Variability of carbon dioxide flux from tropical Cerrado hydroelectric reservoirsReportar como inadecuado

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Aquatic Sciences

, Volume 72, Issue 3, pp 283–293

First Online: 31 March 2010Received: 30 September 2009Accepted: 10 March 2010


Hydroelectric reservoirs generate energy without significant combustion of fossil fuels. However, these systems can, potentially, emit greenhouse gases GHG’s at a rate which may be significant at the global scale, and, possible, co-equal, per kilowatt-hour, to that from conventional coal or oil-fired systems. Although much of the new construction of hydroelectric reservoirs is in the tropics, most of the data on GHG emissions comes from temperate regions. Further, much of the existing data on reservoir gas emissions comes from single sites, usually near the terminal dams. Large tropical reservoirs often involve the impoundments of river systems with complex morphology which in turn can cause spatial heterogeneity in gas flux. We evaluated spatial and seasonal variability in CO2 concentrations and gas flux for five large 50–1,400 km reservoirs in the Cerrado region of Brazil. Most of data set 87% of all measurements showed CO2 supersaturation and net efflux to the atmosphere. There was as much or more variation in pCO2 over space and among seasons. The large studied reservoirs showed different zones in terms of CO2 emission because those fluxes are dependent on flooded biomass, watershed input of organic matter and dam operation regime. Here we demonstrate that the reservoirs in the Brazilian Cerrado have low rates of CO2 emissions compared to existing global comparisons. Our results suggest that ignoring the spatial variability can lead to more than 25% error in total system gas flux.

KeywordsCO2 emission Hydroelectric reservoirs Spatial heterogeneity GHG Tropical freshwaters  Download fulltext PDF

Autor: Fábio Roland - Luciana O. Vidal - Felipe S. Pacheco - Nathan O. Barros - Arcilan Assireu - Jean P. H. B. Ometto - And


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