A state-of-the-art Japanese satellite is helping UCSB researchers to study the Amazon rainforest from the comfort of their own offices.
Ecology, evolution and marine biology professor John Melack and Institute for Computational Earth System Science researcher Laura Hess published a report in the April 11 issue of the journal Nature, which reevaluates the way in which tropical forests work as ecosystems. The researchers used data from a Japanese satellite to make their evaluations, and their findings may have importance to environmentalists studying global warming and climate change.
“The question we are trying to answer is: Are tropical forests taking in more carbon dioxide than they are releasing?” Melack said.
The carbon dioxide release from waterways of worldwide tropical forests is three times higher than previously estimated. Melack, Hess and their co-authors found that Amazon waterways emit 500 million out of the 900 million metric tons of carbon dioxide produced by all tropical forests.
Dry regions of the forest take in roughly the same amount, creating a carbon dioxide balance.
The group has found that most of the carbon dioxide trapped in the waters of rivers, streams and flood plains is the result of decaying materials deposited into the waterways within the forests.
The results may help scientists to analyze how deforestation and other human activities affect the Amazon, and how these outside influences may lead to larger environmental problems like global warming.
“Now that we’ve identified another source of CO2 it makes the whole system appear a little bit more sensitive to disturbance,” said Jeff Richey, a University of Washington researcher and lead author of the Nature paper. “The land-water connection appears to be far more important than anyone thought.”
By accurately mapping the wetlands of the Amazon using data from Japan’s Global Rain Forest Mapping Project, researchers could calculate the amount of carbon dioxide released by waterways. Melack and Hess produced a high-resolution map of the Amazon wetlands, a task previously impossible due to inferior satellite technology. The map shows that up to 20 percent of the landscape is flooded each year.
“Accurately mapping the wetlands would not have been possible without the radar data from the Japanese Earth Resources Satellite that Japan provided for free,” Hess said.
The Japanese space agency provided Jet Propulsion Laboratories in Pasadena with the radar data. The laboratory in turn made the data public. The satellite is able to penetrate tree canopies and clouds showing whether a particular area is flooded or not.
The study is part of the Large Scale Biosphere-Atmosphere Experiment in Amazonia project led by the United States and Brazil, and sponsored by NASA.