In a lake, the upper warmer oxygen-rich water zone is called

Options

A. epilimnion
B. hypolimnion
C. limnetic zone
D. profundal zone

Answer

To answer the question "In a lake, the upper warmer oxygen-rich water zone is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Lake Stratification**: Lakes are typically stratified into different zones based on temperature and oxygen levels. The three main zones are:
- **Epilimnion**: The uppermost layer, which is warm and rich in oxygen.
- **Metalimnion**: The middle layer, where temperature decreases and oxygen levels may vary.
- **Hypolimnion**: The bottom layer, which is cold and has low or no oxygen.

2. **Identifying the Upper Warm Zone**: The question specifically asks for the upper warmer oxygen-rich water zone.
- The **epilimnion** is characterized by being warm and having a high concentration of oxygen due to its exposure to sunlight and contact with the atmosphere.

3. **Evaluating the Options**:
- **Epilimnion**: This is the correct answer as it is the upper layer that is warm and oxygen-rich.
- **Hypolimnion**: This is incorrect because it is the cold, bottom layer with low oxygen.
- **Limnatic Zone**: This refers to the well-lit open area of the lake but does not specifically denote the warmer oxygen-rich layer.
- **Profoundal Zone**: This is the deep, bottom layer of the lake, which is not warm and typically has low oxygen.

4. **Conclusion**: Based on the definitions and characteristics of each zone, the correct answer to the question is **epilimnion**.

### Final Answer:
The upper warmer oxygen-rich water zone in a lake is called the **epilimnion**.

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