Question

Algal blooms in a lake

• A. Leads to oxygen depletion
• B. Increase CO${}_2$ level
• C. Kills fishes and other organisms
• D. All of the above

Answer 1

Answer: (D)

All of the above

Algal blooms refer to the sudden increase in the population of algae in freshwater water systems due to the excessive nutrient enrichment of lake and causes eutrophication. It leads to decrease in the oxygen content of the environment as the dissolved oxygen of the water is used up by the algae growing there and increases the level of Co${}_2$. The depletion of oxygen leads to the death of the fishes and other organisms.

Thus, the correct answer is option D.