Bacterial Habitats in the Antarctic Environment 543 



( for enterococci ) . Counts were made after three days incubation 

 at 25 C. Isolates from the countable slants were used to deter- 

 mine the taxonomic and physiological types in the dominant 

 flora. A summary of the results for each of the three rookeries 

 studied is given in Tables 1, 2 and 3. 



The ringed penguin rookery studied at Half Moon Island 

 (62°36'07" S; 58°52'20" W on 4 February 1959) was situated 

 on a rocky bluff and contained late nesting chicks and adults. 

 The data are shown in Table 1. The freshly voided feces were 

 acidic (samples A and B) while the fresh nest guano, guano 

 from around the nests and a pool of fecal material ( samples C, D 

 and E) were alkaline and quite inhibitory to the test organisms. 

 The guano "humus" (sample F), which probably resulted from 

 protracted bacterial action and weathering, was acidic. Despite 

 the differing age and condition of the materials, the total bac- 

 terial counts were somewhat constant ( 10^ to 10^ organisms per 

 gm). The coliform and enterococci counts of the decomposing 

 material indicated a surprising persistence and even increase in 

 tliese "fecal" types. Their presence in the soil "humus ' may indi- 

 cate preservation by the cold temperatures rather than a con- 

 tinuing development during the decomposition of fecal material. 

 The isolates from the dominant flora indicated that there was a 

 transition from a fecal flora (pseudomonads and diphtheroids) 

 to a guano flora (diphtheroids) to a highly mixed flora in the 

 guano pool to a Bacillus flora in the guano "humus." The fecal and 

 guano flora was saccharolytic while the proteolytic activity of the 

 "humus" was due to Bacillus tinkiensis (8). 



A gentoo penguin rookery located in a somewhat sheltered 

 rocky area of King George Island (62°09' S; 58°0r W), which 

 consisted mainly of chicks past the nesting stage, was studied 

 9 February 1959. The results are given in Table 2. Desiccated 

 feces from the vertical slope of a rock (sample L), old nest 

 guano (sample I) and guano "humus" (sample K) were acidic 

 and devoid of antibacterial activity. Material from a vacated nest 

 and a guano pool (samples H and J) were alkaline and antibac- 

 terial to the test organisms. As in the previous rookery, the total 

 aerobic counts were similar (10' to 10'' organisms per gm) while 

 the coliform and enterococci populations of the various samples 



