Question

Explain the cause of algal bloom in a water body. How does it affect an ecosystem?

Answer 1

Hint: The rapid accumulation or growth of algae in an aquatic ecosystem is known as an algal bloom. The algal blooms which are composed of the phytoplankton are termed as harmful algal blooms that could produce biotoxins naturally. These biotoxins are harmful to humans as well as for aquatic life.

Complete answer:
When an excessive amount of nutrients, phosphates, and nitrates enters in the aquatic ecosystem causes algal blooms. This often enters the ecosystem by the discharge from the sewage treatment plants and the septic tanks, and also by the storm runoff through the fertilized farms and lawns. Slow-moving water and sunlight are also the factors responsible for the cause of algal blooms.

The algal blooms adversely affect the aquatic life such as-
1. The bio-toxins released by them attack the nervous system and skin of humans and nearly kill the fish.
2. The cyanotoxins could cause a serious range of symptoms including excessive tiredness, difficulty in breathing, paralysis, seizures, loss of appetite, diarrhea, and convulsions.
3. The species which eat the algal blooms lack the nutritional value in their food, despite eating in large quantities. This ultimately results in nutritional deprivation and then death.

Note: Eutrophication is a type of pollution that is caused by algal blooms. The excess nutrition stimulates the growth of algae. Because of the excessive growth of these algae on the water surface the aquatic plants do not get proper sunlight and oxygen, as a result, they die.