Levaduras del Río Agrio y El Lago Caviahue, un ambiente acuático ácido de origen volcánico (Neuquén, Argentina)

yeast biodiversity at the acid aquatic environment of the agrio river and caviahue lake was studied. all water samples analyzed contained yeasts in variable concentrations (25 - 1192 ufc l-1). 202 yeasts strains were isolated and on the basis of morphological and physiological studies were assigned to five genera: candida, cryptococcus, cystofilobasidium, rhodotorula and sporobolomyces. cryptococcus and rhodotorula were the most abundant genera, comprising the 98% of the isolated yeast strains. the results of the tests mentioned above suggested the existence of at least eighteen different yeast species. this work provides the first quantitative and qualitative data on yeasts from an aquatic acid environment of natural origin in argentina.