Life on, under and around "The Ice"

(adapted, with permission, from the Scientific Committee on Antarctic Research SCAR)

In contrast to the sparsely vegetated, barren and ice-covered continent, the nutrient-rich waters surrounding Antarctica support a wealth of plant and invertebrate animal life on which large populations of fishes, penguins, sea birds, seals and whales feed. These Antarctic organisms have a number of features that set them apart from those of tropical and temperate waters, such as large body size, slow growth and a low number of species. They are also remarkably well adapted to the severe environmental conditions in which they live. Some of the fish, for example, have special blood proteins which act as a natural "anti-freeze."

The marked seasonal changes in these high latitudes accompanied by the shortened period of light for plant growth, have resulted in species adapted not only to low temperatures but also to seasonal feeding and overwinter energy storage in fats and related substances. These are among the environmental factors which have helped shape the character of Antarctic life with its high degree of specialization.

The Antarctic Convergence influences the distribution of phytoplankton, zooplankton, fish and birds.

At the edge of the Antarctic continent cold water sinks, forming the "bottom water", which moves northwards over the sea floor and fans out into the Atlantic, Pacific and Indian oceans. Above the bottom water lies the relatively warmer, more saline, and nutrient-rich south-flowing circumpolar deep water. The upward movement of this water creates a zone of upwelling, supplying to the surface water large amounts of nutrients that contribute to the luxuriant growth of phytoplankton and other marine life close to the coasts of Antarctica.

The development of "fast ice" close to the continent and "pack ice" south of the Antarctic Convergence also profoundly influences the Antarctic marine ecosystem. The area covered with pack ice undergoes seasonal fluctuations. It is reduced from 24 million square kilometers in September to 18 million square kilometers in February.

Throughout its cycle of waxing and waning, the circum-Antarctic ice belt moves from east to west, and with it follow the multitudes of marine organisms that inhibit the pack ice, zone. On the basis of ice distribution, we can recognize three concentric and rather different zones: the fast ice zone, the pack ice zone, and the open waters.


 • Antarctic Biology and Medicine
Information about the biological ecosystems of Antarctica and how the animals adapt to the extreme climate.
 • Underwater Field Guide to Ross Island & McMurdo Sound, Antarctica
Images of the organisms living on Ross Island and McMurdo Sound.
 • SCAR Home Page
Information on Scientific Committee on Antarctic Research (SCAR) and Antarctic research.
 • Science in the Polar Regions
Links to articles and information about Antarctica.