Question

How pollution can affect food chains?

Answer 1

Hint: A food chain is an interconnected group of organisms within an ecosystem that interact with one another. Each species in a food chain is fed on by the species above it.

Complete answer:
The gradual accumulation of chemical substances in the living tissue of an animal is known as bioaccumulation. This generally takes place when an animal consumes something that’s polluted or absorbs the chemical through its skin. The animal stores the contaminant in its fatty tissues instead of eliminating the chemical in its waste. The toxin may kill an animal immediately. If not, the concentration of a bio accumulated substance tends to increase with the age of the affected species. Organic pollutants like hexachlorobenzene, bioaccumulate inside the animals and plants. Mercury, lead and silver are some of the examples of heavy metals.
When a predator consumes an animal affected by bioaccumulation, the toxin gets biomagnified. When a bird that eats multiple insects that have already ingested a pollution-related chemical, will consume large amounts of the toxin. When biomagnifications affect a food web, the animals on the upper trophic level tend to eat and store more pollutants. A pollutant can remain in an ecosystem for decades if it is not degradable. Examples of such pollutants are DDT and heavy metals like mercury.
The overabundance of nutrients in a water body is called eutrophication. It leads to fish kills, due to a lack of oxygen, which impacts the diversity of an ecosystem. The death of even the smallest organisms can make a big impact on the environment. For example, if pollution kills natural forest decomposers like bacteria and fungus, the ecosystem will fail to break down organic materials on the forest floor. If the organic material doesn’t decompose, the soil fails to receive the nutrients it requires to encourage the growth of plants on which herbivores and omnivores depend.
Food may become scarce to another species when an animal species dies because of exposure to a pollutant. For example, if water pollution causes the death of fish in a lake, the bears in the area would need to seek other sources of food or may migrate to another location.

Note: Plastic has already entered the food chain. Animals carry nanoplastics in their bodies. When they are themselves eaten, those nanoplastics are also ingested. This process is called ‘trophic transfer’ of nanoplastic. Nanoplastics entering the brains of fish through the food chain leads to abnormal behaviour like slower eating hyperactive behaviour. This is how plastic can disrupt the natural balance.