Question

A few lakes in a major metropolitan city start to become green in colour. Considering that there are numerous high raised apartments and housing complexes near these lakes, what could be the reason for the water turning green?

• A. The sewage water from houses are flowing into the lake
• B. The amount of organic nutrients has increased in the lake
• C. The BOD of the lake has increased
• D. Sudden boom in the growth of algae

Answer 1

Answer: (A), (B), (D)

The correct options are
A The sewage water from houses are flowing into the lake
B The amount of organic nutrients has increased in the lake
D Sudden boom in the growth of algae

Constant dumping of sewage water into the lake increases the amount of rich organic nutrients in the water. Nutrient rich water is ideal for the growth of microbes such as algae. Since the amount of nutrient increases sharply, the growth of the algae is also sudden. This is termed as an algal bloom.