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In general, I am interested in ecosystem dynamics and management. As part of the interdisciplinary USDA National Needs program, I am working to link soil hydrology and carbon and nitrogen cycling. I am advised by Jason Kaye, a biogeochemist, and co-advised by Henry Lin. It is my goal to forge my advisors’ expertises.
I currently work in agricultural and relatively unmanaged forested settings. |
Hydrological controls on trace gas emissions:
Abrupt changes in soil water status are “hot moments” for nutrient transport and transformation. Presently, I am working with John Schmidt at the USDA-ARS to examine soil hydrology and biogeochemical cycling in large (33 cm x 30 cm), relatively undisturbed soil cores. These cores were collected from a ditch-drained agricultural catena at the University of Maryland Eastern Shore’s research farm. We manipulate the cores’ water status to identify mechanisms controlling the tempo and mode of nutrient transport and transformation. To do this, we use a variety of instrumentation and analyses including soil moisture probes, tensiometers, gas flux analysis and lysimeters.
Figure Caption: Relationship between water filled pore space and N2O emissions at 3 locations across a ditch-drained agricultural catena. |
Interaction of hydrological and biogeochemical controls on nitrogen transport and transformation:
Soil texture can control nutrient cycling through physical and biological mechanisms. In a small forested catchment located in suburban Baltimore, MD, we are examining these mechanisms’ relative importance during water transport down a hillslope. A gradient in sand content runs perpendicular to and parallel with the hillslope. In this setting, we are working to identify flow paths, their heterogeneity and importance for nutrient cycling and transport. For this work we make use of soil moisture monitoring sensors combined with chemical analyses and natural abundance stable isotope analyses of soil water. Additionally, we use stable isotope tracers to track nitrogen cycling within the soil.
Figure Caption: Soil moisture spikes “flush” nitrate from soil solution in a sandy-textured soil. Absence of nitrate in silty soils suggests a biogeochemical process inhibits the accumulation of nitrate, leading to the absence of a “flushing” response.
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