0The marine life in polar region experiences a temperature difference. The temperature of the surrounding is below zero the temperature inside water is about 4 degrees Celcius throughout. Once this temperature is reached the density of the water remains the same throughout the water. Now the water at the surface which is exposed to the environment will lose heat and as it loses heat temperature decrease and goes below 4 deg Celcius. Now the water is lighter and remains on the top of, i.e. remains on the surface of the water as water below is denser than it.no convection can happen and hence the surface water starts freezing.
