A Taxonomic Study of Antarctic Yeasts

SUMMARYYeast species isolated from samples of water, soil, algae, mosses, penguin dung, etc., from Lakes Vanda, Bonney, Miers, and Fryxell in the Dry Valley region of South Victoria Land, and from Capes Evans and Royds on Ross Island, Antarctica, were studied from the standpoint of taxonomy and ecology.Thirty-one yeast strains were isolated at two different temperatures (10 and 25 C), using three different culture media, each with three different concentrations of NaCl (0, 30, 100 g/liter).Species and varieties identified are as follows: Sporobolomyces antarcticus (sp. nov.), Cryptococcus albidus, Torulopsis psychrophila (sp. nov.), Candida australis (sp. nov.), C. diffluens, C. humicola, C. scottii, Trichosporon cutaneum var. antarcticum (var. nov.), Rhodotorula glutinis var. rufusa, Rh. rubra, Rh. rubra var. miersensis (var. nov.), and Rh. texensis. Of these Sp. antarcticus, Tor. psychrophila, C. diffluens, C. humicola, C. australis, Trich. cutaneum var. antarcticum, Rh. glutinis var. rufusa, and Rh. rubra var. miersensis, are recorded for the first time in the Antarctic yeast flora. Tor. psychrophila and C. scottii are obligate psychrophiles.The marked difference in the yeast flora of Lake Vanda and Lake Bonney deserved consideration. The very unusual conditions pertaining to salinity and temperature gradations in the water of these lakes may be important factors in determining the distribution of yeast found. Very marked interspecific differences were observed among the Antarctic yeasts with respect to the growth rate at different temperatures and degrees of salinity but no conspicuous intraspecific differences were noted.