Biodiversity of testate amoebae and environments of Kerguelen archipelago : current characterization and recent evolution under climatic constraints
The objective of this PhD is to describe the current diversity of testate amoebae on the Kerguelen archipelago depending on climate and environmental context and to understand the recent evolution of the last 260 years by a paleoenvironmental approach combining microscopic observations, sedimentolog...
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2023
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Online Access: | https://theses.hal.science/tel-04221914 https://theses.hal.science/tel-04221914/document https://theses.hal.science/tel-04221914/file/These_HERLEDAN_Maiwenn.pdf |
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ftccsdartic:oai:HAL:tel-04221914v1 2024-02-27T08:35:17+00:00 Biodiversity of testate amoebae and environments of Kerguelen archipelago : current characterization and recent evolution under climatic constraints Biodiversité des amibes à thèque et environnements de l'archipel de Kerguelen : caractérisation actuelle et évolution récente sous contrainte climatique Herlédan, Maïwenn Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG) Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Nord ) Université de Lille Éric Armynot du Châtelet Viviane Bout-Roumazeilles 2023-01-27 https://theses.hal.science/tel-04221914 https://theses.hal.science/tel-04221914/document https://theses.hal.science/tel-04221914/file/These_HERLEDAN_Maiwenn.pdf fr fre HAL CCSD NNT: 2023ULILR002 tel-04221914 https://theses.hal.science/tel-04221914 https://theses.hal.science/tel-04221914/document https://theses.hal.science/tel-04221914/file/These_HERLEDAN_Maiwenn.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-04221914 Sciences de la Terre. Université de Lille, 2023. Français. ⟨NNT : 2023ULILR002⟩ Climate change Testate amoebae Kerguelen Subantarctic islands Biodiversity Paleoenvironment Amibes à thèques [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2023 ftccsdartic 2024-01-28T00:32:18Z The objective of this PhD is to describe the current diversity of testate amoebae on the Kerguelen archipelago depending on climate and environmental context and to understand the recent evolution of the last 260 years by a paleoenvironmental approach combining microscopic observations, sedimentology and geochemistry. Located at the polar front in the sub-Antarctic zone, the Kerguelen archipelago is subject to extreme wind and precipitation conditions while being preserved from direct anthropic impacts. This makes it an ideal natural environment to study the impact of global climate change on the environment.Two scientific campaigns on the Kerguelen archipelago in 2019 and 2021 have allowed us to collect samples of current plants (mainly bryophytes and azorelles), underlying soils and soil cores. The samples studied were selected to reflect the geographical and geological diversity of the archipelago, in terms of rainfall (west-east contrast), sedimentary nature (organic soil, alluvial sediments, etc. ) and petrographic context (basalts - phonolites). Optical observations of the testate amoebae communities growing in the plant samples (101 samples) have allowed us to build a new database of testate amoebae in the archipelago. Sedimentological and geochemical analyses (water content, elemental and isotopic analyses, mineralogy) were carried out in parallel on 485 soil samples in order to characterize the environmental parameters.This work has allowed to update and complete the 1981 database of 50 species with the description of 107 species of testate amoebae. Sedimentological analyses of soils revealed significant differences in terms of weathering between the western and eastern parts of the archipelago, reflecting contrasting rainfall patterns. This trend is also reflected in the testate amoebae assemblages whose diversity, variable according to the type of environment, is much greater in the west. The coupling of these different observations has made it possible to highlight the ecological affinities of ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Antarctic Kerguelen |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
French |
topic |
Climate change Testate amoebae Kerguelen Subantarctic islands Biodiversity Paleoenvironment Amibes à thèques [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
Climate change Testate amoebae Kerguelen Subantarctic islands Biodiversity Paleoenvironment Amibes à thèques [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Herlédan, Maïwenn Biodiversity of testate amoebae and environments of Kerguelen archipelago : current characterization and recent evolution under climatic constraints |
topic_facet |
Climate change Testate amoebae Kerguelen Subantarctic islands Biodiversity Paleoenvironment Amibes à thèques [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
The objective of this PhD is to describe the current diversity of testate amoebae on the Kerguelen archipelago depending on climate and environmental context and to understand the recent evolution of the last 260 years by a paleoenvironmental approach combining microscopic observations, sedimentology and geochemistry. Located at the polar front in the sub-Antarctic zone, the Kerguelen archipelago is subject to extreme wind and precipitation conditions while being preserved from direct anthropic impacts. This makes it an ideal natural environment to study the impact of global climate change on the environment.Two scientific campaigns on the Kerguelen archipelago in 2019 and 2021 have allowed us to collect samples of current plants (mainly bryophytes and azorelles), underlying soils and soil cores. The samples studied were selected to reflect the geographical and geological diversity of the archipelago, in terms of rainfall (west-east contrast), sedimentary nature (organic soil, alluvial sediments, etc. ) and petrographic context (basalts - phonolites). Optical observations of the testate amoebae communities growing in the plant samples (101 samples) have allowed us to build a new database of testate amoebae in the archipelago. Sedimentological and geochemical analyses (water content, elemental and isotopic analyses, mineralogy) were carried out in parallel on 485 soil samples in order to characterize the environmental parameters.This work has allowed to update and complete the 1981 database of 50 species with the description of 107 species of testate amoebae. Sedimentological analyses of soils revealed significant differences in terms of weathering between the western and eastern parts of the archipelago, reflecting contrasting rainfall patterns. This trend is also reflected in the testate amoebae assemblages whose diversity, variable according to the type of environment, is much greater in the west. The coupling of these different observations has made it possible to highlight the ecological affinities of ... |
author2 |
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG) Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Nord ) Université de Lille Éric Armynot du Châtelet Viviane Bout-Roumazeilles |
format |
Doctoral or Postdoctoral Thesis |
author |
Herlédan, Maïwenn |
author_facet |
Herlédan, Maïwenn |
author_sort |
Herlédan, Maïwenn |
title |
Biodiversity of testate amoebae and environments of Kerguelen archipelago : current characterization and recent evolution under climatic constraints |
title_short |
Biodiversity of testate amoebae and environments of Kerguelen archipelago : current characterization and recent evolution under climatic constraints |
title_full |
Biodiversity of testate amoebae and environments of Kerguelen archipelago : current characterization and recent evolution under climatic constraints |
title_fullStr |
Biodiversity of testate amoebae and environments of Kerguelen archipelago : current characterization and recent evolution under climatic constraints |
title_full_unstemmed |
Biodiversity of testate amoebae and environments of Kerguelen archipelago : current characterization and recent evolution under climatic constraints |
title_sort |
biodiversity of testate amoebae and environments of kerguelen archipelago : current characterization and recent evolution under climatic constraints |
publisher |
HAL CCSD |
publishDate |
2023 |
url |
https://theses.hal.science/tel-04221914 https://theses.hal.science/tel-04221914/document https://theses.hal.science/tel-04221914/file/These_HERLEDAN_Maiwenn.pdf |
geographic |
Antarctic Kerguelen |
geographic_facet |
Antarctic Kerguelen |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
https://theses.hal.science/tel-04221914 Sciences de la Terre. Université de Lille, 2023. Français. ⟨NNT : 2023ULILR002⟩ |
op_relation |
NNT: 2023ULILR002 tel-04221914 https://theses.hal.science/tel-04221914 https://theses.hal.science/tel-04221914/document https://theses.hal.science/tel-04221914/file/These_HERLEDAN_Maiwenn.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1792041775133622272 |