Define eutrophication.

Hint: The term eutrophication means excessive nutrients in a water body leads to the formation of land. This causes a decrease in the oxygen level of the water body and thus harms the living organism inside the water bodies.

Complete step by step answer: Eutrophication is also called dystrophication or hypertrophication. The term eutrophication can be defined as the water body enriched with minerals and nutrients that produce excessive growth of algae. Eutrophication means well-nourished. The oxygen level of the water body is decreased after the bacterial degradation of algae. Increased levels of nutrients in lakes, ponds, rivers, and coastal zones result in an increase in the number of phytoplankton. Phytoplankton is also called an algal bloom. Discharge of nitrate or phosphate-containing fertilizers, detergents, or sewage into the aquatic system induces the process of eutrophication by excessive growth of plants and algae in aquatic ecosystems. Phosphates are transported into the water body mainly by erosion as they tightly adhere to the soil. Oxygen consumption takes place for the bacterial degradation of the biomass of dead plants and algae and thus results in a decreased level of oxygen in aquatic ecosystems. This decreased level of oxygen state is called hypoxia. Nitrogen is the limiting factor for the accumulation of algae.

Note: Eutrophication of the lake has become one of the global problems of water pollution. Phosphate is considered as the primary limiting factor of eutrophication as the availability of phosphate promotes excessive growth of aquatic plants and algae as phosphorus is the important element for plants to survive.