Recent research by Saleska and several colleagues indicates that resilience may be true in the short term. During the 2005 drought, the Amazon's forest canopy became greener, suggesting increased photosynthetic activity. The lack of clouds would have provided more sunlight energy to the forest and the trees may have drawn water from deep in the soil, Saleska said.
The new project will delve further into this finding. The researchers will focus primarily on the trees response to drought using tower samplings of gases and aerosols, new data from satellites and modeling simulations.
An additional National Science Foundation grant for $308,000 will let the scientists conduct aircraft surveys using laser-based sensors to help determine whether the Amazon forests are releasing or taking up carbon dioxide.
The Amazon-PIRE study is based on the premise that we can study the feedbacks by 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 Brazil's Tapajos National Forest in 1999.
In addition to conducting field work in Amazonia, the project also will include experiments within Biosphere 2's gigantic controlled-environment facility near Oracle, Ariz. If drought doesnt cooperate in the Amazon, the team can always force a dry spell under glass.
There 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.
|Contact: Mari N. Jensen|
University of Arizona