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Patrons de biodiversité a` l'échelle globale chez les dinoflagellés planctoniques marins

Abstract : Dinoflagellates form a complex group of protists with a variety of morphologies, physiologies, and life cycles that give them a strong adaptation to all aquatic environments (marine and freshwater) and habitats (pelagic and benthic) making difficult to study their diversity and ecology. The objective of this thesis was the search for global biodiversity patterns and community structure of marine pelagic dinoflagellates across the world?s oceans. A morphogenetic sampling protocol, covering the entire spectrum of their size and an important part of their spatio-temporal variability, was developed (Tara-Oceans). Various tools for an automatic acquisition broadband data were tested. Diversity, relative abundance and geographical distribution of the genus Neoceratium were evaluated by FlowCAM in Mediterranean Sea. A study of the structure of biodiversity was conducted by metabarcoding with 18S rDNA (V9 fragment). Building a base of rDNA reference sequences (DinR2) allowed the taxonomic assignment of environmental metabarcodes. The metabarcode approach reveals a remarkable and unexpected diversity of pico-dinoflagellates (<5?m) and, regardless of the studied ecosystem and the sampling period, that abundance of different levels mainly depends to the size fractions (pico-, nano-, micro- and meso- plankton). Structuring of dinoflagellates communities in different size fractions of the photic zone was facing to some environmental factors and opens promising avenues for research
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Submitted on : Wednesday, July 9, 2014 - 11:27:23 AM
Last modification on : Thursday, April 14, 2022 - 3:38:29 AM
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  • HAL Id : tel-00974287, version 2


Noan Le Bescot. Patrons de biodiversité a` l'échelle globale chez les dinoflagellés planctoniques marins. Biodiversité. Université Pierre et Marie Curie - Paris VI, 2014. Français. ⟨NNT : 2014PA066075⟩. ⟨tel-00974287v2⟩



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