Assalaamu alaykum. I asked you two times concerning an issue of tafseer and you sent me links to other fatwas, but that did not really help. That is why I want to formulate my question a little different now: In Surah Ar-Rahmaan and Surah Al-Furqaan, Allaah describes a barrier between fresh and salty water. What was the opinion of ibn Katheer concerning that barrier? I also want you to comment on the claim of scientists who claimed that the black sea or the baltic sea lose some of their salt percentage. Would that not be impossible if there is a barrier between the seas that prevents mixing completely? That is why I called the scientists statement a 'claim'. May Allaah reward you. Wassalaamu alaykum wa rahmatullaah.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger. 

Ibn Katheer interpreted Al-Barzakh (barrier) to mean dry land in one of the verses and interpreted it to mean a divine barrier that prevents them from mixing together; a barrier that no one can see. At-Tabari reported the two interpretations from some scholars of the Salaf (righteous predecessors), but there is no contradiction between the two matters as both interpretations might be correct.

Tafseer Ibn Katheer reads:

"Allaah’s saying (which means) {…and He has set a barrier and a complete partition between them}, meaning, between the sweet water and the saltwater; {a barrier}, means a partition, which is dry land, {…and a complete partition}, means a barrier, to prevent one of them from reaching the other. This is like the verse in which Allaah says (what means): {He has let loose the two seas meeting together. Between them is a barrier which none of them can transgress. Then which of the blessings of your Lord will you both deny.} [Quran 55:19-21]; Allaah also says (what means): {Is He [not best] Who made the earth a stable ground and placed within it rivers and made for it firmly set mountains and placed between the two seas a barrier? Is there a deity with Allaah? [No], but most of them do not know.} [Quran 27:61]"

Tafseer Ibn Katheer also reads:

"(And has set a barrier between the two seas) means, He has placed a barrier between the fresh water and the salty water, to prevent them from mixing lest they corrupt one another. Divine wisdom dictates that each of them should stay as it is meant to be. The sweet water is that which flows in rivers among mankind, and it is meant to be fresh and palatable so that it may be used to water animals and plants and fruits. The salty water is that which surrounds the continents on all sides, and its water is meant to be salty and undrinkable lest the air be corrupted by its smell, as Allaah says (what means): {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.} [Quran 25:53]"

At-Tabari favored the last view, as he said in Jaami’ al-Bayaan (19/284):

"Abu Ja'afar said, 'We have chosen the statement that we have chosen about the meaning of the saying of Allaah: {…and He placed between them a barrier and prohibiting partition} and we did not choose the statement of those who said that its meaning is that Allaah placed a partition of dry land between them because Allaah informed us at the beginning of the verse that He has 'maraja' the two seas; in the language of the Arabs, 'maraja' means 'mixed', as I clarified earlier, so if the dividing barrier between the fresh sea and the sea which is salty and bitter is a land, then there will be no mixing between the two seas in the first place. However, Allaah, the Exalted, informed us that He mixed the two seas, but we know His ability to prevent the salty and bitter sea from spoiling the fresh sea, although they mix with each other. If each of the two seas was separate from the other by land, then there would be no mixing between them and there would be no miracle to draw the attention of the ignorant people about it and to remind them, even though everything that Allaah has created is miraculous and a great admonition and a clear-cut evidence (for the people).'"

As regards the Baltic Sea and the Black Sea, then we do not have information to authoritatively assert about them, but we have already mentioned in fatwa 256738 that there might be variations in the salinity of seas.

Allaah knows best.