Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q7 (CDS-I/2002) Geography › World Physical Geography › Ocean water properties Answer Verified

The average salinity of the ocean water is

Result
Your answer: —  Â·  Correct: C
Explanation

The average salinity of the global ocean is approximately 35 parts per thousand (ppt or ‰) [1][t1]. Salinity is defined as the total content of dissolved salts in seawater, calculated as the amount of salt in grams dissolved in 1,000 grams of water [3]. While expressed as 35 ppt, this value is equivalent to 3.5% by weight, as 35 parts out of 1,000 equals 3.5 parts out of 100 [t2][t10]. Although specific regions vary—such as the Baltic Sea at 7 ppt or the Red Sea at 39 ppt due to evaporation and freshwater influx—the global mean remains consistently cited at 35 ppt [1][c4]. This concentration is primarily composed of sodium and chloride ions, which account for over 90% of the dissolved minerals [t2]. Therefore, 3.5% is the correct percentage representation of the average ocean salinity.

Sources

  1. [1] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 12: The Oceans > Salinity of the Ocean > p. 107
  2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 33: Ocean temperature and salinity > 33.2. Ocean Salinity > p. 518
  3. [3] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 12: Water (Oceans) > SALINITY OF OCEAN WATERS > p. 104
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
61%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

CAPF · 2010 · Q79 Relevance score: 2.51

Salinity in ocean water decreases when :

CAPF · 2016 · Q18 Relevance score: 0.82

Consider the following statements relating to Sea Salinity: 1. The ocean salinity depends on evaporation and precipitation 2. Any change in the temperature or density influences the salinity 3. Major source of sea salinity is terrestrial discharge by rivers Which of the statements given above are correct?

CDS-I · 2006 · Q52 Relevance score: -0.23

Assertion (A): The salinity of oceans is relatively higher near the equator than at other regions. Reason (R): Equator region has heavy rainfall, high relative humidity and calm air.

NDA-II · 2018 · Q27 Relevance score: -1.77

Which one of the following is known as a zone of sharp salinity change in the vertical section of ocean?

CAPF · 2015 · Q93 Relevance score: -2.28

It is reported that there is an ongoing decrease in the pH value of ocean water because of global warming. It happens due to :