Eddy Covariance tower installed by the Sparks lab at MacArthur Agro-Ecology Research Center in central Florida.

The research interests of the Sparks lab are very broad and include questions in plant physiological ecology, ecosystem science, and the application of stable isotopes to ecological questions. My own work tends to focus on the exchange of compounds at the boundary between the atmosphere and terrestrial ecosystems. This exchange has profound and controlling effects on plant ecophysiology, ecosystem function and the chemical composition of both the biosphere and atmosphere. Further, the magnitudes of the fluxes between the earth and the atmosphere often control the pool sizes of important elements and compounds held in each, the balance of which are intrinsic to the maintenance of life on earth (e.g., carbon dioxide, nitrogen, ozone and other oxidants, and many others). For example, fluxes of various reactive trace gases between terrestrial ecosystems and the atmosphere exert significant influences on plant performance, tropospheric photochemistry, global climate, terrestrial biogeochemistry and the maintenance of clean air, water and soil. The study of fluxes between the biosphere and atmosphere requires skills in plant and microbial ecophysiology, with its emphasis on the mechanistic controls over flux; biogeochemistry, with its emphasis on the mass balance of biogeochemical cycles; and atmospheric chemistry, with its emphasis on the reactivity and control over turnover times of various atmospheric constituents. My research program at Cornell University focuses on exchange of compounds at the Earths surface with special emphasis on plant and soil based mechanisms of transfer.

Tree exchange
Diagram of gas exchange from a tree

As an example, my lab has worked extensively on gas-phase reactive nitrogen

compounds for three reasons. First, the input of reactive gaseous nitrogen directly to plants through foliar uptake is a pathway not normally considered in plant physiological ecology. Second, the input (or loss) of gas phase nitrogen is a large and controlling factor in ecosystem nitrogen availability and cycling. Finally, gaseous nitrogen compounds play a central role in controlling the oxidative chemistry of the lower atmosphere and strongly influence regional air quality and global climate.


My lab is also interested in dynamics of many non-nitrogen gas compounds including ozone, methane, and carbon dioxide.

The approaches and systems we use to study these topics vary dramatically. We work in deserts, tropical dry and wet forests, deciduous forests and shrublands and study an array of compounds including reactive and non-reactive nitrogen, carbon dioxide, methane, water vapor, and ozone. We use techniques ranging from eddy covariance and isotopic analysis to molecular methods describing particular biochemical reactions.

In addition, we support many projects using the application of stable isotopes including animal diet, food webs, fluxes, plant ecology, and atmospheric processes.

Many students and other researchers pursue lines of inquiry outside of this model under the general organization of plant ecology. Below are a few examples of current projects in the lab.

  • Exploring carbon gain and water loss trade-off in plants using Oxygen Isotopes (Ellie Goud)
  • Soil carbon stability under global in the Mojave Desert (Kelsey Jensen)
  • The influence of woody plant encroachment as mediated by plant nitrogen ecophysiology (Fiona Soper)
  • Holistic greenhouse gas emissions from sub-tropical pastures (Sam Chamberlain)
  • Using stable isotopes to study colonial waterbird foraging ecology (Liz Craig)
  • Effects of climate change on the physiological ecology of desert biocrust moss (Kirsten Coe)
  • Improving the representation of plant-ozone interactions in global models using physiological measurements (Danica Lombardozzi)


Soil gasses being measured in the field.