ÉMISSION DE GAZ A EFFET DE SERRE (CO2, CH4) PAR UNE RETENUE DE BARRAGE HYDROÉLECTRIQUE EN ZONE TROPICALE (PETIT-SAUT, GUYANE FRANÇAISE) : EXPÉRIMENTATION ET MODÉLISATION
type: Dataset
description: The emissions of carbon dioxide (CO2) and methane (CH4) and the carbon cycle in the Petit-Saut reservoir and in the Sinnamary River (French Guiana) were studied with an aim of developing a coupled physical/biogeochemical model. The development of this model required the study of three processes controlling these emissions: (i) CO2 and CH4 production during the mineralization in anoxic condition of organic matter (OM) from soils and plants, (ii) aerobic CH4 oxidation in the water column of the lake and (iii) the processes involved in gas exchange at the air-water interface. Over 10 years, atmospheric emissions were shown to be very significant, in particular the first three years having followed the reservoir impoundment and then decreased with time. While 50% of the CO2 emissions take place at the surface of the lake, the emissions of CH4 are mainly localized downstream from the turbines. The atmospheric emissions result from the degradation of OM (soil and biomass originating from the tropical forest) flooded during impoundment and their reduction with time rises from the exhaustion of the OM stock. 10 years after impoundement, 20% of the carbon stock were mineralized and emitted to the atmosphere in the form of CO2 and of CH4. Aerobic CH4 oxidation transforms more than 95% of the CH4 diffusing upward from the hypolimnion into CO2 in the water column of the lake and 40% of the CH4 entering the river downstream of the dam. In the whole Petit Saut system, this process is responsible for the oxidation of 90% of the produced CH4 and 30% of the total CO2 emissions. The CH4 and CO2 which reach the water surface of the reservoir and of the river downstream of the dam are emitted to the atmosphere by diffusive flux. The study of this process of gas transfer to the interface air-water shows that, in tropical environment, diffusive fluxes are enhanced by the elevated temperatures and the rainy phenomena. The model is based on the hydrodynamic model SYMPHONY 2D and the biogeo…
landing page: https://theses.hal.science/tel-00079947
keyword: aerobic-methane-oxidation
keyword: atmospheric-emissions
keyword: carbon
keyword: carbon-dioxide
keyword: carbone
keyword: coefficient-dechange
keyword: continental-waters
keyword: couplage-hydrodynamique-biogeochimie
keyword: coupled-physical-biogeochemistry-modeling
keyword: dioxyde-de-carbone
keyword: eaux-continentales
keyword: emissions-atmospheriques
keyword: estuaire
keyword: estuary
keyword: gas-transfer-velocity
keyword: infoeu-reposemanticsdoctoralthesis
keyword: lac
keyword: methane
keyword: methanogenese
keyword: methanogenesis
keyword: milieu-tropical
keyword: modeling
keyword: modelisation
keyword: oxydation-aerobie-du-methane
keyword: river
keyword: riviere
keyword: sduoceansciences-of-the-universe-physicsocean-atmosphere
keyword: theses
keyword: tropical-environment
issued: 2026-05-13T00:25:55.124376
modified: 2026-05-13T00:25:55.124388
language: fr
contact point: Organization
  fn: CCSD

test_moissonnage_selune
type: Agent

ÉMISSION DE GAZ A EFFET DE SERRE (CO2, CH4) PAR UNE RETENUE DE BARRAGE HYDROÉLECTRIQUE EN ZONE TROPICALE (PETIT-SAUT, GUYANE FRANÇAISE) : EXPÉRIMENTATION ET MODÉLISATION
type: Distribution
format: HTML
access URL: https://theses.hal.science/tel-00079947
issued: 2026-05-13T00:25:55.168750
modified: 2026-05-13T00:25:54.995253