The University of Arizona Brazilian Partners Harvard University The University of Arizona

Tapajós Carbon Cycle and Climate


Tapajós Carbon Cycle Studies - Understanding tropical vegetation-climate interactions in the Amazon basin

Our research focuses on fundamental questions regarding regional carbon cycling in the tropics.  We aim to understand how climate has an effect on ecosystem functioning and identify seasonal anomalies and mean inter-annual fluctuations based on the forest responses. Our current Amazon project research -- supported by NSF Partnership for International Research and Education (Amazon-PIRE) and building on the strong legacy of support from NASA – emphasizes local controls on carbon cycling in old-growth Amazon forests given its significance on the terrestrial carbon balance. Our goal is to build upon ongoing investigations of how forest demography and disturbance dynamics control carbon cycling in old-growth Amazon forests. This has been accomplished by integrating 10+ years of eddy covariance observations of net ecosystem exchange of CO2 and ground based forest inventories to extrapolate our understanding of local controls on carbon cycling in old-growth Amazon forest to derive landscape and regional scale carbon balance.

A bottom to top approach that incorporates the measurement of major compartments of biomass stocks (dead and alive) is used  to quantify the role of natural disturbances and recovery processes in the terrestrial flux of carbon as well as vegetation-climate interactions in Amazonian forests and is used to validate the long term eddy flux data. We use permanent sample plots as a standardized method for forest monitoring that allows us to track changes in forest C stocks, correlating observed carbon loss to ecological mechanism: the disturbance-recovery dynamics thought characteristic of old-growth forest but not yet observed in tropical carbon balance studies (Rice et al., 2004; Pyle et al., 2008).

Our ground-based and flux measurements at the Tapajós National Forest near Santarém show that the net CO2 flux from this tower shows the forest losing carbon, an observation not previously seen in the Amazon that will help reconcile previous Amazon carbon estimates of 1-3 Pg C yr-1, an overestimation, as comparable to the whole global terrestrial carbon sink (Saleska et al., 2003)). This work is part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA).


Pyle, E.H., Santoni, G.W., Nascimento, H.E.M., Hutyra, L.R., Vieira, S., Curran, D.J., Haren, J., Saleska, S.R., Chow, V.Y., Carmago, P.B., Laurance, W.F., Wofsy, S.C., 2008. Dynamics of carbon, biomass, and structure in two Amazonian forests. Journal of Geophysical Research-Biogeosciences 113, G00B08, 20 PP.

Rice, A.H., PYLE, E.H., Saleska, S.R., Hutyra, L.R., Palace, M., Keller, M., Camargo, P.B. de, Portilho, K., Marques, D.F., Wofsy, S.C., 2004. Carbon balance and vegetation dynamics in an old-growth Amazonian forest. Ecological Applications 14, S55–S71.

Saleska, S.R., Miller, S.D., Matross, D.M., 2003. Carbon in Amazon forests: Unexpected seasonal fluxes and disturbance-induced losses. Science 302, 1554–1557.


Tara Woodcock, Mauricio Ferreira, Scott Stark, Bradley Christoffersen, Jin Wu, Lissandra Souza, Suellen Marostica (INPA-Manaus),

Project Collaborators

Kenia Wiedemann, Post-doctoral Fellow, University of Arizona;  Natalia Restrepo-Coupé, Research Fellow, University of Technology, Sydney, Australia; Joost van Haren, Assistant Research Professor at Biosphere 2, University of Arizona; Luciana F. Alves, Post-doctoral Fellow, University of Arizona ; Alfredo Huete, Professor, University of Technology, Sydney, Australia; Jim Shuttleworth, Professor, University of Arizona;  Steven Wofsy, Professor, Harvard University; , Plinio Camargo, Professor, University of São Paulo, CENA, Piracicaba Campus, Brazil; Humberto da Rocha, Professor, University of São Paulo, Paulo Artaxo Professor, University of São Paulo, Brazil;  Raimundo Cosme de Oliveira, Researcher, Empresa Brasileira de Pesquisa Agropecuaria (Embrapa); Rodrigo da Silva, Professor, Federal University of East-Pará, Santarém, Brazil; Antonio Manzi, Researcher, National Institute for Amazonian Research (INPA), Manaus, Brazil; Rafael Oliveira, Assistant Professor, University of Campinas (UNICAMP), Brazil.   Many others in Brazil, including researchers of the Museu Goeldi (Belém, Pará), and the Biological Dynamics of Forest Fragments Project (Manaus, Amazonas).