What function do the wind-driven currents play in the transport of heat energy in the oceans?

Wind driven currents create in the equatorial and warm zones of the earth’s oceans. The currents then transmit the warm water north, where the heat in the water is misplaced to the colder atmosphere. In the instance of the Gulf Stream, this transmission of heat to the air warms up England and Europe. 
As the water cools, its' density upsurges because of chilling and increasing salinity. This cold water drops to the bottom of the ocean, where it is then stimulated by another current back south, similar to a train creating a big circuit.