Recent climate change predictions suggest altered patterns of winter precipitation
across the Arctic. It has been suggested that the presence, timing and
quantity of snow all affect microbial activity, thus influencing CO2 production
in soil. In this study annual and seasonal emissions of CO2 were estimated in
High-Arctic Adventdalen, Svalbard, and sub-Arctic Latnjajaure, Sweden, using
a new trace gas-based method to track real-time diffusion rates through the
snow. Summer measurements from snow-free soils were made using a
chamber-based method. Measurements were obtained from different snow
regimes in order to evaluate the effect of snow depth on winter CO2 effluxes.
Total annual emissions of CO2 from the sub-Arctic site (0.662–1.487 kg CO2 m–2
yr–1) were found to be more than double the emissions from the High-Arctic
site (0.369–0.591 kg CO2 m–2 yr–1). There were no significant differences in
winter effluxes between snow regimes or vegetation types, indicating that
spatial variability in winter soil CO2 effluxes are not directly linked to snow
cover thickness or soil temperatures. Total winter emissions (0.004–
0.248 kg CO2 m–2) were found to be in the lower range of those previously
described in the literature. Winter emissions varied in their contribution to
total annual production between 1 and 18%. Artificial snow drifts shortened
the snow-free period by 2 weeks and decreased the annual CO2 emission by up
to 20%. This study suggests that future shifts in vegetation zones may increase
soil respiration from Arctic tundra regions