Question

Lake showing rare circulation periods at irregular intervals are categorized by

• A. Cold monomictic lakes
• B. Warm monomictic lakes
• C. Polymictic lakes
• D. Oligomictic lakes

Hint:

Remember:
- Oligo = Few/Rare.
- Poly = Many.
- Mono = One.
Hence, "Oligomictic" means rarely mixing.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Lakes are classified thermally based on the frequency and pattern of water circulation (mixing) throughout the year.

Step 2: Detailed Explanation:
- Oligomictic lakes: These are tropical lakes characterized by very rare, irregular periods of complete circulation (overturn/mixing).
The water remains thermally stratified almost year-round, and mixing occurs only during exceptionally cold or stormy weather events at irregular intervals of several years.
- Monomictic: Mixes completely once a year.
- Polymictic: Mixes frequently throughout the year.

Step 3: Final Answer:
Lakes showing rare circulation periods at irregular intervals are oligomictic lakes, corresponding to option (D).