Quran on Oceans
Quran on the Barrier Between Seas
(And it is He Who has let free the two seas (kinds of water): this is palatable and sweet, and that is salty and bitter; and He has set a barrier and a complete partition between them.) (25:53)
The fact that the water of the oceans do not mix with each other, has only been discovered lately by oceanographers. This is due to the physical force called "surface tension"26; therefore, waters of neighboring seas do not mix. It is caused by the difference in the density of their waters; surface tension prevents them from mingling with one another, just as if a thin wall were between them. The Amazon River's water pours into the Atlantic Ocean and yet preserves its traits even after it goes out 200 meters in the Ocean.
There are three main salinity regimes in coastal waterways: stratified; partially mixed and fully mixed.
Quran on Darkness in the Seas and Internal Waves
(Or [the state of a disbeliever] is like the darkness in a vast deep sea, overwhelmed with waves topped by waves, topped by dark clouds, (layers of) darkness upon darkness: if a man stretches out his hand, he can hardly see it! And he for whom Allah has not appointed light for him there is no light.) (24:40)
This diagram shows the depth that light will penetrate in clear ocean water. Because red light is absorbed strongly, it has the shallowest penetration depth, and blue light has the deepest penetration depth. (Applied Optics, Vol. 20 (177) Smith, R.C. and K.S. Baker. 1981) Also see official NASA website.
It is well-known and affirmed scientifically that in the extreme depths of the ocean there is no light only darkness. The cause for this is that sunrays cannot reach it, for oceans range from a few hundred meters deep to being 11034 meters deep! The darkness in deep seas and oceans is found around a depth of 200 meters and below. At this depth, there is almost no light. Below a depth of 1000 meters there is no light at all. Therefore, most of the sun's rays are absorbed by the water at 100 meters. This portion of the sea is known as the luminous portion. Thereafter 1% of the sun's rays are visible at 150 meters, and 0.01% of the rays at 200 meters.
The ozone layer in the atmosphere reflects most of the ultra-violet rays, whereas the clouds reflect 30% and absorbs 19% of these rays. Only 51% of these rays reach the sea; between 3 and 30 % of the sunlight is reflected at the sea surface. Then almost all of the seven colors of the light spectrum are absorbed one after another in the first 200 meters, except the blue light.
Quran on Internal Waves
Scientists have recently discovered that there are internal waves which "occur on density interfaces between layers of different densities"28. The internal waves cover the deep waters of seas and oceans because the deep waters have a higher density than the waters above them. Internal waves act like surface waves. They can also break, just like surface waves. Internal waves cannot be seen by the human eye, but they can be detected by studying temperature or salinity changes at a given location.
Internal waves and scales of ocean mixing. (Oceanography, Chris Garrett. Also see: http://www.nature.com/nature/journal/v422/n6931/full/422477a.html )
Internal waves at interface between two layers of water of different densities. One is dense (the lower one), the other one is less dense (the upper one). (Oceanography, gross, p. 204)
For example, Mediterranean Sea's water is warm, saline, and less dense, compared to Atlantic Ocean's water. When Mediterranean 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 although there are large waves, strong currents, and tides in these seas, they do not mix or transgress this barrier.
The major water masses in the deep ocean are differentiated by their temperature and salinity. These properties determine their relative densities, which in turn drive deep thermohaline circulation of the oceans. NADW = North Atlantic Deep Water. AABW = Antarctic Bottom Water. Modified from figure courtesy of Dr. Steve Hovan, Indiana University of Pennsylvania.
This information has only been known to us in this age, with the advanced technology and equipment available to view this. The Prophet lived in a desert climate far from the ocean, and he did not travel across any oceans and the fact that the Quran gives such detailed information on this, is in fact a firm proof of the veracity of the Quran.