156 Marine Microbiology 



soil population of microorganisms has not been assayed, but it 

 is probably considerable during the years of large populations. 

 Antarctic land animals are restricted to birds and seals, both of 

 which are primarily carnivorous and dependent upon the ocean 

 for their food. They contribute very little towards the building 

 of a population of soil microorganisms except in such isolated 

 places as penguin rookeries. The microbiology of these has not 

 been studied. 



3. Arctic regions along major rivers and the ocean continu- 

 ally receive soil, organic materials and microorganisms from con- 

 tinental land masses wliich have relatively warm summer periods. 

 This inoculation is both air- and water-borne. The vast oceans 

 surrounding Antarctica drastically reduce such inoculations by 

 both air and water. 



4. Finally there is a native human population in most arctic 

 regions. This is entirely lacking in Antarctica where up until 

 the last few years man has been only a rare summer visitor. 

 Man tends to accumulate organic litter, which, along with the 

 increased temperature of his habitation, would give small areas 

 with high microbial populations. 



It is possible that not all of the observations concerning 

 thermophilic bacteria in polar regions can be explained by these 

 generalizations, but several of them may be. 



1. The Kara Sea receives the water from the Tobol, Irtysh, 

 Ob, Angara and Yenisei Rivers which drain a tremendous area 

 east of the Ural mountains extending from about 60° to 114° E 

 longitude and from about 46° to 73° N latitude. Water-borne 

 silt from this area is probably the source of the thermophilic 

 bacteria found by Egorova in the bottom mud and the island 

 soil. 



2. The thermophilic bacteria found in the Point Barrow, 

 Alaska region by McBee and McBee (6) were nearly all in or 

 near Eskimo habitation. One sample from near the dog stakes 

 of a recent Eskimo camp had nearly 200 aerobic thermophiles per 

 gram as well as anaerobic themiophilic bacteria. Similar soil from 

 a few yards away showed no aerobic thermophilic bacteria in a 

 one gram sample even when lemming feces were included. 

 Abandoned Eskimo houses and the area suiTounding them such 



