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THE LBA PROJECT: NUTRIENT CYCLES AND TRACE GAS EXCHANGE IN SAVANNAS OF CENTRAL BRAZIL
Citation:
ZEPP, R. G., R. A. BURKE, M. MOLINA, K. KISSELLE, M. BUSTAMANTE, A. KOZOVITS, AND A. PINTO. THE LBA PROJECT: NUTRIENT CYCLES AND TRACE GAS EXCHANGE IN SAVANNAS OF CENTRAL BRAZIL. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Impact/Purpose:
The overall objective of this task is to develop quantitative relationships for assessing the vulnerability of aquatic ecosystems (freshwater and coastal) and their services to global change. The task will contribute experimental and modeling tools for assessments of the interactions of global climate and UV changes with coral reefs and selected watersheds and estuaries in the U.S. and Brazil These activities are contributing to two APGs in the ecosystems focus area of the Global Change Research Multiyear Plan: the 2008 APG (APG 2) on developing information and tools that managers will use in their decision-making about how to adapt to the effects of global change on aquatic ecosystems; and the 2010 APG (APG 3) on providing information and models that will support development of biocriteria for corals. One major task objective is to assess interactions of global warming and UV exposure that are contributing to the observed coral bleaching and disease. Our lab is working with scientists at the NHEERL Gulf Ecology Lab to characterize UV exposure and effects at several coral reef sites in the Florida Keys. This collaboration will contribute to one ERD APM in 2006 and three joint NERL-NHEERL APMs in the 2008 - 2010 period. Other research is examining the effects of changing climate and UV on microbial activity in waters close to beaches in the U.S. Work is being completed on the interactions of land use and climate changes with the ecological functioning of streams in watersheds of the southeastern U.S. The task also includes two sub-tasks that are funded mainly by funds-in IAGs. One sub-task funded by NASA involves research in central Brazil that is part of the Large Scale Biosphere Atmosphere Experiment (LBA). This work involves a close collaboration between EPA and a group of scientists from the Department of Ecology, University of Brasilia, Brazil. The objectives of this project are to assess the impacts of land use and climatic changes on soil nutrient cycles and microbiota, trace gas exchange and water quality in the Brazilian cerrado. Another sub-task funded by the Office of Naval Research is examining interactions between nitrogen and organic substances in aquatic ecosystems that produce the colored dissolved organic matter (CDOM) that controls penetration of solar UV radiation into coastal waters.
Description:
The Cerrado of central Brazil is one of the largest savannah regions on Earth. The stressors affecting ecosystems in this region, including deforestation, fire, soil degradation, unwise agricultural practices, climate change, and urbanization, are all experienced in many U. S. ecosystems. Intense agricultural activities such as land clearing for soybean cultivation and cattle farming are rapidly changing the Cerrado. EPA scientists have been collaborating with ecologists from the Universidade de Brasmlia (UnB) in central Brazil to determine how several of these stressors are affecting soil nutrient cycling, decomposition and the soil-atmosphere exchange of carbon- and nitrogen-containing trace gases. The research is contributing data and scientific understanding for the development of models that describe these stressor-ecosystem interactions.