On the coevolution of Ediacaran oceans and animals

Shen, Yanan; Zhang, Tonggang; Hoffman, Paul F.

doi:10.1073/pnas.0802168105

Cited by 151 publications

(77 citation statements)

References 70 publications

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“…Fe speciation data from well-preserved Neoproterozoic sedimentary rocks suggest an anoxic ferruginous condition as a general feature of deep oceans between 750 and 540 Ma [31]. Fe speciation data of the Ediacaran-early Cambrian sedimentary rocks (Doushantuo, Liuchapo, and Niutitang formations) deposited in outer shelf to basinal environment in South China suggest an anoxic condition in deep oceans [31][32][33], although paleontological data indicate that the largely anoxic basin may be punctuated by brief oxic episodes [34,35].…”

Section: Shallow Marine Anoxiamentioning

confidence: 99%

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

et al. 2012

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The middle Ediacaran Shuram excursion, the largest negative δ 13 C carb excursion in Earth history, has been interpreted as indirect evidence for episodic oxidation and remineralization of deep ocean DOC (dissolved organic carbon). It has been hypothesized that such oxidation event may have occurred when anoxic DOC-laden deep water was brought to shallow shelves during oceanic upwelling, which is expected to cause localized anoxia in shallow environments. To test this prediction, we systematically analyzed rare earth elements (REE) and δ 13 C carb of the upper Doushantuo Formation carbonates in the Yangtze Gorges area of South China, which were deposited in an inner shelf environment and record a large negative δ 13 C carb excursion correlated to the Shuram event. The REE data show a significant positive shift in Ce/Ce* values, synchronous with a pronounced negative δ 13 C carb shift. This positive Ce/Ce* shift is interpreted to represent an oceanic anoxia event in shallow shelf environments, which may have been caused by the upwelling or impingement of oxygen-depleted and 12 C-enriched deep water onto shelves. This anoxia event coincides with a sharp decline in the abundance and diversity of Ediacaran acanthomorphic acritarchs, raising the possibility that these two geobiological events may be causally related. Carbon and sulfur isotope data indicate that deep oceans were episodically oxygenated and deep ocean DOC progressively remineralized during the Ediacaran Period [1,2]. These remineralization events likely involved upwelling of anoxic DOC-laden water to shallow shelves, impacting on the shallow-water redox conditions and biological evolution. Indeed, the Ediacaran fossil record shows a significant biotic turnover in shallow shelf environments during the middle Ediacaran Period, with the early Ediacaran biota characterized by globally distributed acanthomorphic acritarchs [3], and the late Ediacaran ones by classical Ediacara megafossils [4]. Previous researchers have argued that this turnover may have been driven by a middle Ediacaran glaciation event [5], predation pressure from macrophagous metazoans [3], or the oxygenation of continental shelves that released the ecological impetus for the development of acanthomorphic resting stages [6]. Integrated paleobiological and geochemical data from the Doushantuo Formation in the Yangtze Gorges area suggest that this turnover is coincident with a pronounced negative δ 13 C carb excursion that is correlated with the Shuram excursion [7], and thus may be related to shallow water anoxia resulting from upwelling of deep marine waters. The Doushantuo Formation (635-551 Ma in age, including four lithostratigraphic members I-IV in ascending order; Figure 1) in the Yangtze Gorges area was considered to

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Section: Shallow Marine Anoxiamentioning

confidence: 99%

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

et al. 2012

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“…There is no reason to believe that taphonomy governed this opening, as macroscopic compressions are commonly preserved in Proterozoic shales (Hofmann, 1992;Butterfield, 2003). Both macroscopic and demonstrably multicellular eukaryotes first appeared well before the Ediacaran Period (Hofmann, 1992;Butterfield, 2000), but the delayed expansion of diverse, macroscopic algae and macroscopic animals (Xiao et al, 2004;Narbonne, 2005) occurred only in concert with rising oxygen tensions in the Ediacaran atmosphere and oceans (Fike et al, 2006;Canfield et al, 2007Canfield et al, , 2008McFadden et al, 2008;Scott et al, 2008;Shen et al, 2008). In this respect, it is not the oxygen content of the surface ocean that is of concern as much as oxygen levels in and above the oxygen minimum zone.…”

