11. Why does the increased level of nutrients in the water affect the survival of aquatic organisms?
The increased level of nutrients in the water affects the survival of aquatic organisms because there is an increase in the algae formation, which when dies forms food for the decomposers and takes a lot of oxygen from the water hence there is a decrease in the dissolved oxygen in the water. This may affect the aquatic animals as they take in dissolved oxygen for their survival.
Excessive quantities of chemicals washed from the fields enter into ponds. These act as nutrients for algae to flourish once these algae dic it serves as food for decomposers like bacteria. In this process lot of oxygen in these ponds get use. This result in the oxygen level,which kill the aquatic organisms.
Addition of nutrients in water flourishes the growth of microorganisms like algae. When these microorganisms die they become food of bacteria. When bacteria become active, they consume a lot of oxygen present in water. Decrease in oxygen in water becomes trouble for aquatic animals and they start dying due to insufficient amount of oxygen to breathe. The death and decay of aquatic animals in lakes and ponds affect human life also..