The relationship between snow depth and soil respiration in upper montane winter environments Claire Hierseman Winter Ecology Spring 2013 Mountain Research Station, University of Colorado, Boulder

Background: Literature Soil Respiration happens in winter (Oechel et al 1997) The differences in snow depth may relate to differences in CO2 flux (Grogan 2012) cm of snow insulate ground temps from atmosphere (Larsen et al 2012). In areas with greater than 1m of snow, the snow depth might be more important than other factors (Grogan 2012).

Background: Field Day

What is the snow depth threshold for soil respiration to occur, as measured by CO2 flux?

Methods

Results Linear P=0.027 Exponential P=0.027

Results P-value: One tail unpaired t-test without equal variances

Results Controls tell an interesting story Suggests that snowpack quality is important

Discussion Linear or exponential? Linear is most parsimonious Threshold at approximately 30cm Snowpack quality

Conclusions Snow depth is likely a significant factor in the amount of respiration that occurs More precise manipulations should be done in future to articulate precise threshold

Take home point The microbes are active in winter under the snowpack Snowpack affects the amount of respiration that is occurring

Works Cited Grogan, P. “Cold season respiration across a low arctic landscape: the influence of vegetation type, snow depth, and interannual climatic variation.” Bio One 44.4 (2012): DOI: Larsen, K., Grogan, P., Jonasson, S., and Michelsen, A. “Respiration and Microbial dynamics in two subarctic ecosystems during winter and spring thaw: effects of increased snow depth.” Arctic, Antarctic and Alpine Research 39.2 (2007): Mikan, C., Schimel, J., and Doyle, A. “Temperature controls of microbial respiration in arctic tundra soils above and below freezing.” Soil Biology and Biochemistry 34 (2002): Oechel, W., Vourlitis, G., and Hstings, S. “Cold season CO2 emissions from arctic soils.” Global Biogeochemcial Cycles 11.2 (1997):