“Most people think the rise of oxygen was linked to cyanobacteria, and they are not wrong,” said James Eguchi, a NASA postdoctoral fellow at the University of California, Riverside who led a new study suggesting that the first burst of oxygen was added by a spate of volcanic eruptions brought about by tectonics. “The emergence of photosynthetic organisms could release oxygen. But the most important question is whether the timing of that emergence lines up with the timing of the Great Oxidation Event. As it turns out, they do not.”
“Our theory is the only one that accounts for the global impact on the production of oxygen over such a sustained period of time and explains why it was able to rise to the levels we see today, fueling the evolution of life on Earth,” says William Martin at Heinrich-Heine-Universität Düsseldorf.
“Contrary to our first expectations, global climate was not the primary cause of this change in ocean oxygen and nitrogen cycling,” said Princeton University researcher Emma Kast about the planet’s dramatic increase in the oxygen 55 million years ago. The more likely culprit? Plate tectonics. The collision of India with Asia — dubbed “the collision that changed the world” by legendary geoscientist Wally Broecker, a founder of modern climate research — closed off an ancient sea called the Tethys, disturbing the continental shelves and their connections with the open ocean.