What does dissolved oxygen indicate in a water sample?

• A. Water temperature
• B. Presence of pollutants
• C. Ability to support aquatic life
• D. Water clarity

Answer: (C)

Dissolved oxygen is a crucial indicator of the water's ability to support aquatic life. In aquatic ecosystems, oxygen is necessary for the survival of fish, invertebrates, and various other organisms. A higher concentration of dissolved oxygen typically indicates a healthier environment where a diverse range of aquatic life can thrive. Conversely, low levels of dissolved oxygen can lead to conditions that are unsuitable for many species, resulting in stress or even death for aquatic organisms.

This relationship underscores the importance of monitoring dissolved oxygen levels when assessing water quality. While factors such as water temperature and pollutants can indirectly influence dissolved oxygen levels, the direct measurement provides insight into the overall health of the aquatic ecosystem, making it a vital parameter for determining whether the water can sustain living organisms.