Question

With the help of an aquatic food chain having four trophic levels, explain the

process of biological magnification.​

Answer 1

Consider the following example in a lake ecosystem :

$\sf Phytoplankton \longrightarrow Zooplankton \longrightarrow Fishes \longrightarrow Crane$

The above food chain is an example of Grazing Food Chain where

• Phytoplankton are producers
• Zooplankton are primary consumers
• Fishes are secondary consumers
• Crane is the top carnivore

Bio magnification is defined as the increase in accumulation and concentration of toxins at successive tropic levels.

• For instance, industrial effluents discharged into water bodies are decomposed by phytoplankton for anaerobic respiration and metabolism.

• Zooplankton which prey on the former consumes the underlying toxins. Similarly, concentration of such toxins is maximum at the highest tropic level.