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Different polar environments (lakes, glaciers), also in Antarctica, may encapsulate brine pools characterized by a unique combination of extreme conditions, mainly in terms of high salinity and low temperature. Since 2014, we are focusing our attention on the microbiology of brine pockets from three lakes in the Northern Victoria Land (NVL), lying in the Tarn Flat (TF) and Boulder Clay (BC) areas. Microbial communities were analyzed for community structure by next generation sequencing, extracellular enzyme activities, metabolic potentials and microbial abundances. This paper aims at reconsidering all available data to analyzethe influence exerted by environmental parameters on the community composition and activities. Additionally, the prediction of metabolic functions was attempted by the Phylogenetic Investigation of Communities by Re-construction of Unobserved States (PICRUSt2) tool, highlighting that prokaryotic communities were presumably involved in methane metabolism, aromatic compounds biodegradation and organic compounds (proteins, polysaccharides, phosphates) decomposition. The analyzed cryo-environments were different in terms of prokaryotic diversity, abundance and retrieved metabolic pathways. By the analysis of DNA sequences, common operational taxonomic units ranged from 2.2 to 22.0%. The bacterial community was dominated by Bacteroidetes. In both BC and TF brines, sequences of the most thermally tolerant and methanogenic Archaea were detected, some of them related to hyperthermophiles.

The effects of climate change-induced ice melting on the microbial communities in different glacial-fed aquatic systems have been reported, but seasonal dynamics remain poorly inves-tigated. In this study, the structural and functional traits of the aquatic microbial community were assessed along with the hydrological and biogeochemical variation patterns of the Arctic Pasvik River under riverine and brackish conditions at the beginning (May = Ice-melt(-)) and during the ice-melting season (July = Ice-melt(+)). The microbial abundance and morphometric analysis showed a spatial diversification between the riverine and brackish stations. Results highlighted different levels of microbial respiration and activities with different carbon and phosphorous utilization pathways, thus suggesting an active biogeochemical cycling along the river especially at the beginning of the ice-melting period. At Ice-melt(-), Gammaproteobacteria and Alphaproteobacteria were dominant in riverine and brackish stations, respectively. Conversely at Ice-melt(+), the microbial community composition was more homogeneously distributed along the river (Gammaproteobacteria>Alphaproteobacteria> Bacteroidetes). Our findings provide evidence on how riverine microbial communities adapt and respond to seasonal ice melting in glacial-fed aquatic ecosystems.

The Eastern Mediterranean Transient (EMT) lasted from the late-1980s to the mid-1990s and appears as the major climatic perturbation of circulation and water mass properties of the Mediterranean in the past hundred years. About 20% of the waters below 1200 m depth horizon werere placed in the eastern Mediterranean Sea by younger waters of Aegean origin with an average formation rate (1.2 Sv) four times faster than the rate calculated for the Adriatic source waters before the occurrence of EMT. The consequences of the EMT continue also today and have spread in the Western Mediterranean basin. A variety of altered biological processes have been recorded in the pelagic realm of the Mediterranean Sea after the 'EMT' onset and this review discusses them critically and relates the triggering of these climatic phenomena in the future with the possible impacts on the marine biota.

