do plants or soil microbes drive changes in ecosystem respiration?
Caitlin Hicks, a graduate student at the University of Florida, will be studying thawing permafrost near Eight Mile Lake outside of Denali National Park and Preserve in the summer of 2010. As climate warms, the permafrost underlying tundra ecosystems is thawing, causing changes to the carbon cycle of tundra ecosystems. Permafrost thaw can increase the soil organic carbon being released as CO2 by soil microbes or can increase plant growth, which takes CO2 out of the atmospheric via photosynthesis. The relative responses of soil microbes and plants to permafrost thaw determines whether the ecosystem adds CO2 to the atmosphere (microbial response), a positive feedback to climate change, or whether the ecosystem takes CO2 from the atmosphere (plant response), a negative feedback to climate change. The main objective of her research is to quantify the response of four components of ecosystem respiration (aboveground plant structures, belowground plant structures, surface soil microbes, and
