The Qur'an on Seas and Rivers

The Qur’ān on Seas and Rivers 

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. 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 kilometres into the Atlantic at a depth of about 1000 meters with its own warm, saline, and less dense characteristics.  The Mediterranean water stabilises at this depth [see Figure 7].

Figure 7: The Mediterranean sea water as it enters the Atlantic over the Gibraltar sill with its own warm, saline, and less dense characteristics, because of the barrier that distinguishes between them.  Temperatures are in degrees Celsius (C°). (Marine Geology, Kuenen, p. 43, with a slight enhancement.)

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:

“He released the two seas, meeting [side by side]; Between them is a barrier [so] neither of them transgresses.” Qur’ān 55:19-20

However, when the Qur’ān speaks about the divider between fresh and salt-water, it mentions the existence of “a forbidding partition” with the barrier.  God has said in the Qur’ān:

“And it is He who has released [simultaneously] the two seas, one fresh and sweet and one salty and bitter, and He placed between them a barrier and prohibiting partition.” Qur’ān 25:53

One may ask, why did the Qur’ān mention the partition when speaking about the divider between fresh and salt-water, but did not mention it when speaking about the divider between the two seas?

Science has discovered that in estuaries, where fresh (sweet) and salt-water meet, the situation is somewhat different from what is found in places where two 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.”  

This partition (zone of separation) has a different salinity from the fresh water and from the salt water [see Figure 8].

Figure 8: Longitudinal section showing salinity (parts per thousand) in an estuary. We can see here the partition (zone of separation) between the fresh and the salt water. 

This information has been discovered only recently, using advanced equipment to measure temperature, salinity, density, oxygen dissolubility, etc.  The human eye cannot see the difference between the two seas that meet, rather the two seas appear to us as one homogeneous sea.  Likewise, the human eye cannot see the division of water in estuaries into the three kinds: fresh water, salt water and the partition (zone of separation).

Studies related to marine sciences and sea depths did not practically start before the beginning of the 18th century, when appropriate instruments and techniques were available and when advanced submarines were invented. After many decades of research the following facts were established;

The sea divides into two major parts:

- The surface sea that is penetrated by the solar energy and light.

- The deep sea where the solar energy and light are non-existent.

2.   The deep sea and surface sea differ in temperature, density, pressure, the amount of sunlight and the creatures living in each of them. They are separated by internal waves.

Sea internal waves - internal waves cover the deep sea and serve as a boundary between the deep sea and the surface sea. Surface waves cover the sea surface and serve as a boundary between water and air. Internal waves were discovered in 1900’s. The lengths of internal waves range from tens to hundreds of kilometres. Their height ranges from 10 meters and 100 meters.

The deeper the sea, the darker it becomes. As dark as pitch from the depth of about (200) meters. At this depth there starts the thermocline that separates the warm surface waters from the cold waters of the deep. In it we find the internal waves that cover the cold water in the depth of the sea. In deep seas there are several layers of darkness, and light is non-existent in them. Living organisms and fish that live in them depend on chemical energy to produce light with which to find their way. Some species are blind and use means other than sight to sense their surroundings. Darkness begins at the depth of about 200 meters, and the entire visible light disappears at the depth of about 1000 meters. The structure of these fish is mostly water to withstand the enormous pressure.

God has said in the Qur’ān:

“Or [they are] like darknesses within an unfathomable sea which is covered by waves, upon which are waves, over which are clouds - darknesses, some of them upon others. When one puts out his hand [therein], he can hardly see it.” Qur’ān 24:40

This verse mentions the levels of darkness found in deep seas and oceans one on top of the other.  Human beings are not able to dive more than forty meters without the aid of submarines or special equipment.  Human beings cannot survive unaided in the deep dark part of the oceans, such as at a depth of 200 meters.

Figure 9: Between 3 and 30 percent of the sunlight is reflected at the sea surface. Then almost all of the seven colours of the light spectrum are absorbed one after another in the first 200 meters, except the blue light. (Oceans, Elder and Pernetta, p. 27.)

Scientists have only discovered this darkness by means of special equipment and submarines that have enabled them to dive into the depths of the oceans.

We can also understand from the following sentences in the previous verse, “...in a deep sea.  

It is covered by waves, above which are waves, above which are clouds....,” that the deep waters of seas and oceans are covered by waves, and above these waves are other waves.  

It is clear that the second set of waves are the surface waves that we see, because the verse mentions that above the second waves there are clouds.  But what about the first waves?  Scientists have recently discovered that there are internal waves which “occur on density interfaces between layers of different densities.” [see figure 10].

Figure 10: Internal waves at the interface between two layers of water of different densities.  One is dense (the lower one), the other one is less dense (the upper one).

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.