Testing the consequences of the carbon-quality temperature hypothesis for soil organic matter decomposition

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This research will investigate how sensitively carbon dioxide loss from soil responds to increasing temperature and why this varies among different soils. Soils from a variety of ecosystems across the United States will be collected and assayed under controlled laboratory conditions in order to determine how fast soil carbon is respired by microbes at different temperatures and how increases in biologically available nitrogen affect this temperature sensitivity. The research will be testing predictions as to whether recalcitrant soil carbon loss will be more sensitive to increases in temperature than less recalcitrant soil carbon. In addition, the research will test whether increases in nitrogen availability decrease temperature sensitivity. Globally, soil carbon is one of the largest repositories of carbon, yet its fate in a warmer world will be impossible to predict without mechanistic understanding of what controls how soil microbes utilize it. For global change biologists, this research will test a critical set of hypotheses about soil functioning and will provide data that are essential to improving models of how ecosystems respond to climate change and deposition of biologically available nitrogen. At the heart of the research is determining whether warming soils are likely to provide a positive feedback to global temperatures while also identifying those soils and components of soils that are most susceptible to carbon loss due to warming.