Arctic vegetation and soil biological communities interact with a range of biotic and abiotic factors to produce or consume the greenhouse gases (GHG) carbon dioxide, methane, and nitrous oxide. In Arctic environments the parameters controlling these processes are not well understood. We measured soil GHG concentrations and surface fluxes from six vegetation communities at a High Arctic polar oasis and adjacent polar deserts in order to identify regions within the soil profile of production and consumption of CO₂, CH₄, and N₂O. Examined communities included two polar deserts differing in parent material and soil pH, and four lowland tundra communities: prostrate dwarf-shrub, herb tundra, prostrate/hemiprostrate dwarf-shrub tundra, nontussock sedge, dwarf-shrub, moss tundra and a sedge/grass, moss wetland, representative of large areas at lower Arctic latitudes. Polar desert soils were net producers of greenhouse gases during the brief High Arctic growing season, including at depths close to the permafrost layer, and effluxes from the surface were of a similar magnitude to nearby mesic and hydric tundra soils including for CO₂, indicative of soil respiration in desert soils with few roots. Differences in water content, rather than calculated diffusivity, appear to drive gas transport in at least some soils, with all three GHG appearing to move rapidly through, for example, the soil at 10 cm above permafrost in the Prostrate (dominated by Dryas integrifolia) plant community. Such physical processes may obscure or falsely suggest biological processes in soil ecosystems.

Production and consumption of greenhouse gases such as CO₂, CH₄ and N₂O are key factors driving climate change. While CO₂ sinks are commonly reported and the mechanisms relatively well understood, N₂O sinks have often been overlooked and the driving factors for these sinks are poorly understood. We examined CO₂, CH₄ and N₂O flux in three High Arctic polar deserts under both light (measured in transparent chambers) and dark (measured in opaque chambers) conditions. We further examined if differences in soil moisture, evapotranspiration, Photosynthetically Active Radiation (PAR), and/or plant communities were driving gas fluxes measured in transparent and opaque chambers at each of our sites. Nitrous oxide sinks were found at all of our sites suggesting that N₂O uptake can occur under extreme polar desert conditions, with relatively low soil moisture, soil temperature and limited soil N. Fluxes of CO₂ and N₂O switched from sources under dark conditions to sinks under light conditions, while CH₄ fluxes at our sites were not affected by light conditions. Neither evapotranspiration nor PAR were significantly correlated with CO₂ or N₂O flux, however, soil moisture was significantly correlated with both gas fluxes. The relationship between soil moisture and N₂O flux was different under light and dark conditions, suggesting that there are other factors, in addition to moisture, driving N₂O sinks. We found significant differences in N₂O and CO₂ flux between plant communities under both light and dark conditions and observed individual communities that shifted between sources and sinks depending on light conditions. Failure of many studies to include plant-mediated N₂O flux, as well as, N₂O soil sinks may account for the currently unbalanced global N₂O budget.

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.