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confidence: 99%

Tubular compression fossils from the Ediacaran Nama group, Namibia

et al. 2009

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Abundant tubular macrofossils occur in finely laminated siltstones and shales of the 548–542 Ma Schwarzrand Subgroup, Nama Group, Namibia. The Nama tubes occur in both the Vingerbreek and Feldschuhhorn members commonly in dense populations and always in fine-grained, lower shore-face lithologies deposited below fair-weather wave base. The tubes are preserved mostly as compressed casts and molds that range in width from 0.6 to 2.1 mm; apparently incomplete specimens reach lengths up to 10 cm. All specimens show sinuous bending and occasional brittle fracture, indicating an original construction of strong but flexible organic matter. Feldschuhhorn specimens preserve fine longitudinal pleats or folds that record pliant organic walls, but the older Vingerbreek populations do not. Similarly, some specimens in the Feldschuhhorn Member display branching, while Vingerbreek tubes do not. The abundant Feldschuhhorn tubes are assigned to the widespread Ediacaran problematicum Vendotaenia antiqua; however, the distinctive Vingerbreek population remains in open nomenclature. The most abundant fossils in Nama rocks, these tubes resemble populations in Ediacaran successions from Russia, China, Spain, and elsewhere. Beyond their local importance, then, such tubes may turn out to be the most abundant record of Ediacaran life.

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“…Oxidation on land (Johnston et al 2005, Parnell et al 2010 Oxygenation, first animals (Fike et al 2006, McFadden et al 2008, Shen et al 2008, Dahl et al 2010 Mineralized skeletons, burrowing in sediments, zooplankton (Butterfield 2001, Droser and Li 2001, Zhuravlev 2001, Dzik 2005 Ordovician radiation, first terrestrial plants and animals (Masuda and Ezaki 2009, Rubinstein et al 2010, T. Zhang et al 2010 Devonian revolution, oxygenation, first charcoal, first active pelagic swimmers (Glasspool and Scott 2010, Dahl et al 2010, Klug et al 2010) 300…”

Section: Parallel Characteristics and Trendsmentioning

confidence: 99%

Natural and human economies compared

Vermeij

Leigh

2011

Ecosphere

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Abstract. Human economies and natural ecosystems (natural economies) share fundamental properties.Both are adaptive, cooperative systems where agents-individuals and groups-compete for locally limiting resources needed to live and reproduce. Successful competitors differentially propagate better knowledge and technology for making a living. Competition has favored innovations, diversification (of species or human occupations), higher productivity, greater interdependence among economic agents, and the emergence of more powerful, interactive individuals and groups, so productivity, diversity, and scales of activity have tended to increase over time. Because economic innovations accumulate, these trends have accelerated over time in both natural and human economies.The shift from mainly genetic origin and transmission of adaptation in natural economies to mainly cultural adaptation among human beings has accelerated these trends dramatically, and made the modern human economy extraordinarily dependent on nonrenewable resources and much more vulnerable to monopolies and tragedies of the commons, internally generated threats less common or less destructive in natural economies. In nature, these internal disruptions are overcome by the advent of new agents, often not involved in causing these disruptions, that compete in new ways. We argue that a comparable shift in societal norms, which govern individual and group status in human society, is needed to keep monopolies and tragedies of the commons from harming both the human economy and the ecosystems on which we depend.

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On the coevolution of Ediacaran oceans and animals

Cited by 151 publications

References 70 publications

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

Rare earth elements and carbon isotope geochemistry of the Doushantuo Formation in South China: Implication for middle Ediacaran shallow marine redox conditions

Tubular compression fossils from the Ediacaran Nama group, Namibia

Natural and human economies compared

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