Il CNR di Messina svolge ricerche di carattere microbiologico in aree polari, con particolare focus sulle aree marine antartiche e periantartiche, dal 1988. Dal 2009 partecipa anche a diverse spedizioni in aree polari artiche, comprese le Isole Svalbard. In queste ultime, le ricerche del gruppo sono state condotte nel Kongsfjorden nell'ambito di tre progetti: PolyArc, MYKA e ARCA. La comunità microbica marina gioca un ruolo chiave nella rete trofica artica, in quanto controlla diversi processi, fra cui la produzione primaria, il turnover degli elementi biogenici, la degradazione della materia organica e la mineralizzazione di xenobiotici e inquinanti. In questo contesto diversi sono stati gli approcci metodologici e le strategie di campionamento adottate su campo nel Kongsfjorden dal gruppo di ricerca, in funzione anche della logistica e delle risorse disponibili. I molteplici studi condotti hanno avuto carattere multidisciplinare, e rivolti 1) allo studio della struttura della comunità batterica nei sedimenti e nell'acqua (in collaborazione con l'Università di Messina), 2) alla valutazione nel breve periodo dei trends biogeochimici e microbici lungo la colonna d'acqua (in collaborazione con l'Università di Rio de Janeiro e Miserocchi S., ISMAR di Bologna), 3) all'isolamento di batteri potenzialmente degradanti inquinanti come PCB (Giannarelli S., Università di Pisa) e PAH, 4) alla valutazione di bloom fitoplanctonici e al rilevamento di specie potenzialmente tossiche (in collaborazione con Caroppo C., IRSA di Taranto), e 5) alla valutazione della componente microbica (attività, funzioni e composizione) in un'area prossima ai ghiacciai, grazie all'applicazione su campo di un multi campionatore di acqua, prodotto in collaborazione con i colleghi del CNR dell'INM (Caccia M., Bruzzone G.) che hanno sperimentato diversi Autonomous Underwater Vehicles (AUVs). Quest'ultima tematica di ricerca costituisce sicuramente un challenge per studi futuri in quanto consente di acquisire dati ambientali e biologiciin siti inaccessibili all'uomo per problemi legati alla logistica e al campionamento in sicurezza.

Microbial enzyme activities on organic polymers were tested as possible sentinels of anthropic and natural forcings during a two-year study in two coastal Antarctic areas (Road Bay and Tethys Bay respectively). In Road Bay high proteolytic activity rates were measured at a site impacted by the Italian research station sewage, due to faecal wastes; in Tethys Bay low salinity waters related to glacier presence were characterized by high enzyme activities probably associated to detritus from ice melting.

The spatial and temporal distribution of microbial biomass and metabolic rates were investigated in water samples collected along the Pasvik River (Arctic Norway) from 9 stations during two sampling campaigns (May and July 2014). Water samples were analyzed for physico-chemical parameters, viable bacterial abundance (VCs), prokaryotic abundance (PA), microbial enzymatic and respiratory activity. All data were statistically analyzed. VCs were generally homogeneous in May and July. PA showing enhanced abundance in July and higher values in the outer than in inner stations. Microbial respiration was higher in July than in May. Pearson's correlation coefficients showed that physical and chemical parameters affected both the PA and functionality. Respiration was significantly related to Temperature, suggesting its stimulation on the oxidation process. ANOSIM analysis showed seasonal significant differences (R=0.231, p=0.002), with temperature accounting for 11.4% of total variability. Psychrophilic microorganisms of the Pasvik river appear to be quite plastic to acclimate to seasonal changes of the cold habitat in which they live, modifying their abundance and metabolism, although further research is needed for a deepen knowledge of this Arctic ecosystem.

Microbial biofilms play a key role in substrate colonization in aquatic environments, as hot spots of biodiversity and sources of secondary metabolites with biotechnological potential. In Terra Nova Bay (Ross Sea, Antarctica), microbial biofilm communities are under-explored in their structure and functions; particularly, their response to environmental and/or anthropogenic forcings remains to be elucidated yet. Funded by National Antarctic Research Program (XXXIII Italian expedition), the ANT-Biofilm project "Microbial colonization of benthic ANTarctic environments: response of microbial abundances, diversity, activities and larval settlement to natural or anthropogenic disturbances and search for secondary metabolites" (PNRA16_00105) includes short and long term (3-12 months) experiments in two bays (Road Bay and Tethys Bay) characterized by anthropogenic (i.e. sewage) and natural (i.e. low salinity) stressors, respectively. Total, viable and respiring prokaryotes, culturable bacteria, potential enzymatic activity rates, physiological community profiles, microalgae and macrobenthic community are studied. Selected biofilm samples will be sequenced and analyzed by hybridization (i.e. Card-FISH) and bacterial isolates screened for antibiotic resistance and metabolite production. Physical-chemical environmental characterization will be performed. This contribution reports the preliminary results obtained by the four Research Units during the short term experiments.

