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Research Projects Research OverviewImages |
Research Overview We study how the function of ecosystems is structured by the interactions among plants, the soil and soil microbes. As compared to the ecological interactions we observe on the macroscopic scale, soil processes are particularly fragile (e.g.,the delicate relationship between root hair and soil mineral surface, gel-like biofilms feeding on root exudates, or the soil pores that conduct water and gases through the soil matrix). Because traditional soil sampling and incubation methods often destroy these structures, we know very little about the "micro-habitats" that affect the distribution, abundance and activity of plant roots and soil microbes. Most broadly, my research seeks to (1) characterize the soil as a landscape composed of diverse micro-habitats, and (2) understand the processes by which diversity in microhabitats affects the function of ecosystems. I am especially interested in the greenhouse gas methane, in part because the metabolism of methane in soil is conducted by two groups of microbes with radically different ecologies: methane is produced by strictly anaerobic archaebacteria and consumed by aerobic bacteria. Thus I am interested in the factors that affect the oxic/anoxic status among and within soils that can structure the activities of the organisms in these two groups. Conversely, I am also interested in understanding how the activities of these groups provide information about the mix of oxic and anoxic microhabitats in the soil. Such measures have important direct implications for understanding the role of methane in climate change while simultaneously contributing toward a more detailed view of soil ecology. To overcome the limitations imposed by traditional soil assays, I have developed and applied new, non-destructive methods for studying the organisms that metabolize methane in upland (e.g., forest or grassland) soils and in wetland ecosystems. As I describe below, work in my lab typically couples stable isotope and other tracers with dynamical systems models in a way that reveals soil function with minimal disruption. My work with stable carbon isotopes has also enabled inquiry into the sources and fates of plant-derived carbon in the soil.
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