Magnitude and Origin of CO2 Evasion From High-Latitude Lakes

Abstract

Lakes evade significant amounts of carbon dioxide (CO2) to the atmosphere; yet the magnitude and origin of the evasion are still poorly constrained. We quantified annual CO2 evasion and its origin (in-lake net ecosystem production vs. lateral inputs from terrestrial ecosystems) in 14 high-latitude lakes through high-frequency estimates of open water CO2 flux and ecosystem metabolism and inorganic carbon mass-balance before and after ice breakup. Annual CO2 evasion ranged from 1 to 25 g C m−2 yr−1 of which an average of 57% was evaded over a short period at ice-breakup. Annual internal CO2 production ranged from −6 to 21 g C m−2 yr−1, of which at least half was produced over winter. The contribution of internal versus external source contribution to annual CO2 evasion varied between lakes, ranging from fully internal to fully external with most lakes having over 75% of the evasion sustained through a single source. Overall, the study stresses the large variability in magnitude and control of CO2 evasion and suggests that environmental change impacts on CO2 evasion from high-latitude lakes are not uniform.