Question

Write a short note on Biological magnification?

Answer 1

It is the phenomenon in which some pollutants get accumulated in tissue in increasing concentration along the food chain It is well-known for mercury and DDT. Zooplanktons in the food chain accumulates modest level of DDT. however, small fish forming the next level of food chain accumulate more DDT. In this manner, the concentration of DDT magnified at successive tropic level and its concentration is higher in fish eating birds.

Answer 2

Answer:

Biological magnification

Pesticides are used on a large scale to protect crops from various diseases and pests. When these pesticides enter the soil, they are absorbed by plant parts with minerals and water from the soil. These chemicals can enter water sources as a result of rains, furthermore into the bodies of aquatic animals and plants, hence into the food chain. As these chemicals cannot be disintegrated, at each of the tropic levels, they keep getting accumulated, wherein most of the accumulation occurs at the top carnivore’s level. This is termed as biological magnification where there is increase in the concentration of harmful pollutants with each increasing tropic level.

For instance, high DDT concentration in a pond saw the producers (phytoplankton) to have a DDT concentration of 0.04 ppm. As these phytoplankton were consumed by zooplankton – the consumers, the concentration of DDT in the bodies of zooplankton was noted to be 0.23 ppm. When this in turn is consumed by small fish, more of DDT gets collected in their bodies. Consequently, the large fish (top carnivore) feeding on different small fish tend to have the maximum concentration of DDT.