Prokaryotic communites in permafrost soil at Edmonson Point (Northern Victoria Land).

Edmonson Point (EP) in the Northern Victoria Land is a volcanic area close to Mt. Melbourne. It is characterized by alluvial sediments and weathered basaltic outcrops with some ponds and not far penguin rookeries. Here, soils are quite rich in organic content (0.5-1.6 % C org) and are Aquic Haplorthels overlying continuous permafrost. Permafrost soil samples were collected directly from the unfrozen part (35 cm in depth) of the active layer at EP in early January 2014. Temperature was measured from surface to 35 cm (just above the permafrost table), ranging from 7.4 to 1.8°C. Samples were examined for: bacterial community composition by the Ion Torrent (IT) technique, prokaryotic abundance and cell-shape by microscopic image-analysis (IA), viability by Live/Dead (L/D) stain, respiring cell quantification by 5-Cyano-2,3-ditolyl-tetrazolium chloride (CTC+) stain, potential ectoenzymatic activities rates on proteins, polysaccharides and organic phosphates (by leucine-aminopeptidase, ß-glucosidase and alkaline-phosphatase, respectively), physiological profiles by Biolog-Ecoplate(TM), sub-population assessment according to nucleic acid contents by flow-cytometry (FC). Finally, different isolation procedures were adopted to recover aerobic bacteria and a selection of bacterial isolates was identified by the 16S rRNA gene sequencing.