Which term describes water with low dissolved oxygen?

• A. Hypoxic water
• B. Anoxic water
• C. Dead zone
• D. Turbidity

Answer: (A)

Low dissolved oxygen in water is called hypoxia. Dissolved oxygen supports aquatic life, and when its levels fall to just a few milligrams per liter or less, many fish and invertebrates struggle to survive. Anoxic water means there is essentially no oxygen at all, which is a more extreme condition than hypoxia. A dead zone refers to a specific area within a water body where hypoxic or anoxic conditions persist over time, leading to severe ecological impacts, but the term describes the region, not the general condition. Turbidity is about how clear the water is due to suspended particles, and it doesn’t indicate oxygen content. So, the best term for water with low dissolved oxygen is hypoxia.