Faculty Research Fellow
Professor of Biology
Atmospheric Nitrogen Deposition Throughout the Greater Boston Area
Human activities have altered the global nitrogen cycle through emissions from electrical power plants, automobile exhaust, and fertilizer applications. However, much of the scientific and policy focus has been on reducing nitrogen emissions and atmospheric deposition at large geographic scales that do not consider urban hotspots. This work demonstrates that atmospheric deposition rates of nitrogen are not only elevated in cities, but are just as variable as the range of values that span entire urban to rural gradients, such as that from Boston to Harvard Forest, MA. This project builds upon ongoing urban biogeochemistry research to monitor rates of atmospheric deposition at several sites across Greater Boston, partition sources of nitrogen emissions and deposition throughout the Greater Boston area, and include these research and community engagement efforts in training of graduate students in the BU URBAN Graduate NRT Program. Together, these activities will help determine the causes of excess nitrogen with the goal of helping the City of Boston and other localities reduce nitrogen inputs to local waterways and the atmosphere.
Mitigation of Boston Heat Island Effect with Urban Canopy
The frequency and duration of extreme heat waves are projected to continue to increase in urban areas throughout the world, leading to higher risks of heat related deaths. Increasing urban canopy is a key strategy for mitigating excess urban heat by creating a cooling microclimate via shading and evapotranspiration (transpiration and evaporation). However, our ability to predict the mitigation effect of urban vegetation is limited by existing approaches that assume urban trees behave like their rural counterparts. Transpiration rates are known to vary by tree species, climatic conditions, and nutrient availability – factors known to vary between urban and rural environments. This project will develop new estimates of urban transpiration by: 1) empirically quantifying rates in both urban and nearby rural trees; 2) integrating field estimates of transpiration into the advancement of urban heat island models; and 3) applying the newly improved model to identify and test the efficiency of urban canopy mitigation approaches.
PhD, Cornell University
I am broadly interested in ecosystem ecology and the influence that plant-microbial interactions have on nutrient cycling, retention and loss. I am particularly interested in the effects that human activities, such as fossil fuel combustion, introduction of non-native plant species, land use change and climate change, have on forest ecosystems. We currently examine a variety of nitrogen sources, including rain, fog, and anthropogenic nitrogen deposition. We explore how plant-microbial interactions influence nitrogen and carbon retention and loss within natural and managed ecosystems.
We currently work in temperate forests of the northeastern United States, redwood forests of California, and tropical forests of Puerto Rico and Mexico. We focus on three research themes: (1) the effects of winter climate change on forest biogeochemistry and carbon exchange; (2) controls on nitrogen retention and loss in temperate and tropical forest ecosystems, and (3) effects of land-use change and forest regeneration on nutrient cycling.