ECI Faculty

Stephen Porder

Assistant Professor of Biology
(401)863-6356
sporder@brown.edu

My research lies at the intersection between ecology, geology, and biogeochemistry, and focuses primarily on understanding differences in nutrient cycling across tropical landscapes. The tropics are undergoing the fastest population growth and land use change on the planet, and as we add three billion people to the world (mainly in the tropics) over the coming century, we need to understand a great deal more about how these systems will respond to anthropogenic changes.  My interests are mostly in tropical rainforests, the jewels of biological diversity on land, which are currently undergoing almost unimaginably fast destruction.

Despite the importance of these systems from a whole host of perspectives, we know relatively little about how tropical forests work biogeochemically, how nutrients and energy flow through them, and what constraints there are on plant growth, forest regeneration, and sustainable land conversion. In this context, I try to identify biogeochemical patterns across landscapes, to understand how these patterns may affect the function and services of ecosystems, and to consider how to incorporate this variation into models for predicting the response of ecosystems to anthropogenic changes.  To do this my lab combines field work (shooting leaves with a slingshot is a must-learn skill!), chemical and isotopic analyses, GIS and remote sensing.

Meredith Hastings

My research focuses on the reactive nitrogen cycle, with an emphasis on nitrate deposition. The isotopic composition of nitrate represents a powerful new tool for the study of the biogeochemical cycling of reactive nitrogen, its impact on atmospheric composition and its connection to the terrestrial biosphere.

My interest in NOx extends from its connection to the oxidizing efficiency of the atmosphere through its impact on ozone and hydroxyl (OH) concentrations to the biogeochemical cycling of nitrogen in the Earth system via formation of nitric acid (or nitrate), a major component of acid rain and a source of biologically available nitrogen.

Using the isotopic composition of nitrate, I am investigating variations in the sources, chemistry, and transport of NOx. On short time scales, this has implications for studying air quality and acid deposition impacts. On longer time scales, I am interested in the natural variability of NOx sources, and the connection between climate, atmospheric composition, and the biosphere. Using data collected on rain, aerosol, snow and ice core samples, as well as global models, I am studying the impact of various sources and chemical pathways of nitrate production in remote and urban environments, on both short and long timescales.

Meredith will be joining Brown’s Environmental Change Initiative as an Assistant Professor of Geological Sciences and Environmental Studies in 2008.