The Barrier between Rivers and seas (Estuary)Allah (SWT) says: “It is He Who has mixed up (maraja) the two seas, this (one) very fresh [river], and this (other one) very salt, and has made between them a barrier and a forbidding partition.” (Quran 25: 53)
Man from olden times has seen the rivers flow into the sea and noticed that the river water gradually loses its distinctive color and taste as it goes deeper into the sea. He has concluded that the river gradually mixes with seawater; otherwise the river would change into a freshwater sea expanding day by day till it would overwhelm the original sea.
With the advances of science and its endeavor to explore the mysteries of the Universe man started investigating the way a sea meets with a river, and studied samples of water from the area where a river meets a sea. He studied the levels of salinity, and measured temperatures and density, and collected specimens of living organisms and classified them determining the places of their existence and studying their abilities to live in river and marine environments.
Three type of water at EstuaryAfter surveying a large number of estuaries, scholars discovered unknown secrets, and researchers found out that waters are of three types:
1. Water of rivers that is very fresh.
2. Seawater that is very salty.
3. Water of the estuary that is a mixture of salt and fresh water. The estuary is an area separating the river from the sea and moves between them under the influence of tides and the flooding or recession of the river. The closer to the sea the greater its salinity in it; the closer to the river the fresher its water.
Three types of water at Estuary
Around the estuary there is an aquatic barrier that preserves its distinctive properties even if the river is flowing into the sea in the form of a waterfall.
In spit of the forces of tides and floods and recessions that are regarded as very strong factors of mixing, no direct meeting occurs between the water of the river and that of the sea because the barrier surrounding the estuary always separates them. But the water of the river mixes with seawater slowly through the partition represented by the water of the estuary and the water barrier surrounding it.
The three water masses (the water of the river, seawater and the water of the estuary) differ with respect to the degree of salinity. The researchers that classified the organisms living in them discovered the following:
a. Most of the creatures living in the sea, river, or estuary cannot live in an environment other than their own habitat: otherwise, they would die. But a few species, such as salmons and eels, can live in all three habitats and can adapt to every environment.
b. By classifying the three environments where living organisms live, the estuary is regarded as an area of confinement for most of the organisms living in it, for such organisms cannot live save in the aquatic medium the degree of salinity of which suites their osmotic pressure, and they would die if they came out of the habitat that is suitable for them, i.e., the estuary.
Meanwhile, the estuary is a forbidden area for most of the living organisms that live in the sea or the river, for these organisms die if they enter it due to the difference in the osmotic pressure also.
Allah (SWT) has created this wonderful aquatic system to keep these meeting aquatic masses apart and preserve their distinctive properties so that rivers keep their freshness and all aquatic organisms find the suitable environments for their living. If the naked eye cannot see this partition with which Allah (SWT) preserves the estuary, satellites today have provided us with wonderful images showing us the boundaries of the three aquatic masses that get clearer with the increase of the difference in the temperature of the water and the materials it carries.
Moderate Resolution Imaging Spectroradiometer (MODIS) image of the Rio de la Plata estuary (Argentina), with input of river water from the Uruguay and Parana rivers notably visible.
Although freshwater mixes with seawater, there are limits at the two ends of the limited area that impose constrictions on what enters it or comes out of it. This exactly describes the estuary. The Holy Qur’an describes the area where the three aquatic masses meet very precisely and concisely showing the relationship between the three aquatic masses and the organisms living in them.
Allah (SWT) says: “It is He Who has mixed up (maraja) the two seas, this (one) very fresh [river], and this (other one) very salt, and has made between them a barrier and a forbidding partition.” (Quran 25: 53)
Linguistic meanings and the sayings of the commentators:The word “maraja” has two obvious meanings:
Allah (SWT) says: “But they deny the truth when it comes to them, so they are in a confused (mixed up) state (amrin marij).” (Quran 50: 5) In Lisan al-‘Arab (amrin marij: i.e., mixed up) Al-Asfahani said in al-Mufradat: (the original meaning of “Marj” is “mixing up”) Al-Zabidi said: (Allah “maraja” the two seas, the fresh and the salt, means He mixed them up till they met.) Al-Zajjaj said: “maraja” means He mixed up the salt sea with the fresh sea.
Ibn Jarir al-Tabari said: (And it is Allah Who mixed up the two seas and thus “amraja” one with the other and let it flow into it.) The basic sense of “marj” is “mixing up”, as in the Saying of Allah: “In amrin marij”, i.e. mixed up.
Ibn ‘Abbas is reported to have said about the Saying of Allah (He maraja the two seas): It means He cast one on the other. Mujahid said: He let one flow on the other. Al-Dhahhak agreed with Ibn ‘Abbas. This meaning is supported by a group of commentators, such as al-Qurtubi, Abu Hayyan, al-Alusi, al-Khazin, al-Razi, al-Shawkani and al-Shanqiti.
Second: Going to and fro and turbulence (restlessness)
In Mu’jam Maqayis al-Lugha, Ibn Faris said: (The consonants m, r and j together make up a basic unit expressing the idea of going to and fro and turbulence.) He said: “the ring maraja around the finger” means “it became loose.” The same sense applies to all the uses of the word, such as (The trusts and pledges of the people marajat) meaning: They were upset and mixed up. The same meaning is mentioned in al-Sihah by al-Jawhari and in Lisan al-‘Arab. The same is said by al-Zabidi and al-Asfahani.
(The two seas: This is ‘adhbun furat (very fresh) and this is milhun ‘ujaj (very salt))
The fresh sea is the river, The Holy Qur.an describes it with two properties: “‘adhb” and “furat”, which collectively mean that the water of this sea (i.e., the river) is very fresh as implied by the word “furat”. This description excludes the water of the estuary which can be described as ‘adhb (fresh) but cannot be said to be “furat”.
