Biomarker Similarities between the Saline Lacustrine Eocene Green River and the Paleoproterozoic Barney Creek Formations

French, Katherine L.; Birdwell, Justin E.; Berg, Michael Vanden

doi:10.46427/gold2020.746

Cited by 25 publications

(14 citation statements)

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“…S3), a relationship that is contrary to common observations, as summarized in ref. 41. In our case, this pattern is most reasonably explained as reflecting the demise of the freshwater nitrogen-fixing cyanobacteria and/ or α-proteobacteria present in microbial mats brought about by the marine transgression.…”

Section: Sea-level Fall Resulted In Microbial Mat Emergence and Ecologicalsupporting

confidence: 56%

Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon

Fox

Cui

Whiteside

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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The negative organic carbon isotope excursion (CIE) associated with the end-Triassic mass extinction (ETE) is conventionally interpreted as the result of a massive flux of isotopically light carbon from exogenous sources into the atmosphere (e.g., thermogenic methane and/or methane clathrate dissociation linked to the Central Atlantic Magmatic Province [CAMP]). Instead, we demonstrate that at its type locality in the Bristol Channel Basin (UK), the CIE was caused by a marine to nonmarine transition resulting from an abrupt relative sea level drop. Our biomarker and compound-specific carbon isotopic data show that the emergence of microbial mats, influenced by an influx of fresh to brackish water, provided isotopically light carbon to both organic and inorganic carbon pools in centimeter-scale water depths, leading to the negative CIE. Thus, the iconic CIE and the disappearance of marine biota at the type locality are the result of local environmental change and do not mark either the global extinction event or input of exogenous light carbon into the atmosphere. Instead, the main extinction phase occurs slightly later in marine strata, where it is coeval with terrestrial extinctions and ocean acidification driven by CAMP-induced increases inPco2; these effects should not be conflated with the CIE. An abrupt sea-level fall observed in the Central European basins reflects the tectonic consequences of the initial CAMP emplacement, with broad implications for all extinction events related to large igneous provinces.

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Section: Sea-level Fall Resulted In Microbial Mat Emergence and Ecologicalsupporting

confidence: 56%

Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon

Fox

Cui

Whiteside

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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“…and Barney Creek Fm. (Brocks et al., 2005; French, Birdwell, & Berg, 2020). French et al (2020) attributed this pattern, and the abundant co‐occurring 3β‐methylhopanes, to these rocks having been deposited in lacustrine settings, an explanation that does not apply to the restricted marine environment of the sediments studied here.…”

Section: Resultsmentioning

confidence: 99%

Biomarker stratigraphy in the Athel Trough of the South Oman Salt Basin at the Ediacaran‐Cambrian Boundary

2020

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“…Besides GSB and PSB, aromatic carotenoids, and the genes coding for their biosynthesis, have been observed in cyanobacteria and actinobacteria (31)(32)(33)(34). Systematic examination of the fossil record of aromatic carotenoids (23,35) reveals additional enigmatic compounds such as renieratane (XVIII) with one ϕ-ring and one χ-ring, renierapurpurane (XX) with two χ-rings, and β-renierapurpurane (XII) with one perhydro β-ring and one χ-ring. These compounds, which have structures that closely resemble precursor pigments isolated from sea sponges (36,37), have been reported in rocks from marine and nonmarine sources that range in age from Paleoproterozoic (11,20) to Cenozoic (35).…”

Section: Significancementioning

confidence: 99%

“…Systematic examination of the fossil record of aromatic carotenoids (23,35) reveals additional enigmatic compounds such as renieratane (XVIII) with one ϕ-ring and one χ-ring, renierapurpurane (XX) with two χ-rings, and β-renierapurpurane (XII) with one perhydro β-ring and one χ-ring. These compounds, which have structures that closely resemble precursor pigments isolated from sea sponges (36,37), have been reported in rocks from marine and nonmarine sources that range in age from Paleoproterozoic (11,20) to Cenozoic (35). These observations, suggesting that sponges could not be the sole or even primary source, began to make more sense once a cyanobacterial source for χ-ring carotenoids was recognized (38).…”

Section: Significancementioning

confidence: 99%

Niche expansion for phototrophic sulfur bacteria at the Proterozoic–Phanerozoic transition

Cui

Liu

Shen

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Fossilized carotenoid hydrocarbons provide a window into the physiology and biochemistry of ancient microbial phototrophic communities for which only a sparse and incomplete fossil record exists. However, accurate interpretation of carotenoid-derived biomarkers requires detailed knowledge of the carotenoid inventories of contemporary phototrophs and their physiologies. Here we report two distinct patterns of fossilized C40 diaromatic carotenoids. Phanerozoic marine settings show distributions of diaromatic hydrocarbons dominated by isorenieratane, a biomarker derived from low-light-adapted phototrophic green sulfur bacteria. In contrast, isorenieratane is only a minor constituent within Neoproterozoic marine sediments and Phanerozoic lacustrine paleoenvironments, for which the major compounds detected are renierapurpurane and renieratane, together with some novel C39 and C38 carotenoid degradation products. This latter pattern can be traced to cyanobacteria as shown by analyses of cultured taxa and laboratory simulations of sedimentary diagenesis. The cyanobacterial carotenoid synechoxanthin, and its immediate biosynthetic precursors, contain thermally labile, aromatic carboxylic-acid functional groups, which upon hydrogenation and mild heating yield mixtures of products that closely resemble those found in the Proterozoic fossil record. The Neoproterozoic–Phanerozoic transition in fossil carotenoid patterns likely reflects a step change in the surface sulfur inventory that afforded opportunities for the expansion of phototropic sulfur bacteria in marine ecosystems. Furthermore, this expansion might have also coincided with a major change in physiology. One possibility is that the green sulfur bacteria developed the capacity to oxidize sulfide fully to sulfate, an innovation which would have significantly increased their capacity for photosynthetic carbon fixation.

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Biomarker Similarities between the Saline Lacustrine Eocene Green River and the Paleoproterozoic Barney Creek Formations

Cited by 25 publications

References 0 publications

Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon

Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon

Biomarker stratigraphy in the Athel Trough of the South Oman Salt Basin at the Ediacaran‐Cambrian Boundary

Niche expansion for phototrophic sulfur bacteria at the Proterozoic–Phanerozoic transition

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