The Dawah Center – Quran & Science
Modern Science has discovered that in the places where two different seas meet, there is a barrier between them.
This barrier divides the two seas so that each sea has its own temperature, salinity, and density. (Davis, Principles of Oceanography, pp. 92-93)
For example, Mediterranean sea water is warm, saline, and less dense, compared to Atlantic ocean water.
When Mediterranean sea water enters the Atlantic over the Gibraltar sill, it moves several hundred kilometers into the Atlantic at a depth of about 1000 meters with its own warm, saline, and less dense characteristics. The Mediterranean water stabilizes at this depth (Davis, p. 93) [see Figure below].
Although there are large waves, strong currents and tides in these seas, they do not mix or transgress this barrier.
The Qur’ān mentioned that there is a barrier between two seas that meet and that they do not transgress. God has said: