Question

Which of the following effects will be observed in a lake situated near a farm that uses excessive fertilizers?

• A. Oxygen content in the water will decrease.
• B. Less light will penetrate the water.
• C. The population of aquatic organisms of the lake will decrease.
• D. All of these

Answer 1

The correct option is D All of these

Streams draining into the lake introduce nutrients such as nitrogen and phosphorus from the farms that use fertilizers. These nutrients encourage the growth of algae and cause algal bloom. The algae will slowly cover the entire lake and will not allow sunlight to penetrate the water. When these algae will die then bacteria decompose the dead algae. During decomposition, bacteria use oxygen thus, reducing the oxygen level in the water. The aquatic organisms of the lake will not be able to survive in the oxygen-deficient water and die.

Thus, the correct answer is option D.