Princeton Weekly Bulletin December 7, 1998
How do trace metals affect ecosystems?
By Peter Page
Winds scouring the continents carry dust laden with minute quantities of metals to the most remote reaches of Earth. In ocean waters far from land, that trace sprinkling of iron and other metals is one key to determining the productivity of marine ecosystems.
The Center for Environmental Bio-Inorganic Chemistry (CEBIC), a new interdisciplinary research group within the Princeton Environmental Institute, has received a $7.5 million grant from the National Science Foundation and the Department of Energy to study how metalbased enzymes, called metalloenzymes, affect ecosystems. CEBIC, which will receive the grant over a five-year period, will focus particularly on the role that iron plays in the global cycling of carbon dioxide, the greenhouse gas of greatest concern to policy makers struggling to stem global climate change.
François Morel, Albert G. Blanke Jr. Professor of Geosciences and director of both CEBIC and PEI, says the 23 researchers affiliated with the new center will develop improved probes for detecting the abundance and functioning of metalloenzymes in the environment.
"What is unique is that this work is focused on metalloenzymes in organisms that are important in the environment," he observes.
CEBIC collaborators will include scientists in geochemistry, microbiology, molecular genetics, enzymology and bioinorganic chemistry from Princeton, Rutgers and McGill universities; the University of California, San Diego, Santa Barbara and Santa Cruz; and Exxon Corp.
Metals and the environment
Global climate change has created an urgent need to understand how global ecosystems cycle carbon. A substantial body of research points to iron, or the lack of iron, as a key limit on the growth of plankton, the base of the ocean food web and an important contributor to the Earth's carbon cycle.
The limited availability in ocean waters of iron and other trace metals, such as zinc and cobalt, is a check on the total productivity of some oceanic ecosystems. Human activities, including energy production, are increasing the amount of trace metals in global circulation. Industrial emissions of trace metals could either increase or partly offset the atmospheric buildup of carbon dioxide, depending upon how these emissions affect marine ecology.
By studying the molecular workings of metalloenzymes, researchers hope to draw generalized conclusions about the role of trace metals in the global ecosystem.
"The paradoxical idea is to understand largescale processes by focusing on what is happening at the molecular level," says Morel.
Better cleanup
CEBIC research has the potential to bolster applied environmental research in pollution cleanups, particularly of oil spills, according to John Groves, Hugh Stott Taylor Professor of Chemistry. For a number of years researchers in Groves's lab have isolated enzymes involved in the utilization of iron by organisms. In partnership with field researchers in CEBIC, this lab will turn its attentions to organisms culled from the oceans.
"There are organisms out there that will eat hydrocarbons for food, and they are mainly responsible for cleaning up fuel spills," Groves says. "Most of these enzymes contain iron. These are the species we will be studying."
Researchers are eager to learn if the introduction of iron into an ecosystem fouled by an oil spill will spark a population boom in the organisms that consume hydrocarbons.
"How to respond to an oil spill of the magnitude of the Exxon Valdez is a public policy question that needs an answer based in science," Groves says.
CEBIC is one of three Environmental Molecular Science institutes funded by grants from the NSF and DOE; these grants will total $21.4 million over five years. The other two are the Institute on Chemical Sources and Sinks at Liquid/Solid Interfaces, located at Columbia University, and the Institute for Environmental Catalysis at Northwestern University.
CEBIC is the third research center associated with PEI, joining the Center for Energy and Environmental Studies and the Carbon Modeling Consortium. More than 50 faculty members in departments across the University are affiliated with PEI.