Polar Regions are experiencing multiple environmental stressors and the increasing contaminant influxes are likely becoming more severe. As filter-feeders, in Porifera ingestion becomes the primary route in the uptake and accumulation of particle-associated contaminants, which may accumulate in animal tissues. Porifera also provide an important habitat for aquatic prokaryotes that colonize outer surfaces and interstices of ostia and oscula, and may be particularly responsive against contaminants accumulated in the sponge tissues. Symbiotic microorganisms can adhere to the sponge surfaces by forming biofilm with complex 3D-structures, composed by microbial consortia encased in an extracellular polymeric substances. The exopolymeric substances possess high biotechnological potentialities with applications in biomedical, cosmetic, food and environmental fields. Despite Porifera are abundant invertebrates in Antarctica, the associated prokaryotic communities and their biotechnological potentialities were largely disregarded. Funded by the Italian PNRA, the P3 project "Antarctic Porifera: Hot-spots for Prokaryotic diversity and biotechnological Potentialities"" (PNRA16_00020) will aim at linking the ecological traits (e.g., phylogenetic diversity and metabolic activities) and biotechnological potential (e.g., biofilm production, pollutant degradation) of prokaryotes associated with Antarctic Porifera by applying a multidisciplinary approach.

During a GPR survey, two lenses of liquid brines were found at different depths in two adjacent frozen Boulder Clay lakes (Lake-1: 2.5 m; Lake-2: 2.0) with a different salinity (0.2 and 3.6 mS/cm, respectively) and pH (8.17 and 8.76, respectively). Brines were analyzed for bacterial diversity by Ion Torrent DNA and cDNA sequencing, microbial abundances (by image analysis and flow cytometry) and metabolic activities (by Biolog-Ecoplate(TM) and potential rates of ectoenzymatic activities determinations). The analysis of DNA sequences generally showed the predominance of Bacteroidetes, followed by Proteobacteria and Actinobacteria. The highest percentage (6.0 vs 1.7%) of active bacteria (by the analysis of RNA sequences; mainly Bacteroidetes) was observed in Lake-1. This latter harboured microbial populations characterized by higher prokaryotic cell abundances, volumes, biomass and virus abundance than Lake-2. Diverse cell morphotypes were observed in the two lakes. Different metabolic responses were also determined, with higher numbers of respiring cells and higher rates of ectoenzymatic activities, as well as the ability to better utilize carbon sources, in Lake-1 than in Lake-2. Results highlighted differences in the analyzed cryoenvironments in terms of diversity, abundance and metabolism, suggesting that Antarctic lakes might possess distinct microbial features in spite of their spatial proximity.

In the frame of the ARCA project (ARctic: present Climatic change and pAst extreme events) aimed at studying the hydrological cycle in the boreal hemisphere, a first prototype of automatic equipment was specifically designed to perform discrete sampling of waters in the area close to a glacier. The Shark USSV (Unmanned Semi-Submersible Vehicle) designed and built by CNR-ISSIA for the first time collected autonomously samples near the front of the glacier Kronebreen in the Kongsfjorden. Shark was used to tow along a transect and via an adequate rope a small catamaran carrying an Automatic Water Multisampler built by CNR-IAMC. In June 2015, surface water samples were collected by the automatic Multisampler along a transect of 9 stations located from the glacier to the open sea. This research reports the results of the first in situ application of this device related to the study of the distributions of prokaryotes, virus-like particles and nutrients. Viral and prokaryotic abundances were significantly correlated with each other and their spatial distributions were not affected by the presence of the glacier. A low viruses abundance was found compared to the other marine ecosystems and it might be explained by adsorption on particles. The low virus/prokaryotes ratio suggested a lysogenic phase of virus. High nutrient concentrations were detected but they appeared to be not linked to microbial patterns.

