119234, Russia
| | - Rachel A Wood
- School of GeoSciences, University of Edinburgh, James Hutton Road, Edinburgh EH9 3FE, UK
| | - Fred T Bowyer
- School of GeoSciences, University of Edinburgh, James Hutton Road, Edinburgh EH9 3FE, UK
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4
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A diverse Ediacara assemblage survived under low-oxygen conditions. Nat Commun 2022; 13:7306. [PMID: 36435820 PMCID: PMC9701187 DOI: 10.1038/s41467-022-35012-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 11/15/2022] [Indexed: 11/28/2022] Open
Abstract
The Ediacaran biota were soft-bodied organisms, many with enigmatic phylogenetic placement and ecology, living in marine environments between 574 and 539 million years ago. Some studies hypothesize a metazoan affinity and aerobic metabolism for these taxa, whereas others propose a fundamentally separate taxonomic grouping and a reliance on chemoautotrophy. To distinguish between these hypotheses and test the redox-sensitivity of Ediacaran organisms, here we present a high-resolution local and global redox dataset from carbonates that contain in situ Ediacaran fossils from Siberia. Cerium anomalies are consistently >1, indicating that local environments, where a diverse Ediacaran assemblage is preserved in situ as nodules and carbonaceous compressions, were pervasively anoxic. Additionally, δ238U values match other terminal Ediacaran sections, indicating widespread marine euxinia. These data suggest that some Ediacaran biotas were tolerant of at least intermittent anoxia, and thus had the capacity for a facultatively anaerobic lifestyle. Alternatively, these soft-bodied Ediacara organisms may have colonized the seafloor during brief oxygenation events not recorded by redox proxy data. Broad temporal correlations between carbon, sulfur, and uranium isotopes further highlight the dynamic redox landscape of Ediacaran-Cambrian evolutionary events.
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Caxito F, Lana C, Frei R, Uhlein GJ, Sial AN, Dantas EL, Pinto AG, Campos FC, Galvão P, Warren LV, Okubo J, Ganade CE. Goldilocks at the dawn of complex life: mountains might have damaged Ediacaran-Cambrian ecosystems and prompted an early Cambrian greenhouse world. Sci Rep 2021; 11:20010. [PMID: 34625630 PMCID: PMC8501109 DOI: 10.1038/s41598-021-99526-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/24/2021] [Indexed: 02/08/2023] Open
Abstract
We combine U-Pb in-situ carbonate dating, elemental and isotope constraints to calibrate the synergy of integrated mountain-basin evolution in western Gondwana. We show that deposition of the Bambuí Group coincides with closure of the Goiás-Pharusian (630-600 Ma) and Adamastor (585-530 Ma) oceans. Metazoans thrived for a brief moment of balanced redox and nutrient conditions. This was followed, however, by closure of the Clymene ocean (540-500 Ma), eventually landlocking the basin. This hindered seawater renewal and led to uncontrolled nutrient input, shallowing of the redoxcline and anoxic incursions, fueling positive productivity feedbacks and preventing the development of typical Ediacaran-Cambrian ecosystems. Thus, mountains provide the conditions, such as oxygen and nutrients, but may also preclude life development if basins become too restricted, characterizing a Goldilocks or optimal level effect. During the late Neoproterozoic-Cambrian fan-like transition from Rodinia to Gondwana, the newborn marginal basins of Laurentia, Baltica and Siberia remained open to the global sea, while intracontinental basins of Gondwana became progressively landlocked. The extent to which basin restriction might have affected the global carbon cycle and climate, e.g. through the input of gases such as methane that could eventually have collaborated to an early Cambrian greenhouse world, needs to be further considered.
