3. What are the major sources of nitrogen and phosphorus in water? How could nitrogen and phosphorus-induced eutrophication affect the quality of water?

Waste generated due to human activities and agriculture is the main source of nitrogen and phosphorus in the water.

Animal manure and use of fertilizer in the fields, certain types of soaps are the main sources of nitrogen and phosphorus in water, as the waste produced from these activities is released into the water and it can become the main source of phosphorus and nitrogen.

Nitrogen and phosphorus can work like fertilizer in the water bodies, but an excess of nitrogen and phosphorus can lead to severe problems such as

excess of nitrogen and phosphorus can lead to high growth of algae that induced eutrophication and reduce the levels of oxygen dissolved present in the water. Large levels of nitrogen and phosphorus cause algae bloom that create algae toxins which can be dangerous to human health and aquatic animals. Phosphates are compounds that contain phosphorous, and they harm water quality by creating extreme growth of algae.

Major sources of nitrogen and phosphorus in water are river and agricultural runoff.

Explanation:

These can induce the eutrophication and effect the water's biological oxygen demand and can also damage the quality of water and hence create high levels of pollutants as these tend to block the sunlight and block the fish from breathing in it. The phosphorus that agricultural use deposited in water harms the ecological productivity of the water increase in the nutrient level of water and making it sedimentary. Due to the obstruction of the light coming from the sun the photic layer gets harmed and rise in algae blooms in water.