Global climate change research at Brookhaven

The effects of global changes on ecosystems are the subject of intense research at a suite of free-air carbon dioxide (CO2) enrichment (FACE) research facilities developed by Brookhaven for the Terrestrial Carbon Processes Program and the Program for Ecosystem Research of the Office of Biological and Environmental Research, U.S. Department of Energy. These two DOE programs directly support four BNL-designed FACE facilities in the United States, and, through the FACE program at Brookhaven, provide technical support to two others located in Europe.

Each year, hundreds of investigators use FACE facilities in highly integrated research programs covering a wide range of interdisciplinary topics from molecular biology and physiology to global ecosystem-level processes.

Within each FACE facility, elevated levels of CO2 or other trace gases can be constantly maintained at levels expected to prevail in the mid-twenty-first century. This is accomplished without significant change in natural airflow throughout plots of vegetation 15 to 30 meters in diameter and at heights from ground level to at least 20 meters. By using such a large plot, we can greatly reduce or even eliminate effects of the plot edge on the rest of the vegetation, a major problem with enclosure studies. Thus, field data from FACE credibly represent many of the responses of plants and ecosystems to changes in atmospheric chemical conditions we expect to see over the next 50 years. The large size of FACE plots, encompassing hundreds of square meters, also allows many ecosystem-level questions to be addressed by large teams of investigators.

FACE experiments allow the simultaneous application of multiple interacting variables to crops and natural ecosystems, including increased CO2 and O3, altered nutrient or water regimes, and warming of the vegetation. In this way, FACE is a "window on the future," revealing how ecosystems will respond to environmental changes in general and to altered atmospheric chemistry in particular.

Most of the FACE sites include multiple species and address interactions of populations in the various systems in which they are set. Thus, biodiversity topics are also studied in FACE experiments. Hundreds of scientists use these facilities to explore the structure and function of a variety of different ecosystems from crop monocultures to maturing forests.

This suite of FACE facilities is, therefore, a distributed DOE facility for fundamental research. Topics ranging from the expression of genes regulating the important enzyme Rubisco to the development of theory describing community-level responses to the experiments are laying the scientific foundations for understanding the consequences of CO2 emissions and the potential ecological impacts of energy-related gases such as ozone. These studies are also revealing the inner workings of ecosystem-scale functions, such as forest succession and cycling of nutrients in native ecosystems. FACE experiments have so far generated more than three hundred research articles in peer-reviewed literature, including many cover photos in journals such as Nature and Global Change Biology.

For more information on Brookhaven's FACE program, go to http://www.face.bnl.gov/.

by George Hendrey, Earth System Sciences Division, Environmental Sciences Department, BNL