Saturday, June 26, 2021


 From Science:

When continental plates smashed together about 12 million years ago, they didn’t just raise new mountains in central Europe—they created the largest lake the world has ever known. This vast body of water—the Paratethys Sea—came to host species found nowhere else, including the world’s smallest whales. Two new studies reveal how the sea took shape and how surrounding changes helped give rise to elephants, giraffes, and other large mammals that wander the planet today.

To build that timeline, paleo-oceanographer Dan Palcu of the University of São Paulo and his colleagues at the main campus assembled clues from geological and fossil records. At its largest extent, the ancient sea stretched from the eastern Alps into what is now Kazakhstan, covering more than 2.8 million square kilometers. That’s an area larger than today’s Mediterranean Sea, they note this week in Scientific Reports. Their analyses further estimate the lake once contained more than 1.77 million cubic kilometers of water, more than 10 times the volume found in all of today’s fresh- and saltwater lakes combined.

But climate shifts caused the lake to shrink dramatically at least four times in its 5-million-year lifetime, with water levels falling by as much as 250 meters between 7.65 million and 7.9 million years ago. During that largest episode of contraction, the lake lost as much as one-third of its water and more than two-thirds of its surface area. That sent water salinity in the lake’s central basin—which closely matches the outlines of today’s Black Sea—skyrocketing, from about one-third as salty as today’s oceans to a level on par with seawater. (Read more.)


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