Multiscale Soil Carbon Distribution in Two Sub-Arctic Landscapes

• Main Author: Wayolle, Audrey A.J.
• Other Authors: Wookey, Philip A., Williams, Mat, Wilson, Clare, Scottish Alliance for Geosciences Environment and Society (SAGES), School of Natural Sciences, Biological and Environmental Sciences
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Stirling 2011
• Subjects: carbon; Arctic soils; multiscale; sub-Arctic; tundra heath; birch forest; tundra forest ecotone; sampling scheme; Abisko; Kevo; Climatic changes Observations; Paleoclimatology; Arctic; Global warming; permafrost; Tundra; Lapland
• Online Access: http://hdl.handle.net/1893/6502; http://dspace.stir.ac.uk/bitstream/1893/6502/1/WayolleThesis.pdf

In recent years, concern has grown over the consequences of global warming. The arctic region is thought to be particularly vulnerable to increasing temperatures, and warming is occurring here substantially more rapidly than at lower latitudes. Consequently, assessments of the state of the Arctic are a focus of international efforts. For the terrestrial Arctic, large datasets are generated by remote sensing of above-ground variables, with an emphasis on vegetation properties, and, by association, carbon fluxes. However, the terrestrial component of the carbon (C) cycle remains poorly quantified and the below-ground distribution and stocks of soil C can not be quantified directly by remote sensing. Large areas of the Arctic are also difficult to access, limiting field surveys. The scientific community does know, however, that this region stores a massive proportion (although poorly quantified, soil C stocks for tundra soils vary from 96 to 192 Gt C) of the global reservoir of soil carbon, much of it in permafrost (900 Gt C), and these stocks may be very vulnerable to increased rates of decomposition due to rising temperatures. The consequences of this could be increasing source strength of the radiatively forcing gases carbon dioxide (CO2) and methane (CH4). The principal objective of this project is to provide a critical evaluation of methods used to link soil C stocks and fluxes at the usual scales spanned by the field surveys (centimetre to kilometre) and remote sensing surveys (kilometre to hundreds of kilometres). The soil C distribution of two sub-arctic sites in contrasting climatic, landscape/geomorphologic and vegetation settings has been described and analysed. The transition between birch forest and tundra heath in the Abisko (Swedish Lapland) field site, and the transition between mire and birch forest in the Kevo (Finnish Lapland) field site span several vegetation categories and landscape contexts. The natural variability of below-ground C stocks (excluding coarse roots > 2 mm diameter), at ...