Consider the following statements
I.Algal blooms are formed by free floating algae
II.Algal bloom causes fish mortality and deterioration of water quality
III.Water hyacinth the world's most problematic aquatic weed is also called "Terror of Bengal"
Which of the statements given above are correct about algal blooms?

Options

A. I,II
B. I,III
C. II and III
D. all of these

Answer

To determine which statements about algal blooms are correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze Statement I: "Algal blooms are formed by free-floating algae."**
- Algal blooms occur when there is an excessive growth of algae in water bodies, primarily due to nutrient enrichment (eutrophication). These algae are indeed free-floating, as they thrive on the surface of the water.
- **Conclusion**: Statement I is correct.

2. **Analyze Statement II: "Algal bloom causes fish mortality and deterioration of water quality."**
- Algal blooms can lead to a decrease in water quality. When algae die, they decompose, a process that consumes oxygen from the water. This increased demand for oxygen (measured as Biological Oxygen Demand or BOD) can lead to hypoxic conditions, which can be fatal for fish and other aquatic organisms.
- **Conclusion**: Statement II is correct.

3. **Analyze Statement III: "Water hyacinth, the world's most problematic aquatic weed, is also called 'Terror of Bengal.'"**
- Water hyacinth (Eichhornia crassipes) is indeed considered one of the most problematic aquatic weeds globally and is often referred to as the "Terror of Bengal" due to its rapid growth and negative impact on water bodies.
- **Conclusion**: Statement III is correct.

### Final Conclusion:
All three statements are correct regarding algal blooms and their effects.

### Answer:
**All of the statements (I, II, and III) are correct.**

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