Question

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

Answer 1

Nutrient enrichment of a water body leads to its ageing and growth of algae or algal blooms. This is called eutrophication. Causes of its occurrence can be natural or due to human activities that lead to contamination of the water body with industrial effluents, domestic sewage, agricultural and livestock wastes etc. These factors make the availability of nutrients high, paving way for algal growth.

Harmful algal blooms may affect an ecosystem adversely:-

• Algae form a thick layer over the water surface, cutting off the interface between water body and atmosphere. This also restricts the sunlight from penetrating underwater. This results in decrease and death of aquatic flora.
• Algae rob the water off of dissolved oxygen making it unavailable for the aquatic life.
• Some Blue Green algae may release hepatotoxins and neurotoxins that are harmful to both aquatic fauna and human consumption.
• They decrease the population of fishes, submerged water plants etc, drastically.