It is soil bacteria that release methane into the atmosphere and not the plants themselves, a researcher with the University of South Australia says.
Back in 2006 it was asserted in an article in Nature magazine that plants were responsible for up to 45 per cent of the methane produced in the world's atmosphere.
AdvertisementSo Dr.Ellen Nisbet, a molecular biologist with the varsity, took up a comprehensive investigation into the issue and found out that plants were only a passive transmitter of the methane present in other places - - for example methane in water, soaked into the soil, could be taken up by a plant and released.
Dr.Nisbet's team determined that methane was not produced by plants and but by soil-based bacteria.
"At a time when people are so concerned about the environment and the problem of global warming, any assertion that plants could be responsible for an increase in methane was really alarming," Dr Nesbit said.
"Of particular concern in the Keppler, Hamilton, Brass and Röckmann paper published in Nature was the inference that invaluable areas of tropical rainforest were emitting big amounts of methane that could be tracked using satellite imagery. "
"I'm the daughter of an atmospheric chemist and am a molecular biologist myself, so my first thought was that it was very strange. So, I got together a group of colleagues to investigate.
With fellow researchers from Cambridge University, the Universities of London, Stockholm, Oxford and Bristol, Dr.Nesbit's team set up a range of experiments to clear the record for plants.
"In the light of improved procedures for obtaining methane concentrations from satellite data, we found that clouds were a potential source of bias in the original study. So it seems very unlikely that tropical rainforests are producing vast amounts of methane."
The results of the study, Emission of Methane from Plants, were published in Transactions of the Royal Society this week.
Dr Nisbet says she hopes the new research will get wide coverage and help play a role in rebuilding plants' reputation.
"Forests are immensely precious and growing plants remove enormous amounts of carbon dioxide from the atmosphere each day through photosynthesis - carbon dioxide that would otherwise be causing global warming," she said.
"Plants are a life source fundamental to our ongoing well being."