Recent research by scientists from the University of Science and Technology of China has shed new light on the mysterious Cambrian Explosion, a pivotal period in Earth’s history when life diversified rapidly. Approximately 541 million years ago, this era saw a significant increase in the variety and complexity of early animals.
The prevailing theory has been that global oceanic oxygenation was the main driver behind this rapid evolution. However, new findings suggest that the basic metabolic needs of early animals might have already been met by existing oxygen levels.
Some scientists argue that oceanic oxygenation could be a consequence of the Cambrian Explosion rather than its cause. They propose that there might be positive feedback loops between oxygen levels and animal evolution, making the relationship more complex than previously thought.
To delve deeper into this relationship, researchers analyzed excess barium contents and isotope compositions in Cambrian metalliferous black shales from the Yangtze Block in South China. Their study revealed that during the Ediacaran-Cambrian transition, global oceanic oxygenation may have increased the sulfate reservoir through sulfide oxidation while simultaneously decreasing the barium reservoir via barite precipitation.
High concentrations of barium in water are known to inhibit the survival of aquatic animals. Therefore, the removal of sulfate and barium, both harmful to early marine life, could have significantly improved the habitability of oceans, facilitating the Cambrian Explosion.
The study, offering fresh perspectives on marine conditions during this critical period, was published in the journal National Science Review.
Reference(s):
Chinese researchers unveil key factors of Cambrian Explosion of life
cgtn.com
