 Rob Jackson
Professor
jackson duke.edu
My research examines feedbacks between people and the biosphere, including studies of the global carbon and water cycles, biosphere/ atmosphere interactions, and global change. I am currently Director of Duke's Center on Global Change and Duke's Stable Isotope Mass Spectrometry Laboratory. In the quest for solutions to global warming, I also direct the new Department of Energy-funded National Institute for Climatic Change Research for the southeastern U.S. and co-direct the Climate Change Policy Partnership, working with energy and utility corporations to find practical strategies to combat climate change.
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 Alison Appling
PhD candidate
apa3duke.edu
Interests - Nitrogen cycling in floodplains, plant uptake of water and nitrogen, denitrification
I study the processes by which floodplain organisms mitigate nitrogen pollution in river water. Excess nitrogen from farm runoff and industrial waste pollutes drinking water and causes algal blooms and fish kills downstream. Natural floodplains often act as biological nitrogen sieves, removing nitrogen from river water before the water continues downstream. My research focuses on two key processes that contribute to this sieving process: (1) plant uptake of river nitrogen into biomass, and (2) the microbial process of denitrification. Ultimately, my research will contribute to an understanding of how land and river management decisions can affect water quality.
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| Installing moisture probes in a floodplain soil pit in Montana |
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 Justin Baker
Visiting Scholar, PhD candidate at Texas A&M University
jsb24duke.edu
Interests - biofuels and environmental economics
A recent US energy bill demands 36 billion gallons of liquid biofuels produced by 2022. Economists are curious how such federal policies affect the larger economy. To this end, I have created a computer model of the US agricultural and forestry sectors. The model factors in both the price of carbon (assuming a cap-and-trade system for carbon emissions) and the physical effect of climate change on crop production. Most recently I am finding that federal incentives for biofuel production may lead farmers to return more than half of Conservation Reserve Program land to agricultural production. The conservation benefits lost from this reversal (such as soil C sequestration) need to be weighed against the gains from biofuel production. In the future, I plan to explore policy implications for water resources by adding regional hydrologic functions and groundwater dynamics to this model.
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 Sean Berthrong
PhD candidate
seanbduke.edu
Interests - microbial ecology, biogeochemistry, ecosystem ecology
My research focuses on the interactions between microbes, plants, and biogeochemical cycles in soil. My work combines innovative molecular methods and soil chemical analyses to crack open the “microbial black box” and develop a more mechanistic understanding of how microbes and plants regulate soil processes. To pursue these goals, I work on grasslands in Argentina and Uruguay that have been converted to plantations of eucalypt and pine; I also work in the North Carolina piedmont region.
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| Eucalyptus globulus plantation in Uruguay |
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 Will Cook
Associate in Research
cwcookduke.edu
The Duke Free Air CO2 Enrichment (FACE) experiment studies how elevated carbon dioxide and nitrogen affect a Loblolly Pine (Pinus taeda) plantation with a naturally succeeding understory. My research at FACE focuses belowground, on the effects of elevated CO2 and N on root biomass and soil respiration. Surprisingly, even after 12 years, the stimulation of root growth and respiration under elevated CO2 is still increasing. N fertilizer decreases both fine root biomass and soil respiration, but increases coarse root biomass. In the lab, I maintain a handful of websites, run various analytical instruments, and serve as lab manager. I also enjoy the role of resident naturalist, specializing in birds, lepidopterans, and woody plants.
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| Measuring soil respiration at the FACE site |
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 Dushmantha Jayawickreme
Postdoctoral Research Associate
dj51duke.edu
My research interests are largely centered on understanding the influence of land-use and land-cover (LULC), and LULC change on near surface soil moisture distribution and groundwater recharge. In addition to geospatial, statistical, and modeling approaches, I use near surface geophysics to gain more detailed insights in to below ground hydrologic consequences of vegetation. This novel approach has so far provided an interesting array of observations highlighting spatial and temporal interactions between climate, vegetation and soil moisture in the shallow subsurface. In my post-doc research I intend to utilize and improve electrical resistivity imaging and other geophysical methods to explore hydrologic and biogeochemical implications of land-use conversions in native grasslands of Argentina and Uruguay.
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| Time-lapse electrical resistivity imaging of a forest-grassland ecotone |
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 Esteban Jobbágy
International Collaborator/Visiting Scholar
jobbagyunsl.edu.ar
I study the influence of plants on the cycle of materials (water, nutrients, salts, carbon) in terrestrial ecosystems; the impact of vegetation changes (afforestation of grasslands, deforestation and cropping in forests, overgrazing degradation) on ecosystem functioning, its interaction with the hydrological system; biological carbon uptake and sequestration; biogeography of terrestrial ecosystems; and productive systems design. Approaches and methodology include: hydrological observations, physical and chemical determinations on soils and sediments, ecophysiological measurements on plants, biophysical characterization of the terrestrial surface with remote sensing, simulation models, and stable isotope natural abundance.
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| Eucalyptus plantation and adjacent grassland in Uruguay |
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 Alexia Kelley
Postdoctoral Research Associate
amk37duke.edu
I am interested in how ecosystem processes change along environmental gradients. My dissertation work examines how nitrogen cycling associated with patterned-ground features varied along an arctic biomclimatic gradient. My current research examines how the interaction between soil type and CO2 concentrations affects microbial controls on nitrogen cycling. I am specifically interested in how changes in the functional composition of the microbial community can affect biogeochemical processes such as carbon degradation and nitrogen mineralization. This work is being conducted at the LYCOG (Lysimeter CO2 Gradient) experiment in Temple, TX.
