News
General Interest
UA scientists receive $2.5 million grant to study the future of Amazon forests
November 16, 2007
By Stephanie Doster
Biosphere 2 interior
Photo courtesy of Biosphere 2
An international team of scientists led by a University of Arizona professor has received a five-year, $2.5 million grant from the National Science Foundation to improve society’s understanding of the future of the Amazon forests under climate change and provide an international education to science students.
The project will combine scientific observations in the Amazon with experiments in the tropical forest biome of the UA’s new program at Biosphere 2, the unique large-scale earth system science facility near Oracle, Ariz.
Because the forests of the Amazon basin form the largest contiguous, intact tropical forest on Earth, they act as a storehouse of carbon that could influence the path global climate change takes, said Scott Saleska, assistant professor of ecology and evolutionary biology, Biosphere 2 science steering committee member and the project’s principal investigator.
“Understanding the impacts climate change will have on the Amazon is important because a prominent global climate model suggests that increased drought will cause these forests to collapse. Other models predict resilience,” Saleska said. “The question is, which is right? This new project will allow us to start answering that question. The answer is critically important: a collapse obviously would be devastating to the Amazon—an area with such mystical appeal and tremendous biodiversity—but it also could be bad news for climate change globally because all the carbon in those trees would go into the atmosphere as carbon dioxide, amplifying climate change.”
The Partnerships for International Research and Education (PIRE) grant is also designed to provide a new generation of culturally-experienced scientists with the knowledge they will need to address global environmental problems. The grant combines international collaboration with interdisciplinary undergraduate and graduate training in earth system science and remote sensing and modeling. Students will work in the Amazon forest in an annual field course in tropical ecology and biogeochemistry, and they will conduct related experiments in Biosphere 2. They also will have the opportunity to work with Brazilian scientists and students through exchanges at Brazilian scientific institutions.
The North and South American partnership includes the UA; Harvard University; and, in Brazil, the University of São Paulo; the Federal University of Pará; the National Institute for Amazonian Research (INPA); the Brazilian Agricultural Research Agency (EMBRAPA); and Museu Paraense Emilio Goeldi, which runs one of the oldest field research stations in the Amazon.
At the UA, Alfredo Huete, professor of soil, water and environmental science, and W. James Shuttleworth, professor of hydrology and water resources and atmospheric sciences, are co-principal investigators. A number of other UA researchers also will participate in the project, including Institute for the Study of Planet Earth (ISPE) faculty members Brian Enquist and Biosphere 2 director Travis Huxman, ecology and evolutionary biology; Tim Finan, Bureau of Applied Research in Anthropology; Joellen Russell, geosciences; and Scott Whiteford, director of UA’s Center for Latin American Studies. Saleska, Huete, and Shuttleworth also are affiliated with ISPE.
The researchers will focus primarily on the trees’ response to drought using remote sensing, tower samplings of gases and aerosols, new datasets derived from satellites, and modeling simulations. A separate but related National Science Foundation grant for $308,000 will also allow scientists to conduct aircraft surveys using laser-based sensors to help determine whether forests are emitting or taking up carbon dioxide.
To grow, trees must take up carbon dioxide, which reduces the levels of atmospheric carbon dioxide. In the climate model that predicts a collapse, Saleska explained, the leafy, dense forest will slow photosynthesis when a drought begins, triggering a feedback loop. As plant growth slows more and more, the forest removes less and less carbon dioxide from the atmosphere. That build-up of carbon dioxide would increase global warming and hasten the forest's collapse.
Recent work by Saleska and several colleagues, however, indicates that the opposite may be true in the short-term. During the 2005 drought, the forest canopy became greener, suggesting increased photosynthetic activity by trees that perhaps drew water from deep in the soil, Saleska explained.
“The PIRE study is based on the premise that we can study the feedbacks looking in some detail at interannual variation over a roughly ten-year period,” said Saleska, who began collecting data in the Amazon after first visiting the Tapajos National Forest there in 1999.
In addition to working in the field, the project will also take researchers and students to the tropical forest biome in Biosphere 2, an enormous greenhouse that the UA leases. If drought doesn’t cooperate in the Amazon, the team can always force a dry spell under glass.
“We can make the weather be what we want it to be,” Saleska said. “We can induce a big drought, observe what it does, and learn how the vegetation responds to the dry conditions.”