Sclerochronolgy and geochemistry of Northwestern Atlantic bivalves : exploration of en- vironmental proxies of global changes
Global changes resulting from anthropogenic activities have important repercussions on coastal regions, particularly in the Northwest Atlantic and the St. Lawrence system (Quebec, Canada). The development of analysis and recording tools to reconstruct pre-instrumental environmental variations is nec...
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Other Authors: | , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
Published: |
HAL CCSD
2020
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Subjects: | |
Online Access: | https://theses.hal.science/tel-03396570 https://theses.hal.science/tel-03396570/document https://theses.hal.science/tel-03396570/file/These-2020-SML-Ecologie_marine-DORE_Justine.pdf |
Summary: | Global changes resulting from anthropogenic activities have important repercussions on coastal regions, particularly in the Northwest Atlantic and the St. Lawrence system (Quebec, Canada). The development of analysis and recording tools to reconstruct pre-instrumental environmental variations is necessary to understand these changes. This PhD work uses sclerochronology and sclerochemistry to explore the ability of three species of subarctic bivalve molluscs (Arctica islandica, Cyrtodaria siliqua et Mactromeris polynyma) to archive variations in their environment in physical (growth) and geochemical (trace elements and isotopes) form, and to develop robust and reliable environmental proxies. In particular, the species studied have made it possible to trace the phytoplankton dynamics and climate of the Northwestern Atlantic. This thesis demonstrates the potential of the species as high-frequency biogenic and Eulerian archives of variations in the coastal environment of the Lower St. Lawrence Estuary and the Northwestern Atlantic, and underlines the interest of favouring a multi-archive and multi-proxy approach. Les changements globaux issus des activités anthropiques ont d’importantes répercussions sur les régions côtières notamment dans l’Atlantique Nord-Ouest et le système Saint-Laurent (Québec, Canada). Le développement d’outils d’analyse et d’enregistrement pour reconstruire les variations environnementales pré-instrumentales est nécessaire pour comprendre ces changements. Ce travail de doctorat utilise la sclérochronologie et la sclérochimie dans le but d’explorer la capacité de trois espèces de mollusques bivalves subarctiques (Arctica islandica, Cyrtodaria siliqua et Mactromeris polynyma) à archiver les variations de leur environnement sous forme physique (croissance) et géochimique (éléments traces et isotopes), et de développer des traceurs environnementaux robustes et fiables. Les espèces étudiées ont notamment permis de retracer la dynamique phytoplanctonique et le climat de l’Atlantique Nord-Ouest. ... |
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