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| Open tunnel day at the "tunnel" CO2 gradient experiment in Temple, Texas |
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 John Kim
PhD candidate
jhk11duke.edu
Interests - ecosystem services, carbon sequestration, groundwater recharge, woody plant invasion, agriculture, land-use/cover changes
My work is broadly centered around understanding impacts of human and natural processes on the ebb and flow of ecosystem services. Despite their established importance, these services exist mainly as externalities in most social and political settings. Currently, I am looking at how land-use/cover changes are affecting carbon and groundwater storages in grassland ecosystems. Grasslands are often productive lands with large carbon storage and limited surface water supplies. In these systems, vegetation changes such as cultivation or woody plant invasion have high potential to affect ecosystem services such as carbon sequestration and water provision. My goal is to assess and value the changes to these services in order to help determine the optimal land-use changes under global environmental changes.
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| Soil coring to 7 m depth in South Africa |
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 Mark Little
Postdoctoral Research Associate
ml144duke.edu
In addition to reducing emissions, engineered removal of CO2 from the atmosphere represents one possible way to reduce atmospheric CO2. First developed as a method to increase the recovery of fluid fossil fuels from abandoned oil fields and un-mineable coal seams, the injection of compressed CO2 into deep, structurally stable geologic formations is now viewed as a viable storage option for CO2. My research seeks to determine potential environmental risk associated with leaks of CO2 into shallow aquifers used for drinking water by using various geochemical data from aquifers, groundwater and potential storage sites to make recommendations. CO2 intrusion into the shallow aquifers will decrease pH and may release toxic metals present in the aquifer media, e.g. Arsenic and Zinc. I am also involved in a project to determine the salinity history of groundwater in a native grasslands in Argentina.
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| Exposing aquifer sediments to CO2 |
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 Marcelo Nosetto
Postdoctoral Research Associate
marcelo.nosettogmail.com
Interests: water and salts dynamics in arid to humid ecosystems, groundwater-vegetation interactions, biogeochemistry.
I am interested in the reciprocal influences between water/salts dynamics and vegetation. I am currently focused on the interactions between shallow groundwater and crops in the flat humid landscapes of the Pampas. I also study the effects of land-use on the water cycle and energy balance components and the potential climatic impacts of land-use changes. The approaches and methodologies I used involve: remote sensing and GIS, hydrological observations, physical and chemical analysis in soil, water and sediments, natural and artificial water tracers and modeling, among others.
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| Groundwater observations in a maize field |
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 Gervasio Piñeiro
Postdoctoral Research Associate
pineiroagro.uba.ar
Interests - biogeochemistry, afforestation impacts, atmospheric deposition
I am analyzing biogeochemical impacts of afforestations in Uruguay and Argentina, performing mass balances of C, N, Na, Ca, Mg, K, Cl, P, and S, and evaluating the relative impact of alternative plantation species (Eucalyptus and Pines). I am also evaluating atmospheric depositions over souther South America with a network of collection sites, with special interest in tracking spatial redistribution of nutrients and water in the region. Finally I am also analyzing the C cycle in agricultural systems with a special emphasis in developing C sequestration strategies in both food and biofuel crop systems.
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| Eucalyptus plantation and adjacent grassland in Uruguay |
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 Andrew Procter
PhD candidate
andrew.procterduke.edu
Interests - biogeochemistry, C sequestration, microbial ecology
Rising levels of atmospheric CO2 are a primary cause of climate change, but what about their direct effects on ecosystems? I work on a collaborative project in Texas aimed at this question. We expose prairie to a continuous gradient of CO2 concentrations spanning from preindustrial levels to levels expected mid-century. We are investigating numerous aspects of the system, including changes in plant physiology, ecosystem water balance, and nutrient cycling. I am curious how the capacity of this ecosystem to store carbon changes along the gradient, and how microbial processes (decomposition, N cycling) affect this capacity. My current work involves analyzing soil respiration and soil microbial community composition along the gradient.
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| The "tunnel" CO2 gradient experiment in Temple, Texas |
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 Eileen Thorsos
PhD candidate
ert7duke.edu
Interests - biogeochemistry, plant nutrient cycling, biotic-abiotic feedbacks
I study how plants physically and chemically modify their environments in order to (1) improve our understanding of plants' biogeochemical effects and (2) enhance our ability to maximize the ecosystem services plants provide. Wetland restoration projects are excellent systems for such research: In them, we can both address fundamental questions about how ecosystems function and investigate ways to improve multiple wetland ecosystem services during restoration. In my dissertation research, I specifically address how functional plant traits affect greenhouse gas emissions from a restored wetland.
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| Sampling gas emissions from a restored wetland |
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 Danielle Way
Postdoctoral Research Associate
danielle.wayduke.edu
Interests - plant physiological ecology and global change ecology
I study the mechanisms underlying plant responses to global change factors such as rising temperatures, CO2 concentrations and drought stress. Much of my work involves investigating how plants respond to stressful conditions, what limits their ability to acclimate to global change and how these responses scale up to the community level. Some of my current projects include: 1) examining whether drought is more stressful at low CO2 concentrations; 2) studying how the emission of isoprene from leaves is affected by growth CO2 and the repercussions of this for photosynthetic thermotolerance; and 3) determining how growth temperature alters tree growth.
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| Measuring gas exchange at the "tunnel" site in Temple, TX. |
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