The Mediterranean will still take 26,000 years to expel its excess salt

Aug. 12 () –

It will take at least another 26,000 years to compensate for the excess salt in the Mediterranean Sea, originated in its partial desiccation millions of years ago due to its isolation from the Atlantic Ocean.

A new study of Australian National University (ANU) offers more clues about what happened to the Mediterranean during a tumultuous period that likely included the most catastrophic flood event in Earth’s recorded history.

The Zancleano mega-flood occurred about five million years ago after the collapse of the Gibraltar sill, or floodgate, which reconnected the Mediterranean Sea with the Atlantic Ocean. Global sea levels dropped 10 meters as the Mediterranean filled and it became once again an ocean basin teeming with life.

Lead author, PhD researcher Udara Amarathunga, said the flood is known as the most abrupt global-scale environmental change since the disappearance of the dinosaurs. “This event is considered the renaissance of the Mediterranean,” said Amarathunga it’s a statement.

“Our study fills a gap in history. The mega-flood triggered the end of the Messinian Salinity Crisis (MSC), which began about six million years ago. The MSC saw the Mediterranean basin partially dry up when the Atlantic-Mediterranean gateway closed, leaving behind huge bodies of salt and killing most life forms.

“As the mega-flood rapidly refilled the Mediterranean, the salt became concentrated in the eastern basin. Our work indicates that it will take another 26,000 years to eliminate all excess salt in the Atlantic Ocean and return the Mediterranean to the conditions of a normal sea basin”.

This long transition period was unknown to scientists until now.

Amarathunga said it’s unlikely we’ll see another transformation of this size anytime soon, making it a unique example of how quickly, and surprisingly, the Earth system can change its behavior.

But there are still many unanswered questions. “It is not clear how such a transformation would have changed the regional climate”Amarathunga said. “Also, further studies could tell us more about how organisms evolved as the Mediterranean was reborn.”

The study is published in NatureGeoscience.