Ocean water is constantly moving. Thermohaline circulation is another thing to think about when discussing deep ocean currents. It is also known as "The Great Ocean Conveyor" because it works like a conveyor belt. It is driven by heat and salinity of the sea water which is where the term thermohaline comes from. Temperature and salinity make up the density of the water. There are different densities that occur in the ocean waters of the world and this is what causes the currents. Cold and salty water from the northern Pacific and northern Atlantic return warmer and less salty water. The North Atlantic deep water is what causes the thermohaline circulation.
I am going to take a stab at this and assume you meant to write "deep ocean water." As it says in the article referenced below, "deep ocean currents are the result of sinking and upwelling water, and termohaline (temperature and salinity) differences."
Not a great deal is currently known about these deep ocean currents and they are being researched by a number of robotic submarines to try and get more of an understanding of them.
They are sometimes referred to as "submarine rivers" and they flow according to changes in density and temperature rather than according to wind and other conditions that drive currents closer to the surface. Once water sinks low enough, the pressure and other factors can actually cause density to increase which again, contributes to how that water will then move around deep below the surface.
Generally deep ocean currents are classified as those below the firs 400m of water.