Most of Earth's mass extinctions caused by… mineral deficiencies
Image credit: Sheila Terry/SPL
 
Are you getting enough minerals? A new theory suggests most of Earth’s mass extinction events could have been caused by a lack of essential trace elements in the world’s oceans, causing fatal deficiencies in marine animals, from plankton to reptiles.

Earth has been hit with five mass extinction events. The two most dramatic ones had pretty clear causes. The dinosaurs were probably wiped out 66 million years ago thanks to a massive meteor falling on modern-day Mexico, while the end-Permian extinction, which wiped out 90 per cent of species 252 million years ago, was probably the result of massive volcanoes in Siberia.
But that leaves three other mass extinctions, with no agreed cause.

“It’s a complex scenario,” says John Long from Flinders University in Adelaide, Australia. He says there are probably a lot of causes conspiring to drive these mass extinctions. But his latest work suggests fluctuations in essential minerals in the ocean could be an important, and so-far completely unexplored, cause.

Essential selenium

 

Earlier this year, researchers discovered that periods when the ocean had high levels of trace elements – like zinc, copper, manganese and selenium – seemed to overlap with periods of high productivity, including the Cambrian explosion, when most groups of living animals first appeared.