Nutrient rich lake is :

Options

A. Oligotrophic lake
B. Eutrophic lake
C. Both (1) & (2)
D. None of these

Answer

**Step-by-Step Solution:**

1. **Understanding Lake Types**: Begin by recognizing the two main types of lakes discussed: oligotropic lakes and eutropic lakes.

2. **Characteristics of Oligotropic Lakes**: Oligotropic lakes are characterized by low nutrient content, which leads to low primary productivity. This means they have clear waters and low algal production. Therefore, oligotropic lakes cannot be classified as nutrient-rich.

3. **Characteristics of Eutropic Lakes**: In contrast, eutropic lakes are nutrient-rich. They have high levels of nutrients, particularly phosphorus and nitrogen, which promote high productivity. This leads to increased algal growth.

4. **Consequences of Eutrophication**: The increased algal growth in eutropic lakes results in higher organic matter. As this organic matter decomposes, it requires oxygen, leading to a rise in biological oxygen demand (BOD) and a decrease in dissolved oxygen levels in the water.

5. **Conclusion**: Based on the characteristics and consequences of the two types of lakes, it is clear that the nutrient-rich lake is the eutropic lake.

**Final Answer**: The nutrient-rich lake is a **eutropic lake**.

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