Geologists find parallels between ancient, global-scale extinction events and modern threats to Earth’s oceans.

A series of mass extinctions that rocked the Earth’s oceans during the Devonian Period over 300 million years ago may have been triggered by the evolution of tree roots. This is according to a research study led by scientists at Indiana University–Purdue University Indianapolis (IUPUI), along with colleagues in the United Kingdom.

Evidence for this new view of a remarkably volatile period in Earth’s pre-history was reported on November 9 in the scientific journal Geological Society of America Bulletin. It is one of the oldest and most respected publications in the field of geology. The study was led by Gabriel Filippelli, Chancellor’s Professor of Earth Sciences in the School of Science at IUPUI, and Matthew Smart, a Ph.D. student in his lab at the time of the study.

“Our analysis shows that the evolution of tree roots likely flooded past oceans with excess nutrients, causing massive algae growth,” Filippelli said. “These rapid and destructive algae blooms would have depleted most of the oceans’ oxygen, triggering catastrophic mass extinction events.”