What is a common consequence of eutrophication for aquatic ecosystems?

What is a common consequence of eutrophication for aquatic ecosystems?

• A. Increase in biodiversity
• B. Improved water clarity
• C. No change to ecosystem
• D. Oxygen depletion and loss of fish

Answer: (D)

Excess nutrients in water fuel rapid algal growth, and when those algae die and decompose, bacteria use a lot of the dissolved oxygen in the water. That drop in oxygen creates hypoxic conditions, which stress or kill fish and other aerobic organisms, leading to habitat loss and reduced biodiversity. So the common outcome is oxygen depletion and fish loss. The situation also tends to reduce water clarity and disrupt ecosystems rather than improve them, so increases in biodiversity or no change aren’t typical results.