A lake with an inflow of domestic sewage rich in organic waste may result in

Options

A. drying of the lake very soon due to algal bloom
B. an increased production of fish due to lot of nutrients
C. death of fish due to lack of oxygen
D. increased population of aquatic food web organisms

Answer

**Step-by-Step Solution:**

1. **Understanding the Problem**: The question asks about the consequences of a lake receiving domestic sewage that is rich in organic waste. This scenario is often associated with environmental issues, particularly eutrophication.

2. **Defining Eutrophication**: Eutrophication is the process where water bodies become enriched with nutrients (like nitrogen and phosphorus) leading to excessive growth of algae. This is typically caused by the inflow of organic waste, such as sewage.

3. **Effects of Nutrient Enrichment**: When a lake receives an influx of nutrients, it leads to a rapid increase in algal populations, known as algal blooms. This can cover the surface of the water, blocking sunlight from reaching aquatic plants.

4. **Consequences of Algal Blooms**: As algae die and decompose, the decomposition process consumes a significant amount of oxygen from the water. This leads to a condition called hypoxia (low oxygen levels).

5. **Impact on Aquatic Life**: The lack of oxygen in the water can be fatal for fish and other aquatic organisms. Fish require dissolved oxygen for survival, and when the oxygen levels drop significantly, it can lead to the death of these organisms.

6. **Choosing the Correct Option**: Given the options provided:
- Option A (drying of the lake due to algal bloom) is incorrect because while algal blooms can cause issues, they do not directly lead to the drying of the lake.
- Option B (increased production of fish) is also incorrect as the opposite occurs due to low oxygen levels.
- Option C (death of fish due to lack of oxygen) is the correct answer, as explained above.
- Option D (increased population of aquatic food web organisms) is incorrect because the death of fish and other organisms would decrease the population.

7. **Final Answer**: Therefore, the correct answer is **Option C: death of fish due to lack of oxygen**.

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