addition of phophates and nitrates/fertilizers into water leads to

Options

A. Decreased growth of decomposers
B. Reduced algal growth
C. Increased Biological Oxygen Demand
D. Nutrient entrichment (eutrophication)

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks what happens when phosphates and nitrates (commonly found in fertilizers) are added to water bodies.

2. **Identifying the Process**: When phosphates and nitrates are introduced into aquatic environments, they contribute to nutrient enrichment. This process is known as eutrophication.

3. **Explaining Eutrophication**: Eutrophication occurs when water bodies receive excess nutrients, primarily phosphorus and nitrogen. This leads to an overgrowth of algae, known as algal blooms.

4. **Consequences of Algal Blooms**: The rapid growth of algae can block sunlight from reaching other aquatic plants, disrupting the ecosystem. When the algae die, they are decomposed by bacteria, which consume oxygen in the water.

5. **Impact on Oxygen Levels**: The decomposition process increases the biological oxygen demand (BOD) in the water, leading to lower oxygen levels. This can result in hypoxic conditions, which are harmful to aquatic life.

6. **Conclusion**: Therefore, the addition of phosphates and nitrates into water leads to nutrient enrichment, algal blooms, and increased biological oxygen demand, ultimately resulting in water pollution.

**Final Answer**: The addition of phosphates and nitrates into water leads to eutrophication, which increases algal growth and biological oxygen demand.

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