Michelle M. McKnight

To model the impacts of climate change associated warming in Arctic soils, Queen’s University Biology researchers set up greenhouse and fertilizer amendment plots in the low Arctic tundra, 300 km NW of Yellowknife in the North West Territories. After a dozen years of tending the plots, the bacterial and fungal microbial communities of both the surrounding soil and the roots of Arctic birch were characterized using DNA analysis.

DNA sequencing of the green house-warmed plots showed little change in the structure of the soil or the root microbial communities, even though organic decomposers appeared to increase their activity. These increased nutrients seem to be used for growth by the dwarf birch trees and there was little left over for the soil communities. In plots with added phosphate or phosphate and nitrogen fertilizers, the microbial community did shift since presumably there were plenty of nutrients for both the above ground and below ground communities. Under these circumstances, DNA from bacteria associated with lichens decreased in relative abundance, whereas DNA from plant-associating bacteria and fungi increased. Particularly notable was an overall increase in relative abundance of ectomycorrhizal fungi, which promote plant growth. These changes may indeed foreshadow climate change mediated shits from lichens to a birch shrub dominated landscape, or as popularly termed, the “greening” of the Arctic. Read the article in Arctic, Antarctic, and Alpine Research.