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What is Eutrophication?
Eutrophication is the process by which water receives excess nutrients like phosphates and nitrates, causing excessive growth of algae and water plants.
What is the process and effects of Eutrophication?
Untreated sewage and fertilisers that are not absorbed by crops may be washed by rainwater into nearby lakes or rivers.
The nitrates and phosphates in fertilisers or untreated sewage enhance the growth of algae and water plants. They are used in the synthesis of proteins and nucleic acids.
This leads to the increased growth and multiplication of algae and floating water plants in the rivers or lakes. This phenomenon is called eutrophication.
Overgrowth (Overcrowding) of algae and floating water plants prevent sunlight from reaching the submerged plants.
Submerged algae and water plants die due to lack of sunlight.
The dead algae and water plants are decomposed by aerobic bacteria and fungi
As the bacteria feed on the decaying organic matter, they grow and multiply rapidly, using up the oxygen in the water.
Other organisms such as fish die due to lack of oxygen.
What are the disadvantages of the use of insecticides?
Insecticides may become ineffective after some time as some insects become resistant to the insecticides and pass on the favourable genes to their offspring and over time, the population of insects will rise again.
Insecticides may end up affecting organisms other than insects. If they are carried by rainwater into streams, rivers, or lakes, they can accumulate in high concentrations in the bodies of aquatic organisms such as fish.
What is bioaccumulation?
What is biomagnification or bioamplification?
Bioaccumulation is the accumulation of chemical substances such as pesticides in an organism.
Biomagnification occurs when toxins or insecticides are passed from one trophic level to the next with increasing concentration along the food chain.