The Pasvik river is one of the largest river in the Northern Fennoscandia. Its water conditions are representative of Eastern European rivers. The river collects snowmelt, and it is typically a freshwater environment at its inner zone and brackish at its outer zone. Sediment samples were collected from 9 stations during two seasonal surveys (May and July 2014). Physical-chemical parameters were monitored at sampling time. Samples were analyzed for viable heterotrophic bacteria, total prokaryotic abundance, microbial enzymatic activity rates, and phylogenetic composition of bacterial community. Microbial enzymatic activities generally increased in July, but showed spatial and temporal variability. In May, leucin aminopeptidase showed the highest values at outer stations (9.37 mmol/g/h). The bacterial community resulted highly variable among the sampling stations with the predominance of the Proteobacteria, followed by the Actinobacteria and CF group of Bacteroidetes. In July, an increased abundance of the Acidobacteria was observed at St.1 (from 4.7 to 22.1%). This study highlights both seasonal (May and July) and spatial differences within the microbial community that inhabit sediments along the Pasvik river. This finding is probably strictly dependent on freeze-thaw cycles of the water body, with consequent organic inputs to sediments in July. The microbial community appears to be adapted to fluctuating conditions modulated by seasonality.

To understand how the climate change affects the microbial community in the Arctic Sea and the ongoing heating results in cascading effects on the globally delicate climatic equilibrium is an important challenge of recent research performed in vulnerable ecosystems such as the Svalbard Islands. Within the UVASS (Unmanned Vehicles for Autonomous Sensing and Sampling) project, an unmanned marine vehicle (PROTEUS, Portable RObotic TEchnology for Unmanned Surveys), equipped with an automatic water multisampler, designed and built by ISSIA-CNR and IAMC-CNR respectively, were applied to study the response of planktonic communities, particularly prokaryotes, in the extreme environment of Kongsfjorden. During June 2017, seawater samples collected by those automatic systems along three transects located from glaciers to the open sea were analyzed for nutrients, organic matter and its utilization by microbial activity, using Biolog-Ecoplates(TM) and extracellular enzymatic activity rates (leucine aminopeptidase, beta-glucosidase and phosphatase activities). Richness and Shannon-Weaver index and Principal Component Analysis were used to depict differences in the microbial catabolic potential. Variations in organic matter distribution and in the functional diversity of microbial assemblages were observed. Freshwater runoff from ice melting was found to increase the amount of terrestrial organic matter to the fjord and microbial processes allowed organic matter decomposition.

Two distinct hypersaline brine pockets (TF4 and TF5) separated by a 12 cm-thick ice layer were sampled from Tarn Flat, an unexplored Antarctic perennially frozen lake. Samples were analyzed for prokaryotic (Bacteria and Archaea) diversity (Ion Torrent sequencing), microbial abundances (image analysis and flow cytometry) and metabolic activities (Biolog-Ecoplate(TM) and potential rates of ectoenzymatic activities). The two sites shared only 22 and 18% of OTUs for Bacteria and Archaea, respectively. Shannon diversity for archaeal and bacterial communities was higher in TF5 than TF4 (p value < 0.001). Both bacterial communities were dominated by Proteobacteria, followed by Bacteroidetes and Actinobacteria. The Archaeal community was mainly constituted by Euryarchaeota and Crenarchaeota. Prokaryotic and virus-like particle abundances were in the order of 109 cells/l and 1010 VLP/l, respectively, in both samples, with slightly higher counts in TF4 than TF5. However, the VLP/PA ratio was 2.7 times higher in TF4 than in TF5. Larger cells were detected in TF5 (0.105 µm3) than TF4 (

