Antarctic Region

The Southern Ocean covers around 10% of the world’s ocean surface, and includes some of the most productive marine regions on Earth. It is bounded to the south by the Antarctic continent, and to the north by the Antarctic Polar Front, where the Antarctic Circumpolar Current forms an oceanographic boundary separating colder, more productive Antarctic waters from warmer waters to the north. Physical and ecological processes in the Southern Ocean are dominated by the advance and retreat of sea ice, which extends northwards as far as 55°S, covering 18-20 million km2 in winter.

The Southern Ocean comprises several deep ocean basins, with prominent plateaus, banks, ridges and seamounts. Several small, isolated island groups lie in the sub-Antarctic region close to the Polar Front, forming breeding sites for vast numbers of seabirds and seals. Primary productivity in the Southern Ocean is highly seasonal, and herbivores including copepods, salps and euphausiids are important components of the marine ecosystem as prey species. The Antarctic krill (Euphausia superba) is the keystone species of the Antarctic marine ecosystem; its predators include whales, seals, penguins and other seabirds, as well as fish and squid. Abundant populations of these predators are present in the Southern Ocean, especially in the highly productive seasonal ice zone (within the maximum northern extents of sea ice in winter and summer). Many of these species have been major targets for commercial exploitation both historically and at the present time. The marine benthic fauna of the Southern Ocean has a high degree of endemism, as well as high species richness within some taxa. Benthic organisms have developed a variety of adaptations to extreme temperature conditions and the seasonal availability of food, forming unique and diverse communities.

Climate change, tourism, and the direct and indirect effects of fishing, tourism and other human activities are the major threats to the Antarctic marine ecosystem. The environment and resources of the Southern Ocean are afforded protection under the instruments of the Antarctic Treaty System (ATS). The ATS can be defined as the Antarctic Treaty itself, together with its associated instruments: the Convention on the Conservation of Antarctic Seals (CCAS), the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) and the Protocol on Environmental Protection to the Antarctic Treaty. The latter two instruments have the most relevance for the development of MPAs. The Antarctic Treaty and the Environmental Protocol apply to the entire area south of 60°S, however CCAMLR covers a wider marine area, extending from the continent to a line just to the north of an approximation of the oceanographic and ecological boundary formed by the Polar Front.