This project will support U.S. scientists to participate in a SCOPE sponsored workshop that will address integration of terrestrial and aquatic phosphorus cycles in the Amazon Basin of South America. The goal of the workshop is to assemble and integrate data on the phosphorus cycle for the Amazon Basin. The workshop will address sources, sinks and fluxes of P, mechanisms of supply of biologically active P, and evaluate the environmental effects of current and projected use of phosphorus in relation to biogeochemical cycles of carbon, nitrogen, and sulphur. This information will be integrated in a regional analysis. The workshop will bring together recognized experts from several disciplines to evaluate current understanding of phosphorus cycling in the Amazon Basin. The products of the workshop will be 1) a publication of the position and data papers presented, 2) identification of areas where careful management of phosphorus resources will be required to optimize food and fiber production and minimize hazard in various environments, and 3) development of a conceptual model and extension of a simulation model to integrate existing knowledge and develop a better understanding of P cycling in relation to carbon, nitrogen and sulphur in the Amazon Basin.