Because the soil is such a large storehouse of carbon, the effects of temperature on soil carbon dynamics have important implications for the global carbon cycle and climate change. Soil organic matter is composed of a variety of materials that differ in their decomposability. The extent to which decomposition of these various components is influenced by temperature is a critical factor that determines whether soils will act as a sink or source for atmospheric CO2 under the climate of the future. This question is unaddressed in leading climate-carbon models, masking a potentially large source of uncertainty. This has substantial implications for changes in soil carbon stocks. Using a combination of complementary laboratory, field, and cross-site experiments integrated through model development, these researchers will examine the responses of biochemical and biological processes to temperature, especially constraints on enzyme production. They will also explicitly investigate the effects of the soil's mineral matrix alone. The hypotheses and experimental approach are directly aligned with the mechanisms by which soil organic matter decomposition occurs: organic matter becomes available for decomposers (desorption) and it is attacked by soil microorganisms (enzymatically). Thus, this project will generate new knowledge that applies fundamental kinetic theory to decomposition in real-world situations.
The broader impacts of this project include development of symposia at two national global-change meetings. Undergraduate students will participate in the Summer Ecology Research program, thus gaining valuable research experience. The principal investigators will assist two graduate students in developing scientific leadership skills, such that the graduate students will eventually mentor undergraduates in their research.
