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

Explanation

In a village in Karnataka, people started cultivating crops all around a lake which was always filled with water. They added fertilizers to their field in order to enhance the yield. Soon they discovered that the water body was completely covered with green floating plants and fishes started dying in large numbers. Analyze the situation and give reasons for excessive growth of plants and death of fish in the lake.
Use of fertilizers increased the level of organic nutrients which in turn support the growth of small, green, aquatic plants and so, the surface of water was completely covered with plants. The process is called eutrophication. Consumption of oxygen by these plants led to death of fishes and other aquatic animals. Since water surface was covered with these planktons, underwater plants were deprived of light and died.