Peat circles
Photo: Tarmo VirtanenResearch carried out in the CARBO-North project has revealed that greenhouse gas emissions from tundra peatlands may be much more significant than previously thought. Maija Repo, with colleagues from the University of Kuopio, the University of Helsinki and the Komi Science Center, measured gas emissions from areas of frost-disturbed peat.

Globally, N₂O contributes to 6% of global warming and has been thought to originate mainly from agricultural and tropical soils. Arctic soils, especially unvegetated areas of bare peat caused by cryoturbation, could be expected to show high levels of N₂O emissions because there is no competition for nitrogen from vegetation or microbes.

Static chamber equipment
Photo: Simo JokinenMaija and her colleagues measured N₂O gas emissions using the 'static chamber' technique, in an area of subarctic tundra 70km from Vorkuta. They looked at 10 different types of surface but it was the peat circles that showed exceptionally high rates of N₂O emissions (up to 31 mg N₂O per m² each day). The total amounts emitted during the 6 month snow-free season were similar to those recorded for boreal croplands and tropical forests over a whole year.

Peat circles can be large in area (10-500 m²) and on the peat plateau in the tundra account for about 4% of the total area. Global warming is expected to lead to increased cryoturbation, which in turn would lead to more greenhouse gas N₂O. This is known as a 'positive feedback' to climate change.

More details of the research can be found in an article recently published online in Nature GeoScience, details below.

Repo, M.E., Susiluoto, S., Lind, S.E., Jokinen, S., Elsakov, V., Biasi, C., Virtanen, T. & Martikainen, P.J. (2009) Large N₂O emissions from cryoturbated peat soil in tundra. Nature Geoscience Online Feb 15th 2009.
10.1038/ngeo434

See also: New Scientist article

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