The „Great Oxygenation Event“ (GOE), the process whereby the Earth’s atmosphere was continuously enriched with oxygen, a waste product of photosynthesis, began ~2.43 billion years ago. The source, according to science, was photosynthesizing cyanobacteria. But why did this all-important turnaround occur so late? Cyanobacterial life existed, as rock samples show, at least 300 million years before the GOE. Achim Herrmann, who is researching the spread of early cyanobacteria in his doctoral thesis at TU Kaiserslautern, is hot on the trail for answers. His current research paper has now been published in the journal Nature Communications.