The very salt water is the water of the seas. The Holy Qur’an describes it with two properties: “milh” and “’ujaj”. ‘Ujaj means very salt, thus excluding the water of the estuary, for it is a mixture of salt and fresh water and cannot be described as milhun ‘ujaj (very salt).
Thus with these four properties we can demarcate the following three masses of water:
1. (This is)‘adhbun furat (very fresh water): the water of the river,
2. (This is) milhun ‘ujaj (very salt water): seawater, and
3. (and placed between them barzakhan and hijran mahjura): Barzakh is the aquatic barrier surrounding the estuary.
What about the hijran mahjura?Hijr or hajr means “prohibition and restriction”. The mind is described as “hijr” because it prevents one from doing what ought not to be done. Allah (SWT) says: “There is indeed in them (oaths mentioned above) sufficient proofs for men of hijr (understanding).” (Quran 89: 5) A fool is usually prohibited by the judge from disposing of his wealth, for it is in hijr or hajr, the latter being preferable. In a hadith narrated by Abu Dawud, al-Tirmidhi, al-Nasa’i and Ahmad Allah’s Messenger (peace be upon him) said to a Bedouin: “You have “tahajjarta” (restricted) what is wide or spacious.”
Ibn Manzur said: “You have ‘tahajjarta” what is wide” means “You have restricted what Allah has made spacious and kept it for yourself exclusively.” We can understand here that the living organisms in the estuary live in confinement and are not allowed to come out of it.
This area is also described as mahjurah (i.e., prohibited). From this expression we may imply another meaning apart from the first; namely, the other organisms are not allowed to enter it either. Therefore, it is hijr (prison) for the organisms living in it, and admittance to it is not permissible for those living outside it. The meaning of the verse is then: He placed between the sea and the river an aquatic partition, i.e., the aquatic barrier surrounding the estuary, and made the water between the river and the sea a place of confinement for its living organisms and forbidden for the organisms living outside it in the sea or the river.
The Estuary region has its own organisms
See how human knowledge fails to grasp the details of what the Holy Qur’an has stated. Some of the commentators mention that the barrier is land (as barrier of earth). Some others declared their inability to specify and describe it and said that it was a partition that could not be seen by anybody. All this shows us that the knowledge given to Muhammad (peace upon him) included what could not be perceived by the human mind at the time of the Messenger (peace be upon him) and during several centuries following it.
In the Qur’anic Verse: “It is He Who has mixed up (maraja) the two seas, this (one) very fresh [river],” (Quran 25: 53)
the Qur’anic text does not describe the water as ‘adhb (fresh) but it modifies this characteristic with the modifier “furat” to intensify the freshness of the water; otherwise, the reader may wrongly think that the estuary is included in this description, for it is characterized by some freshness. Thus describing the water of the sea referred to as very fresh excludes the estuary from this description and keeps it for the river as such, by saying: “This is very fresh (‘adhbun furat).” Likewise, the Qur’anic text excludes the estuary from the zone of the very salt sea through modifying the adjective “salt” with the modifier “‘ujaj” to intensify the salinity of the seawater, lest one should claim that the estuary also has salinity and thus it is part of the salt sea. By adding the word “‘ujaj” the Qur’anic text excludes the estuary from this description, which is kept for the sea as such. Consequently we have three distinct zones or areas: a very salt sea, a very fresh sea (river) and the estuary that is a mixture of fresh and salt water.
Now see how people of great talent were unable, several centuries after the revelation of the Holy Qur’an, to understand such subtle facts and mysteries and how science finally came to reveal them. Allah (SWT) tells the Truth when He says:
“Say: ‘Praise be to Allah.” He will show you His Signs and you will recognize them.” (Quran 27: 93)
See how the intended meaning has been settled at last after the commentators were uncertain about it for a long time. Allah (SWT) says:
“For every news there is a reality and you shall come to know.” (Quran 6: 67) Allah (SWT) also says: “And you shall certainly know the truth of it after a while.” (Quran 38: 88)
Who informed the Prophet?
Then who informed the illiterate Prophet, who lived in an illiterate nation in a desert environment where there was no river or an estuary, of these subtle secrets concerning the aquatic masses of various structures: very fresh, very salt and a barrier and an area of confinement in-between, and that hajr means the area into which organisms living in the other two aquatic areas are not admitted.
How long did this take man to discover? How many minute instruments and modern equipment has he used to find out these facts, which the illiterate Prophet (peace be upon him) mentioned 14 hundred years ago very precisely and concisely?
Look into the fine difference that distinguishes between the meeting of two salt seas and that between a salt sea and a fresh one. You will see that in the first case there is no zone of confinement because the osmotic difference in the two seas is not great, which allows the living organisms in the two seas to transfer from one sea to the other. In the case of the meeting of the salt sea and the fresh one (the river), there must be an estuary where the water is a mixture that is neither very salt nor very fresh, which results in great differences in the osmolity and consequently makes the estuary a zone of confinement for the organisms living in it preventing them from moving into the sea or the river. This also prohibits the organisms living in the sea or the river from entering the estuary. See how the Holy Qur’an expresses these facts clearly, nicely and concisely. In describing the meeting of the two salt seas it says: “He has let free (MARAJA) the two sees meeting together. Between them is a barrier that they do not transgress” in describing the meeting between the salt water and the fresh water, it says: “It is He Who has mixed up (maraja) the two seas, this (one) very fresh [river], and this (other one) very salt, and has made between them a barrier and a forbidding partition.”
Whence, then, did this knowledge come to Muhammad (peace be upon him) other than from Allah, Who knows everything?