Free Air CO2 Experiment (FACE) predicts forest ecosystem response to elevated carbon dioxide. Scientist is measuring photosynthesis of pine trees, and the experiment provides other data on tree growth and carbon sequestration.

Increasing concentrations of carbon dioxide (CO2) in the atmosphere, resulting from fossil-fuel combustion and other sources, are an international concern because of the possible effects on climate. Predictions of climate impacts will be most reliable if based on experiments that mimic real world conditions, meaning they are conducted in open-air field sites rather than greenhouses or other enclosures. These types of long-term, controlled field studies in a number of different ecosystems have been made possible by the development of the Free-Air CO2 Enrichment (FACE) methodology at Brookhaven National Laboratory. The unique FACE facilities and techniques enable scientists to increase the concentration of trace gases such as CO2 in the atmosphere above the ground in a controlled way in intact ecosystems, and to study plant response to the altered conditions. Several FACE facilities are operating around the world. Research supported by the Office of Science has revealed differential responses among species within a single ecosystem; increasing CO2 causes some plants to grow faster and larger and to use less water.

Scientific Impact: The FACE approach gives many biologists access to a large facility that encompasses hundreds of individual plants in an intact ecosystem. This is an economical way to build an understanding of how a particular ecosystem will respond to rising levels of CO2, information that is critical to understanding and predicting overall environmental impacts.

Social Impact: FACE studies will help society plan for the predicted CO2-rich atmosphere of the future. For instance, results from a FACE facility operated by Brookhaven in North Carolina showed that, in 50 years, if forests worldwide were to grow 25 percent faster than they do now, then plant life could serve as a "sink" for about half the expected CO2 emissions from fossil-fuel combustion.

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Schlesinger, W.H. and Andrews, J.A., "Soil respiration and the global carbon cycle," Biogeochemistry 48: 7-20 (2000).

Smith, S.D., Huxman, T.E., Zitzer, S.F., Charlet, T.N., Housman, D.C., and Coleman, J.S., "Elevated CO2 increases productivity and invasive species success in an arid ecosystem," Nature 408: 79-82 (2000).

Lüscher, A., Hartwig, U.A., Suter, D. and Nösberger, J., "Direct evidence that symbiotic N2 fixation in fertile grassland is an important trait for a strong response of plants to elevated atmospheric CO2," Global Change Biology 6: 655-662 (2000).

URL: http://www.face.bnl.gov/

Technical Contact: Dr. Roger Dahlman, Environmental Sciences Division, Office of Biological and Environmental Research, 301-903-4951

Press Contact: Jeff Sherwood, DOE Office of Public Affairs, 202-586-5806

SC-Funding Office: Office of Biological and Environmental Research