Fig. 2. CO₂ fluxes separated by climate zones and ecosystem types.

Box = 25th and 75th percentiles, whiskers = 1.5* inter-quartile range. Black line = median. Blue lines represent average estimates of CO₂ emissions for inland waters as reported in the literature^{11, 20, 21}. Colours refer to climate zones as defined in Fig. 1. Note that the y-axis is presented on a log₁₀ scale to show a wide range of flux values. Letters indicate significant differences between ecosystem types (Kruskal–Wallis test and Dunn’s post hoc test, P < 0.05).