Nicole Smith Downey
PhD Environmental Science and Engineering, Cal Tech, 2006
Current Position: Owner and Principal Consultant, Earth System Sciences, LLC
Nicole Smith Downey has examined the uptake of molecular hydrogen by soils and received her PhD in environmental science and engineering from the California Institute of Technology. She worked on an integrated model of the terrestrial biogeochemical cycle of mercury.
Nicole received a BS in environmental biology, summa cum laude, from Beloit College in Beloit, Wisconsin in 2001. She was a member of Phi Beta Kappa and a Morris K. Udall Scholar. At Caltech, she earned an MS in environmental science and engineering in 2003, having been named an Institute Fellow and an EPA Science to Achieve Results (STAR) Graduate Fellow. Nicole has also participated in research at the University of Alaska's Toolik Lake Research center, the Bilsa Biological Reserve in Ecuador, and the Harvard Forest in central Massachusetts. Nicole's thesis had two parts. She developed a technique utilizing microwave satellite data to detect when soil freezes and thaws and used that tool to measure changes in the length of the growing season across the arctic. She also created the first global model explaining how soil takes up molecular hydrogen based on moisture and temperature responses she measured in the lab. This model describes how environmental variability controls the uptake of hydrogen by soils, and was combined with an atmospheric chemistry model to describe the role of soils in the atmospheric budget of H2.
As an Environmental Fellow, Nicole worked with Professor Daniel Jacob of the Division of Engineering and Applied Sciences and the Department of Earth and Planetary Sciences. When proposing her research, she described it this way: "Methylated mercury is a pollutant that bioaccumulates in the food chain and acts as a neurotoxin in higher organisms. Humans ingest mercury (Hg) primarily through seafood, and concerns have spawned government warnings about fish consumption across the globe. The global Hg cycle is poorly understood, limiting our ability to develop effective regulations of anthropogenic Hg emissions. A major uncertainty is the fate of Hg within terrestrial ecosystems, including rates of deposition and reemission from plants and soils and emissions from biomass burning. I propose to develop a mechanistic model of terrestrial Hg emissions that will be coupled with a global atmospheric and oceanic Hg model for a fully integrated simulation of the fate of Hg in the environment. This process-based model will enable me to determine the factors controlling Hg deposition and accumulation in ecosystems, and to examine changes in the terrestrial Hg cycle under different global change scenarios for the 21st century."
Daniel Jacob, School of Engineering & Applied Sciences