Changes in the Asian monsoon have affected emissions of methane from the Tibetan Plateau over the last 6,000 years, finds a new paper.
The concentration of methane in the atmosphere has more than doubled over the past century, though it is very short lived compared to carbon dioxide and hasn't been considered much of a factor in climate change. Factors in methane levels include leaks from gas wells, increased rice cultivation and ruminant animals in the dairy and meat industry. It could also be caused partly by climate change feedbacks on natural processes, but that remains the subject of intense investigation.
The results focus on a single wetland from the Tibetan Plateau that experienced strong climate variations over the past 6,000 years. They show that during relatively dry intervals, the biomass of methane-producing microorganisms decreased while methane-consuming microorganisms apparently became more efficient. The combined result would have been less methane emission to the atmosphere.
The Tibetan Plateau experienced strong climate variations over the past six thousand years. Credit: University of Bristol
According to project leader and Director of the University of Bristol Cabot Institute Professor Rich Pancost, "What we have done is connect the dots, providing strong evidence for previous researchers’ inferences. In modern settings, methane emissions from dryer settings are generally low. Consequently, previous researchers have speculated that as the Asian monsoon became weaker over the past six thousand years, methane emissions also decreased. Here, we show that this is exactly what happened to this peatland on the Tibetan Plateau."
The authors used a combination of chemical tools to reconstruct the past changes in microbial populations. First author Yanhong Zheng said, "All organisms have cell membranes but the molecules that comprise those membranes differ, especially for microorganisms; if these molecules are preserved in soils or sediments, they act as molecular fossils – or biomarkers – for those organisms in the past. We can then quantify them and that gives insight into ancient microbial communities."
The authors focused on archaeol, a compound that likely derives from methanogens (or methane-producing organisms) in these settings. During a dry interval from six to four thousand years ago, its concentration decreased by about 50 per cent, suggesting that the methane producing community became much smaller, probably because these organisms favor wet habitats.
Pancost added, "This is only a single site, but our study has wider implication for how these systems work. The dry interval we studied arose from large scale changes in atmospheric circulation patterns, and just as past changes impacted methane emissions, so will future climate change."
Citation: Yanhong Zheng, Joy S. Singarayer, Peng Cheng, Zhao Liu, Xuefeng Yu, Paul J. Valdes, Richard D. Pancost, 'Holocene variations in peatland methane cycling associated with the Asian summer monsoon system', Nature Communications
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- We're Playing Classical Music All Wrong
- Football Physics: The Science Of Deflategate
- The Plot Of The Week: CMS Search For Majorana Neutrinos
- Superbugs: How Montezuma's Revenge Impacts Society Long After That Trip
- Is Glass A Solid Or A Liquid? Yes
- Atmospheric Warming Heats The Bottom Of Ice Sheets Also
- Deflate-gate: Cheating People versus a Flawed Pre-Game Process
- "Your article makes no sense! What if the pats heat their footballs up to 120 degrees before the..."
- "Thanks as usual for the update. A small typo: annichilate in the third paragraph. And a question..."
- "Error bars are the responsible thing to do. I don't see an aesthetic problem. Nice pix last week..."
- "I think a smaller market means a lot higher quality. We get so many terrible pop songs because..."
- "The air inside a leather football is not an ideal gas. That is what I meant.As far as the..."
- Sociologists discover young women and men prefer egalitarian relationships
- Citizen scientists have positive news for Puget Sound seabirds
- Sleeping on stomach increases risk of sudden death in epilepsy
- BPA exposure during pregnancy correlated to oxidative stress in child, mother
- Ventricular assist devices induce heart muscle regeneration