The Miraculous Barrier Between Salt Water and Fresh Water in the Quran

The Quran is full of signs that reflect the divine wisdom of Allah, many of which have been scientifically confirmed centuries after its revelation. One of these signs is the mention of a barrier between saltwater and freshwater, a phenomenon that science only understood in modern times.

In Surah Al-Furqan (25:53), Allah says:

“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.”

And again in Surah Ar-Rahman (55:19–20):

“He released the two seas, meeting [side by side]; between them is a barrier [so] neither of them transgresses.”

This is a fascinating observation. Despite the fact that saltwater and freshwater bodies meet in places like estuaries, they do not mix completely. The barrier that prevents them from merging is called the halocline in oceanography, where the difference in density between the two types of water keeps them distinct. This is known today as the “barrier effect,” something that wasn’t known or studied during the time of the Prophet Muhammad (peace be upon him).

These verses, revealed more than 1,400 years ago, describe a natural phenomenon that was only scientifically explained in the 20th century. The fact that the Quran accurately mentions this, long before human knowledge could verify it, is a powerful sign for those reflecting upon the signs of Allah.

This is just one of the countless examples of the miraculous nature of the Quran. Allah’s wisdom is eternal, and His signs are present in the world around us, waiting for us to uncover them.