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?

The correct answer is Option 4 (1, 2 and 3). All three statements accurately describe the dynamics of ocean salinity.

• Statement 1 is correct: Salinity is primarily governed by the water cycle. Evaporation concentrates salts by removing freshwater, while precipitation dilutes it, lowering salinity. This is evident in the low salinity of the equatorial belt due to heavy rainfall.
• Statement 2 is correct: Salinity, temperature, and density are interrelated. Changes in temperature affect evaporation rates and ice formation/melting, which in turn alter salinity. Furthermore, salinity is a key determinant of seawater density; higher salinity increases density, driving global thermohaline circulation.
• Statement 3 is correct: While volcanic activity and hydrothermal vents contribute, terrestrial discharge is the primary source. Rivers carry dissolved minerals and salts weathered from rocks on land into the oceans. Although river water is "fresh," it contains minute concentrations of salts that accumulate over geological timescales.