Nature highlights the results of Brazilian research program on Amazonia

A review article published in the January 19 edition of Nature magazine synthesizes the results of the studies performed over the last 20 years in the Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA) coordinated by the National Institute of Amazonian Research (INPA).

By Fábio de Castro

Agência FAPESP – A review article published in the January 19 edition of Nature magazine synthesizes the results of the studies performed over the last 20 years in the Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA) coordinated by the National Institute of Amazonian Research (INPA).

According to the article, the LBA has identified signs that the south and east sections of the Amazon Rainforest are undergoing a transition to a regime of biophysical disturbances, with changes in the hydrologic and energy cycles.  

The LBA was initiated 20 years ago with the goal of understanding the biogeochemical processes of the forest and increasing knowledge about the relationships between soil use and the Amazonian climate. The project has generated more than 2,000 publications and some 300 theses, according Paulo Artaxo of the Applied Physics Department at the Institute of Physics at the Universidade de São Paulo (USP). Artaxo is one of the experiment coordinators and is a coauthor of the article. He is member of the coordination for The FAPESP Research Program on Global Climate Change.

“The LBA made an important contribution to uncovering the physical, chemical and biological processes responsible for the forest’s extremely complex workings. These processes range from climate dynamics to the interaction between forest biology and its intrinsic function from the point of view of heat, energy, water vapor and carbon flows,” Artaxo told Agência FAPESP.

He reports that the LBA helped show that the Amazon is highly resilient, meaning it can overcome a critical situation and return to its excellent natural state. However, the experiment also concluded that there are limits to this capacity.

 “Over its evolutionary process, the forest developed mechanisms that allow it to return to its point of equilibrium. There is a limit, however, that can be exceeded depending upon the level of disturbance that man provokes in the ecosystem. This delicate equilibrium must be respected so that the process of occupying Amazonia doesn’t further destabilize the way the ecosystem works,” he affirmed.

Artaxo states that the LBA made it possible to identify where these limits lie and what the consequences would be if they were exceeded. “Deforestation and the resulting changes in water vapor, energy and aerosol flows disturb the hydrologic cycle. This disturbance sets off a chain of reactions resulting in hydric stress. The LBA had the merit of uncovering some of these mechanisms,” he said.

The article highlights that agricultural expansion and climate variability have become significant agents of disturbance in the Amazon basin. The LBA studies have demonstrated the considerable resilience of Amazonian forests to moderate annual drought, but they also show that interactions between deforestation, fire and drought potentially lead to carbon storage losses and changes in regional precipitation patterns and river discharge.

“Although the basin-wide impacts of land use and drought may not yet surpass the magnitude of the natural variability of hydrologic and biogeochemical cycles, there are some signs of a transition to a disturbance-dominated regime. These signs include changing energy and water cycles in the southern and eastern portions of the Amazon basin,” he affirmed.

Aside from the review article—which according to Artaxo was the result of one of the synthesis workshops of the LBA experiment—Nature invited him to publish an article in the World View section of the same edition of the magazine, which is dedicated to presenting scientists’ personal opinions. The article, titled “To break barriers in climatic research,” presents the Brazilian researcher’s vision of the process of implementing the LBA.

“The editors proposed that I write it because they were interested in knowing how such a large and complex experiment could have been implemented in such a logistically inaccessible region in a developing country like Brazil over 20 years. No other nation has been able to implement an experiment of this size up until now,” he stated.

Artaxo reports that the LBA experiment not only generated ample and solid scientific production but also earned considerable visibility abroad and contributed significantly to the formation of human resources in many areas of research. “The success of the LBA is something Brazil should be proud of. The experiment will be able to serve as a guide for the development of similar initiatives in other developing countries,” he said.

Artaxo notes that many of the thematic projects of FAPESP are directly associated with the LBA, especially in areas such as the study of carbon and aerosol flows, changes in the use of soil, the water cycle and climate modeling.

Contributors to the review article included researchers from Inpa, USP, Embrapa (the Brazilian Agricultural Research Corporation), the Universidade Federal do Acre (UFAC), the Universidade de Brasília (UnB), the Universidade Federal de Minas Gerais (UFMG), the Imazon Center of Geotechnology, the Porto Rico Botanical Gardens and the following North-American institutions: Columbia University, Harvard University, the University of Maryland, the Center for Ecological Analysis and Synthesis and the Woods Hole Research Center.

The article "The Amazon basin in transition," (doi:10.1038/481239a) by Paulo Artaxo and others, can be read by Nature subscribers at www.nature.com/news/break-down-boundaries-in-climate-research-1.9844.