Twenty or 30 years ago, interest in the Southern Ocean was largely driven by its exceptional characteristics. The Southern Ocean was such an anomaly, with extremes of productivity (thought to be high), nutrients (also high), temperatures (low), populations of krill and whales, and, of course, the presence of ice. There was also created, perhaps, an allure because of its distance and because it was so unusual, relative to the familiarity of the North Atlantic, for example. It has turned out, not surprisingly, that these exceptional characteristics illustrate the exceptional importance of the Southern Ocean to global ocean phenomena. By virtue of creating water masses the Southern Ocean may play a significant role in the ocean's nutrient distributions. Low temperatures over large areas mean that, potentially, it is a significant sink for dissolved gases such as oxygen and carbon dioxide. It is generally believed that Antarctica (as well as the Arctic) may be more susceptible to climate change than either temperate or tropical ecosystems, because these ecosystems function within a few degrees of the freezing point of water. Altogether, the processes here will tell us much about how the ocean works today and in the distant past.