Les bassins de gestion des eaux pluviales, dont l’horizon de surface est parfois fortement contaminé, peuvent être naturellement ou volontairement colonisés par la végétation. L’objectif de ce travail est de mieux comprendre le rôle de la végétation dans le contrôle de la mobilité des métaux lourds comme le Zinc, le Cuivre et le Cadmium. Le premier volet de ces travaux, consacré à la caractérisation de la végétation se développant dans ces bassins, a montré que ces ouvrages abritaient une flore diversifiée, allant d’une végétation rudérale éparse à une végétation dense caractéristique de zones humides. Ensuite, une analyse physico-chimique multiparamétrique d’échantillons prélévés à la surface de bassins colonisés par des espèces végétales dominantes a été réalisée. Nous avons montré que les carbonates et la matière organique contrôlaient particulièrement la mobilité du Cu, Cd et Zn dans ces milieux. Les paramètres les plus variables temporellement et spatialement, sont essentiellement liés au cycle de la matière organique (nitrates, fraction métallique lié à la matière organique) mais également à l’apport de particules anthropiques (texture, métaux). Lorsque la plante est à son maximum de croissance, la mobilité potentielle des métaux est la plus élevée alors que la phase de sénescence de la plante semble conduire à un meilleur piégeage de ces contaminants. Cette thèse invite à considérer la végétation comme un agent de transformation de l’horizon de surface et à intégrer cette composante dans les futurs travaux sur la contamination des ouvrages d’assainissement urbain. / Urban stormwater basins surfaces can be highly contaminated and can be spontaneously or intentionaly vegetated. The aim of this work is to better characterize the role of the vegetation on heavy metal (Zn, Cd, Cu) mobility. Firstly, vegetation inventory has pointed out the high species diversity in these devices (from ruderal vegetation to wetland plants). Then, a physico-chemical characterization of surface samples vegetated by dominant species has been carried out. We have shown that carbonates and organic matter play a major role in the control of heavy metal mobility. The parameters which are the most spatially and temporally variable are essentially related to organic matter cycle (nitrate, heavy metal fraction bound to organic matter), and to the introduction of stormwater suspended matter (heavy metals, texture). At the maximum of plant growth phase, heavy metal mobility is enhanced and the period of plant death leads to a better heavy metal retention in the basin surface. This thesis invites us to consider plants as agents of surface stormwater basin transformation and to include plants in future research work.

Dans la seconde moitié du dix-neuvième siècle, le Sultanat de Zanzibar a été au cœur des politiques abolitionnistes et coloniales aussi bien françaises que britanniques. En effet, l’île de Zanzibar ne fut pas seulement le plus grand marché aux esclaves de l’océan Indien mais aussi la porte d’entrée privilégiée des trafiquants d’esclaves, des abolitionnistes, et des partisans de la colonisation en Afrique Orientale. Cette thèse s’intéresse aux controverses, ayant opposé la France et la Grande-Bretagne dans les eaux territoriales de Zanzibar, sur le droit de visite des bateaux transportant des esclaves ainsi que sur le droit des boutres à battre pavillon français et à échapper ainsi aux contrôles de la Royal Navy. Cette recherche souligne combien ces questions furent importantes, non seulement pour les relations de la France, de la Grande-Bretagne et du Sultanat de Zanzibar, mais aussi pour le droit international et les relations internationales jusqu’à la veille de la Première Guerre mondiale. Ce travail montre que les opérations de lutte contre la traite qui ont eu lieu à Zanzibar ont inspiré de nombreux officiers de marine, des consuls, des diplomates, des juristes, et des hommes politiques, aussi bien français que britanniques, quant à la conception et à la mise en œuvre « d’interventions humanitaires ». Ainsi l’histoire des opérations de lutte contre la traite menées dans le sultanat de Zanzibar permet d’éclairer de manière originale l’histoire du concept d’intervention humanitaire ou « d’humanité » (« intervention in the score of humanity »). Cette recherche souligne combien la nature de ces interventions humanitaires a sans cesse oscillé entre de véritables idéaux abolitionnistes et des enjeux coloniaux pressants. / In the second half of the nineteenth century the Zanzibar Sultanate became the focal point of French as well as British imperial and humanitarian policies. In fact, the island was not only the most important slave trade emporium of the Indian Ocean but it was also the great gateway to East Africa for slave traders, humanitarians, or imperialists alike. This thesis looks at the controversies which took place in Zanzibar waters between France and Britain over the right of searching vessels suspected of being engaged in the slave trade as well as the right of dhows to fly the French flag and escape the Royal Navy’s scrutiny. This research highlights how important these questions were, not only for the relations of France, Britain, and the Zanzibar Sultanate, but also for international law and international relations up until the eve of the First World War. This work demonstrates that the anti-slave trade operations which took place in Zanzibar inspired many navy officers, consuls, diplomats, Foreign Secretaries, and lawyers – whether British, French, or American – on the theory and the practice of “humanitarian interventions”. Indeed, the history of anti-slave trade operations implemented in the Zanzibar Sultanate sheds a new light on the history of the concept of humanitarian intervention, or “intervention in the score of humanity” – (“l’intervention d’humanité”) – as it was then called. This research underlines how these humanitarian interventions unceasingly swung between genuine humanitarian ideals and pressing imperial issues.

Le voyage des étudiants africains en situation coloniale constitue le sujet d’une mise en scène récurrente dans la littérature africaine d’expression française des années cinquante. À l’époque des combats décoloniaux, politiques et idéologiques, certains écrivains comme Cheikh Hamidou Kane, Camara Laye ou Aké Loba font de l’expérience de la colonisation culturelle le cœur de leurs œuvres littéraires. Leurs textes portant sur le voyage pour études des héros vers la France s’articulent autour d’une isotopie narrative, spatiale et existentielle : une migration en forme d’impasse, reposant sur quantité de promesses trahies, de rêves aux perspectives brisées, d’expériences de déréliction mortifère. L’étude du fonctionnement littéraire de la déception progressive des personnages d’élèves africains colonisés permet de mettre au jour le processus de subjectivation qui détermine leur horizon bouché. Car les trompe-l’œil idéologiques de l’entreprise coloniale dissimulent un mouvement de capture existentielle qui arraisonne les personnages et les transforme en sujet de domination. Depuis le tournant des indépendances politiques, le traitement littéraire de ces aventures échouées continue d’interroger le temps présent. Ces êtres tendus entre des espaces et des univers de valeurs antagoniques questionnent la négociation des identités postcoloniales. Comme si, en entrant dans la fabrique du personnage colonisé, partant à la rencontre de ses mécanismes et de ses modèles, nous avions rendez-vous avec les formes contemporaines de leur développement mondialisé. / The travels of African students in a colonial situation are a recurring subject in Frenchspeaking African literature of the 1950s. At the time of de-colonial, political and ideological struggles, some writers such as Cheikh Hamidou Kane, Camara Laye or Aké Loba have put the experience of cultural colonization at the heart of their literary work. Their writings, aboutthe study trips of the main characters to France, are based on a spatial and existential isotopy: a dead-end migration, based on many betrayed promises, dreams with broken perspectives, experiences of deathly dereliction. The study of the literary device of the progressive disenchantment of these characters – African, colonized students – allows to shed light on thesubjectivation process that shapes their barred horizons. Indeed, the ideological deceit of the colonial endeavor hides a movement of existential capture that grabs the character and makes them subjects of domination. Since the turning point of political independencies, the literary outlook on those failed adventures keeps interrogating our present times. These beings, stretched between spaces and universes of opposed values, question the negotiation of postcolonial identities. As if, by entering the mold of the colonized character, by going to meet its mechanisms and models, we had an appointment with the modern-day shapes of their globalized development.

Cette thèse cherche à montrer comment au Vietnam, l’architecture et l’urbanisme relèvent de la rencontre de deux cultures, celle du colonisateur et celle du colonisé. L’enjeu est de mettre en lumière la diversité des échanges culturels – expressions et significations – à travers le bâti, en procédant à une étude critique de l’idée selon laquelle l’architecture et l’urbanisme seraient uniquement des instruments du pouvoir colonial. Nous avons cherché à identifier les conditions de production et d’utilisation du bâti pour appréhender la complexité et la diversité des phénomènes à l’œuvre. Nous avons privilégié trois approches. La première concerne l’étude des acteurs et de la circulation des savoirs qui nous permet d’envisager les différents discours et théories qui ont existé autour de l’architecture métissée, ainsi que leur réception. La seconde prend en considération les politiques de gestion de l’espace urbain en s’attachant à mettre en valeur les négociations et les résistances au projet d’encadrement colonial. Enfin le troisième volet se place au niveau de l’articulation des enjeux techniques et sociaux et permet de mettre au jour les mécanismes constitutifs de cette architecture interculturelle. / This dissertation aims to demonstrate how the history of architecture and town planning in Vietnam became enmeshed in the encounter of two cultures: that of the colonized and that of the colonizer. The goal is to first examine the diversity of cultural exchanges – both their manifestations and meanings – through the built environment, and then provide a critique of the idea equating architecture and colonial power. In order to consider the diversity and the complexity of the phenomenon at work, this dissertation identifies the conditions of production and use of the built environment. This study privileges three approaches. The first considers the actors and the circulation of knowledge so as to explore the construction and the reception of the different discourses and theories that enveloped hybrid architecture. The second approach takes into account the politics of administrating urban space by emphasizing the negotiations and the resistance to the colonial project of construction and enclosure. Finally the third part analyzes the articulations between social and technical issues, which reveal the mechanisms constitutive of this intercultural architecture.

