Before revision: There are two types of ice rinks in prevalent use today: natural ice rinks, where freezing occurs from cold ambient temperatures, and artificial ice rinks (or mechanically frozen), where a coolant produces cold temperatures in the surface below the water, causing the water to freeze.
After revision: There are two types of ice rinks in prevalent use today: natural ice rinks, where freezing occurs from cold ambient temperatures, and artificial ice rinks (or mechanically frozen), where a coolant produces cold temperatures underneath the surface of the water, causing the water to freeze.