Fire in the Amazon
Amazonian forests are vulnerable to repeated and coupled perturbations
(Press-News.org) Intentional burning in tropical forests has accounted for nearly 20% of all greenhouse-gas emissions since preindustrial times and will have major implications for Earth's climate and biodiversity in years to come. To better understand the complex dynamics surrounding these fires, a team of researchers led by Jennifer K. Balch, of the University of Colorado-Boulder, conducted a six-year controlled burn experiment in an Amazonian rainforest block located in Mato Grasso, Brazil. The results are described in an article that is part of BioScience's just-released Special Section on Tropical Forest Responses to Large-Scale Experiments, in the September 2015 issue.
The researchers tested three fire regimes--annual, triennial, and no burning. In the first three years of the study, trees in the experimental plots proved resilient to the effects of fire, with low mortality in all of the areas. However, an extreme drought in 2007 led to more-severe fires and contributed to an abrupt increase in tree deaths. In the triennially burned plot, greater daytime drying allowed firelines to continue burning overnight, despite increased night-time air moisture and lower temperatures. The authors report that this could "explain how widespread forest fires can occur in Amazon forests."
In light of the coupled effects of fire and drought, the authors note that "seasonal closed-canopy Amazon forests can sustain initial fire disturbance but not repeated or coupled disturbances." They also found that the severe drought-fire effects led to a partial grassland transition, which fueled future burns. The authors highlight that this dynamic, if seen at larger scales, could have "substantial consequences for future flammability because grasses more than tripled fine fuel loads compared to forest litter."
Additionally, the authors argue that this grass incursion "will lead to a lower carbon state where observed aboveground forest carbon stocks may be reduced by 90%." Such changes "can potentially reverse the carbon sink observed in intact Amazon forests," with potential global-scale effects.
BioScience, published monthly by Oxford Journals, is the journal of the American Institute of Biological Sciences (AIBS). BioScience is a forum for integrating the life sciences that publishes commentary and peer-reviewed articles. The journal has been published since 1964. AIBS is a meta-level organization for professional scientific societies and organizations that are involved with biology. It represents nearly 160 member societies and organizations. Follow BioScience on Twitter @BioScienceAIBS.
Oxford Journals is a division of Oxford University Press. Oxford Journals publishes well over 300 academic and research journals covering a broad range of subject areas, two-thirds of which are published in collaboration with learned societies and other international organizations. The division been publishing journals for more than a century, and as part of the world's oldest and largest university press, has more than 500 years of publishing expertise behind it. Follow Oxford Journals on Twitter @OxfordJournals
ELSE PRESS RELEASES FROM THIS DATE:
LA JOLLA--When you're taking a walk around the block, your body is mostly on autopilot--you don't have to consciously think about alternating which leg you step with or which muscles it takes to lift a foot and put it back down. That's thanks to a set of cells in your spinal cord that help translate messages between your brain and your motor neurons, which control muscles.
Now, for the first time, researchers have created a method to watch--in real time--the activity of those motor neurons. The new technology, developed by Salk scientists and published in Neuron, is ...
Georgia Institute of Technology researchers have developed a new artificially intelligent system that crowdsources plots for interactive stories, which are popular in video games and let players choose different branching story options.
With potentially limitless crowdsourced plot points, the system could allow for more creative stories and an easier method for interactive narrative generation. Current AI models for games have a limited number of scenarios, no matter what a player chooses. They depend on a dataset already programmed into a model by experts.
Tropical Storm Fred is losing its punch. Satellite imagery shows that there are no strong thunderstorms developing in the tropical storm indicating that the storm is weakening.
The RapidScat instrument that flies aboard the International Space Station measured Tropical Storm Fred's winds on September 1 at 4 a.m. EDT. RapidScat saw that the strongest winds tightly circled the center and were on the northern side of the storm, as strong as 24 and 27 meters per second (53.6 mph/ 86.4 kph and 60.4/97.2 kph).
On September 1 at 13:00 UTC (9 a.m. EDT) the MODIS instrument ...
High water tables can be a boon to crop yields
A high water table - usually a bane to crop yields - can provide much-needed water during drought and to crops planted in coarse-grained soils, found a new study published online in Water Resources Research.
3-D maps illustrate formation of the Hangai Dome in central Mongolia
Scientists used 1.7 million seismic wave measurements from 227 earthquakes across East Asia to create animated 3-D images of subsurface rock formations under the Hangai Dome in central Mongolia as part of their recent study accepted in Geophysical ...
A new study by WCS (Wildlife Conservation Society) has found that coral reef diversity 'hotspots' in the southwestern Indian Ocean rely more on the biomass of fish than where they are located, a conclusion that has major implications for management decisions to protect coral reef ecosystems.
Using data gathered over a 12-year period from nearly 270 coral reefs across the southwestern Indian Ocean, the WCS study found that the highest conservation priorities in the region should be reef systems where fish biomass exceeds 600 kilograms per hectare. This finding conflicts ...
Can water ever be too clean? If the intent is to store it underground, the answer, surprisingly, is yes. In a new study, Stanford scientists have shown that recycled water percolating into underground storage aquifers in Southern California picked up trace amounts of arsenic because the water was too pure.
The research, published online in the journal Environmental Science & Technology, sheds light on a poorly understood aspect of groundwater recharge with purified recycled water, namely the potential mobilization of arsenic. Arsenic is a naturally occurring element that ...
ATLANTA - Sept. 2, 2015 - The number of men with breast cancer who undergo surgery to remove the unaffected breast has risen sharply, according to a new report by American Cancer Society and Dana Farber Cancer Institute researchers. The report, appearing in JAMA Surgery, is the first to identify the trend, which mirrors a trend seen in U.S. women over the past two decades.
Breast cancer in men is rare, accounting for only about 1 percent of all cases in the United States. In women (particularly younger women), the use of contralateral prophylactic mastectomy (CPM) surgery ...
Genes are not only important for regular memory performance, but also for the development of Alzheimer's disease. Researchers at the University of Basel now identified a specific group of genes that plays a central role in both processes. This group of molecules controls the concentration of calcium ions inside the cell. Their results appear in the current issue of the journal JAMA Psychiatry.
Intact memory capacity is crucial for everyday life. This fact becomes apparent once a memory disorder has developed. Alzheimer's disease is the most common cause of age-associated ...
WASHINGTON, DC, September 2, 2015 -- Social scientists have long argued documentary films are powerful tools for social change.
But a University of Iowa (UI) sociologist and his co-researchers are the first to use the Internet and social media to systematically show how a documentary film reshaped public perception and ultimately led to municipal bans on hydraulic fracking.
By measuring an uptick in online searches as well as social media chatter and mass media coverage, Ion Bogdan Vasi, an associate professor of sociology at the UI and corresponding author of a new ...
A new study of more than 300 women suggests that exposure to certain phthalates -- substances commonly used in food packaging, personal-care and other everyday products -- could be associated with miscarriage, mostly between 5 and 13 weeks of pregnancy. The research, appearing in the ACS journal Environmental Science & Technology, is the first epidemiological study on non-work-related exposure to phthalates to provide evidence for the possible link among a general population.
Out of concern over the potential health effects of phthalates, the U.S. has banned six of these ...
LAST 30 PRESS RELEASES: