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Fernández, Leonardo D.

Nom
Fernández, Leonardo D.
Affiliation principale
Fonction
Doctorant
Email
leonardo.fernandez@unine.ch
Identifiant ORCID

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  • Publication
    Métadonnées seulement
    Soil protistology rebooted: 30 fundamental questions to start with
    (2017-8-1)
    Geisen, Stefan
    ;
    Mitchell, Edward 
    ;
    Wilkinson, David M
    ;
    Adl, Sina
    ;
    Bonkowski, Michael
    ;
    Brown, Matthew W.
    ;
    Fiore-Donno, Anna Maria
    ;
    Jassey, Vincent E.J.
    ;
    Krashevska, Valentyna
    ;
    Lahr, Daniel J.G.Daniel J.G.
    ;
    Marcisz, Katarzyna
    ;
    Mulot, Matthieu 
    ;
    Payne, Richard
    ;
    Singer, David 
    ;
    Anderson, O. Roger
    ;
    Charman, Dan J.
    ;
    Ekelund, Flemming
    ;
    Griffiths, Bryan S.
    ;
    Rønn, Regin
    ;
    Smirnov, Alexey
    ;
    Bass, David
    ;
    Belbahri, Lassaâd 
    ;
    Berney, Cédric
    ;
    Chatzinotas, Antonis
    ;
    Clarholm, Marianne
    ;
    Dunthorn, Micah
    ;
    Feest, Alan
    ;
    Fernández, Leonardo D. 
    ;
    Foissner, Wilhelm
    ;
    Fournier, Bertrand 
    ;
    Gentekaki, Eleni
    ;
    Hájek, Michal
    ;
    Helder, Johannes
    ;
    Jousset, Alexandre
    ;
    Koller, Robert
    ;
    Kumar, Santosh
    ;
    La Terza, Antonietta
    ;
    Lamentowicz, Mariusz
    ;
    Mazei, Yuri
    ;
    Santos, Susana S.
    ;
    Seppey, Christophe 
    ;
    Spiegel, Frederick W.
    ;
    Walochnik, Julia
    ;
    Winding, Anne
    ;
    Lara, Enrique 
    Protists are the most diverse eukaryotes. These microbes are keystone organisms of soil ecosystems and regulate essential processes of soil fertility such as nutrient cycling and plant growth. Despite this, protists have received little scientific attention, especially compared to bacteria, fungi and nematodes in soil studies. Recent methodological advances, particularly in molecular biology techniques, have made the study of soil protists more accessible, and have created a resurgence of interest in soil protistology. This ongoing revolution now enables comprehensive investigations of the structure and functioning of soil protist communities, paving the way to a new era in soil biology. Instead of providing an exhaustive review, we provide a synthesis of research gaps that should be prioritized in future studies of soil protistology to guide this rapidly developing research area. Based on a synthesis of expert opinion we propose 30 key questions covering a broad range of topics including evolution, phylogenetics, functional ecology, macroecology, paleoecology, and methodologies. These questions highlight a diversity of topics that will establish soil protistology as a hub discipline connecting different fundamental and applied fields such as ecology, biogeography, evolution, plant-microbe interactions, agronomy, and conservation biology. We are convinced that soil protistology has the potential to be one of the most exciting frontiers in biology.
  • Publication
    Métadonnées seulement
    Microbial eukaryote communities from Patagonian-Antarctic gradient of lakes evidence robust biogeographical patterns
    (2016-9-30)
    Schiaffino, M. Romina
    ;
    Lara, Enrique 
    ;
    Fernández, Leonardo D. 
    ;
    Balagué, Vanessa
    ;
    Singer, David 
    ;
    Seppey, Christophe 
    ;
    Massana, Ramon
    ;
    Izaguirre, Irina
    Microbial eukaryotes play important roles in aquatic ecosystem functioning. Unravelling their distribution patterns and biogeography provides important baseline information to infer the underlying mechanisms that regulate the biodiversity and complexity of eco- systems. We studied the distribution patterns and factors driving diversity gradients in microeukaryote communities (total, abundant, uncommon and rare community composition) along a latitudinal gradient of lakes distributed from Argentinean Patagonia to Maritime Antarctica using both denaturing gradient gel electrophoresis (DGGE) and high-throughput sequencing (Illumina HiSeq). DGGE and abundant Illumina operational taxonomic units (OTUs) showed both decreasing richness with latitude and significant differences between Patagonian and Antarctic lakes communities. In contrast, total richness did not change significantly across the latitudinal gradient, although evenness and diversity indices were significantly higher in Patagonian lakes. Beta-diversity was characterized by a high species turnover, influenced by both environmental and geographical descriptors, although this pattern faded in the rare community. Our results suggest the co-existence of a ‘core biosphere’ containing reduced number of abundant/dominant OTUs on which classical ecological rules apply, together with a much larger seedbank of rare OTUs driven by stochastic and reduced dispersal processes. These findings shed new light on the biogeographical patterns and forces structuring inland microeukaryote composition across broad spatial scales.
  • Publication
    Accès libre
    Assessing the patterns and causes of diversity in free-living unicellular eukaryotes (protists) using biogeographical, macroecological and landscape genetic approaches
    (Neuchâtel, 2017)
    Fernández, Leonardo D. 
    Cette thèse de doctorat a permis de tester l’hypothèse qu’à large échelle spatiale, les patrons observés et les causes qui influencent la diversité et la structure génétique des populations d’eucaryotes unicellulaires (protistes) sont similaires à ceux observées chez des organismes multicellulaires (plantes et animaux).
    Afin de tester cette hypothèse, cette thèse s’est penchée sur (1) les patrons observés et les causes qui influencent la diversité des amibes à thèque (un groupe polyphylétique principalement représenté par les Euglyphida et Arcellinida) le long d’un gradient latitudinal à travers le Chili (de 18 à 56 ºS); (2) les patrons observés et les causes qui influencent la diversité de différents groupes de protistes du sol (Bacillariophyta, Cercomonadida, Ciliophora, Euglyphida et Kinetoplastida) en fonction de l’altitude dans des forêts de hêtre dans le Plateau Suisse et le Jura; et (3) les patrons observés et les causes qui influencent la structure génétique des populations d’une micro-algue d’eau douce (Chlorophyta: Mamiellophyceae) dans la Patagonie Argentine.
    Globalement, les analyses ont montré qu’à large échelle spatiale, les protistes ont des patrons de diversité latitudinale et altitudinale, ainsi qu’une structuration génétique semblable à ceux que l’on retrouve chez des organismes multicellulaires. De plus, les résultats montrent que ces patrons sont créés et maintenus par une combinaison de processus écologiques, historiques et évolutifs. Cette thèse a donc renforcé l’hypothèse qui considère que les patrons observés et les causes qui maintiennent la diversité des plantes et des animaux à différents niveaux écologiques d’organisation sont aussi effectifs chez les microorganismes. Les organismes modèles choisis dans cette thèse peuvent être considérés comme représentatifs de la diversité de stratégies trophiques, de morphologies, modes de locomotion ainsi que de la variété de physiologies et probablement aussi de modes de reproduction que l’on rencontre chez les protistes. Par conséquent, les résultats de cette thèse peuvent être considérés comme valides chez un grand nombre d’eucaryotes microscopiques.
    Abstract
    This PhD thesis tested the hypothesis that, at broad spatial scales, the patterns and underlying causes of diversity and population genetic structure of unicellular eukaryotes (protists) are similar to those observed for multicellular organisms (plants and animals).
    To test this hypothesis, this thesis investigated (1) the pattern and causes of latitudinal diversity in soil testate amoebae (a polyphyletic group mainly represented by Arcellinida and Euglyphida) along southwestern South America, Chile (from 18 to 56 ºS), Chile; (2) the patterns and causes of altitudinal diversity in several groups of soil protists (Bacillariophyta, Cercomonadida, Ciliophora, Euglyphida and Kinetoplastida) along an elevation gradient of beech forests in the Swiss lowlands and Jura Mountains; and (3) the pattern and causes of population genetic structure in a freshwater eukaryotic microalga (Chlorophyta: Mamiellophyceae) in the Argentinean Patagonia.
    Overall, the analyses revealed that at broad spatial scales, protists have patterns of latitudinal diversity, altitudinal diversity and population genetic structure similar to those of multicellular organisms. In addition, the evidence revealed that these patterns are originated and maintained by a combination of ecological, historical and evolutionary processes. Therefore, this thesis supported the hypothesis that the patterns and causes that produce and maintain the diversity of plants and animals at different ecological levels of organization could also be valid for microorganisms. The model organisms used in this thesis are also good representatives of the diversity of trophic, morphological, locomotive, physiological and probably reproductive strategies exhibited by protists. Consequently, the results of this thesis could be valid for a large number of eukaryotic microorganisms.