M.Sc. - University of Western Ontario
Our lab used a long-term field experiment to look at the effects of climate change on an old-field ecosystem. Department of Plant Pathology anInfrared heaters warmed plots either year-round, or during the winter only, in an attempt to isolate the effects of climate change on winter processes. The effects are difficult to predict, due to two opposing processes that take place. The snow acts as an insulating layer to the soil, so if warming reduces snowpack thickness, the soil may undergo more freeze-thaw cycles. On the other hand, warming may delay the timing of freezing in fall, and may also lead to an earlier spring. Nitrogen was also added to some of the plots, to reflect the increased nitrogen deposition that is expected from higher agricultural, transport, and industrial emissions in the future.
My role in this project was to examine how these factors affected microbial biomass, extracellular enzyme activity, and fungal:bacterial ratios. One of our most interesting findings was that extracellular enzyme activity was insensitive to the treatments, yet showed strong seasonal shifts. Microbial biomass was also insensitive to the treatments in general, although there was a significant increase in microbial biomass N in the summer.
See here for more information about this project.