This award is part of the Arctic System Science (ARCSS) Program, a U.S. Global Change Program. The research project will measure the movement of carbon dioxide to and from the soil and vegetation in the Arctic. The near-surface soil in the Arctic contains carbon equivalent to approximately 60 percent of the carbon currently in the Earth's atmosphere as carbon dioxide. Much of this carbon is stored in the soil as dead organic matter. Its fate is subject to the net effects of global change on the plant and soil systems of northern ecosystems. Recent findings indicate that the arctic has become a source of atmospheric carbon dioxide. This change coincides with recent climatic variation in the arctic, and suggests a positive feedback of arctic ecosystems on atmospheric carbon dioxide and global change. The research will use enclosures, towers and aircraft to make its measurements. This project is a component of a larger interdisciplinary program known as the ARCSS FLUX Program.