In the Kongsfjorden site (Svalbard Islands) glaciers retreat is one of the most evident signs of global warming. Such evidence has strong implications on the marine ecosystem. An oceanographic cruise was performed within the ARCA (ARctic: present Climatic change and pAst extreme events) Project in May 2016 to study the chemical-physical, biochemical and biological characteristics of superficial waters along a transect of 7 surface stations in inner Kongsfjorden until the Kronebreen glacier (stations 4-5-14-6-23-7 and 8, glacier). Station 4 was also sampled from surface to 100 m. The studied parameters were: temperature, salinity, dissolved oxygen, turbidity, nutrients, chlorophyll-a (Chl-a), Total Suspended Matter (TSM), chromophoric Dissolved Organic Matter (c-DOM) absorption, total bacterioplankton abundance and its respiring fraction, heterotrophic bacteria on Marine agar, extracellular enzymatic activity (leucine aminopeptidase - LAP, beta-glucosidase -GLU and alkaline phosphatase -AP). Temperature and salinity values decreased from station 4 to station 8 (near the glacier) and an opposite trend was observed for turbidity and nutrients values. TSM also peaked at station 8 while reduced concentrations of Chl-a characterized the surface waters. Ammonia, nitrite+nitrate and orthophosphate ranges were 0.45-1.44 µmol/l, 0.12-5.60 µmol/l, 0.10-0.48 µmol/l, respectively. CDOM absorption slope values (range 275-295 nm) varied from 0.0077 to 0.0109 nm-1. Total and respiring bacterioplankton counts were in the magnitude order of 106 and 104 cells/ml respectively and of 10^2 Colony Forming Units/ml. Enzymatic activity patterns were in the order AP>LAP>GLU, with rates lower than 1.78, 1.25 and 0.25 nmol respectively. Temperature affected negatively nutrients, TSM and turbidity, positively GLU. AP was associated to the heterotrophic bacteria (Pearson r=0.59). AP and c-DOM absorption spectra were significantly related (r=0.71), as well as LAP and Chl-a (r=0.97), suggesting fresh material stimulated enzymatic synthesis.

In the framework of the ARCA project (ARctic: present Climatic change and pAst extreme events) aimed at studying the hydrological cycle and its consequences on the climate in the boreal hemisphere, a first prototype of automatic equipment was specifically designed to perform discrete sampling of waters in the area close to a glacier. The Shark USSV (Unmanned Semi-Submersible Vehicle) designed and built by CNR-ISSIA was used for collecting samples in the stretch of sea near the Kronebreen glacier (Kongsfjorden); this was the first time that an autonomous sampling was carried out near the front of the glacier. Shark was used to tow along a transect and via an adequate rope a small catamaran carrying an Automatic Water Multisampler built by CNR-IAMC. In June 2015, surface water samples were collected by the automatic Multisampler along a transect of 9 stations located from the Kronebreen glacier (St 6) to an outer stations (St 9). This research reports the results of the first in situ application of this device related to the study of the distributions of prokaryotes, virus-like particles and nutrients.

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.

The perennial ice cover of Antarctic lakes sometimes encapsulate lenses of brines. In October-November 2014, a screening of several frozen lakes in the Northern Victoria Land through the ground probing radar investigation was made. Tewo lenses of liquid brines were found at different depths in two adjacent frozen Boulder Clay lakes and had a different salinity and pH. Brines were sampled under sterile conditions and analysed by microscopic image analysis to assess prokaryotic abundance, cell shape and respiring cells and by flow cytometry to determine virus abundance. The physiological profiles by Biolog ecoplate were determined as well as the potential ectoenzymatic activities rates (leucine aminopeptidase, beta-glucosidae and alkaline phosphatase).

Our contribution is devoted to test the hypothesis that Continental Antarctic permafrost harboured prokaryotic communities rich in viable cells and metabolic potentials. With this aim, three permafrost cores collected in Boulder Clay (Northern Victoria Land) were examined for the prokaryotic abundance, viability, and potential metabolism using culture-indedependent methods. Samples were analysed by microscopic image-analysis to assess abundance and cell-shape determinations and by flow-cytometry to recognise sub-populations according to nucleic acid contents. The quantification of viable and respiring cells was performed by image analysis using the Live/Dead and 5-Cyano-2,3-ditolyl-tetrazolium chloride stains, respectively. The potential ectoenzymatic activities rates on proteinaceous (leucine-aminopeptidase) and glucidic (ß-glucosidase) organic matter and on organic phosphates (alkaline-phosphatase) were determined as well as the physiological profiles by Biolog-Ecoplate(TM). In comparison, another permafrost sample, collected from the Dry Valleys (Upper Victoria Valley), was analysed with the same methods.

