A land bridge connecting Europe and Africa once existed, if not for the disaster that “rebirthed” the Mediterranean.
According to a recent study published in the scientific journal Nature Communications, the Mediterranean Sea literally evaporated about 5.5 million years ago, losing as much as 69% of its water compared to what we see today.
Evidence for this terrifying event was revealed by a research team led by Earth system scientist Giovanni Aloisi from the French National Center for Scientific Research (CNRS) through the analysis of chlorine isotopes in salt deposits on the seabed.
The Mediterranean nearly disappeared 5.5 million years ago – (Photo: Pibernat/Garcia-Castellanos).
Along with building models and numerical simulations, the authors indicate that this event—known as the Messinian Salinity Crisis (MSC)—occurred in two stages.
The first stage involved 35,000 years of restricted water flow between the Mediterranean and the Atlantic Ocean, through what is now the Strait of Gibraltar.
As seawater was not replenished with fresh water, the processes of salt deposition and water evaporation in the Mediterranean accelerated.
In the second stage, which lasted for the next 10,000 years, the Mediterranean Sea became completely isolated. In some areas, the water level may have dropped by up to 2.1 kilometers.
During this second phase, the underwater land bridge across the Strait of Sicily emerged, splitting the Mediterranean and creating a land bridge connecting Africa and Europe.
This led to faster evaporation rates in the eastern Mediterranean, where sea levels dropped the most, leaving behind numerous large salt deposits.
Scientists have long debated how the MSC occurred and whether it happened when the Mediterranean was entirely separated from the Atlantic Ocean.
This new study indicates that both schools of thought are correct, and it was a process that unfolded in two stages.
The researchers did not delve into the reasons why the Mediterranean became isolated, but this phase occurred during the Middle Pleistocene of the Quaternary period, a time of significant and widespread tectonic activity.
Therefore, it is possible that these geological activities inadvertently caused some changes to the topography and restricted the flow between this sea and the Atlantic Ocean.
The MSC itself would cause further upheaval, as pressure increased on the surface crust and surrounding areas dried out.
“The enormous size of the Mediterranean basin due to the lowered water levels would cause climate impacts on a global scale, including changes in precipitation patterns,” the authors explain.
Today, the Strait of Gibraltar is much wider and deeper than during the first stage of the MSC. Without this connection to the Atlantic, it is estimated that the current sea level in the Mediterranean would decrease by nearly half a meter each year.
Today, we still have the Mediterranean Sea thanks to a “great flood” event shortly after that drying period, known as the Zanclean Flood, which occurred about 5.33 million years ago and quickly filled the seas as well as reconnected it with the Atlantic.
