The correct option is 2 and 3 only.
Explanation
The temperature of ocean water is not uniform; it varies horizontally (with latitude) and vertically (with depth). The horizontal distribution of surface water temperature is primarily influenced by the amount of insolation received at different latitudes.
Statement 1 is Incorrect
According to standard geographical data, the average temperature of surface water of the oceans is approximately 27°C, not 10°C. This value represents the warmer surface layers, particularly in tropical and subtropical regions, before the temperature begins to decline towards the poles.
Statement 2 is Correct
The temperature of surface water gradually decreases from the equator towards the poles. This occurs because the amount of solar insolation decreases as latitude increases. Consequently, ocean waters in equatorial regions are warmest, while those in polar regions are coldest.
Statement 3 is Correct
The rate of decrease in temperature with increasing latitude is generally observed to be 0.5°C per latitude. This gradient reflects the progressive reduction in solar energy reaching the Earth's surface as one moves away from the equator.
Key Takeaway
Ocean surface temperature is inversely related to latitude, with an average surface temperature of roughly 27°C and a poleward temperature decay rate of approximately 0.5°C per latitude.