Black Sea Outflow Reshaped Mediterranean Climate 11,000 Years Ago

An international team led by the University of Barcelona determined that a large release of freshwater from the Black Sea to the Aegean Sea significantly altered ocean circulation in the Eastern Mediterranean around 11,000 years ago. Researchers analyzed a 42,000-year-old marine sediment core from the Aegean Sea, identifying the Black Sea as a key driver in the formation of Sapropel 1, a widespread layer of organic-rich sediment.

Previously, scientists primarily attributed Sapropel 1’s formation to increased rainfall and river runoff from North Africa. This new study challenges that view, demonstrating the substantial impact of Black Sea outflow on water stratification and deep-water formation in the Aegean.

Understanding this ancient climate event provides insights into how large freshwater inputs can disrupt ocean currents, with implications for predicting the consequences of future climate change and meltwater events. The team hopes to further refine understanding of the interplay between climate, hydrology, and ocean circulation in warm periods.