Abstract Mycorrhizal fungi are important contributors to the functioning of boreal forests, since they act in the bilateral carbon and nutrient transport between above- and belowground parts of the ecosystem. In ectomycorrhizal (ECM) symbiosis of woody host plants, both fungal and plant partners depend on resources provided by the other. A single tree may simultaneously host several ECM fungal partners, which greatly enhance the host's nutrient uptake. At the same time nearly 20% of host primary production is allocated to mycorrhizal fungi. Although fungi depend on host-derived carbon, it is poorly understood how reduced carbon availability, e.g., due to herbivory, affects the ECM fungal symbionts. In this thesis I studied the impact of simulated insect defoliation or mammal browsing on mycorrhizal fungi of boreal woody hosts. Quantitative and qualitative changes in biomass partitioning in different fungal compartments were detected. None of the experiments showed that defoliation or shoot clipping treatments reduced the intensity of ECM colonisation, while treatments often shifted fungal composition towards less biomass producing ECM morphotypes. Above- and belowground diversity in ECM symbionts tended to decrease due to shoot or foliar damage. In addition, in some cases defoliation also reduced fungal biomass in fine roots and decreased ECM sexual reproduction by reducing the number of sporocarps produced. Defoliation induced a similar response pattern in the host and in ECM fungi with a stronger response to increasing severity of treatment (e.g. degree of removed foliage or repeated years of defoliation). This was also confirmed when relating the effects of host and ECM fungal symbionts to defoliation using present and previously published data. The present results suggest that belowground adaptation of boreal trees to the changing environment is mediated by changes in fungal community or biomass partitioning. The lack of response in the intensity of ECM colonisation further emphasises the importance of the symbiosis to boreal trees.

Escherichia coli est une espèce commensale du tube digestif, mais elle peut aussi se révéler être un dangereux pathogène intra ou extra intestinal. Un même clone pouvant passer d'un état commensal à pathogène, la compréhension des mécanismes impliqués dans la diversification d'E. coli dans ces deux habitats représente un enjeu majeur de santé publique. Des expériences d'évolution expérimentale utilisant E. coli ont permis de révéler différentes facettes de l'adaptation bactérienne. Cependant, ces expériences de laboratoire utilisant des conditions artificielles, on peut s'interroger sur la pertinence des observations qui en découlent en milieu naturel et plus globalement s’interroger sur la part de la sélection naturelle dans la diversification de E. coli dans la nature. Pour répondre à ces questions, j'ai analysé les profils génomiques de diversification de E. coli au cours (1) d’une adaptation au tube digestif de souris ou (2) dans des infections extra-intestinales. Dans les deux cas, j’ai pu montrer une importante convergence au niveau du gène : un même gène étant muté plusieurs fois indépendamment, un signe que l’adaptation est active. Dans les infections aigues, des mutations touchant des régulateurs globaux ont été retrouvées, alors que dans le tube digestif les cibles de l’adaptation semblaient plus spécifiques. Enfin, les échantillons issus des infections incluant des souches a fort taux de mutation dites mutatrices, j'ai pu documenter pour la première fois la génomique de l'émergence de bactéries mutatrices en milieu naturel.En conclusion, mes travaux montrent que l’adaptation joue un rôle important dans la diversification de E. coli en milieu naturel et que ce processus s’apparente à celui observé dans des milieux artificiels de laboratoire. L’adaptation semble néanmoins plus active en conditions d’infections aigues que dans le tube digestif de souris. / Escherichia coli is a commensal species living in the digestive tract of vertebrates, but can also be a harmful pathogen involved in both intra and extraintestinal diseases. As clones can behave both as commensals and pathogens, the comprehension of the mechanisms involved in the diversification of E. coli in those two habitats represents a major public health concern. In vitro experimental evolution studies using E. coli have unraveled the different faces of bacterial adaptation. However, as those experiments used artificial conditions, the relevance of these observations and more generally the contribution of adaptation to the diversification of E. coli in the wild remain questionable. To answer these questions, I analyzed the genomic profiles of diversification of E. coli during (1) adaptation to the mice digestive tract or (2) during acute extraintestinal infections. In both cases, I found a strong convergence at the gene level, i.e. observation of several impendent mutations in the same gene, suggesting a dynamic adaptation. In acute infections, mutations in global regulators were recovered, while more specific genes were recruited in the mice gut. Finally, the existence of clones with high mutation rate in the infections, allowed me to document for the first time the genomics of mutator emergence in the wild. In conclusion, my work shows that adaptation is playing an important role in the diversification of E. coli, and that this process is fairly similar to the one observed in the laboratory. Nevertheless, adaptation seems more active during infections than in the mice gut.

