sweetsaltwaters“He has let free the two bodies of flowing water, meeting together: Between them is a Barrier which they do not transgress.” – [Al-Qur’an 55:19-20]

In the Arabic text the word barzakh means a barrier or a partition. This barrier, however, is not a physical partition.

The Arabic word maraja literally means: ‘they both meet and mix with each other’. Early commentators of the Qur’an were unable to explain the two opposite meanings for the two bodies of water, i.e. they meet and mix, and at the same time there is a barrier between them. 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.9 Oceanologists are now in a better position to explain this verse. There is a slanted unseen water barrier between the two seas through which water from one sea passes to the other.

But when the water from one sea enters the other sea, it loses its distinctive characteristic and becomes homogenized with the other water. In a way this barrier serves as a transitional homogenizing area for the two waters.

This phenomenon is also mentioned in the following verse of the Qur’an:

“And made a separating bar between the two bodies of flowing water?” [Al-Qur’an 27:61]

This phenomenon occurs in several places, including the divider between the Mediterranean and the Atlantic Ocean at Gibralter. A white bar can also be clearly seen at Cape Point, Cape Peninsula, South Africa where the Atlantic Ocean meets the Indian Ocean.

But when the Qur’an speaks about the divider between fresh and salt water, it mentions the existence of “a forbidding partition” with the barrier.

“It is He Who has let free the two bodies of flowing water: one palatable and sweet, and the other salty and bitter; yet has He made a barrier between them, and a partition that is forbidden to be passed." [Al-Qur’an 25:53]

Modern science has discovered that in estuaries, where fresh (sweet) and salt water meet, the situation is somewhat different from that found in places where two salt water seas meet. It has been discovered that what distinguishes fresh water from salt water in estuaries is a “pycnocline zone with a marked density discontinuity separating the two layers.”10 This partition (zone of separation) has a salinity different from both the fresh water and the salt water.11

This phenomenon occurs in several places, including Egypt, where the river Nile flows into the Mediterranean Sea.

These scientific phenomena mentioned in the Qur’an was also confirmed by Dr. William Hay, a well-known marine scientist and Professor of Geological Sciences at the University of Colorado, U.S.A.


Prof. Durga Rao is a world renowned expert in the field of Marine Geology and was a professor at King Abdul Aziz University in Jeddah. He was asked to comment on the following verse:

“Or (the Unbelievers’ state) – is like the depths of darkness in a vast deep ocean, overwhelmed with billow topped by billow, topped by (dark) clouds:depths of darkness, one above another: if a man stretches out his hand, he can hardly see it! For any to whom Allah giveth not light, there is no light!” [Al-Qur’an 24:40]

Prof. Rao said that scientists have only now been able to confirm, with the help of modern equipment, that there is darkness in the depths of the ocean. Humans are unable to dive unaided underwater for more than 20 to 30 metres, and cannot survive in the deep oceanic regions at a depth of more than 200 metres. This verse does not refer to all seas because not every sea can be described as having accumulated darkness layered one over another. It refers especially to a deep sea or deep ocean, as the Qur’an says, “darkness in a vast deep ocean”.

This layered darkness in a deep ocean is the result of two causes:

1. A light ray is composed of seven colours seen in the rainbow. These seven colours are Violet, Indigo, Blue, Green, Yellow, Orange and Red (VIBGYOR). The light ray undergoes refraction when it hits water. The upper 10 to 15 metres of water absorb the red colour. Therefore, if a diver is 25 metres under water and gets wounded, he would not be able to see the red colour of his blood, because the red colour does not reach this depth. Similarly, orange rays are absorbed at 30 to 50 metres, yellow at 50 to 100 metres, green at 100 to 200 metres, and finally, blue beyond 200 metres and violet and indigo above 200 metres. Due to successive disappearance of colour, one layer after another, the ocean progressively becomes darker, i.e. darkness takes place in layers of light. Below a depth of 1000 meters there is complete darkness.12

2. The sun’s rays are absorbed by clouds which in turn scatter light rays thus causing a layer of darkness under the clouds. This is the first layer of darkness. When light rays reach the surface of the ocean they are reflected by the wave surface giving it a shiny appearance. Therefore, it is the waves which reflect light and cause darkness. The unreflected light penetrates into the depths of the ocean. Thus, the ocean has two parts. The surface characterized by light and warmth and the depth characterized by darkness. The surface is further separated from the deep part of the ocean by waves.

The internal waves cover the deep waters of seas and oceans because the deep waters have a higher density than the waters above them.

The darkness begins below the internal waves. Even the fish in the depths of the ocean cannot see; their only source of light is from their own bodies.

The Qur’an describes this aptly: “Darkness in a vast deep ocean overwhelmed with waves topped by waves”.

In other words, above these waves there are more types of waves, i.e. those found on the surface of the ocean. The Qur’anic verse continues, “topped by (dark) clouds; depths of darkness, one above another.”

These clouds as explained are barriers one over the other that further cause darkness by absorption of colours at different levels.

Prof. Durga Rao concluded by saying,

“1400 years ago a normal human being could not explain this phenomenon in so much detail. Thus the information must have come from a supernatural source”.

“It is He Who has Created man from water: then has He established relationships of lineage and marriage: for thy Lord has power (over all things).” [Al-Qur’an 25:54]

Was it possible 14 centuries ago for any human being to guess that every living being was made from water? Moreover would such a guess be conceivable by a human being in the deserts of Arabia where there has always been scarcity of water?