Question

Explain the causes and effects of eutrophication. [3 MARKS]

Answer 1

Each point: 1 Mark

1. When too much of fertilizers and organic waste is present in the water bodies, aquatic organisms like blue – green algae (cyanobacteria) and other microbes grow rapidly.
2. This occurs because organic matter supplies plenty of nutrients for their growth and during their growth dissolved oxygen is used up fast that results in increased BOD(biological oxygen demand).
3. Rest of the aquatic animals and plants due to less oxygen in water begin to die and this process is called eutrophication. On the surface of a eutrophic lake you can easily find algal blooms floating over that add up to the death of aquatic organisms.