ANTARCTIC OCEAN. The name Antarctic Ocean is given to the sea waters lying within the Ant arctic regions, and since the great continents do not extend so far south as the limits of the Antarctic regions, this ocean has no out side continental land boundaries, and its waters merely mingle with those of the Pacific, the Indian, and Atlantic oceans without any signifi cant lines of separation. Between the latitude of Cape Horn and the Antarctic lands the whole circumference of the globe presents an unbroken expanse of waters, save for a few islands here and there. The floor of the Antarctic gradually shoals from the middle latitude depths toward the South Pole. There are some embayments running toward the Pole which show depths of two to three thousand fathoms, which equal the depths on the outer boundary; but the results of soundings by the Belgic-a expedition in 1898 and of a study of the currents seem to show that the various land areas now grouped together and called the outer edge of the Ant arctic continent rise up from broad shallows or elevated plateaus about two to five hundred feet below the surface of the ocean. In general. at lat. 80° S., the waters of the Antarctic Ocean have an average annual temperature at the sur face of 29°.8 F., which is warmer than the aver age temperature of the air in the same latitude (2S°.7 F.). At great depths and near the ocean floor the water temperature is betwten 32° F. and 35° F., but between these depths and the surface there is usually found a wedge-shaped layer of water with a temperature varying from 28° F. to 32° F.
The Antarctic drift is mainly from the west on the outer border and from the southwest and south at the interior of the Antarctic region. There are two great Antarctic currents: one crosses 11w Antarctic circle toward the north, between long. 120° and long. 140° W., but swerves toward the east in lat. 50°. and near the South American continent separates, part going northward past. Peru. and part preserving its eastward movement past Cape Horn, whence it returns to the Antarctic between long. 60° E. and SO° E.: the other current crosses the Antarctic Circle. going north between long. SO° and long. 100° E., and swerves to the eastward, forming the west Australian current. The floor deposits of the ocean are, in the outer region.
glohigerina ooze, along and for some distance within the Antarctic Circle terrigenous deposits of blue mud, etc.. and in the interior region immediately surrounding the land, but extending from 10° to 20° from it, pteropod ooze.
The waters are full of life at all depths. Alg.re arc abundant, but pteropods and foraminifera decrease in numbers as the Pole is approached. The deep sea fauna is richer than that of any other region visited by the Challenger in its voyage of exploration. A small whalebone whale, the grampus, the pilot whale, seal, penguins, skim, and teal all live in the Antarctic or on its shores. Fish have not been found in large num bers, but must be somewhat abundant, as their remains are found in the stomachs of the pen guins and seals. No traces of land mammals have ever been found on the Antarctic shores.
The winds at the interior of the Antarctic region are probably directed spirally outward from the polar centre, so that they blow as south east winds; but on the outer border winds are generally from the west, perhaps mostly from the northwest, rather than from the southwest. The annual precipitation immediately around the South Pole is probably less than 10 inches. but this increases to about 25 inches on the outer boundary of the Antarctic continental lands, from whence there is probably a poleward decrease. The average summer temperatures are below 30° P. within most of the Antarctic Circle: this is the lowest summer temperature observed on the surface of the globe. It may be that the Antarc tic winters are not so cold as the Arctic winters, on account of the great expanse of water encir cling the Antarctic land-masses, but it is more likely that there is little difference in the winter temperatures near the two poles. The lowest win ter temperature observed in lat. 70° S. was about —45° F. During a year in lat. 70° and lower, the Belgica experienced 257 days with snowfall and 14 days of rain.
BIBLIOGRAPHY. Murray. "Antarctic Research." Bibliography. Murray. "Antarctic Research." Geographical Journal, Volume HI. (London, 1394) ; Tricker. The Antarctic Regions (London, 1900) ; Cook, Through the First Antarctic -fight (New York, 1900). For history of Antarctic exploration. see POLAR RESEARCH. paragraph on Antarctic Explorations.