Write a short note on algal bloom.

(N/A) Algal bloom refers to the excessive growth of planktonic (free-floating) algae in water bodies,which imparts a distinct color to the water.
$1$. Causes: It is primarily caused by the presence of high levels of nutrients,such as nitrogen and phosphorus,in the water. This process is known as eutrophication.
$2$. Impact on Ecosystem: These blooms cause deterioration of water quality and fish mortality.
$3$. Toxicity: Some bloom-forming algae are extremely toxic to human beings and animals.
$4$. Oxygen Depletion: The decomposition of large amounts of algae consumes significant amounts of dissolved oxygen,leading to the death of aquatic organisms.