L'objectif de la thèse est de mesurer comment et combien la société bisontine a été touchée par le processus de décolonisation. L'étude d'une communauté urbaine est à la confluence de plusieurs champs historiographiques (histoire politique, culturelle, de la colonisation et de la décolonisation, de la guerre froide). Dans le cadre de cette histoire vue d'en bas, il s'agit de comprendre comment les habitants vivent (comprennent, ressentent, interprètent) la décolonisation. Ce travail englobe la période qui court de 1945 aux années 1960. Une double démarche a été poursuivie l'une comparant échelon local et national, l'autre envisageant la compréhension du milieu bisontin pour lui-même. La diversité des sources (officielles, groupes constitués, presse, entretiens) et leur confrontation ont permis d'établir une double conclusion. D'une part, l'exemple bisontin démontre que le processus de décolonisation a concerné la société française, y compris dans un espace qui pouvait apparaître périphérique. Il s'agit moins d'une reproduction d'un vécu national sous direction parisienne que d'un partage d'expériences communes au territoire métropolitain. D'autre part, ces similitudes n'empêchent pas des variations, sans doute non exclusives à l'espace bisontin, qui reflètent certaines caractéristiques locales : force du catholicisme social, construction d'une lutte commune entre catholiques de gauche et communistes, radicalité des choix de certains acteurs (procès Rapiné). Enfin, dans ce processus, la guerre d'Algérie a profondément marqué le vécu bisontin au point de produire parfois une histoire particulière et différente du récit national. / This doctoral thesis aims at assessing the impact of the decolonisation process on the population of Besançon. The study of an urban community involves taking an interest in various historiographical fields (such as the political and cultural history of both colonisation and decolonisation, as well as the Cold War). From a people's history perspective, our purpose is to grasp how people experienced decolonisation (how they understood, felt, thought, acted). This research covers the period from 1945 up to the 1960s. A two-angled approach has been applied, including comparisons on local and national levels and a thorough investigation of Besançon's social environment in and of itself. The diversity of sources (official sources, organised groups, press articles, interviews) and their comparison have allowed us to draw several conclusions. The example of Besançon demonstrates that the decolonisation process affected French society, even in areas that could be considered peripheral. It was actually less the replica of the nation's reality following a Parisian leadership than the sharing of a series of collective experiences on a nation-wide scale. These shared experiences may allow for variations, undoubtedly not restricted to the area of Besançon, which do indeed reflect local characteristics: the strength of social Catholicism, left-wing Catholics joining forces with Communists, the radical choices of key protagonists (e.g. the Rapiné trial). Finally, the Algerian War so dramatically influenced Besançon's experience of decolonisation that it created a singular history, different from the national narrative on some specific points.

