New Theory for What Caused Earth's Second-Largest Mass Extinction
Scientists have been trying to unravel what killed nearly all of Earth’s animals 400 million years ago. Could it be monstrous deformities caused by toxic metals in the ocean?
Toxic metals unleashed by depleted oxygen in the oceans may have helped trigger one of the largest extinctions of life in the planet’s history, new research suggests.
High levels of lead, arsenic, and iron—which continue to harm animals and humans today— appear to have caused deadly deformities in tiny, plankton-like creatures that teemed in Earth’s ancient seas.
The series of extinctions that occurred during the Ordovician and Silurian periods between 445 and 415 million years ago wiped out as much as 85 percent of all animal species on Earth. It was the second largest mass extinction in history, coming at a time when nearly all existing animals lived in the oceans.
Scientists previously suggested a number of possible scenarios to explain the
