“Unveiling the Role of Oceanic Oxygenation in the Cambrian Explosion: New Insights from Chinese Research”
Chinese researchers have uncovered a connection between oceanic oxygen levels and the early evolution of animals, shedding fresh insights on the Cambrian Explosion.
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Oceanic Oxygen
Around 541 million years ago, during the early Cambrian period, there was a rapid surge in the diversity of species, variation in morphology, and complexity of ecosystems among early animals.
While it was previously thought that increasing global oceanic oxygen was the primary catalyst for this swift evolution, recent discoveries indicate that the oxygen levels necessary to meet the basic metabolic needs of early animals may have already been sufficient. Some scientists now consider oceanic oxygenation as an outcome rather than a trigger of the Cambrian Explosion, suggesting that it could have interacted with animal evolution through positive feedback mechanisms.
Consequently, the precise cause-and-effect relationship between oceanic oxygen levels and the early evolution of animals remains enigmatic.
To gain further insights into the marine conditions conducive to the Cambrian Explosion, researchers from the University of Science and Technology of China analyzed Cambrian metalliferous black shales in the Yangtze Block of South China. Their study revealed that during the Ediacaran-Cambrian transition, global oceanic oxygenation likely increased the sulfate reservoir through the oxidation of sulfide, while simultaneously reducing the barium reservoir through barite precipitation.
High levels of barium in water can hinder the survival of aquatic animals. By reducing both sulfate and barium, which are harmful to animals, the marine environment may have become more hospitable, potentially facilitating the Cambrian Explosion of early animals.
