Cebic's Mission

In recent years, human activity has affected several of the earth's most important biogeochemical cycles. Deforestation and the burning of fossil fuels have altered the balance between inorganic and organic forms of carbon, increasing the atmospheric concentration of carbon dioxide and contributing to global warming. Widespread planting of legumes and the production of chemical fertilizers have made available more "fixed" nitrogen and, in certain areas, increased the rate of growth of plants and photosynthetic microorganisms. Desertification, the conversion of biologically productive land mass into dessert, has increased the concentrations of trace metals in areas of the seas. Volatilization of metal-containing substances in waste incinerators, cars, and fossil-fuel-burning power plants has also increased the trace metal concentration in some marine environments.

Legions of marine microorganisms extract iron, zinc, and other trace metals from sea water, store them, then use them to catalyze biochemical processes that enable not just the survival and growth of individual organisms but also the global flux of essential elements like carbon and nitrogen. Among other things, trace metals are needed to:

• make inorganic carbon available for photosynthesis, cell growth, and fuel, reducing the atmospheric concentration of the greenhouse gas CO₂ in the process
  
• break down hydrocarbons, a class of molecules that nourishes some organisms and poisons others
  
• cycle nitrogen from one chemical form into another, making it available, e.g., for producing the world's food supply and nourishing toxic algal blooms—and then making it unavailable again.
Some trace metal ions are essential, others are toxic. Metals like lead, mercury, and cadmium can substitute for essential metals, rendering metal-containing biomolecules nonfunctional or harmful. Even essential metals are toxic when present in excess.

We won't be prepared to effectively manage ecosystems and the global environment until we understand in detail both beneficial and toxic trace-metal activities. To this end, Cebic's research program addresses many interrelated, molecular-level questions regarding the fate and function of trace metals in aquatic systems, particularly marine systems.

To organize our discussion of the major research topics of CEBIC it is convenient to simply follow a metal from its entry into the environment to its point of biological action in a microorganism...

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© 2000 The Princeton Environmental Institute, Princeton, New Jersey. Cebic is an Environmental Molecular Sciences Institute made possible by grants from the National Science Foundation and the U.S. Department of Energy. François M. M. Morel, Director.