The effects of increased air temperature and soil moisture on microbial metabolic diversity and soil respired carbon dioxide concentrations in three selected Arctic tundra communities

Where considerable research has already examined the effects changing climate may have on arctic tundra carbon pools, there currently lacks a research effort focused on coupled changes to air temperatures and moisture additions to arctic tundra soils. This study evaluates how increasing air temperature and moisture additions will affect the metabolic diversity of microbial communities and soil respired CO2 concentrations (two markers for evaluating changes to the carbon pool in arctic tundra soils) of three diverse arctic tundra plant communities. Experimental treatments depicting two future arctic scenarios were created in the laboratory to evaluate these changes.;Soil respired CO2 concentrations, Average Well Colour Development, Richness and Shannon-Weaver scores (unitless measures of metabolic diversity in microbial communities) were recorded and analyzed for trends among the three sites, between soil horizons, across treatments, and over time. Results revealed that the two plant communities dominated by dwarf birch shrubs (i.e., Moist Birch Hummock and Closed Mat Shrub Tundra) exhibited decreased metabolic diversity of microbial communities and increased soil respired CO2 concentrations in the warmer and wetter treatment 2. Conversely, non-vascular dominated Heath Lichen decreased in metabolic diversity of microbial communities and slightly increased soil respired CO2 concentrations in the warmer and wetter treatment 2.;This study concludes that dominant vegetation type in each arctic plant community, and hence quality of supplied litter to each ecosystem's soil, may provide the link in determining the direction of change arctic plant communities may take. In a warmer and wetter arctic with a more active climate, plant communities with vascular dominant strands are well placed for succession over non-vascular dominant ones. If current climate model forecasts materialize, the results of this study show that carbon pools will decrease at an accelerated pace and thereby, accelerate respiration of CO2 from arctic tundra soils.