Tree roots may have caused mass extinctions

https://www.sciencealert.com/the-arrival-of-tree-roots-may-have-triggered-mass-extinctions-in-the-ocean

The gist of that research, Phosphorous picked up by tree roots stored in the roots and plant, and when it dies the phosphorus dissolves more easily in deteriorating plants meaning phosphorous is released to go into the seas and that extra phos is what caused extinctions.

We will see if further research corroborates that hypothesis.