Water pollution causes

Options

A. Increased photosynthesis
B. increased deoxygeneration and turbidity
C. decreased turbidity
D. increased oxygenation .

Answer

### Step-by-Step Solution:

1. **Understanding Water Pollution**: Water pollution refers to the contamination of water bodies (like rivers, lakes, oceans) due to harmful substances or pollutants.

2. **Identifying Causes of Water Pollution**: One major cause of water pollution is the excessive use of fertilizers in agriculture. When it rains, runoff from fields carries these fertilizers into nearby water bodies.

3. **Effects of Nutrient Runoff**: The excessive nutrients (especially nitrogen and phosphorus) in the water lead to a phenomenon called algal bloom. This is when algae grow rapidly due to the abundance of nutrients.

4. **Consequences of Algal Blooms**: Algal blooms can deplete oxygen levels in the water as the algae die and decompose. This process consumes a significant amount of dissolved oxygen, leading to decreased oxygen availability for aquatic life.

5. **Increase in Turbidity**: As the oxygen levels decrease, the decomposition of organic matter (including dead algae) contributes to an increase in turbidity. Turbidity refers to the cloudiness or haziness of a fluid caused by large numbers of individual particles.

6. **Conclusion**: Based on the analysis, the correct answer to the question about the causes of water pollution is **B: increased deoxygenation and turbidity**. This reflects the negative effects of nutrient runoff leading to algal blooms, oxygen depletion, and increased turbidity in water bodies.