Question

In a village in kamataka people started cultivating crops all around a lake which was always filled with water. They added fertilizers to there field in order to enhance the field. Soon they discovered that the waterbody was completely cared with green floating plant and death of fish in the lake

Answer 1

Answer:

When manure or commercial fertilizers enter surface water, the nutrients they release stimulate microorganism growth. Without sufficient dissolved oxygen in surface water, fish and other aquatic species suffocate. The resulting dead fish and other aquatic species degrade the water quality and cause unpleasant odors.

Answer 2

$\large\bf\red{Solution☞}$

During rains fertilizers used for agriculture spreads to the lakes. Fertilisers contain phosphates and nitrates by which water body became enriched with these chemicals. These chemicals promote excessive growth of aquatic plants and the surface of the water was completely covered with plants. (eutrophication)

Depletion of light in the water body and insufficient availability of dissolved oxygen and nutrients resulted in the death of fish.