Twelve million years ago, an incredible event shaped our planet’s history. The collision of continental plates in Central Europe created Paratethys, once the largest lake on Earth. This vast inland sea covered over 2.8 million square kilometers—more than today’s Mediterranean Sea. Holding around 1.77 million cubic kilometers of water, Paratethys dominated the landscape, leaving a lasting impact on wildlife and evolution before it disappeared.
Recent studies highlighted in Science show how this massive lake transformed with fluctuating climates. It underwent cycles of drying and refilling, significantly affecting the ecosystem across Europe and Western Asia.
The Birth of Paratethys
Paratethys emerged from tectonic shifts in the land. As these forces reshaped the region, they formed a nearly enclosed depression, perfect for filling with water. This unique environment allowed for the development of many species that thrived in isolation, disconnected from ocean life.
A Lake of Extremes
However, Paratethys wasn’t static. It faced several drying events, shrinking dramatically at least four times during its existence. The most severe contraction occurred about 7.7 million years ago, where water levels plummeted by up to 250 meters. According to paleo-oceanographer Dan Palcu, these changes provide insights into how ecosystems respond to climate fluctuations.
“Studying Paratethys helps us understand how ancient ecosystems reacted to climate change. This knowledge is crucial as we face current environmental challenges, like the toxic conditions seen in some seas today,” Palcu emphasized.
These drying periods caused many species to perish, particularly the plankton that formed the base of the food chain. Yet, some resilient species adapted and thrived when conditions improved.
Unique Creatures of Paratethys
During its prime, Paratethys teemed with life, including small, unique marine mammals. Fossils show that many of its whales, dolphins, and seals were dwarf versions of their oceanic relatives. The smallest known whale, Cetotherium riabinini, measured only about 3 meters long, smaller than a bottlenose dolphin.
As the lake ebbed away, it reshaped life on land too. The emergence of vast grasslands fostered the evolution of early ancestors of modern sheep, goats, and even those of giraffes and elephants, as noted by Madelaine Böhme from the University of Tübingen.
The Transition to a New World
By around 6.7 to 6.9 million years ago, Paratethys faced its dramatic end. A natural outlet formed, probably near present-day Aegean Sea, allowing the lake to drain into the Mediterranean. This catastrophic event not only ended the existence of the largest lake but also created new opportunities for life. The species that adapted to Paratethys’s shores dispersed, leading to the diverse wildlife we see today across Eurasia and Africa.
While Paratethys is long gone, its fascinating history reminds us of the ever-changing nature of our planet and the resilience of life within it. Understanding this past helps us navigate the challenges we face in the modern world.
