About 6 million years ago, an extraordinary event occurred that reshaped the Mediterranean Sea and its waters. This phenomenon, known as the Messinian salinity crisis, turned the ocean into a huge salt basin.
But how did one million cubic kilometers of salt get deposited on the sea floor of the Mediterranean Sea in a short period of time? Until now, it remained a mystery.
Scientists have now made great progress. By analyzing chlorine isotopes in salt from the Mediterranean sea floor, they revealed two distinct stages of this intense evaporation event.
Stages of desiccation and salt accumulation
The first dry phase lasted about 35,000 years. During this period, salt deposition occurred exclusively in the eastern Mediterranean. This is because the outflow from the Mediterranean Sea to the Atlantic Ocean was restricted, resulting in a basin filled with saline water in the east.
But the second stage was a completely different story. In less than 10,000 years, salt accumulation occurred throughout the Mediterranean.
Rapid evaporation events caused sea levels to drop sharply by 1.7-2.1 kilometers in the east and about 0.85 kilometers in the west, causing the Mediterranean basin to lose up to 70% of its total water volume.
Furthermore, changes of such monumental scale did not occur without consequences. The effects of the dramatic drop in sea level were not limited to the marine environment itself, but were widespread.
Factors associated with water loss in the Mediterranean Sea
Local volcanic eruptions may be caused by a release of pressure on the Earth’s crust. These eruptions can be thought of as the Earth’s response to the rapid loss of weight of such significant amounts of water.
Furthermore, this large-scale evaporation event may have also influenced global climate patterns. The sudden low-pressure system caused by the drop in sea levels rippled outward, impacting weather systems over a wide range of areas.
These results provide a deeper understanding not only of the Messinian salinity crisis, but also of the potential for extreme drying events to dramatically alter ecosystems and climate on a global scale.
In the final moments of this salinity crisis, sea levels in the Mediterranean Sea were almost a kilometer lower than those in the Atlantic Ocean. This extreme difference will ultimately lead to the collapse of the Strait of Gibraltar.
Mediterranean water loss and marine life
The Messinian salinity crisis also posed significant challenges to marine life in the Mediterranean basin.
The extreme hypersalinity was inhospitable to most marine life and would have led to mass extinction of species that could not adapt.
However, evidence suggests that some extremophiles (organisms that can survive in highly salty environments) managed to survive during this period.
The fossil record suggests that isolated pockets, or refugia, of low-salinity water existed and may have provided temporary habitat for certain species. These pockets depict resilience in an environment of extreme ecological stress.
Mediterranean water restoration
The collapse of the Strait of Gibraltar served as an entry point for the Atlantic Ocean to flow back into the Mediterranean Sea. This sudden influx of water ended a prolonged dry spell, filling the Mediterranean basin with water and restoring water levels.
As a result, the Mediterranean Sea transitioned from a mostly dry, hypersaline basin dominated by thick salt deposits to a flourishing open ocean once again, with normal ocean conditions and ecosystems returning over time.
This event marked the resolution of the Messinian salinity crisis and permanently restructured the geography and ecological dynamics of the region.
modern climate issues
Insights gained from studying the Messinian salinity crisis provide valuable lessons for understanding current and future environmental change.
This event shows that rapid geological and hydrological changes can cause cascading effects on climate, ecosystems, and even tectonic activity.
Modern concerns about rising temperatures, changing precipitation patterns, and water scarcity reflect some of the climate change that may have been felt during this crisis.
Scientists are stressing the importance of global cooperation and sustainable resource management to learn from this historic event and reduce the impact of pressing environmental challenges on both natural systems and human societies. Masu.
Significance of the research
This study of the water history of the Mediterranean has provided new insights into historical geological events and deepened our understanding of these past events.
Examining these discoveries gives scientists and researchers the opportunity to improve predictions about future geological phenomena.
Understanding the patterns and causes of past events allows for better preparation and response strategies, which may reduce the negative impact of similar events that may occur in the future.
Learning from geological history
This study highlights the importance of learning from past geological activity to make informed decisions to protect communities and the environment from natural disasters. It raises critical questions: Can we apply the lessons learned to protect our future?
The findings serve as a call to action, urging society to incorporate the lessons of history into future planning and preparation efforts.
The research was led by G. Aloisi, a scientist at the French National Center for Scientific Research (CNRS) is one of France’s largest government research institutes.
The research will be published in a journal nature communications.
Image credit: Pibernat & Garcia-Castellanos
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