ENVIRONMENTAL QUALITY
Planting Scientific Seeds

Standing in a hydraulic lift, Rich Norby collects leaves in ORNL's sweetgum forest being used to test effects of an atmosphere enriched in carbon dioxide.

What are the effects of radioactive and toxic substances from industrial facilities on the plants and animals that make up an ecosystem? How do ecosystems interact with the earth's atmosphere? ORNL has helped answer these and other questions for more than half a century, creating new fields of ecological study.

In the 1950s ORNL researchers pioneered the use of radionuclides as tracers for the natural movement of elements in ecosystems, including forest nutrients and pollutants. Work by Stan Auerbach, Dan Nelson, Jerry Olson, and others led to the development of the field of radioecology.

Olson, Bob O'Neill, and others pioneered the development of computer models to understand ecosystem structure and function and the movement of elements, nutrients, and pollutants in forest ecosystems, spawning systems ecology.

In 1958 ORNL scientists established a major study of the Clinch River—first regularly sampled in 1947 because it was near ORNL—along with numerous federal and state agencies. This was the first multi-agency effort to evaluate potential long-term hazards of radionuclide releases from a major nuclear facility.

Using a Ford Foundation grant in the early 1960s, ORNL researchers developed advanced mathematical and computer approaches to understanding changes in terrestrial ecosystems. They tagged a forest stand with cesium-137—a pioneering large-scale use of a radioactive waste material—to provide data for new computer models, which showed the ill effects of long-term contamination of landscapes by radioactive fallout from atmospheric weapons testing.

Because of its contributions, in 1967 ORNL was selected and funded by the National Science Foundation to lead a major U.S. ecosystem research program under the International Biological Program. This multimillion-dollar effort involving several hundred scientists and graduate students worldwide produced valuable information on the role of ecosystems in the global carbon cycle.

In the same year, the Walker Branch Watershed research facility was first used to study ecosystem processes in water and on land and then atmospheric deposition of pollutants. In 1975, Steve Lindberg determined that 40 to 70% of sulfuric and nitric acids deposited on forests arrive as dry particulates rather than in rain.

ORNL research then began on the biological effects of chemicals produced by converting coal to liquid and gaseous "synfuels." In 1980 cricket eggs exposed to synthetic fuel chemicals were found to produce insects with an extra eye or head. Owing to these studies, Barbara Walton, Glenn Suter, and Larry Barnthouse helped develop the field of ecological risk assessment and an ecological risk assessment framework later adopted by the U.S. Environmental Protection Agency.

By the 1980s ORNL was an established leader in the development and use of computer models of ecosystems, including "individual-based models" of Michael Huston, Don DeAngelis, and Mac Post that predicted ecological and evolutionary changes in forests and fish populations. During the 1990s O'Neill, Virginia Dale, and others contributed to the development of the field of landscape ecology (e.g., studies of effects of fires and volcanic eruptions).

By 1990 ORNL's Sandy McLaughlin, Dale Johnson, Lindberg, and others completed 10 years of research support to the National Acid Precipitation Assessment Program. This work led to restrictions on industrial emissions of sulfur and nitrogen oxides.

In 1994 ORNL established the world's largest global change experiment in a forest. It demonstrated the effects of both drought and unusually wet conditions potentially resulting from climate change.

In 1998 ORNL began operating the Free Air Carbon Dioxide Enrichment facility, to evaluate the effects of increased atmospheric carbon dioxide on a sweetgum plantation. Early findings showed that the plantation's trees grow faster than those in a normal atmosphere.

ORNL mercury research led by Ralph Turner resulted in a faster, less costly removal of soil mercury from Oak Ridge land contaminated by a mid-century hydrogen bomb project. Conclusions of studies by Lindberg and others on atmospheric mercury were used by EPA in its report to Congress, resulting in federal recommendations for controls of mercury emissions from combustion sources.

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