The Quran 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.1
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 kilometers into the Atlantic at a
depth of about 1000 meters with its own warm, saline, and less dense
characteristics. The Mediterranean water stabilizes at this depth2
(see figure 13).
Figure 13: 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
Although there are large waves,
strong currents, and tides in these seas, they do not mix or transgress this
The Holy Quran mentioned that there is a barrier between two
seas that meet and that they do not transgress. Allah has said:
He has set free the two seas meeting
together. There is a barrier between them. They do not transgress.
But when the Quran speaks about the divider between fresh
and salt water, it mentions the existence of “a forbidding partition” with the
barrier. Allah has said in the Quran:
He is the one who has set free the two
kinds of water, one sweet and palatable, and the other salty and bitter. And He
has made between them a barrier and a forbidding partition. (Quran,
One may ask, why did the Quran 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?
Modern 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.”3
This partition (zone of separation) has a different salinity from the fresh
water and from the salt water4
(see figure 14).
Figure 14: 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. (Introductory Oceanography,
Thurman, p. 301, with a slight enhancement.)
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).
(1) Principles of Oceanography,
Davis, pp. 92-93.
(2) Principles of Oceanography,
Davis, p. 93.
(3) Oceanography, Gross, p. 242.
Also see Introductory Oceanography, Thurman, pp. 300-301.
(4) Oceanography, Gross, p. 244, and
Introductory Oceanography, Thurman, pp. 300-301.