What are the signs of nitrate contamination in water?

Nitrate contamination in water is often indicated by excessive algae growth and changes in aquatic life. When nitrate levels are elevated, they provide an abundance of nutrients that can lead to algal blooms, a phenomenon where algae grow rapidly and can outcompete other marine life for resources such as light and oxygen. This excessive growth can result in decreased oxygen levels in the water as the algae die and decompose, harming fish and other aquatic organisms.

Changes in aquatic life often accompany these algal blooms. Species that are sensitive to changes in water quality may decline, while more tolerant species may flourish. The overall health of the aquatic ecosystem can be severely impacted by these changes, demonstrating the critical link between nitrate levels and aquatic health.

The other options suggest scenarios that do not accurately reflect the consequences or indicators of nitrate contamination. Clear water and healthy fish typically signify a balanced ecosystem free from such contaminants, while strong chemical odors and low pH levels do not specifically correlate with nitrate presence and could stem from other issues in water quality. Thus, recognizing excessive algae growth and the resulting impact on aquatic life serves as a reliable indicator of nitrate contamination.