Fig. 7. CH4 is higher and CO2 is lower in African lakes than in boreal lakes.
The ratio of dissolved CH4 and CO2 concentrations (A to C), dissolved CH4 (D to F), CO2 (G to I) concentrations, and N2O saturation levels (%N2O) (J to L) in surface waters of several African tropical lakes compared to paired CO2 and CH4 measurements (n = 224) in lakes located in the boreal climatic zone compiled from literature in (26) located in Finland, Canada, Siberia (latitude, >60°N) and %N2O in Finland (50) sorted into three size classes (0.1 to 1 km2, 1 to 10 km2, and >10 km2). Surface water temperature in boreal lakes was 9.8°C (median) versus 25.8°C in African lakes. Box indicates the median; bars indicate the first and third quartile. n indicates the number of data points.