Annual follow-up of gross diffusive carbon dioxide and methaneemissions from a boreal reservoir and two nearby lakes in Quebec,Canada

摘要

Surface water pCO_2and pCH_4measurementswere taken in the boreal zone of Quebec, Canada, from sum-mer 2006 to summer 2008 in Eastmain 1 reservoir and twonearby lakes. The goal of this follow-up was to evaluateannual greenhouse gas (GHG) emissions, including springemissions (N.B. gross emissions for reservoir), through fluxcalculations using the thin boundary layer model. Our mea-surements underscored the winter CO_2accumulation due toice cover and the importance of a reliable estimate of springdiffusive emissions as the ice breaks up. We clearly demon-strated that in our systems, diffusive CH_4flux (in terms ofCO_2equivalent) were of minor importance in the GHG emis-sions (without CH_4accumulation under ice), with diffusiveCO_2flux generally accounting for more than 95% of the an-nual diffusive flux. We also noted the extent of spring dif-fusive CO_2emissions (23% to 52%) in the annual carbonbudget.