Annual follow-up of carbon dioxide and methane diffusive emissions from two boreal reservoirs and nearby lakes in Québec, Canada.

Surface water pCO₂ and pCH₄ measurements were made in Québec (Canada) during consecutive seasons from 2006 to 2008 in two boreal reservoirs and nearby lakes. The goal of this follow-up was to evaluate greenhouse gas emissions from the water bodies studied, through flux calculations using the Thin Boundary Layer Model. Our measurements underscored the winter CO₂ accumulation due to ice cover and the importance of a reliable estimation of spring diffusive emissions as the ice breaks up. We clearly demonstrated that in our systems, CH₄ diffusive fluxes (in terms of CO₂ equivalent) were of minor importance in the GHG emissions, with CO₂ diffusive fluxes generally representing more than 95% of the annual diffusive fluxes. We also noted the extent of CO₂ spring diffusive emissions (16% to 52%) in the annual budget. [ABSTRACT FROM AUTHOR]