oai-hal-tel-00932300v1
type: Dataset
description: Methane, a major greenhouse gas, is produced and consumed mainly by the metabolic activity of microorganisms affiliated to the domains Archaea and Bacteria. In order to understand the biogeochemical cycling of methane, it is essential to identify all the biological actors involved, as well as environmental factors modulating their activity. Freshwater lakes are a major source of methane because environmental conditions occurring in these ecosystems favor methanogenesis over other terminal processes of anaerobic degradation of organic matter. In this thesis, studies of communities involved in the biogeochemical cycling of methane were carried out in the water column and anoxic sediment of Lake Pavin (Auvergne), the unique French meromictic lake. This ecosystem has been selected as study site due to the high concentrations of methane in its deep water layer which contrast with the very low emission of this gas in the atmosphere. These geochemical observations suggest an intense activity of production and consumption of methane, providing an appropriate framework for studying the communities involved. Molecular approaches to characterize the spatial structure, composition, activity areas and factors (bottom-up and top-down) potentially involved in the regulation of methanogens and methanotrophs were, in this work, systematically associated to cultural and microcalorimetric approaches to acquire data on the physiology of microorganisms involved in the methane cycle. The results show that methanogens are distributed throughout the permanent anoxic water column (monimolimnion) and mainly in the superficial layer of the sediment situated under the monimolimnion. This metabolic group, mainly represented by species affiliated to Methanosaetaceae and Methanoregulaceae, is particularly active in the benthic zone which would be the main source of methane in this ecosystem. A new species of methanogen, Methanobacterium lacus, was isolated from these sediments and described. It e…
identifier: NNT: 2011CLF22176
issued: 2026-05-07T09:14:51.885132
language: fr
modified: 2026-05-07T09:14:51.885137
title: Diversity of archaea and implication of prokaryotes in the biochemical cycle of methane in continental aquatic environments : taxonomic and functional studies in the water column and the anoxic sediments of Lake Pavin
contact point: Organization
  fn: CCSD
keyword: anaerobic-environments
keyword: archaea
keyword: bacteria
keyword: bacteries
keyword: biologie-moleculaire
keyword: ecologie-microbienne
keyword: environnements-anaerobies
keyword: infoeu-reposemanticsdoctoralthesis
keyword: lac-pavin
keyword: lake-pavin
keyword: lake-sediments
keyword: methanogenes
keyword: methanogens
keyword: methanotrophes
keyword: methanotrophs
keyword: microbial-ecology
keyword: molecular-biology
keyword: phages
keyword: sdvsalife-sciences-q-bioagricultural-sciences
keyword: sediments-lacustres
keyword: theses
landing page: https://theses.hal.science/tel-00932300

https://rec.harvest-normandie.data4citizen.com/dataset/oai-hal-tel-00932300v1/resource/682116d9-efda-4acb-a032-84e2750ea3d0
type: Distribution
format: HTML
issued: 2026-05-07T09:14:51.889236
modified: 2026-05-07T09:14:51.866132
title: Diversity of archaea and implication of prokaryotes in the biochemical cycle of methane in continental aquatic environments : taxonomic and functional studies in the water column and the anoxic sediments of Lake Pavin
access URL: https://theses.hal.science/tel-00932300

test_moissonnage_selune
type: Agent