Effects of forestry on emission of CO2 from boreal lakes

Sammanfattning: Inland waters have long been neglected in the global carbon cycle. They represent only 2,8% of the land area, but it has come clear that inland waters play a key role in the transformation of terrestrial fixed carbon to the atmosphere. Human activities do have an impact on the carbon cycling and it is important to understand how these changes affects natural biogeochemical and climatological processes. The purpose of this report was to investigate how forestry impacts the emission of carbon dioxide from boreal lakes and to evaluate which role lakes play in the global carbon cycle. The study was accomplished as a literature study and the search words that have been used are carbon cycling, carbon dioxide, forestry, boreal lakes, dissolved organic carbon and pCO2. The results show that in many studies does forestry increase the export of dissolved organic carbon from terrestrial environments to boreal lakes. This increase subsidies the net heterotrophy in boreal lakes, making them net sources of carbon dioxide to the atmosphere. The processes behind increased concentrations and emissions are however complex and factors like local topography, hydrology and climate are thought to have impacts on how much carbon dioxide that is produced at a given level of dissolved organic carbon. Forestry seems to have an increasing effect on the carbon dioxide emissions, but the key drivers behind this process are expressed differently between regions and the reasons underlying these differences remain to be explored in order to make precise global carbon models.