![volcanic-fertilization-of-the-oceans-drove](https://utterbuzz.com/wp-content/uploads/2021/12/volcanic-fertilization-of-the-oceans-drove-640x360.gif)
Scientists have discovered that two intense spells of volcanic activity triggered a period of global cooling and falling oxygen levels in the oceans, which caused one of the most severe mass extinctions in Earth history – the ‘Late Ordovician Mass Extinction’, 450 million years ago.