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You should now have approximately 40 minutes left for this exercise.
The final aspect of ocean topography for today's session are the mediterranean seas.
Mediterranean seas are ocean basins that are nearly totally disconnected from the remainder of the world ocean. Exchange of water does take place through a narrow passage between the mediterranean sea and the adjacent ocean basin; but it is so restricted that the water in the mediterranean sea develops entirely different characteristics from the remainder of the world ocean.
The characteristics of mediterranean seas depend on the balance between rainfall and evaporation. Mediterranean seas with a net freshwater loss (evaporation exceeds precipitation) have water of much higher salinity than all other parts of the world ocean. Their water can be traced as a tongue of high salinity extending from the passage between the mediterranean sea and the adjacent ocean basin. Mediterranean seas with freshwater gain (precipitation exceeds evaporation) have much lower salinity than the remainder of the world ocean. Their water can be traced through a salinity minimum.
Mediterranean seas are not all deep. The Baltic Sea and the Persian Gulf are examples of mediterranean seas found entirely on the continental shelf. The Arctic Ocean, the Red Sea and the European-African Mediterranean Sea are examples of abyssal basins.
The next two pages show examples of deep mediterranean seas.
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© 2000 M. Tomczak