What does dissolved oxygen indicate in assessing non-point source pollution impacts?

What does dissolved oxygen indicate in assessing non-point source pollution impacts?

• A. Water's ability to support aquatic life.
• B. Levels of salinity.
• C. Water temperature.
• D. pH balance.

Answer: (A)

Dissolved oxygen shows how much oxygen is available for aquatic life. This is the direct measure of a water body's capacity to support fish, insects, and other aerobic organisms. When non-point source pollution brings in organic matter or nutrients, microbes break down that material and consume oxygen in the process, often lowering dissolved oxygen levels and stressing or harming aquatic life. So, dissolved oxygen best indicates the water’s ability to sustain living organisms. Temperature, salinity, and pH influence or interact with oxygen levels, but they don’t directly measure how well the ecosystem can support life the way dissolved oxygen does.

Dissolved oxygen shows how much oxygen is available for aquatic life. This is the direct measure of a water body's capacity to support fish, insects, and other aerobic organisms. When non-point source pollution brings in organic matter or nutrients, microbes break down that material and consume oxygen in the process, often lowering dissolved oxygen levels and stressing or harming aquatic life. So, dissolved oxygen best indicates the water’s ability to sustain living organisms. Temperature, salinity, and pH influence or interact with oxygen levels, but they don’t directly measure how well the ecosystem can support life the way dissolved oxygen does.