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Changes in Methane Flux along a Permafrost Thaw Sequence on the Tibetan Plateau
- Source :
- Environmental sciencetechnology. 52(3)
- Publication Year :
- 2017
-
Abstract
- Permafrost thaw alters the physical and environmental conditions of soil and may thus cause a positive feedback to climate warming through increased methane emissions. However, the current knowledge of methane emissions following thermokarst development is primarily based on expanding lakes and wetlands, with upland thermokarst being studied less often. In this study, we monitored the methane emissions during the peak growing seasons of two consecutive years along a thaw sequence within a thermo-erosion gully in a Tibetan swamp meadow. Both years had consistent results, with the early and midthaw stages (3 to 12 years since thaw) exhibiting low methane emissions that were similar to those in the undisturbed meadow, while the emissions from the late thaw stage (20 years since thaw) were 3.5 times higher. Our results also showed that the soil water-filled pore space, rather than the soil moisture per se, in combination with the sand content, were the main factors that caused increased methane emissions. These findings differ from the traditional view that upland thermokarst could reduce methane emissions owing to the improvement of drainage conditions, suggesting that upland thermokarst development does not always result in a decrease in methane emissions.
- Subjects :
- geography
geography.geographical_feature_category
Plateau
010504 meteorology & atmospheric sciences
Global warming
Growing season
Permafrost
Wetland
General Chemistry
010501 environmental sciences
Atmospheric sciences
Tibet
01 natural sciences
Methane
Thermokarst
chemistry.chemical_compound
Lakes
Soil
chemistry
Environmental Chemistry
Environmental science
Water content
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 15205851
- Volume :
- 52
- Issue :
- 3
- Database :
- OpenAIRE
- Journal :
- Environmental sciencetechnology
- Accession number :
- edsair.doi.dedup.....967eb25b6a2c50174641ac5095863604