Figure 2.

Water column depth profiles of (A) CH₄ and CO₂ concentrations and (B) δ¹³C of CH₄ and dissolved inorganic carbon (DIC) for Lake Kuivajärvi, and (C) CH₄ and CO₂ concentrations and (D) δ¹³C of CH₄ and DIC for Lake Lovojärvi. For clarity, the depth profiles of CH₄ and CO₂ above 12 m depth in Lovojärvi are shown specifically in a subfigure (C). The oxic-anoxic interface is defined with a black vertical dashed line in Lovojärvi (C and D). The data are presented as average ± standard deviation (SD) of 2–3 replicates for Kuivajärvi (A and B) and of 2 replicates for Lovojärvi (C and D), except for δ¹³C of DIC for Lovojärvi that was only represented by 1 replicate per depth (D). In many cases, the error bars for SDs are narrower than the data symbols.