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Geophysical Research Letters 33 (2006) 21407
Methane and carbon dioxide emissions from tropical reservoirs: Significance of downstream rivers
Frédéric Guérin 1, Gwenaël Abril 1, Sandrine Richard, Benoît Burban, Cécile Reynouard, Patrick Seyler 2, Robert Delmas 3
(11/2006)

Methane (CH4) and carbon dioxide (CO2) concentrations and water-air fluxes were measured in three tropical reservoirs and their respective rivers downstream of the dams. From reservoirs, CH4 and CO2 flux were in the range of 3 +/- 2 and 254 +/- 392 mmol.m-2.d-1, respectively. Rivers downstream of dams were significantly enriched in CH4 and CO2 originating from reservoir hypolimnions. From rivers, CH4 and CO2 flux were in the range of 60 +/- 38 and 859 +/- 400 mmol.m-2.d-1, respectively. Despite their relatively small surfaces, rivers downstream of dams accounted for a significant fraction (9-33% for CH4 and 7-25% for CO2) of the emissions across the reservoir surfaces classically taken into account for reservoirs. A significant fraction of CH4 appeared to degas at the vicinity of the dam (turbines and spillways), although it could not be quantified.
1 :  Environnements et Paléoenvironnements OCéaniques (EPOC)
CNRS : UMR5805 – INSU – Université Sciences et Technologies - Bordeaux I – Ecole Pratique des Hautes Etudes – Observatoire Aquitain des Sciences de l'Univers
2 :  Laboratoire des Mécanismes et Transfert en Géologie (LMTG)
CNRS : UMR5563 – Observatoire Midi-Pyrénées – Université Paul Sabatier [UPS] - Toulouse III – Institut de recherche pour le développement [IRD] : UMR154
3 :  Laboratoire d'aérologie (LA)
CNRS : UMR5560 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III
Planète et Univers/Sciences de la Terre
Biogeosciences: Trace gases – Biogeosciences: Carbon cycling (4806) – Hydrology: Dams – Hydrology: Limnology (0458 – 4239 – 4942) – Global Change: Land cover change