Exploring microbial life in the brines of a perennially frozen lake (Tarn Flat, Antarctica)

Two pockets of liquid hypersaline brines, separated by a layer of ice with a thickness of 12 cm, were sampled from the unexplored Antarctic perennially frozen lake Tarn Flat at two depths (3.90 and 4.50 m) characterized by different salinity and pH values. Prokaryotic cell abundance and phenotypic traits were quantified by Image Analysis; prokaryotes, high and low nucleic acid content cells and virus-like particle abundances were quantified by flow cytometry; the biodiversity indices of the microbial assemblage were assessed by Biolog ecoplates. The potential rates of ectoenzymatic activities (Leucine aminopeptidase, beta-glucosidase and alkaline phosphatase) were assessed by fluorimetry.