ANTARCTIC ZOOGEOGRAPHY AND 

 SOME OF ITS PROBLEMS 



Robert Cushman Murphy 



In considering problems of Antarctic distribution the chief cir- 

 cumstance to be appreciated is the extreme isolation of the land areas 

 and littoral waters. At all points the Antarctic Continent is separated 

 from other parts of the world by five hundred or more miles of prac- 

 tically oceanic depths. Because of the permanent westerly winds 

 which characterize the sub-Antarctic zone, there are, moreover, few 

 compensating interchanges between the warm and cold air and water 

 of the south temperate and polar belts, respectively. No land mass 

 interferes with the fixed meteorological circulation between the lati- 

 tudes of 55° and 65° S.; while the parallel of 60° S., which serves in 

 many respects as a convenient demarcation between the sub-Antarctic 

 and the truly Antarctic regions, encircles an oceanic waste without 

 touching any islet or other land whatsoever. 



Recent expeditions have established the fact that the south polar 

 climate renders terrestrial life conditions more severe than those of 

 any other part of the world. Not only is the winter no less cold at 

 high latitudes than in corresponding regions of the north, but the 

 summer is very much colder, and temperature varies far less in rela- 

 tion to latitude. At the South Orkneys, which lie well outside the 

 circle, the mean temperature of the atmosphere for the three warmest 

 months barely passes the freezing point, and yet at 77° S. the average 

 of the warmest month is only slightly colder (30° F.). The annual 

 means of high southern latitudes, as determined by Meinardus, are 

 as follows: 30° F. in 60° S., 25° F. in 70° S., 18° F. in 80° S., and 15° F. 

 in 90° S. 



Even more important than the conditions mentioned is the highly 

 unfavorable combination of low temperature with high winds. For 

 duration, intensity, and frequency of storms the Antarctic has no 

 counterpart, and when we still further take into account the relatively 

 low humidity and a general deficiency of sunlight, we reach a climax 

 in the way of an inhospitable environment. South of the westerly 

 belt of the southern oceans the prevailing winds are easterly, flowing 

 down from the higher parts of the ice-clad continent toward the pe- 

 ripheral barometric lows. That the blizzards of Adelie Land are of 

 this nature, rather than anticyclonic phenomena, is indicated by the 

 manner in which these terrific outrushes of air, chilled by the intense 

 cold of the great plateau, the average altitude of which is estimated at 



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