Question

Frequent occurrence of water blooms in a lake indicates
A. Nutrient deficiency
B. Oxygen deficiency
C. Excessive nutrient pollution
D. Absence of herbivores in lakes

Answer 1

Hint: Water blooming occurs due to the large amount of nutrients in the water. It is the reason for the over growth of planktonic free floating algae. It is also called the algae blooming. It gives the distinct color to the water bodies. It will cause fish mortality and deterioration of water quality. Cyanobacteria in lakes, ponds and reservoirs multiplied during the summer season will cause extensive growth which is called the bloom.

Complete answer:
Option A: Water bodies need nutrients for the growth of plants and fishes in the lake. Freshwater fishes are high in nutrients. So the nitrogen level is decreased then it loses the nutrients. It may lead to the death of aquatic species. Here the reproduction process is reduced because of low nutrients in the water. Option A is incorrect.
Option B: Oxygen deficiency is mainly caused by the excessive growth of algae and phytoplankton. It leads to high deposition of nitrogen and phosphorus in water. Phosphorus is the reason for the growth of algae. If the algae dies and decomposes then the process uses the dissolved oxygen. Option B is incorrect.
Option C: Excessive nutrient pollution is the process of producing more nitrogen and phosphorus and they react with each other and act as a fertilizer to help the growth of algae. This may reduce the amount of dissolved oxygen in water and produce the water blooming. Algae blooms cause a bad smell, color change and release toxins. Option C is correct.
Option D: Herbivores are the animals which eat the green plants. Large amounts of herbivores plant growth will also reduce the propagation of sunlight into the water. It also reduces the dissolved oxygen and reduces the growth of plants and fishes. Option D is incorrect.

Hence, Option C is the correct answer.

Note:
Eutrophication is the process of deceiving more nutrients such as nitrogen and phosphorus in the lake or pond. It is sediment in the surrounding watershed and becomes fertile. If additional nutrients are added to the lake then it will cause algae blooming and additional growth of plants. It will cause water pollution. Water loses its originality and it is very poor in quality. The lake looks green in color then it is affected by the algae blooming or nutrient pollution.