Write critical notes on the
Eutrophication

Explanation

Biological magnification: Increase in the concentration of the pollutant or toxicant at successive trophic levels in an aquatic food chain is called biological magnification or Bio-magnification. This happens in the instance where toxic substance accumulated by an organism is not metabolized or excreted and thus passes on the next higher trophic level. This phenomenon is well known regarding DDTand mercury pollution.
As shown in the above example, the concentration of DDT is increased at successive trophic levels. Starting at a very low concentration of 0.003 PPb (PPb part per billion) in water, which ultimately reached an alarmingly high concentration of 25 ppm (ppm = parts per million) in fish - eating birds through biomagnification. High concentrations of DDT disturb calcium metabolism in birds, which causes thinning of egg shell and their premature breaking, eventually causing decline in bird populations.