The U.S. Geological Survey (USGS), in collaboration with other government agencies and universities, conducts nearly 100 different projects and activities related to global change at science centers across the country. In response to the priorities and needs of the multiagency U.S. Global Change Research Program (USGCRP), the USGS has focused its efforts on areas where it has the expertise to make valuable contributions: understanding the effects of global change on terrestrial ecosystems, coastal wetlands and ecosystems, and fish and wildlife; improving knowledge of hydroclimatic variability; understanding the biogeochemistry of greenhouse gases; characterizing and understanding past climates; monitoring Earth surface processes that affect or are effected by climate; improving the ability to model and forecast the impacts of climate and other global changes; characterizing the current state of the land surface; archiving and providing access to satellite and other global change-related data; and developing decision support system capabilities in response to the needs of natural resource managers within the Department of the Interior.
One project that integrates much of the data, information, knowledge, and skills gained from these activities is directed at understanding the carbon budget of the Mississippi River Basin. Understanding what is happening to CO2 is an important goal of the USGCRP. Mounting evidence suggests that the terrestrial system, particularly in the North American hemisphere, acts as a significant carbon sink. USGS scientists are examining possible links between accelerated terrestrial carbon sequestration and human influences on erosion and deposition. They are also investigating whether significant amounts of carbon are added to soils and sediments through modifications of hydrologic systems and nutrient supplies. The project combines spatial analyses of a wide variety of geographic data at multiple scales, site-specific studies of relevant processes, estimations of whole-basin and subbasin carbon and sediment budgets, and the development and implementation of terrestrial carbon cycle models. Such research will help quantify the interactive effects of land use, erosion, sedimentation, and soil development on carbon storage in the Mississippi River Basin.
Another integrated project focuses on the role of natural and human-induced processes in the evolution of the Rio Puerco River Basin. Arid and semiarid regions provide an excellent laboratory to study the effects of climate changes on fluvial systems. During the past 100 years, the Rio Puerco River Basin in central New Mexico has undergone a series of dramatic landscape changes caused by the incision of arroyos. Whether the incision was due to changing climatic conditions or changes in land use is unknown. Understanding the forces responsible for the incision is critical in planning restoration projects to return the basin to its "original state." USGS scientists are studying this system to provide resource managers with important data, information, and tools to help them in their decision making