Video Transcript
Which of the following seas has a
below-average salinity? (A) The Red Sea, (B) the North Sea,
(C) the Dead Sea, (D) the Arabian Gulf.
This question asks about the
salinity of different seas. Salinity is the amount of salt
dissolved in a body of water. The salinity of seas mainly depends
on two factors. The first is water input. Freshwater is added to seas by
precipitation and rivers. This freshwater decreases the
salinity. This is because the amount of salt
is dissolved in a larger amount of water. The second factor is
evaporation. Water evaporates when it is
subjected to higher temperatures. Increasing evaporation increases
the salinity. This is because the amount of salt
is dissolved in a smaller amount of water. The average salinity of seas around
the world is approximately 35 grams per liter.
To determine which sea has a
below-average salinity, we need to determine which of them has a high water input
and low evaporation rates. The Red Sea receives relatively
small amounts of rain and has no major river pouring into it. As a result, it has low water
input. It also has high evaporation rates
as it lies near the equator with hot temperatures all year. The North Sea has high water input
as it receives high precipitation and water from rivers and streams. It also has low evaporation rates
as it lies away from the equator.
The Dead Sea is a landlocked sea
and is considered one of the saltiest bodies of water on Earth. Its high salinity is due to the
fact that it is not connected to any seas or oceans and has extremely low water
input with a high evaporation rate. The Arabian Gulf is similar to the
Red Sea as it has low water input and high evaporation rates.
From this information, we can
conclude that the North Sea, with high water input and low evaporation rates, has a
below-average salinity.