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Affiliation(s)
- Fabricio Caxito
- grid.8430.f0000 0001 2181 4888CPMTC Research Center, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901 Brazil
| | - Cristiano Lana
- grid.411213.40000 0004 0488 4317Departamento de Geologia, Universidade Federal de Ouro Preto, Ouro Preto, MG 35400-000 Brazil
| | - Robert Frei
- grid.5254.60000 0001 0674 042XDepartment of Geoscience and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Gabriel J. Uhlein
- grid.8430.f0000 0001 2181 4888CPMTC Research Center, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901 Brazil
| | - Alcides N. Sial
- grid.411227.30000 0001 0670 7996NEG-LABISE, Universidade Federal de Pernambuco, Recife, PE 50740-530 Brazil
| | - Elton L. Dantas
- grid.7632.00000 0001 2238 5157Laboratório de Estudos Geodinâmicos, Geocronológicos E Ambientais, Universidade de Brasília, Brasília, DF 70910-900 Brazil
| | - André G. Pinto
- grid.8430.f0000 0001 2181 4888CPMTC Research Center, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901 Brazil
| | - Filippe C. Campos
- grid.8430.f0000 0001 2181 4888CPMTC Research Center, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901 Brazil
| | - Paulo Galvão
- grid.8430.f0000 0001 2181 4888CPMTC Research Center, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901 Brazil
| | - Lucas V. Warren
- grid.410543.70000 0001 2188 478XDepartment of Geology, São Paulo State University, Rio Claro, SP 13506-900 Brazil
| | - Juliana Okubo
- grid.410543.70000 0001 2188 478XDepartment of Geology, São Paulo State University, Rio Claro, SP 13506-900 Brazil
| | - Carlos E. Ganade
- grid.452625.20000 0001 2175 5929Geological Survey of Brazil – CPRM, Rio de Janeiro, RJ 22290-255 Brazil
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6
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Becker-Kerber B, de Barros GEB, Paim PSG, Prado GMEM, da Rosa ALZ, El Albani A, Laflamme M. In situ filamentous communities from the Ediacaran (approx. 563 Ma) of Brazil. Proc Biol Sci 2021; 288:20202618. [PMID: 33402067 DOI: 10.1098/rspb.2020.2618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Precambrian filamentous microfossils are common and diverse. Nevertheless, their taxonomic assignment can be difficult owing to their overall simple shapes typically lacking in diagnostic features. Here, we report in situ communities of well-preserved, large filamentous impressions from the Ediacaran Itajaí Basin (ca 563 Ma) of Brazil. The filaments are uniserial (unbranched) and can reach up to 200 µm in width and up to 44 mm in length. They occur as both densely packed or sparsely populated surfaces, and typically show a consistent orientation. Although simple in shape, their preferred orientation suggests they were tethered to the seafloor, and their overall flexibility (e.g. bent, folded and twisted) supports a biological (rather than sedimentary) affinity. Biometric comparisons with modern filamentous groups further support their biological affinity, suggesting links with either large sulfide-oxidizing bacteria (SOB) or eukaryotes. Other morphological and palaeoecological characteristics further corroborates their similarities with modern large filamentous SOB. Their widespread occurrence and association with complex Ediacaran macrobiota (e.g. frondose organisms, Palaeopascichnus) suggest that they probably played an important role in the ecological dynamics of these early benthic communities by providing firm substrates for metazoans to inhabit. It is further hypothesized that the dynamic redox condition in the latest Ediacaran, with the non-continuous rise in oxygen concentration and periods of hypoxia, may have created ideal conditions for SOB to thrive.
