Eutrophication and Algal Bloom

Table of Contents

Eutrophication is one of the most important topics from the Environment and Ecology Section. Eutrophication is an effect on the water body due to water pollution and enrichment of the water body with minerals which in turn helps algae grow exponentially and thus consume the Dissolved Oxygen (DO). The scarcity of DO leads to the death of aquatic animals present in that water body.

In this article, we will try to understand the meaning, mechanism, and effects of Eutrophication and Algal Bloom from our exam point of view.

Eutrophication – Ageing of Lakes

The nutrient-enrichment of the lakes promotes the growth of algae, aquatic plants and various fauna. This process is known as natural eutrophication.
On the basis of their nutrient content, lakes are categorized as Oligotrophic (very low nutrients), Mesotrophic (moderate nutrients) and Eutrophic (highly nutrient rich).

Eutrophication and Algal Bloom

Eutrophic water body: it is a body of water rich in nutrients and deprived it oxygen.
Eutrophication is the response to the addition of nutrients such as nitrates and phosphates .
Phytoplankton (algae and blue-green bacteria) thrive on the excess nutrients and their population explosion covers almost entire surface layer. This condition is known as algal bloom.

Mechanism of Eutrophication

Phytoplankton are photosynthetic during day time adding oxygen to the aquatic ecosystem.
But during nights, they consume far more oxygen as they respire aggressively.
The primary consumers like small fish are killed due to oxygen deprivation caused by algal blooms.
Death of primary consumers adversely affects the food chain.
Further, more oxygen is taken up by microorganisms during the decomposition process of dead algae, plants and fishes.
Warm water is conducive to blooms.