A large number of fish are suddenly foun | Class 11 Chemistry Chapter Environmental Chemistry, Environmental Chemistry NCERT Solutions

Question:

A large number of fish are suddenly found floating dead on a lake. There is no evidence of toxic dumping but you find an abundance of phytoplankton. Suggest a reason for the fish kill.

Answer:

The amount of dissolved oxygen present in water is limited. The abundance of phytoplanktons causes depletion of dissolved oxygen. Phytoplanktons are degraded by bacteria present in water. For their decomposition, they require a large amount of oxygen. Hence, they consume the oxygen dissolved in water. As a result, the BOD level of water drops below 6 ppm, inhibiting the growth of fish and causing excessive fish-kill.


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Welcome to the NCERT Solutions for Class 11 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 18: A large number of fish are suddenly found floating dead on a lake. There is no evidence of toxic dum....