Given below are two statements, one labelled as Assertion (A) and the other labelled as Reason (R). Select your answer from the following options.

Assertion(A): The oceanic salinity decreases from the equator towards the pole.

Reason(R): Low precipitation in the polar regions accounts for its maximum salinity.

The correct answer is A is true but R is false.

Key Points

• Generally, salinity decreases from the equator towards the pole but the highest salinity is seldom recorded near the equator because near the equator, there is heavy rainfall, high relative humidity, cloudiness, and calm air of the doldrums.
• The polar areas experience very little evaporation and receive large amounts of freshwater from the melting of ice. This leads to low levels of salinity, ranging between 20ppt and 32ppt.
• The maximum oceanic salinity (37ppt) is observed between 20° N and 30° N and 20° W - 60° W. It gradually decreases towards the north.

Confusion Points

• One needs to understand here that statement first is correct.
• As on an average, salinity decreases from equator towards the poles.
• However, it is important to note that the highest salinity is seldom recorded near the equator though this zone records high temperature and evaporation but high rainfall reduces the relative proportion of salt. Thus, the equator accounts for only 35‰ salinity.
• If we talk about the statement of Reason- it is incorrect because Salinity further decreases in the polar zones because of influx of Glacial melt-water.