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Affiliation(s)
- Bruno Becker-Kerber
- Programa de Pós-Graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos, Washington Luiz, 325 km, São Carlos (SP) 13565-905, Brazil.,Unité Mixte de Recherche (UMR), Centre National de la Recherche Scientifique (CNRS), IC2MP 7285, University of Poitiers, 86073 Poitiers, France
| | - Gabriel Eduardo Baréa de Barros
- Programa de Pós-Graduação em Biologia Comparada, Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), Universidade de São Paulo (USP), Avenue Bandeirantes, 3900-Vila Monte Alegre, 14049-900, Ribeirão Preto, São Paulo, Brazil
| | - Paulo Sergio Gomes Paim
- Programa de Pós-Graduação em Geologia, Universidade do Vale do Rio dos Sinos, 93.022-750, São Leopoldo (RS), Brazil
| | - Gustavo M E M Prado
- Programa de Pós Graduação em Geoquímica e Geotectônica, Instituto de Geociências, Universidade de São Paulo (USP), Avenue Bandeirantes, 3900-Vila Monte Alegre, 14049-900, Ribeirão Preto, São Paulo, Brazil
| | | | - Abderrazak El Albani
- Unité Mixte de Recherche (UMR), Centre National de la Recherche Scientifique (CNRS), IC2MP 7285, University of Poitiers, 86073 Poitiers, France
| | - Marc Laflamme
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, Ontario, Canada L5 L 1C6
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7
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Li C, Shi W, Cheng M, Jin C, Algeo TJ. The redox structure of Ediacaran and early Cambrian oceans and its controls. Sci Bull (Beijing) 2020; 65:2141-2149. [PMID: 36732967 DOI: 10.1016/j.scib.2020.09.023] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 02/04/2023]
Abstract
The rapid diversification of early animals during the Ediacaran (635-541 Ma) and early Cambrian (ca. 541-509 Ma) has frequently been attributed to increasing oceanic oxygenation. However, the pattern of oceanic oxygenation and its relationship to early animal evolution remain in debate. In this review, we examine the redox structure of Ediacaran and early Cambrian oceans and its controls, offering new insights into contemporaneous oceanic oxygenation patterns and their role in the coevolution of environments and early animals. We review the development of marine redox models which, in combination with independent distal deep-ocean redox proxies, supports a highly redox-stratified shelf and an anoxia-dominated deep ocean during the Ediacaran and early Cambrian. Geochemical and modeling evidence indicates that the marine redox structure was likely controlled by low atmospheric O2 levels and low seawater vertical mixing rates on shelves at that time. Furthermore, theoretical analysis and increasing geochemical evidence, particularly from South China, show that limited sulfate availability was a primary control on the attenuation of mid-depth euxinia offshore, in contrast to the existing paradigm invoking decreased organic carbon fluxes distally. In light of our review, we infer that if oceanic oxygenation indeed triggered the rise of early animals, it must have done so through a shelf oxygenation which was probably driven by elevated oxidant availability. Our review calls for further studies on Ediacaran-Cambrian marine redox structure and its controls, particularly from regions outside of South China, in order to better understand the coevolutionary relationship between oceanic redox and early animals.
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Affiliation(s)
- Chao Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China.
| | - Wei Shi
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
| | - Meng Cheng
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
| | - Chengsheng Jin
- Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, China
| | - Thomas J Algeo
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China; State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan 430074, China; Department of Geology, University of Cincinnati, Cincinnati OH45221, USA
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8
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Abstract
The Ediacaran period (635–541 Ma) was a time of major environmental change, accompanied by a transition from a microbial world to the animal world we know today. Multicellular, macroscopic organisms preserved as casts and molds in Ediacaran siliciclastic rocks are preserved worldwide and provide snapshots of early organismal, including animal, evolution. Remarkable evolutionary advances are also witnessed by diverse cellular and subcellular phosphatized microfossils described from the Doushantuo Formation in China, the only source showing a diversified assemblage of microfossils. Here, we greatly extend the known distribution of this Doushantuo-type biota in reporting an Ediacaran Lagerstätte from Laurentia (Portfjeld Formation, North Greenland), with phosphatized animal-like eggs, embryos, acritarchs, and cyanobacteria, the age of which is constrained by the Shuram–Wonoka anomaly (c. 570–560 Ma). The discovery of these Ediacaran phosphatized microfossils from outside East Asia extends the distribution of the remarkable biota to a second palaeocontinent in the other hemisphere of the Ediacaran world, considerably expanding our understanding of the temporal and environmental distribution of organisms immediately prior to the Cambrian explosion. The Doushantuo biota of China is incredibly important for understanding the evolution of complex animals. Willman et al. report on evidence of Doushantuo-like biota from the Ediacaran of North Greenland, indicating that these important organisms were distributed across multiple palaeocontinents.
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9
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Wood R, Donoghue PCJ, Lenton TM, Liu AG, Poulton SW. The origin and rise of complex life: progress requires interdisciplinary integration and hypothesis testing. Interface Focus 2020. [DOI: 10.1098/rsfs.2020.0024] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Understanding of the triggers and timing of the rise of complex life
ca
2100 to 720 million years ago has expanded dramatically in recent years. This theme issue brings together diverse and novel geochemical and palaeontological data presented as part of the Royal Society ‘
The origin and rise of complex life: integrating models
,
geochemical and palaeontological data
’ discussion meeting held in September 2019. The individual papers offer prescient insights from multiple disciplines. Here we summarize their contribution towards the goal of the meeting; to create testable hypotheses for the differing roles of changing climate, oceanic redox, nutrient availability, and ecosystem feedbacks across this profound, but enigmatic, transitional period.
