Permafrost Thawing and Vegetation Change Effects on Cryoturbation Rates and C and CH4 Dynamics.
Funded by Department of Energy
Permafrost soils cover 8.6% of the Earth land area and contain at least one third of the global soil organic carbon pool in the upper 1m where C pools are protected from decomposition by cold temperatures. It has been recognized that rapid climate warming in the Arctic is contributing to several structural and functional changes in tundra ecosystems, possibly through increases in winter precipitation. Greater snow cover and higher surface temperatures in the Arctic are likely to expose C stored over millennia to decomposers, resulting in a major source of C to the atmosphere. However, greater winter snow cover is also likely to contribute to the expansion of shrubs into tundra ecosystems, possibly by affecting soil microbial carbon and nutrient cycling under deeper snow and thus increasing net primary production, the overall net result being unknown. Since the mechanisms governing permafrost C cycle in response to climate and biotic changes are not well understood, the primary objective of the proposed research is to determine how increasing soil thaw depth and changes in vegetation composition contribute to C storage capacity by affecting soil mixing (cryoturbation) rates, soil C cycling rates (CH4 and CO2), microbial community composition and the relative importance of different soil organic matter stabilization mechanisms of arctic ecosystems. We will study these interactions in two existing snow manipulation experiments of varying duration at Toolik Lake, northern Alaska.
- Tim Filley
- Miquel Gonzales-Meler, University of Illinois;
- Kunda Taneva, University of Alaska, Anchorage
- Jeffrey Wekjer, University of Alaska, Anchorage
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