Carbon cycling and methane exchange in Eurasian tundra ecosystems

This paper provides an overview of data and results obtained through a numb er of studies of actual and potential trace gas exchanges in northern Euras ia, made possible through the Swedish-Russian Tundra Ecology -94 expedition . It was found that: i) long-term accumulation rates of carbon in organic t undra soils, i.e. net uptake of atmospheric CO2, correlated with simple cli matic parameters, such as mean July temperature and annual precipitation; i i) the release of carbon through ecosystem respiration is also strongly con trolled by climate. Increased temperature and decrease of water-logging enh anced the CO2 flux. However, the release of organic soil carbon as CO2 is a lso constrained by other factors such as poor decomposability of the stored organic compounds; and iii) methane emissions from typical tundra habitats in northern Eurasia were found to be slightly lower than from seemingly si milar habitats in North America. This difference can probably be attributed to lower temperatures along the Russian arctic coast than at North America n sites in general.