Cold conditions and low inputs of nitrogen to boreal ecosystems are thought to result in a “closed” nitrogen cycle characterized by nitrogen limitation of primary production, strong competition for nitrogen between plants and microbes, low rates of dissimilatory processes such as nitrification and denitrification, and limited gaseous or leaching losses of nitrogen. However, observations of large nitrous oxide (N₂O) emissions in other high-latitude ecosystems as well as elevated concentration of nitrate in streams of our study region challenge this paradigm. We are studying the sources of nitrogen in boreal ecosystems and measuring emissions of gaseous N₂O and nitrogen (N₂) from soils with a particular focus on potential effects of permafrost thaw.