Main content area

Greenhouse gas emission and storage in a small shallow lake

Bartosiewicz, M., Laurion, I., MacIntyre, S.
Hydrobiologia 2015 v.757 no.1 pp. 101-115
carbon dioxide, greenhouse gas emissions, greenhouse gases, lakes, meteorology, methane, models, rain, summer, temperature profiles, temporal variation
Small lakes are likely to show considerable temporal variability in greenhouse gas emissions given their transient stratification and short residence time. To determine the extent that CO₂ and CH₄ emission and storage depends on surface meteorology, we studied a shallow lake during 2 years with contrasting rainfall and thermal stratification. Gas fluxes were estimated with wind-based and surface renewal models and compared to direct measurements obtained with floating chambers. The assessment of greenhouse gases storage revealed that the lake gained CO₂ in association with rainfall in both the rainier (2011) and drier summer (2012). In 2011, stratification was less extensive and disrupted frequently. The lake was a source of CO₂ and CH₄, and ebullition exceeded diffusive fluxes of CH₄. In 2012, stratification was more persistent, the lake was a sink for CO₂ during dry periods, CO₂ and CH₄ accumulated in the hypolimnion later in the summer when rainfall increased, diffusive fluxes of CH₄ were similar to those in 2011 mid-summer and over four times higher during overturn. Ebullition was lower in the drier summer. Fluxes measured with chambers were closer to estimations from the surface renewal model and about two times values estimated with wind-based models.