Question

During an educational trip, a botany student saw a beautiful lake in a village. She collected many plants from that area. She noticed that villagers were washing clothes around the lake and at some places waste material from houses was destroying its beauty. After few years, she visited the same lake again. She was surprised to find that the lake was covered with algae, a stinking smell was coming out and its water had become unusable. Can you explain the reason for this condition of the lake?

Answer 1

The reason behind the destroyed condition of the lake was continuous deposition of the domestic waste which is generated in the houses of villagers and the use of organic compounds like detergents and fertilizers in the lake.


The continuous use of these products acts as a nutrient for the rapid growth of algae and other aquatic plants and bacteria which consumes all the oxygen available in water and thus anaerobic condition develops. The anaerobic bacteria begin to break down the organic waste and produce chemicals that have foul smell and harmful to human health. The lack of oxygen in water causes oxygen dependent aquatic life to die and there would be loss of biodiversity.