What is the purpose of monitoring dissolved oxygen in water quality assessments?

Monitoring dissolved oxygen levels in water quality assessments is crucial because it serves as an indicator of the health of aquatic life. Aquatic organisms, particularly fish and invertebrates, depend on dissolved oxygen for respiration. The concentration of dissolved oxygen in water reflects its ability to support these organisms. If the levels are too low, it can lead to stress for aquatic species or even result in mortality. Additionally, changes in dissolved oxygen levels can provide insight into the overall ecosystem health and functioning, as oxygen levels can be affected by factors such as temperature, organic matter decomposition, and water flow.

In contrast, measuring temperature changes, assessing water flow rates, or determining sediment levels does not directly provide insight into the viability of aquatic organisms. While these factors are also important in understanding water quality, they do not serve the primary role that dissolved oxygen plays in evaluating the well-being of aquatic ecosystems.