Frozen lakes are a prominent structure in the ice-free regions of Antarctica and such perennial glacial lakes sometimes encapsulate lenses of brines, representing an extreme cryogenic ecosystem. The study of these unique environments allows insights on the geochemical processes affecting the microbial life in analogues terrestrial cryoecosystems and increases our perceptions on possible traces of life that must be sought beyond Earth. In order to find new extreme refugia for microbial life, in October-November 2014 a screening of several frozen lakes in the Northern Victoria Land through the ground probing radar (GPR) investigation was made. Two lenses of liquid brines were found at different depths in two adjacent frozen Boulder Clay lakes (Lake-1: 2.5 m; Lake-2: 2.0) and had a different salinity (0.2 and 3.6 mS/cm, respectively) and pH (8.17 and 8.76, respectively). Brines were sampled under sterile conditions and analysed by microscopic image-analysis to assess prokaryotic abundance, cell-shape, and respiring cells (CTC+) and by flow-cytometry to determine virus abundance. Moreover, the physiological profiles by Biolog-Ecoplate(TM) were determined as well as the potential ectoenzymatic activities rates (leucine-aminopeptidase, LAP; ß-glucosidase, ?-GLU; alkaline-phosphatase, AP).

The microbial assemblage plays a key role in the coastal and pelagic food web of the Ross Sea; it controls many processes, including primary production, turnover of biogenic elements, degradation of organic matter and mineralization of xenobiotics and pollutants. Prokaryotic abundance and activity shift significantly over the annual cycle as sea ice melts and phytoplankton blooms develop. Marine microbs in the Ross Sea exibit a diversity which also depends on the timing, location and sampling method; research devoted to this group is increasing, using also genetic and molecular approaches in surface and deep waters. Our contribution will focus on the presentation of microbial data (standing stock and activity, as well as diversity and biotechnological potentialities of bacterial isolates) collected in the Ross Sea (coastal and pelagic) from 1988 to 2016, in the framework of the Italian National Programme for Antarctic Research (PNRA). Particular emphasis will be given to the interannual and decadal variability of microbial community in coastal and pelagic zones of the Ross Sea.

Recent climate changes in Arctic regions have caused retreat of glaciers, increases in meltwater outflow and massive inputs of suspended sediment load to the coastal marine environment (Malone et al., 2016). Moreover, climate warming in the Arctic can potentially affect large-scale microbial processes including population dynamics and trophic level interactions. Viral, prokaryotic and phytoplanktonic communities play a key role in relevant processes such as carbon fluxes and nutrient regeneration and can be viewed both as sentinels and amplifiers of global change. Monitoring of environmental changes, especially those related to ice melting, requires the availability of advanced technologies, able to promptly record phenomena occurring at different spatial and time scales. Moreover, the development of new sampling technology in extreme environments can be used in areas not reachable by vessels or subject to oil spill. In the context of ARCA project the main aims of our research unit were: i) to assess the variability of planktonic abundance and activities over short time scales in a site of the study area; ii) to design and built an automatic sampler for extreme polar environments; iii) to search for cold-adapted OIL/PAH(Polycyclic aromatic hydrocarbons)-degrading bacteria in the Arctic region.

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.

The recent discovery on Mars of the possible presence of seasonal brines has increased interest in analogous environments on Earth. In fact, the ice cap of several Antarctic lakes encapsulates sometimes brine pools characterized by a unique combination of extreme conditions. Moreover, the study of these cryoecosystems allows insights on geochemical processes affecting the microbial life and on how the latter can be supported in similar terrestrial environments and in other icy worlds of the universe. In order to find new extreme ecological niches of life, in the framework of Italian National Research Programme in Antarctica (PNRA), in October-November 2014 a screening of several frozen lakes in the Northern Victoria Land through the ground probing radar (GPR) investigation was made. Two hypersaline brines found at two different depths (B1-3.90 m; B2-4.50 m) in a perennially frozen Turn Flat lake were studied. The two pockets of liquid brines were separated from an ice layer of 12 cm and had a different salinity (84-92 and 74-75 psu respectively) and pH (7.22 and 6.74 respectively). Brines were sampled under sterile conditions and analysed by microscopic image-analysis to assess abundance, cell-shape, viable (Live/Dead) and respiring cells (5-Cyano-2,3-ditolyl-tetrazolium chloride stain). Moreover, the physiological profiles by Biolog-Ecoplate(TM) were determined as well as the potential ectoenzymatic activities rates (leucine-aminopeptidase, LAP; ß-glucosidase, ?-GLU; alkaline-phosphatase, AP).