The Mediterranean almost disappeared for an unbelievable reason

A land bridge connecting Europe and Africa would still exist if not for the disaster that "reborn" the Mediterranean.

According to a study just published in the scientific journal Nature Communications , the Mediterranean literally evaporated about 5.5 million years ago , losing 69 percent of the water we see today.

Evidence for this terrifying event was revealed by a team led by Earth system scientist Giovanni Aloisi from the French National Center for Scientific Research (CNRS) through an analysis of chlorine isotopes in salt deposited on the seafloor.

The Mediterranean almost disappeared 5.5 million years ago - (Photo: Pibernat/Garcia-Castellanos).

Combining modelling and numerical simulations, the authors show that this event – ​​called the Messinian Salinity Crisis (MSC) – unfolded in two phases.

The first phase included 35,000 years of limited water flow between the Mediterranean and the Atlantic Ocean, through what is now the Strait of Gibraltar.

The more the sea water is not replenished with fresh water, the more the process of salt deposition and evaporation in the Mediterranean is accelerated.

During the second phase, which lasted the next 10,000 years, the Mediterranean Sea became completely isolated. In some areas, the water level may have dropped by as much as 2.1 km.

In this second phase, the underwater landmass across the Strait of Sicily will be exposed, dividing the Mediterranean and creating a land bridge connecting Africa and Europe.

That led to faster evaporation rates in the eastern Mediterranean, where sea levels fell most sharply, leaving behind vast salt deposits.

Scientists have long debated how the MSC emerged and whether it occurred when the Mediterranean Sea completely separated from the Atlantic Ocean.

This new research shows that both schools of thought are correct, and that it's a two-stage process.

Researchers do not delve into why the Mediterranean became isolated, but this period falls within the Miocene of the Quaternary, a period of intense and widespread tectonic activity. 

So it is possible that these geological activities have inadvertently caused some changes to the terrain and restricted the flow between this sea and the Atlantic Ocean.

The MSC itself will cause further upheaval, as pressure increases on the surface crust and surrounding areas dry out.

"The enormous size of the Mediterranean depression due to the drop in water level will have global-scale climate impacts, including changes in rainfall patterns," the authors explain.

Today, the Strait of Gibraltar is much wider and deeper than it was during MSC Phase 1. Without this connection to the Atlantic, it is estimated that the Mediterranean sea level would now be dropping by almost half a meter per year.

We still have the Mediterranean today thanks to a "cataclysmic" event shortly after that dry period, called the Zanclean flood , which occurred about 5.33 million years ago and rapidly filled the sea and reconnected it with the Atlantic Ocean.