Question

11. What is an algal bloom?

Answer 1

An algal bloom is an abnormal increase in the mass of algae in a water body. This significantly disrupts the ecosystem and affects the biota. A common reason of an algal bloom is the sudden increase of nutrients in the water body. These may come from the release of sewage waste, which is rich in nitrates, phosphates and other ions. These nutrients are a source of high productivity and facilitate the growth of algae. Slowly, the growing algae forms a blanket over the surface of the water body, causing discoloration of the water and reduced supply of oxygen to the aquatic animals. This eventually proves to be fatal for the animals and plants in the ecosystem. This phenomenon of increased nutrients in a water body making it highly productive is called as eutrophication.