question_answer 11)

Why does the increased level of nutrients in the water affect the survival of aquatic organisms?

Answer:

Addition of nutrients in water flourishes the growth of microorganisms like algae which use up the dissolved oxygen from the water. When algae die, they become food for decomposers such as bacteria — these also use the dissolved oxygen, thus reducing oxygen content even further. Their thick growth also stops sunlight from reaching the water. This enrichment of water by nutrients which leads to excessive plant growth and depletion of oxygen is known as eutrophication. Decrease in oxygen in water, becomes trouble for other aquatic organisms and they start dying due to insufficient amount of oxygen to breathe.