Question

In a village in Karnataka, people started cultivating crops all around a lake that was always filled with water. They added fertilizers to their field in order to enhance the yield. Soon they discovered that the waterbody was completely covered with green floating plants and fishes started dying in large numbers. Analyze the situation and give reasons for the excessive growth of plants and the death of fish in the lake.

Answer 1

1. Since people used excessive fertilizers in the fields, they were carried down to the lake during rains through underground seepage systems.
2. As many fertilizers contain phosphates and nitrates, the water body became enriched with these chemicals, a phenomenon called eutrophication.
3. These chemicals promoted excessive growth of aquatic plants and the surface of the water was completely covered with plants.
4. The depletion of light in the water body and insufficient availability of dissolved oxygen and nutrients resulted in the death of fish.