How does anomalous expansion of water help aquatic organisms in cold climates ?
The anomalous expansion of water helps in survivals of water animals in very cold climates. Initially when temperature of water falls, it becomes heavier and sinks down. This process continues till 4°C. Then after this expansion takes place. The surface layer of water gets freezed. Ice being bad conductor of heat does not allow loss of heat from the water below and results in survival of water animals.
When water is cooled it contracts and its density, increases until the temperature reaches 4°C, on further cooling water starts expanding with decrease in its density. This is anomalous phenomenon. The aquatic organisms can live there easily.