I am broadly interested in the carbon cycle and how the carbon balance of ecosystems is determined by the interplay of plant and soil processes.  For my masters, I studied whether the sediments of restored seagrass and mangrove ecosystems were actively accumulating carbon and which plant sources were contributing to their soil carbon.  For my PhD, my main project is partitioning ecosystem respiration of tundra undergoing permafrost thaw into plant and soil sources. Warming in the subarctic is causing permafrost to thaw, which causes increased ecosystem respiration rates, meaning more CO2 is respired to the atmosphere where it can cause further warming. The source of that ecosystem respiration increase partly determines what the implications are for our climate. If the increase is due to plant respiration, then the increase is a restrained or neutral feedback to warming, because plants are also photosynthesizing, fixing carbon from the atmosphere. If the increase is due to soil respiration (particularly old, deep soil), then the increase is a positive feedback to warming, because carbon that has been stored for hundreds to thousands of years is being lost to the atmosphere.  I am partitioning ecosystem respiration in a natural gradient of permafrost thaw in Healy, AK and in two warming experiments—CiPEHR in Healy, AK and a peatland warming experiment in Abisko, Sweden run by researchers from Vrije Universiteit (Amsterdam).

Other projects of my PhD include measuring soil carbon accumulation rates in soils undergoing permafrost thaw and a decomposition study. The decomposition study involves using a common substrate to measure changes in the decomposition environment that occur with natural thaw and experimental warming (CiPEHR) and a common garden study to understand how changes in plant community composition that occur with thaw may affect the quality and quantity of carbon inputs to the soil.

In my research, I use the natural abundances of carbon isotopes as tools. For my masters, I used the δ13C of various plants (mangroves, seagrasses, phytoplankton, Spartina) to trace which of these plants were contributing to sediment organic carbon. For my PhD, I use the δ13C and ∆14C (radiocarbon) of respired CO2 to calculate the contributions of plant and soil respiration to total ecosystem respiration. I also used the radiocarbon values of soil organic carbon to age soil in order to model carbon accumulation rates.

Lastly, I very much enjoy in teaching science to people of all ages. I participated in the NSF GK-12 program at UF for two years. Through SPICE I taught physical science to eighth graders and developed a module on renewable energy. A lesson from this module on building wind turbines is being published in a peer-reviewed journal for science teachers, so that teachers across the country can use the lesson in their classrooms.

back to people