Introduction
NEW! Nature article just published, April 11, 2002: Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2 (Adobe pdf file).
NEW! Nature News and Views - Carbon goes with the flow (Adobe pdf file).
The objective of our CAMREX (Carbon in the Amazon River Experiment) project for two decades has been to determine the sequence of processes that controls the distributions and transformations of water and bioactive elements (C, N, P, and O) in the Amazon River system. The basic questions we are addressing are:
- How are biogeochemical signatures of the river system imparted by aggregated land surfaces, and at what rates and scales?
- How are the signatures of land-derived and in-situ processes modified during transit through the river system?
- What role does the evasion (outgassing) of CO2 from the river system to the atmosphere play in the carbon cycle of moist tropical forests?
Our overall perspective in CAMREX is that the Amazon is a test case for developing extendable models of how hydrologic and biogeochemical cycles are coupled at regional to continental scales in the humid tropics. 
Our studies serve the dual purposes of gaining a broad mechanistic understanding, and of establishing data baselines needed to assess anthropogenic perturbations to these globally critical and ecologically complex systems. As documented in over 100 publications, the resulting CAMREX dataset represents a time series unique in its length and detail for very large river systems. Our studies serve the dual purposes of gaining a broad mechanistic understanding of large river networks, and of establishing data baselines needed to assess future anthropogenic perturbations to these globally critical and ecologically complex systems.
Funded primarily by the US NSF and NASA and Brazilian FAPESP, CAMREX is a joint project of the University of Washington (UW, Seattle) and the Centro de Energia Nuclear na Agricultura (CENA, Piracicaba), with colleagues at the Instituto Nacional de Pesquisas da Amazônia and other Brazilian and U.S. institutions.