Skip to Main content Skip to Navigation
Journal articles

Spatial and Temporal Variability of Diffusive CO 2 and CH 4 Fluxes From the Amazonian Reservoir Petit‐Saut (French Guiana) Reveals the Importance of Allochthonous Inputs for Long‐Term C Emissions

Abstract : Variability in greenhouse gas emissions from reservoirs creates uncertainty in global estimates of C emissions from reservoirs. This study examines the temporal and spatial variability in CO2 and CH4 surface water concentrations and diffusive fluxes from an Amazonian reservoir using an original data set combining both a high temporal (1 central site × 22 years) and spatial (44 sites × 1 season) resolution monitoring. The gas concentrations at the central site decreased over time and suggested reduced bioavailability of C in the initial flooded soil but exhibited strong seasonal variation. Not accounting for this variability may result in uncertainties in estimates of annual concentrations (ranging from −68.9% to +260% for CH4 and from −71.5% to +156% for CO2) and thus in estimates of diffusive gas emissions. Gas concentrations and diffusive fluxes exhibited high spatial variability in the reservoir, 24 years after impoundment. In particular, diffusive fluxes were higher in littoral and transitional areas than in open areas, suggesting a large contribution of allochthonous C to current gaseous emissions. Not accounting for this spatial variability in diffusive fluxes may underestimate the total emissions expressed in CO2 equivalents from the whole reservoir by 50.7%. Our study stresses the importance of well‐resolved temporal and spatial monitoring to provide reliable estimated of C emissions and a comprehensive understanding of the processes involved; both of these inputs are needed to support decision‐making for developing energy strategies.
Document type :
Journal articles
Complete list of metadata

https://hal.inrae.fr/hal-03161901
Contributor : Raymond Schiano <>
Submitted on : Monday, March 8, 2021 - 10:37:32 AM
Last modification on : Tuesday, September 7, 2021 - 3:44:46 PM

Identifiers

Citation

Fanny Colas, Vincent Chanudet, Martin Daufresne, Lucie Buchet, Régis Vigouroux, et al.. Spatial and Temporal Variability of Diffusive CO 2 and CH 4 Fluxes From the Amazonian Reservoir Petit‐Saut (French Guiana) Reveals the Importance of Allochthonous Inputs for Long‐Term C Emissions. Global Biogeochemical Cycles, American Geophysical Union, 2020, 34 (12), ⟨10.1029/2020GB006602⟩. ⟨hal-03161901⟩

Share

Metrics

Record views

27

Files downloads

59