Ecophysiology of soil bacteria in the vicinity of Henryk Arctowski Station, King George Island, Antarctica

Microbial abundance and diversity in soil samples from a ca. 0.2 km2 area in Admiralty Bay, King George Island, were analysed by epifluorescence microscopy and plate counts. Total bacterial counts (TC) varied little compared to the elemental content of the organic matter (c.v.TC 51% vs. c.v.C,N,S 131, 171 and 204%, respectively). The number of copiotrophic colony forming bacteria (CFU) fluctuated widely (CVCFU 171%). These factors together with the highly variable time course of colony formation by bacterial populations from each sampling site, indicate the high diversity and mosaic character of the microbial communities in the area. Morphological, physiological and enzymatic features of 48 bacterial strains isolated on nutrient agar were determined through API 20NE and API ZYM systems and by classical tests. These tests confirmed the high physiological diversity within the CFU populations. Only 14 of the 48 isolates tested by API 20NE system were identifiable in the API database.