Importance of CO₂ evasion from small boreal streams

Abstract

Boreal lakes are known to be supersaturated with CO 2 and to be significant sources of CO 2 to the atmosphere. In this study it is shown that small boreal streams are relatively more supersaturated with CO 2 and also represent an important source of CO 2 evasion to the atmosphere from boreal catchments. Small boreal streams account for an annual (ice‐free seasons) average of 8.0% and a seasonal high of 34.4% of the total CO 2 evaded from streams and lakes. A seasonal pattern is found, with evasion from streams being greatest during the summer and least during the spring. The evasion of CO 2 by small boreal streams represents 77% of the total CO 2 and 36% of the total organic carbon and total inorganic carbon exported by the streams from the catchments to the lakes. Knowledge of this important transfer and loss mechanism for CO 2 will allow for more accurate modeling of boreal catchment C budgets.