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Affiliation(s)
- Rachel Wood
- School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FE, UK
| | | | | | - Alexander G. Liu
- Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK
| | - Simon W. Poulton
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
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10
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Bowyer FT, Shore AJ, Wood RA, Alcott LJ, Thomas AL, Butler IB, Curtis A, Hainanan S, Curtis-Walcott S, Penny AM, Poulton SW. Regional nutrient decrease drove redox stabilisation and metazoan diversification in the late Ediacaran Nama Group, Namibia. Sci Rep 2020; 10:2240. [PMID: 32042140 PMCID: PMC7010733 DOI: 10.1038/s41598-020-59335-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/30/2019] [Indexed: 12/01/2022] Open
Abstract
The late Ediacaran witnessed an increase in metazoan diversity and ecological complexity, marking the inception of the Cambrian Explosion. To constrain the drivers of this diversification, we combine redox and nutrient data for two shelf transects, with an inventory of biotic diversity and distribution from the Nama Group, Namibia (~550 to ~538 Million years ago; Ma). Unstable marine redox conditions characterised all water depths in inner to outer ramp settings from ~550 to 547 Ma, when the first skeletal metazoans appeared. However, a marked deepening of the redoxcline and a reduced frequency of anoxic incursions onto the inner to mid-ramp is recorded from ~547 Ma onwards, with full ventilation of the outer ramp by ~542 Ma. Phosphorus speciation data show that, whilst anoxic ferruginous conditions were initially conducive to the drawdown of bioavailable phosphorus, they also permitted a limited degree of phosphorus recycling back to the water column. A long-term decrease in nutrient delivery from continental weathering, coupled with a possible decrease in upwelling, led to the gradual ventilation of the Nama Group basins. This, in turn, further decreased anoxic recycling of bioavailable phosphorus to the water column, promoting the development of stable oxic conditions and the radiation of new mobile taxa.
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Affiliation(s)
- F T Bowyer
- University of Edinburgh, School of GeoSciences, James Hutton Road, Edinburgh, EH9 3FE, UK. .,University of Leeds, School of Earth and Environment, Leeds, LS2 9JT, UK.
| | - A J Shore
- University of Edinburgh, School of GeoSciences, James Hutton Road, Edinburgh, EH9 3FE, UK
| | - R A Wood
- University of Edinburgh, School of GeoSciences, James Hutton Road, Edinburgh, EH9 3FE, UK
| | - L J Alcott
- University of Leeds, School of Earth and Environment, Leeds, LS2 9JT, UK
| | - A L Thomas
- University of Edinburgh, School of GeoSciences, James Hutton Road, Edinburgh, EH9 3FE, UK
| | - I B Butler
- University of Edinburgh, School of GeoSciences, James Hutton Road, Edinburgh, EH9 3FE, UK
| | - A Curtis
- University of Edinburgh, School of GeoSciences, James Hutton Road, Edinburgh, EH9 3FE, UK
| | - S Hainanan
- Ministry of Mines and Energy, 6 Aviation Road, Private Bag, 13297, Windhoek, Namibia
| | | | - A M Penny
- Finnish Museum of Natural History, University of Helsinki, Jyrängöntie 2, 00560, Helsinki, Finland
| | - S W Poulton
- University of Leeds, School of Earth and Environment, Leeds, LS2 9JT, UK
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11
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Organically-preserved multicellular eukaryote from the early Ediacaran Nyborg Formation, Arctic Norway. Sci Rep 2019; 9:14659. [PMID: 31601898 PMCID: PMC6787099 DOI: 10.1038/s41598-019-50650-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 09/12/2019] [Indexed: 02/04/2023] Open
Abstract
Eukaryotic multicellularity originated in the Mesoproterozoic Era and evolved multiple times since, yet early multicellular fossils are scarce until the terminal Neoproterozoic and often restricted to cases of exceptional preservation. Here we describe unusual organically-preserved fossils from mudrocks, that provide support for the presence of organisms with differentiated cells (potentially an epithelial layer) in the late Neoproterozoic. Cyathinema digermulense gen. et sp. nov. from the Nyborg Formation, Vestertana Group, Digermulen Peninsula in Arctic Norway, is a new carbonaceous organ-taxon which consists of stacked tubes with cup-shaped ends. It represents parts of a larger organism (multicellular eukaryote or a colony), likely with greater preservation potential than its other elements. Arrangement of open-ended tubes invites comparison with cells of an epithelial layer present in a variety of eukaryotic clades. This tissue may have benefitted the organism in: avoiding overgrowth, limiting fouling, reproduction, or water filtration. C. digermulense shares characteristics with extant and fossil groups including red algae and their fossils, demosponge larvae and putative sponge fossils, colonial protists, and nematophytes. Regardless of its precise affinity, C. digermulense was a complex and likely benthic marine eukaryote exhibiting cellular differentiation, and a rare occurrence of early multicellularity outside of Konservat-Lagerstätten.
