Natural carbon sinks have partially been able to offset the anthropogenically mediated increase in CO_2.   Lakes are a part of the global carbon cycle and have generally been considered as carbon sinks and as unimportant pathways for greenhouse gases. They were however later shown to be important carbon sources, where respiration of organic carbon exceeds the CO₂ uptake by the photosynthesis. Still, there are uncertainties about the sources of CO₂ from inland waters, and the mechanisms that control global evasion of CO_2.  

The external inflow of organic carbon together with internally produced carbon by photosynthesis, is used in the respiration of organisms where CO₂ is produced. CO₂ is on the other hand consumed by photosynthesis. Lake characteristics, different weather variables and environmental surroundings has been found to affect the amount of emitted CO₂ in lakes, which ultimately determines if the lake functions as a carbon source or a carbon sink.  

The specific aims were to (1) investigate seasonal, diel and spatial variations in CO_2, (2) if variations in CO₂ are explained by lake characteristics and environmental variables such as weather condition, depth and oxygen saturation and (3) to compare temporal variations of CO₂ in the open water habitats of the lakes.