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.

A large number of fish are suddenly found floating dead on a lake. The

1.	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» Solution :Phytoplankton CONSISTS of organic contaminants such as grass leaves ETC. In water these materials are DEGRADED by BACTERIA and a large amount of dissolved oxygen will be used up for this process. As the amount of DO drops below 6 ppm, fish cannot SURVIVE and they float dead.