Résumé confidentiel / Résumé confidentiel

En portant pour la première fois depuis la défaite de 1940 l’étendard tricolore sur le sol européen, le Corps Expéditionnaire Français accomplit un geste capital pour le relèvement national. La force du symbole ne saurait occulter ses vicissitudes. La thèse propose une histoire totale du CEF, du débarquement allié en Afrique du Nord en novembre 1942 à son retrait d’Italie en juillet 1944. Au-delà des opérations militaires, il importait de revenir sur la genèse du CEF : d’évaluer la mobilisation générale de l’AFN à laquelle répondent sans enthousiasme Européens et indigènes, d’étudier les affres de la fusion entre l’armée d’Afrique et les Forces Françaises Libres et d’observer les liens entre Français et Alliés, alors que les armes fournies par Washington accentuent la dépendance tricolore. Enjeu diplomatique pour Alger, la participation française est examinée à la lumière des débats sur la stratégie méditerranéenne. Théâtre d’opérations secondaire, la campagne d’Italie se révèle fort éprouvante. La thèse analyse alors l’anatomie de la bataille : la violence de la guerre de positions pendant l’hiver 1943-1944, les souffrances des combattants et les pertes physiques et psychiatriques. Elle s’intéresse aussi aux loisirs des soldats, à l’exercice de la discipline et à la nature des relations coloniales au sein de l’armée. La thèse évalue ensuite le rôle du CEF dans la libération de Rome en juin 1944. Cette victoire est toutefois ternie par les nombreux viols et pillages commis à l’encontre des civils italiens. Enfin, si le CEF marque une étape décisive dans la reconstruction de l’armée française, il révèle également la césure qui se dessine entre la métropole et son Empire. / By fighting under the tricolour flag for the first time on European soil since the defeat of 1940 the French Expeditionary Corps (FEC) made an important symbolic gesture towards national recovery. The symbolism of this historical moment should not, however, obscure the difficulties behind it. This thesis presents a wide-ranging study of the FEC from the Allied landings in North Africa in November 1942 to the FEC’s withdrawal from Italy in July 1944. It not only examines military operations but also highlights the political and diplomatic difficulties faced during the FEC’s creation: the lukewarm public response to the levée en masse in French North Africa, the problematic amalgamation of Vichy’s Army of Africa with the Free French Forces and the uneasy relationship between French and Allied leaders, French diplomacy impeded by dependence on U.S. arms. French participation in the Italian campaign is also examined in the light of Allied debates on military strategy in the Mediterranean Theatre. Though a peripheral war zone, the Italian peninsula was the scene of a gruelling struggle. This thesis offers a detailed analysis of the combat experience: the violence of the war of attrition in the winter of 1943-44, the suffering of the combatants and the physical and psychiatric casualties. It also examines questions relating to soldiers’ leisure, discipline and colonial relations within the army. It then evaluates the role of the FEC in the liberation of Rome in June 1944, a victory tarnished by incidents of rape and looting. Ultimately, while the FEC marks a decisive step in the reconstruction of the French Army, it also reveals a growing rift between France and its Empire.

The objective of this study is to assess the uncultured bacterial diversity in the snowpack of the Mont Blanc (MtBl) glacier containing Saharan dust deposited during four dust events during the period 2006 – 2009 by means of molecular phylogenetics. The final goal is to discover the bacteria that could be involved in the establishment of snow microbiota. Bacterial diversity was evaluated using rybotyping and subsequent sequencing of partial (V3-V5) and full-length 16S rRNA genes. For comparison purpose we also studied following samples: “clean” MtBl snow containing no Saharan dust; Saharan sand collected in Tunisia; Saharan dust collected in Grenoble (200 m a.s.l.) and recovered later on MtBl (4250 m a.s.l.). In order to verify possible microbial activity in situ, both rDNA and rRNA approaches were implemented for the “clean” snow sample. To evaluate the survival/colonization abilities of bacterial phylotypes recovered in snow samples with Saharan dust, we analyzed their closest strain physiology as well as sources of environmental clones using a threshold of ≥98% sequence similarity. For the result interpretation, we also used data on dust elemental composition and dust particles size distribution. As a result 8 clone libraries (including rRNA-based one) were constructed using V3-V5 16S rRNA gene sequences for 5 snow samples (4 with Saharan dust and one “clean”), sample of Saharan dust collected in Grenoble and Saharan sand sample. Furthermore, 4 clone libraries were generated using full-length 16S rRNA gene amplicons obtained from 4 of the above snow samples (three with Saharan dust and one ‘clean'). Species content and dominant phylotypes and their assigning to major divisions varied significantly in alpine snow on a Mont Blanc