Site: Arctic LTER

The very high dissolved organic carbon (DOC) content of Imnavait Creek during spring snowmelt.
Credit: ARC LTER

Dissolved organic carbon (DOC) released from thawing permafrost soil can be respired by microbes almost twice as fast if the DOC is first exposed to UV light. Arctic LTER long term data indicate that direct photochemical degradation of DOC from land is the dominant mechanism of DOC oxidation in streams and lakes.