Water from the Atlantic and Mediterranean seas can mix under certain conditions, and in fact, they do mix to some extent. However, the mixing between these two bodies of water is not complete, and there are distinct differences between them.
The Atlantic Ocean and the Mediterranean Sea are connected by the Strait of Gibraltar, which is a narrow passage between the southernmost tip of Spain and the northernmost part of Morocco. The strait acts as a barrier, limiting the exchange of water between the two bodies.
The Mediterranean Sea has a higher salinity compared to the Atlantic Ocean due to its high evaporation rates and limited freshwater input from rivers. The Atlantic Ocean, on the other hand, has lower salinity due to the influence of freshwater from various sources, such as rivers and precipitation.
Although there is some mixing of waters at the surface, the denser, saltier Mediterranean water tends to sink below the lighter Atlantic water, creating a layering effect. This process is known as "stratification" and restricts deep mixing between the two bodies of water.
However, there are occasions when mixing occurs on a larger scale. During periods of intense storm activity or significant weather events, strong winds and currents can disrupt the stratification and allow for more substantial mixing between the Atlantic and Mediterranean waters. These events are relatively rare and do not result in a complete homogenization of the two bodies of water.
It is important to note that while there is limited mixing between the Atlantic and Mediterranean seas, the exchange of water, heat, and nutrients plays a significant role in the overall climate and ecology of the region.