Question

What are the key factors contributing to pronounced thermal stratification in lakes during summer?

1. Increased solar intensity during summer heats the surface layer significantly, while lower layers remain cooler.
2. The rapid mixing of water layers by strong winds prevents the formation of distinct temperature gradients.
3. The thermally stratified layers offer resistance to mixing by wind, helping to maintain the temperature differences.
4. A decrease in solar radiation during summer leads to the formation of thermal gradients.

• A. i only
• B. None of these
• C. iii only
• D. i, iii

Answer 1

Answer:

D. i, iii

• The pronounced thermal stratification observed in lakes during summer is primarily driven by two factors.

• Firstly, the increase in solar intensity leads to significant heating of the surface water (Epilimnion), creating a stark temperature difference with the cooler, deeper water (Hypolimnion).

• Secondly, these established temperature gradients make the water layers more resistant to mixing by wind.