Ocean Currents

I was wondering, why gyres circulate counter clockwise in the southern hemisphere, and why they move clockwise in the northern hemisphere?

Ocean currents are the veritcal or the horizontal movement of surface and deep water, why do currents aid in the circulation of the earth's mosture, or the resultant of weather, or water pollution?

Surface currents are those found in the upper 400 meters or 1,300 feet which also make up 10 percent of all the oceans water's. The surface current's are normally caused by the wind, because of the friction that it creates well moving over the water. The friction then makes the to move in a circuler or spiraling pattern, creating Gyres. The speed of the surface currents is largest closer to the oceans surface and gets slower about 100 meters or 328 feet below the surface.

Deep water currents, also called thermohaline circulation is found below 400 meters and make up about 90% of the ocean. Just like surface currents gravity plays a role in the making of deep water currents but the lower currents are more commonly caused by the desity differences in the water.