Scientists Take Stock of Research on the Dynamics of the Amazon Rainforest

Researchers affiliated with GOAmazon and the Large Scale Biosphere-Atmosphere Experiment in Amazonia presented the findings of projects conducted in recent years and discussed priorities for 2017-21 (photo: Neil Palmer-CIAT/Wikimedia Commons)

The results of 20 research projects devoted to investigating the dynamics of the Amazon Rainforest and to understanding how it is affected by human activities and climate change were presented at a meeting held on November 28-30 at the National Institute for Research on Amazonia (INPA) in Manaus, Amazonas State, Brazil.

Six projects are part of the Green Ocean Amazon (GOAmazon) field campaign, which is supported by FAPESP, the United States Department of Energy (DoE) and the Amazonas State Research Funding Agency (FAPEAM), among other partners. The remaining 14 projects are linked to a call for proposals issued three years ago by the National Council for Scientific & Technological Development (CNPq) under the auspices of the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA), which is led by INPA, a body subordinated to Brazil’s Ministry of Science, Technology, Innovation & Communications (MCTIC).

“These projects are in the concluding stages, and we organized the meeting to share results; identify gaps in research on the Amazon; foster collaboration among researchers; and, on that basis, get into a position to plan the LBA scientific agenda for the years 2017 to 2021,” said Niro Higuchi, the program’s scientific manager.

Future priorities will include studies of the carbon cycle, particularly the role of methane, and studies of water in Amazonia. “We need a better understanding of the processes that occur underground, including both these physical and chemical matters and also the biological part of the system,” he said.

The highlights among the results presented at the event were advances achieved in chemistry of the atmosphere. “Before these projects, we didn’t have a clear idea of how the pollution created by a city like Manaus, which has 2 million inhabitants and is surrounded by immense areas of forest, interacts with natural emissions from plants, such as volatile organic compounds (VOCs). The results of these projects show that there is an interaction and that it has consequences for the functioning of the ecosystem. That opens up a series of new questions to be answered,” Higuchi said.

Important progress has also been made in physiology. “Some studies enable us to understand how plant metabolism works under different conditions, such as primary or secondary forest, isolated fragments, or pasture. This information will be fed into the models to improve their parameterization. Our main challenge is refining climate models to reduce uncertainty,” he explained.

Floodable areas

According to data presented by Bruce Forsberg, a researcher affiliated with INPA and a principal investigator for one of the projects selected by CNPq in its call procedure, the Amazon’s floodable areas are major sources of greenhouse gases, especially carbon and methane. The project measured variables relating to the dynamics of gases in Janauacá Lake (110 km from Manaus). Fosberg’s group is now modeling the data to feed it into climate change and land use scenarios.

According to Forsberg, the influence of climate change on river flow rates in Amazonia and floodable areas has already been modeled. Preliminary results show that in eastern Amazonia, where there are plans to build dams for hydropower, flow rates will be lower in both the dry and the wet seasons, so those plans may prove unviable.

Jochen Schogart, another researcher at INPA, presented the findings of a research project that has evaluated the disturbance to blackwater-flooded forest areas (igapós) resulting from implementation of the Balbina hydroelectric development. He said that changes in the structure and composition of the flora in floodable areas have been observed.

Also present at the meeting was Paulo Artaxo, a professor at the University of São Paulo’s Physics Institute (IF-USP), a researcher affiliated with the LBA program and one of the creators of GOAmazon, who highlighted studies designed to assess the effects of flooded areas on the Amazon’s carbon balance.

“One LBA project identified trees that are over 1,000 years old in flooded areas, such as those near Mamirauá, a nature reserve, and the Ramsar Site west of Manaus. This was a considerable surprise: we thought ancient trees couldn’t survive in flooded areas because wood decomposes so quickly there. This new knowledge changes the way we calculate tree mortality rates in the Amazon and the region’s carbon balance,” Artaxo said.

He also pointed to studies performed after the severe droughts that occurred in 2005 and 2010 and strongly altered the carbon cycle. “More research is required for a better understanding of the impact of extreme climate events on the carbon cycle,” he said. “We need to process the data and analyze it with care so that we can achieve a clearer vision of the likely effects on the Amazon of a scenario in which extreme climate events are frequent.”

Another priority, in his view, is research on interactions between natural aerosols and those caused by human activity and on how these interactions influence cloud formation and the hydrologic cycle in the Amazon.

“The GOAmazon field campaign ends in December, but we’ll be analyzing the data collected for some time,” Artaxo said. “Some 40 articles linked to the campaign have been published to date, and at least another 50 are being prepared.”

A number of important questions about Amazonia still need to be answered, he added, but there is considerable uncertainty about how this research will be funded in the coming years.

According to Higushi, funding will continue as before for the LBA. It has typically had an annual budget of R$3 million, and this should again be the case in 2017.

“Research in Amazonia cannot and must not stop,” Higushi said. “We’re prioritizing routine collection. Specific campaigns will have to become less frequent.”