Wetlands are a well-established and prolific source of atmospheric methane. Yet despite an abundance of seething swamps and flooded forests in the tropics, ground-based measurements of methane have fallen well short of the quantities detected in tropical air by satellites.
In 2011, Sunitha Pangala, a PhD student at The Open University, who is co-supervised by University of Bristol researcher Dr Ed Hornibrook, spent several weeks in a forested peat swamp in Borneo with colleague Sam Moore, assessing whether soil methane might be escaping to the atmosphere by an alternative route.
Sunitha Pangala said: "Methane emissions normally are measured by putting sealed chambers on the ground to capture gas seeping or bubbling from the soil. We also enclosed tree stems in chambers and the results were surprising. About 80 per cent of all methane emissions was venting through the trees."
The roots of trees, like all plants, need oxygen to survive. One strategy that trees use to cope in waterlogged soil is to enlarge porous structures, known as lenticels, in their stems to allow air to enter and diffuse to their roots. Pangala and colleagues have shown that these common adaptations in wetland trees are two-way conduits that also allow soil gas to escape to the atmosphere.
Dr Gauci said: "This work challenges current models of how forested wetlands exchange methane with the atmosphere. Ground-based estimates of methane flux in the tropics may be coming up short because tree emissions are never included in field campaigns."
The eight tree species investigated by the team are common in the tropics, including the vast Amazon Basin. Establishing whether tree-mediated emissions of methane are ubiquitous in tropical wetlands is now the focus of a new three-year Natural Environment Research Council grant to Dr Gauci and Dr Hornibrook that begins later this year.
'Trees are major conduits for methane egress from tropical forested wetlands' by Pangala S.R., Moore S., Hornibrook E.R.C., and Gauci V. in New Phytologist.
University of Bristol: http://www.bristol.ac.uk
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
A skin-eating fungus that infiltrated Europe through the global wildlife trade is threatening to inflict massive losses on the continent's native salamanders including extinction of whole species and could do the same in North America, scientists say.
A gray wolf was recently photographed on the north rim of the Grand Canyon in Arizona in what would be the first wolf sighting in the national park since the last one was killed there in the 1940s, conservation groups said on Thursday.
Two years after Sandy, researchers in New Jersey want to bring more powerful predictions to the people
In order to save the Amazon, it's not enough for deforestation to stop; areas that have been denuded also need recuperation. A Brazilian research scientist has released a report with the World Wildlife Fund that suggested actions to curb the effect of humans on the world's largest rainforest.
Smithsonian photographer Laurie Penland details the exhausting, but rewarding, work of scraping invasive species off the hull of a boat
Politicians who ignore message cannot in future say they take science seriously, open letter says
In the wake of Hurricane Sandy two years ago, shocking photos showed the huge extent of the destruction caused by the storm. Only days after the storm struck, before and after satellite images from Google revealed the widespread damage to coastal areas of New York and New Jersey. Last year, before and after photos showed progress but still a lot of work to be done.
Australian scientists say they have successfully tested a vaccine aimed at protecting wild koalas from chlamydia.
A startup that might have a record-breaking solar cell is in danger of going out of business.The power unit is a rectangular slab about the size of a movie theater screen. It’s mounted on a thick steel post, and equipped with a tracking mechanism that continuously points it at the sun. The slab is made of over 100,000 small lenses and an equal number of even smaller solar cells, each the size of the tip of a ballpoint pen. This contraption is part of one of the most efficient solar power devices ever made.
There are several captive breeding programs for pandas around the world; but one facility in China hopes to release the endangered animals back into the wild