When the landmass that is now the Indian subcontinent slammed into Asia about 50 million years ago, the oxygen in the world's oceans increased, altering the conditions for life, scientists say.
The collision was already known to have changed the configuration of the continents, the landscape, global climate and more.
"These results are different from anything people have previously seen," said Emma Kast, a graduate student at Princeton University in the US.
Kast used microscopic seashells to create a record of ocean nitrogen over a period from 70 million years ago -- shortly before the extinction of the dinosaurs -- until 30 million years ago.
This record is an enormous contribution to the field of global climate studies, said John Higgins, an associate professor at Princeton
Every organism on Earth requires "fixed" nitrogen -- sometimes called "biologically available nitrogen."