Aspectos do comportamento de gás metano dissolvido na água de reservatórios brasileiros / Aspects of dissolved methane behavior in water bodies of brazilian reservoirs

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Extended water bodies such as the hydroelectric reservoirs here studied can be greenhouse gas sources ( CH IND.4 and CO IND.2 ) due to decay of part of submerged forest biomass and also due to allochtonous and autochtonous organic compounds. This work presents concentrations, ebullitive and diffusive fluxes of the gases dissolved in the water column in the following reservoirs : Miranda, Xingó, Ribeirão das Lages and Lobo, between October 2001 and August 2003. In the course of this work methane profiles were determined by a commercial methane sensor, a solid state device, the electrical resistance of which varies as a function of absorbed methane providing a signal related to dissolved gas concentration. Diffusion chambers were used to measure CH IND.4 and CO IND.2 exchange rates at the air-water interface; bubble capture funnels were used for ebullitive emission. Some physical and chemical variables were also measured. Dissolved methane profiles showed high concentrations, generally with increasing values from water surface to sediment. However, the oxidative methane sink in the water column consumes this gas in its upward migration path and together with wind-propelled convection produces different profile types. Diffusive flux was also calculated from diffusive exchange experiments of these gases at the air-water interface, which showed CH IND.4 and CO IND.2 emission, sometimes CO IND.2 absorption, by the reservoir

ASSUNTO(S)

brazilian reservoirs methane sensor efeito estufa methane reservatórios hidrelétricos diffusion chambers greenhouse gas sensor ch ind.4 câmaras de difusão gás metano

ACESSO AO ARTIGO

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