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12
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Tarhan LG, Droser ML, Cole DB, Gehling JG. Ecological Expansion and Extinction in the Late Ediacaran: Weighing the Evidence for Environmental and Biotic Drivers. Integr Comp Biol 2019; 58:688-702. [PMID: 29718307 DOI: 10.1093/icb/icy020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The Ediacara Biota, Earth's earliest communities of complex, macroscopic, multicellular organisms, appeared during the late Ediacaran Period, just prior to the Cambrian Explosion. Ediacara fossil assemblages consist of exceptionally preserved soft-bodied forms of enigmatic morphology and affinity which nonetheless represent a critical stepping-stone in the evolution of complex animal ecosystems. The Ediacara Biota has historically been divided into three successive Assemblages-the Avalon, the White Sea, and the Nama. Although the oldest (Avalon) Assemblage documents the initial appearance of several groups of Ediacara taxa, the two younger (White Sea and Nama) Assemblages record a particularly striking suite of ecological innovations, including the appearance of diverse Ediacara body plans-in tandem with the rise of bilaterian animals-as well as the emergence of novel ecological strategies such as movement, sexual reproduction, biomineralization, and the development of dense, heterogeneous benthic communities. Many of these ecological innovations appear to be linked to adaptations to heterogeneous substrates and shallow and energetic marine settings. In spite of these innovations, the majority of Ediacara taxa disappear by the end of the Ediacaran, with interpretations for this disappearance historically ranging from the closing of preservational windows to environmentally or biotically mediated extinction. However, in spite of the unresolved affinity and eventual extinction of individual Ediacara taxa, these distinctive ecological strategies persist across the Ediacaran-Cambrian boundary and are characteristic of younger animal-dominated communities of the Phanerozoic. The late Ediacaran emergence of these strategies may, therefore, have facilitated subsequent radiations of the Cambrian. In this light, the Ediacaran and Cambrian Periods, although traditionally envisioned as separate worlds, are likely to have been part of an ecological and evolutionary continuum.
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Affiliation(s)
- Lidya G Tarhan
- Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA
| | - Mary L Droser
- Department of Earth Sciences, University of California, 900 University Avenue, Riverside, CA 92521, USA
| | - Devon B Cole
- Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, CT 06511, USA
| | - James G Gehling
- South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia.,University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
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13
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Integrated records of environmental change and evolution challenge the Cambrian Explosion. Nat Ecol Evol 2019; 3:528-538. [DOI: 10.1038/s41559-019-0821-6] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 01/22/2019] [Indexed: 11/08/2022]
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14
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Boag TH, Stockey RG, Elder LE, Hull PM, Sperling EA. Oxygen, temperature and the deep-marine stenothermal cradle of Ediacaran evolution. Proc Biol Sci 2018; 285:20181724. [PMID: 30963899 PMCID: PMC6304043 DOI: 10.1098/rspb.2018.1724] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/13/2018] [Indexed: 11/12/2022] Open
Abstract
Ediacaran fossils document the early evolution of complex megascopic life, contemporaneous with geochemical evidence for widespread marine anoxia. These data suggest early animals experienced frequent hypoxia. Research has thus focused on the concentration of molecular oxygen (O2) required by early animals, while also considering the impacts of climate. One model, the Cold Cradle hypothesis, proposed the Ediacaran biota originated in cold, shallow-water environments owing to increased O2 solubility. First, we demonstrate using principles of gas exchange that temperature does have a critical role in governing the bioavailability of O2-but in cooler water the supply of O2 is actually lower. Second, the fossil record suggests the Ediacara biota initially occur approximately 571 Ma in deep-water facies, before appearing in shelf environments approximately 555 Ma. We propose an ecophysiological underpinning for this pattern. By combining oceanographic data with new respirometry experiments we show that in the shallow mixed layer where seasonal temperatures fluctuate widely, thermal and partial pressure ( pO2) effects are highly synergistic. The result is that temperature change away from species-specific optima impairs tolerance to low pO2. We hypothesize that deep and particularly stenothermal (narrow temperature range) environments in the Ediacaran ocean were a physiological refuge from the synergistic effects of temperature and low pO2.
