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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.

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 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).

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.

With the aims to assess the microbial biogeochemistry in SES and to understand its connection with natural and/or anthropogenic pressures, the microbial signatures (biomass and metabolic rates) were analyzed in the Ionian-Adriatic system. Prokaryotes underwent fast modification of structure and metabolism within the water masses

Permafrost covers more than 25% of the Earth's surface. It is extremely sensitive to global climate warming and its degradation could have dramatic impacts on the entire Earth system (Panikov et Sizova 2007). Permafrost hosts a potentially large pool of microorganisms, which is supposed to be the only life forms known to have retained viability over geological time. Thawing of the permafrost renews their physiological activity and exposes ancient life to modern ecosystems (Gilichinsky et al. 2008). The adaptation mechanisms of microorganisms, at species or population level, make them susceptible to extreme environmental condition. The survival of microorganisms in permafrost raises the question of what constitutes the limit for microbial life. Several studies of microbial populations have been conducted in Arctic or Antarctic permafrost (Guglielmin et al. 2005), but few studies concern the prokaryotic assemblage. Our contribution aims at filling some gaps in the knowledge about this peculiar and till now poorly studied microbial assemblage, evaluating the experimental methods to investigate it in terms of abundance, viability, ectoenzymatic activities and physiological profiles at community level.

The trophic structure and related indices were investigated to assess the microplankton functionality in Engraulis encrasicolus (Chordata: Actinopterygii, Clupeiformes) spawning area of the Sicilian Channel. The integrated analysis of trophic parameters and correlated indices (C/N, N/P, POC/LAP+?GLU, POC/Chl-a) highlighted both the heterogeneity and the dynamism of the planktonic communities.

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International audience

La plupart des ouvrages routiers utilisent de l'enrobé bitumineux fabriqué en centrale d'enrobage à chaud. L'objectif initial de la thèse visait à identifier les conditions relatives à la combustion ayant une influence sur la qualité de l'enrobé fabriqué et si, en étudiant la qualité de l'enrobé fabriqué selon différentes conditions industrielles, il était possible de mettre en relation les émissions et le vieillissement des enrobés. Ces aspects ont été abordés pour deux centrales d'enrobage de type Tambour Sécheur Enrobeur au fuel lourd et au gaz naturel, afin de caractériser et dissocier les émissions produites en centrale au cours de la combustion de celles produites par les différents enrobés fabriqués, en précisant chaque contribution à l'ensemble. Ainsi, l'objet principal de la thèse a consisté à élaborer une méthodologie d'analyse multi-échelles du procédé d'enrobage. Une première échelle, celle de l'enrobage en centrale a d'abord été considérée afin d'analyser, in situ, la production d'enrobé selon une méthodologie appropriée et d'obtenir des plages d'émissions en relation avec la consommation. Il a aussi été mené en parallèle une étude à l'échelle du laboratoire, pour évaluer le procédé de malaxage de l'enrobé, en caractérisant les émissions et le vieillissement de l'enrobé produit. Les concentrations de O2, CO2, CO, SO2, COT, CH4 et HAP ont été mesurées sur les deux centrales, pour la totalité des paramètres dans des conditions dédiées de fabrication et une partie d'entre eux dans des conditions usuelles. En laboratoire, des mesures spécifiques de COT et de HAP ont permis de caractériser les émissions issues de l'enrobé en utilisant un malaxeur thermo-régulé équipé d'une cheminée. Deux indicateurs ont été proposés: l'un lié à la combustion en centrale, pour repérer des conditions de fabrications stabilisées, et l'autre lié au potentiel d'émission des matériaux en laboratoire, pour permettre les comparaisons des émissions pour des températures, types de bitumes et formules différentes. L'indicateur potentiel d'émission des matériaux, comme l'indicateur de combustion, on l'a montré au fur et mesure de l'étude, dépendent du process étudié de type enrobage en tambour sécheur (avec renouvellement du bitume), malaxage en malaxeur de laboratoire (avec une masse de bitume constante) ou encore agitation du bitume sur un banc d'essai. Les résultats obtenus restent aujourd'hui caractéristiques des équipements utilisés tout en offrant des perspectives permettant de dégager des conclusions à toutes les échelles pour les COT émis en fonction de la température. The major part of road works use Hot Mix Asphalt HMA produced in HMA plants. The initial objective of the thesis aimed at identifying the conditions relating to combustion having an influence on the HMA quality and, by studying the quality of the HMA according to various industrial conditions how it would be possible to link the emissions and to aging of the asphalt. These topics were considered for two Drum Mixer plants running in with fuel and natural gas in order to characterize and uncouple emissions produced in a HMA Plant, during combustion, from those produced by the various manufactured bituminous mixtures, by specifying each contribution to the whole airborne emissions. Thus, the main objective of the thesis finally consisted in working out a methodology of multi-scales analysis of HMA process. A first scale, that of processing asphalt in a HMA plant, was initially considered in order to analyze in situ the production of bituminous mix according to a suitable methodology and to obtain a range of emissions in relation to comsumption. Besides, it was also carried out a study at the laboratory scale in order to evaluate the process of bituminous mix, by characterizing the emissions and the aging of the bituminous mix produced. The concentrations of O2, CO2, CO, SO2, TOC, CH4 and PAH were measured on the two HMA plants under dedicated running-in conditions and part of them under usual conditions. In laboratory tests, specific measurements of TOC and PAH made it possible to characterize the emissions resulting from the bituminous mix by using a thermo-mixer equipped with a chimney. Two indicators were proposed : one related to the quality of combustion in HMA Plants in order to find stabilized conditions of production, and the other related to the potential of materials emission in laboratory in order to allow emissions comparisons for temperatures, types of binders and different formula. According to the study, the emissions potential indicator as well as quality combustion indicator depends on the process studied, i.e. HMA produced in a drum Mixer (with renewal of the bitumen), HMA produced in a laboratory mixer (with a constant bitumen mass) or still in a bitumen fumes generator. The results obtained remain today characteristic of the equipment used, while offering ways that make it possible to draw conclusions at eachs scale concerning the TOC emitted in relation with the temperature.