<P> The resulting Antarctic Bottom Water (AABW) sinks and flows north and east, but is so dense it actually underflows the NADW . AABW formed in the Weddell Sea will mainly fill the Atlantic and Indian Basins, whereas the AABW formed in the Ross Sea will flow towards the Pacific Ocean . </P> <P> The dense water masses formed by these processes flow downhill at the bottom of the ocean, like a stream within the surrounding less dense fluid, and fill up the basins of the polar seas . Just as river valleys direct streams and rivers on the continents, the bottom topography constrains the deep and bottom water masses . </P> <P> Note that, unlike fresh water, seawater does not have a density maximum at 4 ° C but gets denser as it cools all the way to its freezing point of approximately − 1.8 ° C . This freezing point is however a function of salinity and pressure and thus - 1.8 ° C is not a general freezing temperature for sea water (see diagram to the right). </P> <P> Formation and movement of the deep water masses at the North Atlantic Ocean, creates sinking water masses that fill the basin and flows very slowly into the deep abyssal plains of the Atlantic . This high - latitude cooling and the low - latitude heating drives the movement of the deep water in a polar southward flow . The deep water flows through the Antarctic Ocean Basin around South Africa where it is split into two routes: one into the Indian Ocean and one past Australia into the Pacific . </P>

The only continuous current in the world ocean that makes a complete transit around the globe is