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Affiliation(s)
- Thomas H. Boag
- Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Richard G. Stockey
- Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Leanne E. Elder
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
| | - Pincelli M. Hull
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
| | - Erik A. Sperling
- Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA
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15
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Dynamic oxygen and coupled biological and ecological innovation during the second wave of the Ediacara Biota. Emerg Top Life Sci 2018; 2:223-233. [PMID: 32412611 DOI: 10.1042/etls20170148] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/29/2018] [Accepted: 06/02/2018] [Indexed: 11/17/2022]
Abstract
Animal life on Earth is generally accepted to have risen during a period of increasingly well-oxygenated conditions, but direct evidence for that relationship has previously eluded scientists. This gap reflects both the enigmatic nature of the early animal fossil record and the coarse temporal resolution of Precambrian environmental change. Here, we combine paleontological data from the Ediacara Biota, the earliest fossil animals, with geochemical evidence for fluctuating redox conditions. Using morphological and ecological novelties that broadly reflect oxygen demand, we show that the appearance of abundant oxygen-demanding organisms within the Ediacara Biota corresponds with a period of elevated global oxygen concentrations. This correlation suggests that a putative rise in oxygen levels may have provided the necessary environments for the diversification of complex body plans and energetically demanding ecologies. The potential loss of organisms with relatively high oxygen requirements in the latest Ediacaran coupled with an apparent return to low oxygen concentrations further supports the availability of oxygen as a control on early animal evolution. While the advent of animal life was probably the product of a variety of factors, the recognition of a possible connection between changing environmental conditions and the diversification of animal morphologies suggests that the availability of oxygen played a significant role in the evolution of animals on Earth.
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16
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Exploring the drivers of early biomineralization. Emerg Top Life Sci 2018; 2:201-212. [PMID: 32412623 DOI: 10.1042/etls20170164] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/12/2018] [Accepted: 05/15/2018] [Indexed: 11/17/2022]
Abstract
The first biomineralized hard parts are known from ∼810 Million years ago (Ma), consisting of phosphatic plates of probable protists formed under active biological control. Large skeletons in diverse taxa, probably including total-group poriferans and total-group cnidarians, first appear in the terminal Ediacaran, ∼550 Ma. This is followed by a substantial increase in abundance, diversity and mineralogy during the early Cambrian. The biological relationship of Ediacaran to early Cambrian skeletal biota is unclear, but tubular skeletal fossils such as Cloudina and Anabarites straddle the transition. Many Ediacaran skeletal biota are found exclusively in carbonate settings, and present skeletons whose form infers an organic scaffold which provided the framework for interactions between extracellular matrix and mineral ions. Several taxa have close soft-bodied counterparts hosted in contemporary clastic rocks. This supports the assertion that the calcification was an independent and derived feature that appeared in diverse groups, which was initially acquired with minimal biological control in the highly saturated, high-alkalinity carbonate settings of the Ediacaran, where the carbonate polymorph was further controlled by seawater chemistry. The trigger for Ediacaran-Cambrian biomineralization is far from clear, but may have been either changing seawater Mg/Ca ratios that facilitated widespread aragonite and high-Mg calcite precipitation, and/or increasing or stabilizing oxygen levels. By the Early Cambrian, the diversity of biomineralization styles may have been an escalating defensive response to increasing predation pressure, with skeletal hard parts first appearing in abundance in clastic settings by the Fortunian. This marks full independence from ambient seawater chemistry and significant biological control of biomineralization.
