Question

Addition of phosphate fertilisers to water bodies causes :

• A. enhanced growth of algae
• B. increase in amount of dissolved oxygen in water
• C. deposition of calcium phosphate
• D. increase in fish population

Answer 1

The Correct Option is A

The addition of phosphate fertilizers to water bodies leads to a phenomenon known as eutrophication. Let's explain this concept step-by-step:

Eutrophication: This is the process where water bodies become excessively enriched with nutrients, leading to the overgrowth of algae and other aquatic plants. Phosphates from fertilizers are one of the primary nutrients that contribute to this process.

Reason for Enhanced Algae Growth:

• Phosphates act as a nutrient, especially for algae. When they are introduced into water bodies through runoff from agricultural lands, they provide an abundant source of nutrients that promote the rapid growth of algae.
• This excessive growth of algae is often referred to as an algal bloom.
• Algal blooms can reduce the amount of sunlight reaching other aquatic plants, and when the algae die and decompose, they consume large amounts of oxygen in the water.

Why Other Options are Incorrect:

• increase in amount of dissolved oxygen in water: In fact, the opposite occurs. Algal blooms lead to oxygen depletion because decomposing algae consume oxygen.
• deposition of calcium phosphate: Phosphate fertilizers do not cause calcium phosphate deposition directly in water bodies.
• increase in fish population: Oxygen depletion caused by algae death and decay often leads to fish kills, reducing the fish population instead of increasing it.

Conclusion: The correct answer is that the addition of phosphate fertilizers to water bodies leads to enhanced growth of algae. This understanding is crucial for managing and preventing pollution in aquatic ecosystems.