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In the ocean, ice melting from the poles brings light freshwater into contact with dense saltwater. Hence, Earth's rotation causes oceanic fronts to form, creating an anticyclonic circulation.
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Figure 7.1: Left: Surface temperatures of the ocean show a sharp temperature gradient, just as in the atmosphere. Right: Anticyclonic current around Antarctica.
Figure 7.2: Salinity as a function of depth. Near the surface is the cold fresh water melting from the ice, then between 100 and 200 meters the water becomes much saltier (and more dense), as well as warmer. There is a sharp gradient between the fresh and salt water.