“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.”