glacier associated with four depositions of Saharan dust over a 3-year. Dominant phylotypes revealed are belonged to Actinobacteria, Proteobactreia, Firmicutes, Deinococcus-Thermus, Bacteroidetes and Cyanobacteria. Such variability was detected by both partial and full-length 16S rRNA gene sequencing and seems to be caused more by conditions of dust transport than bacterial load from the original dust source. Also the preservation period of dust in snowpack could affect the species composition. Thirteen icy phylotypes as candidates into snow microbiota establishing were recognized in snow containing Saharan dust and only two in “clean” snow sample. Of them, both dominant and minor phylotypes of Cyanobacteria, Proteobacteria, Actinobacteria и Firmicutes were revealed. Data on the closest strain physiology of recognized icy phylotypes suggests that representatives of genera Massilia (Betaproteobacteria), Tumebacillus (Firmicutes), Phormidium and Stigonema (both Cyanobacteria) are most relevant findings in terms of propagation in snow. By analyzing 16S rRNA from the “clean” snow containing no Saharan dust and comparing the data with those obtained for 16S rDNA library, it has been shown that Stigonema-like cyanobacterium identified could be propagating in snow at subzero temperature. Among all identified phylotypes, 10% were categorized as HA-phylotypes based on their con-specificity (≥98% similarity) with normal (non-pathogenic) human microbiome representatives. Furthermore, 11% out of all phylotypes showed less than 90% similarity with known taxa, thus, presenting novel taxa. Sequencing of both partial (V3-V5) and full-length 16S rRNA genes permitted to describe microbial diversity more fully and get more detailed picture. / The objective of this study is to assess the uncultured bacterial diversity in the snowpack of the Mont Blanc (MtBl) glacier containing Saharan dust deposited during four dust events during the period 2006 – 2009 by means of molecular phylogenetics. The final goal is to discover the bacteria that could be involved in the establishment of snow microbiota. Bacterial diversity was evaluated using rybotyping and subsequent sequencing of partial (V3-V5) and full-length 16S rRNA genes. For comparison purpose we also studied following samples: “clean” MtBl snow containing no Saharan dust; Saharan sand collected in Tunisia; Saharan dust collected in Grenoble (200 m a.s.l.) and recovered later on MtBl (4250 m a.s.l.). In order to verify possible microbial activity in situ, both rDNA and rRNA approaches were implemented for the “clean” snow sample. To evaluate the survival/colonization abilities of bacterial phylotypes recovered in snow samples with Saharan dust, we analyzed their closest strain physiology as well as sources of environmental clones using a threshold of ≥98% sequence similarity. For the result interpretation, we also used data on dust elemental composition and dust particles size distribution. As a result 8 clone libraries (including rRNA-based one) were constructed using V3-V5 16S rRNA gene sequences for 5 snow samples (4 with Saharan dust and one “clean”), sample of Saharan dust collected in Grenoble and Saharan sand sample. Furthermore, 4 clone libraries were generated using full-length 16S rRNA gene amplicons obtained from 4 of the above snow samples (three with Saharan dust and one ‘clean'). Species content and dominant phylotypes and their assigning to major divisions varied significantly in alpine snow on a Mont Blanc glacier associated with four depositions of Saharan dust over a 3-year. Dominant phylotypes revealed are belonged to Actinobacteria, Proteobactreia, Firmicutes, Deinococcus-Thermus, Bacteroidetes and Cyanobacteria. Such variability was detected by both partial and full-length 16S rRNA gene sequencing and seems to be caused more by conditions of dust transport than bacterial load from the original dust source. Also the preservation period of dust in snowpack could affect the species composition. Thirteen icy phylotypes as candidates into snow microbiota establishing were recognized in snow containing Saharan dust and only two in “clean” snow sample. Of them, both dominant and minor phylotypes of Cyanobacteria, Proteobacteria, Actinobacteria и Firmicutes were revealed. Data on the closest strain physiology of recognized icy phylotypes suggests that representatives of genera Massilia (Betaproteobacteria), Tumebacillus (Firmicutes), Phormidium and Stigonema (both Cyanobacteria) are most relevant findings in terms of propagation in snow. By analyzing 16S rRNA from the “clean” snow containing no Saharan dust and comparing the data with those obtained for 16S rDNA library, it has been shown that Stigonema-like cyanobacterium identified could be propagating in snow at subzero temperature. Among all identified phylotypes, 10% were categorized as HA-phylotypes based on their con-specificity (≥98% similarity) with normal (non-pathogenic) human microbiome representatives. Furthermore, 11% out of all phylotypes showed less than 90% similarity with known taxa, thus, presenting novel taxa. Sequencing of both partial (V3-V5) and full-length 16S rRNA genes permitted to describe