Climatic trends at the Bear Brook watershed in Maine: Biogeochemistry of the vernal transition

Patel, K; Fernandez, I

From the introduction: "The northeastern region of the United States has been experiencing significant changes in climate; air temperatures have increased by about 0.8°C in the past century, with winter temperatures increasing more than summer temperatures (Hayhoeet al. 2007). Climate models predict a continuing warming trend, with projected increases of 2-5°C by 2100 (Groffmanet al. 2012; IPCC, 2013). Long-term studies at the Bear Brook Watershed in Maine (BBWM) provide a framework to understand the relationships between changing climate and biotic and abiotic ecosystem processes. Snow acts as an insulator over the soil, reducing geothermal energy loss from the soil. It also forms a barrier to direct insolation and conduction from above. When the soil system transitions from winter conditions under the snowpack to exposed post-snowmelt conditions (i.e. the vernal transition), rapid changes take place in the physical soil environment (Groffmanet al. 2001). With changing climate, snowmelt is demonstrating increased temporal variability, and biogeochemical processes could be influenced by these changes (Fitzhugh et al. 2003; Campbell et al. 2010). It is therefore of increasing importance to understand the biogeochemical characteristics of the vernal transition in order to determine the consequences of shifting temporal patterns of climate.