Publications by authors named "Victor Melezhik"
Article Synopsis
- The role of oxygen in the evolution of early animals, particularly the Ediacara biota, is debated due to conflicting geochemical evidence regarding ocean oxygen levels during their rise and decline.
- Fossil evidence suggests that the Ediacara biota diversified after a significant ocean oxygenation event, the Shuram negative C-isotope Excursion, but there's contradictory data about oxygen levels during that time.
- New research analyzing uranium isotope variations from multiple locations indicates a major shift in ocean oxygen levels, suggesting that global marine redox changes influenced the biodiversity of the Ediacara biota throughout its existence.*
The stable isotope record of marine carbon indicates that the Proterozoic Eon began and ended with extreme fluctuations in the carbon cycle. In both the Paleoproterozoic [2500 to 1600 million years ago (Ma)] and Neoproterozoic (1000 to 542 Ma), extended intervals of anomalously high carbon isotope ratios (δ(13)C) indicate high rates of organic matter burial and release of oxygen to the atmosphere; in the Neoproterozoic, the high δ(13)C interval was punctuated by abrupt swings to low δ(13)C, indicating massive oxidation of organic matter. We report a Paleoproterozoic negative δ(13)C excursion that is similar in magnitude and apparent duration to the Neoproterozoic anomaly.
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