Which description characterizes eutrophic water?

• A. Eutrophic water has low nutrients and clear water.
• B. Eutrophic water has high nutrients, more algae growth, and lower dissolved oxygen.
• C. Eutrophic water is devoid of algae and has high dissolved oxygen.
• D. Eutrophic water refers to extremely salty conditions.

Answer: (B)

The concept being tested is how nutrient levels drive water quality and oxygen availability in aquatic ecosystems. Eutrophic conditions occur when a body of water has abundant nutrients, especially nitrogen and phosphorus, which fuel excessive algae and aquatic plant growth. This rapid biomass growth often leads to algal blooms that reduce light penetration and later, when the algae die, decomposition by bacteria uses up a lot of dissolved oxygen. The result is water that can be rich in nutrients and algae but with lower dissolved oxygen, stressing or killing aquatic life.

This is why the description with high nutrients, more algae growth, and lower dissolved oxygen fits eutrophic water best. The other descriptions describe scenarios that don’t match eutrophy: low nutrients with clear water indicate oligotrophic conditions; water devoid of algae and with high dissolved oxygen is not eutrophic; and extremely salty conditions describe salinity effects, not nutrient-driven eutrophication.