Variations in the Black Sea water salinity from its latest salinization to the present state: Estimation based on mathematical modeling

Abstract

Analysis of the historic stages in the development of the Black Sea allows us to recognize several stages associated with global climate changes and tectonic processes in the Earth's crust. These processes have resulted in sea level variations; repeated changes in the regimes of its salinization and freshening; and the accumulation in the Black Sea depression of specific bottom sediments, which now reach 10-15 km in thickness and reflect all features of the geological past of this region (10). Abstract —The available published data were used to reveal the principal conditions and factors that control the formation and evolution of the Black Sea water salinity. Formalization of the major processes that contribute to the formation of sea salinity structure enabled, based on the present-day data on water balance, the reproduc- tion of profiles of water salinity and the coefficient of vertical water exchange K Z after 2, 4, 6, 8, and 10 ka since the beginning of water exchange with the Sea of Marmara through the Bosphorus. The time during which the present-day profile of the Black Sea water salinity had formed was evaluated. The results of simulation for dif- ferent formation stages of the Black Sea salinity structure were used to determine the major ways of salt input into the sea (with river runoff and waters of the Lower Bosphorus Current) and its removal from the sea (the Upper Bosphorus Current). It was established that the Black Sea water salinity regime has virtually attained a stationary state.