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17
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Heterogeneous and dynamic marine shelf oxygenation and coupled early animal evolution. Emerg Top Life Sci 2018; 2:279-288. [DOI: 10.1042/etls20170157] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/19/2018] [Accepted: 05/29/2018] [Indexed: 02/06/2023]
Abstract
It is generally agreed that early diversification of animals and significant rise of atmospheric and oceanic oxygen (O2) levels occurred in the Ediacaran (635–541 million years ago, Ma) and early Cambrian (ca. 541–509 Ma). The strength and nature of their relationship, however, remain unclear and debated. A recent wave of paleoredox research — with a particular focus on the fossiliferous sections in South China — demonstrates high spatial heterogeneity of oceanic O2 (redox) conditions and dynamic marine shelf oxygenation in a dominantly anoxic ocean during the Ediacaran and early Cambrian. This pattern shows a general spatiotemporal coupling to early animal evolution. We attribute dynamic shelf oxygenation to a complex interplay among the evolving atmosphere, continents, oceans, and biosphere during a critical period in Earth history. Our review supports the idea of a complex coevolution between increasing O2 levels and early diversification of animals, although additional work is required to fully delineate the timing and patterns of this coevolution and the mechanistic underpinnings.
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18
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Pehr K, Love GD, Kuznetsov A, Podkovyrov V, Junium CK, Shumlyanskyy L, Sokur T, Bekker A. Ediacara biota flourished in oligotrophic and bacterially dominated marine environments across Baltica. Nat Commun 2018; 9:1807. [PMID: 29728614 PMCID: PMC5935690 DOI: 10.1038/s41467-018-04195-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 04/13/2018] [Indexed: 11/26/2022] Open
Abstract
Middle-to-late Ediacaran (575–541 Ma) marine sedimentary rocks record the first appearance of macroscopic, multicellular body fossils, yet little is known about the environments and food sources that sustained this enigmatic fauna. Here, we perform a lipid biomarker and stable isotope (δ15Ntotal and δ13CTOC) investigation of exceptionally immature late Ediacaran strata (<560 Ma) from multiple locations across Baltica. Our results show that the biomarker assemblages encompass an exceptionally wide range of hopane/sterane ratios (1.6–119), which is a broad measure of bacterial/eukaryotic source organism inputs. These include some unusually high hopane/sterane ratios (22–119), particularly during the peak in diversity and abundance of the Ediacara biota. A high contribution of bacteria to the overall low productivity may have bolstered a microbial loop, locally sustaining dissolved organic matter as an important organic nutrient. These oligotrophic, shallow-marine conditions extended over hundreds of kilometers across Baltica and persisted for more than 10 million years. The environments and food sources that sustained Ediacara biota 575-541 million years ago remain unclear. Here, the authors perform lipid biomarker and isotopic analyses on biota fossil-containing Ediacaran strata from Baltica and propose the presence of a microbial loop bolstered by bacteria.
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Affiliation(s)
- Kelden Pehr
- Department of Earth Sciences, University of California, Riverside, 900 University Avenue, Riverside, CA, 92521, USA
| | - Gordon D Love
- Department of Earth Sciences, University of California, Riverside, 900 University Avenue, Riverside, CA, 92521, USA.
| | - Anton Kuznetsov
- Institute of Precambrian Geology and Geochronology, RAS, nab. Makarova 2, St. Petersburg, 199034, Russia
| | - Victor Podkovyrov
- Institute of Precambrian Geology and Geochronology, RAS, nab. Makarova 2, St. Petersburg, 199034, Russia
| | - Christopher K Junium
- Department of Earth Sciences, Syracuse University, 322 Heroy Geology Lab, Syracuse, NY, 13244, USA
| | - Leonid Shumlyanskyy
- M.P. Semenko Institute of Geochemistry, Mineralogy and Ore Formation, National Academy of Sciences of Ukraine, 34 Palladina Av, Kiev, 03142, Ukraine
| | - Tetyana Sokur
- Institute of Geological Sciences, National Academy of Sciences of Ukraine, Olesya Honchara Str., 55-b, Kiev, 01054, Ukraine
| | - Andrey Bekker
- Department of Earth Sciences, University of California, Riverside, 900 University Avenue, Riverside, CA, 92521, USA.
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