Diversity and community composition of active microbial communities in southern high latitude ecosystems

• Main Author: Maturana Martínez, Claudia
• Other Authors: Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université, Universidad austral de Chile, Pierre E. Galand, Humberto González
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2021
• Subjects: Southern high latitude marine ecosystems; Bacterioplankton; 16S rRNA; Chilean Patagonia; Southern Ocean; Fjords; Écosystèmes marins des hautes latitudes australes; Bactérioplancton; ARNr 16S; Patagonie chilienne; Océan austral; [SDV.GEN.GPO]Life Sciences [q-bio]/Genetics/Populations and Evolution [q-bio.PE]; Austral; Patagonia; Pacific
• Online Access: https://tel.archives-ouvertes.fr/tel-03420826; https://tel.archives-ouvertes.fr/tel-03420826/document; https://tel.archives-ouvertes.fr/tel-03420826/file/MATURANA_Claudia_these_2021.pdf

Southern high latitudes marine ecosystems (HLME) are highly sensitive to climate change, impacting physical, chemical, and biological processes, however, their prominent role in climate modulation and water masses circulation, contrast with the relatively low number of studies on their functioning. Relatively few studies on bacterioplankton community structure have been reported for southern Chilean Patagonia and for the Southern Ocean (SO) on a large scale, and none have targeted the active fraction of the bacterioplankton community. We used 16S rRNA sequencing to analyze and describe the community structure of the active bacterioplankton communities in southern HLME. The main objective of this thesis was to characterize de diversity and abundance of bacterioplankton communities along environmental and geographical gradients in southern HLME. First, we investigated whether nearby fjords of the southern Chilean Patagonia, with similar climate and location but different freshwater inflows, had different communities. Second, we investigated interannual changes experienced by the bacterioplankton community of the Yendegaia fjord. Third, we examined the large-scale spatial structure of the bacterioplankton community along a transect across the Pacific sector of the SO. Ours results show that southern polar bacterioplanktonic communities are structured according to physical, chemical, and biological parameters characteristic of the area. In addition, we also demonstrated that changes in environmental, spatial, and temporal parameters affect the structure of bacterioplanktonic communities. Thus, highlighting the importance of microbial ecology studies in areas sensitive to global climate change such as southern HLME. Les écosystèmes marins des hautes latitudes méridionales (HLME) sont très sensibles au changement climatique, ayant un impact sur les processus physiques, chimiques et biologiques. Cependant, leur rôle important dans la modulation du climat et la circulation des masses d'eau contraste avec le nombre ...