How can aquatic animals survive when the lakes and seas freeze?

drnaga

Dr.Naga Rathinam
How can aquatic animals survive when the lakes and seas freeze?

AS you know when heat is applied a metal, a liquid or even a gas, it expands. Hence it is said that heat expands and cold contracts. There is, however, one exception to this rule. When the temperature of waterfalls below four degrees Celsius, it does not contract, but expands. It keeps on expanding till it reaches zero degrees Celsius. As a result, ice is formed on the surface and since it is lighter than the water below, it floats on the surface. The fish and other animals freely move about in the water "below. Isn't it a miracle of Nature?
 
From my point of view most of the aquatic animals are ectothermic which shows that when these animals are cold their requirement for oxygen is fewer. Moreover there are some fresh water fishes which can survive without oxygen in enough cold.
 
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