Question

Excess of phosphate and nitrate ions from fertilizer can contaminate water in ponds and lakes by encouraging excessive :

• A. Growth of algae, a species of water plant
• B. Increase in salt
• C. Release of heat
• D. Increase of oxygen

Answer 1

The correct option is A Growth of algae, a species of water plant

Unlike temperature and dissolved oxygen, the presence of normal levels of nitrates and phosphates usually does not have a direct effect on aquatic insects or fish. However, excess levels of nitrates and phosphates in water can create conditions that make it difficult for aquatic insects or fish to survive.

Algae and other plants use nitrates and phosphates as a source of food. If algae have an unlimited source of nitrates, their growth is unchecked. Thus the water gets contaminated.