Question

Which of the following statements does not apply to eutrophication.

• A. It is natural ageing of a lake by nutrient enrichment of its water
• B. In a young lake the water is cold and clear and supports less life
• C. The nutrients such as sulphur and phosphorus encourage the growth of aquatic organisms in the lake
• D. Pollutants released by man radically accelerate the ageing process of a lake
• E. Overgrowth of algae leads to scum that depletes the level of dissolved oxygen in water

Answer 1

The correct option is B In a young lake the water is cold and clear and supports less life

Eutrophication is the process of natural ageing of lakes. When pesticides or fertilizers wiped out from agriculture field due to rain or excessive irrigation and enters into the water body. The entry of pesticide or fertilizers into the water body makes it nutrient enriched and supports algal bloom. The overgrowth of algae depletes the dissolved oxygen which leads to the death of other aquatic animals and increases the temperature of water. Thus, the correct answer is 'In a young lake the water is cold and clear and supports less life'.