The Antarctic Convergence occurs in the region between 50 and 60 degrees south latitude and encircles the Antarctic continent. Here cold surface water moving north away from the continent meets the warmer, southerly moving surface water of the Subantarctic zone. Where the two water masses meet, the colder, more dense Antarctic surface water sinks below the warmer water which it is encountering to a depth of about 3000 feet. Now called the Subantarctic Intermediate Water, it continues its journey north, often spreading far beyond the equator, and a deeper mass of cold water called the Antarctic Bottom Water has been traced as far north as Bermuda. The Antarctic Convergence is also marked by an abrupt change in the temperature and salinity of the ocean, also called it's thermohaline properties. North to south the Antarctic Convergence is characterized by a drop in surface water temperature of two to three degrees Celsius, from about six degrees to about 3 degrees. At the same time there is also a measurable drop in the salinity of the sea water. The change in salinity is the result of a number of factors. The most important being the lower temperature which was mentioned earlier. The colder water cannot hold as much salt as the warmer water to the north. Due to the cold temperatures and the lack of direct sunlight, less water evaporates off the Southern Ocean than the surrounding water, which also aids in keeping the salinity low. A third reason for the low salinity is the formation of sea ice. When the ice forms in winter it gives up a large percent of its salt. This excess salt forms a very dense saline mixture with the surrounding water which sinks to the bottom and becomes the Antarctic Bottom Water. When the ice melts in the summer in introduces large quantities of fresh water back into the surface water which contributes to the low salinity south of the convergence. The Antarctic Convergence plays a key role in separating the Antarctic from the rest of the world. It signifies an abrupt change in the characteristics of the water. This difference, in turn plays a key role in setting up the Antarctic ecosystem by provided the perfect conditions for certain types of organisms to thrive. This gives the region a dynamic all of its own.