• Eutrophication is a process that occurs in bodies of water like lakes, ponds and rivers due to excessive nutrients, specifically nitrogen and phosphorus.
  • These excess nutrients may originate from factors such as runoff of fertilisers from agricultural land, or sewage pollution.
  • Nutrient enrichment leads to rapid growth of algae and other plant species in the water, a condition also known as an algal bloom.

Consequences of Eutrophication

  • The rapid growth of algae and plants can cause the water surface to become blocked, preventing light from reaching deeper parts of the water body.
  • This lack of light limits the growth of other photosynthetic organisms and disrupts the normal trophic relationships.
  • As these algae and plant species die, they are broken down by decomposers.
  • Decomposition uses up the available dissolved oxygen in the water, creating an anoxic, or oxygen-depleted, condition.
  • The oxygen depletion can lead to the death of many aquatic species, particularly fish and other animals that require dissolved oxygen for respiration.
  • The result is a significant decrease in biodiversity in the affected water body.

Prevention and Control

  • Eutrophication can be prevented or controlled through measures such as using less or more targeted application of fertilisers in agriculture.
  • Better disposal and treatment of human and animal waste can also help in preventing the enrichment of water bodies with excess nutrients.
  • Constructed wetlands and buffer strips along water bodies can filter out and absorb excess nutrients before they can enter the water.
  • Restoration of affected ecosystems involves measures like oxygenation of the water, removal of built-up sediment, or even addition of chemical agents to precipitate out excess nutrients.
  • It is important to note that prevention is always more effective and less costly than trying to restore an ecosystem after eutrophication has occurred. Hence, sustainable practices and regulation are key to managing the issue.