The process by which a water body gradually becomes enriched with nutrients and minerals, mainly phosphorus and nitrogen, leading to enormous growth of algae on the surface of the water, thus decreasing the amount of dissolved oxygen in the water is known as:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. Eutrophication.
The process described is known as eutrophication. It occurs when a water body, such as a lake or pond, becomes excessively enriched with nutrients, particularly nitrogen and phosphorus, often from agricultural runoff, sewage, or industrial waste. This nutrient overload stimulates rapid growth of algae, forming dense algal blooms on the water surface. These blooms reduce sunlight penetration, disrupt aquatic ecosystems, and, upon decomposition, significantly decrease the dissolved oxygen levels, harming fish and other aquatic organisms and leading to deterioration of water quality.