Greenhouse gas production and consumption in High Arctic deserts

Polar deserts dominate the High Arctic covering over 1 358 000 km2 but little is known about greenhouse gas (GHG) production or flux in polar desert soils. We measured soil-atmosphere GHG exchange for CO2, CH4, and N2O, and net production of these gases in the active layer at 30 sites across three polar deserts in the High Arctic on Ellesmere Island, Canada for a total of 180 production/consumption estimates. There was inter-annual consistency in patterns of GHG net production and a consistent, significant, positive relationship (r2 = 0.91-0.93; p < 0.05) between CO2 production and N2O production in Arctic desert sites. This differs from the negative correlations found in wet or moist tundra ecosystems and may arise from the large N2O emissions in dolomitic desert ecosystems. Global change processes that increase microbial activity in deserts will likely increase N2O emissions but increases in activity in wetter tundra will decrease N2O emissions. However, given the unusual co-consumption of CH4 and N2O in the deserts, it is not clear if models of GHG production developed for other ecosystems will apply to these unique Arctic environments.