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Molecular investigations into permafrost-protected carbon in Alaskan soils
Soil core processing Cutting a newly extracted permafrost core into sections. Click on the photo for an enlarged image.   Carbon (C) stored within permafrost in northern boreal forest soils may become available for microbial metabolism if soil temperatures continue to increase over the coming decades, resulting in a positive feedback to climate warming. Understanding the potential of permafrost carbon to be degraded requires a detailed understanding of the microbiology and biochemistry of permafrost soils. Utilizing novel techniques in molecular biology, fluorometry, and mass spectrometry, we will analyze the biological and chemical constraints on C cycling at the molecular level.

There are three primary factors that may limit the rate at which decomposition of permafrost C occurs:
  • chemical limitation, whereby high lignin and phenolic concentrations or low nitrogen (N) concentrations limit decomposition,
  • biological limitation, whereby the microorganisms producing the proper suite of enzymes to decompose soil organic C are not present, and
  • physical limitation, whereby low temperatures and low oxygen availability limit decomposition

Our strategy involves taking cores from two different permafrost conditions:
  • a site with continuous permafrost and a shallow active layer (~40 cm) near Coldfoot, AK
  • soils with a warmer climate, average annual temperatures near 0°C, discontinuous permafrost, and a deeper active layer (~55 cm) near Fairbanks, AK

The following methods will be employed:
  • incubation for potential CO 2 and DOC fluxes
  • pyrolysis-gas chromatography/mass spectrometry (PYR-GCMS)
  • specific ultraviolet absorbance (SUVA, a measure of aromatic DOC) and fluorescence spectroscopy
  • quantitative PCR (QPCR)
  • the measurement of enzyme activity associated with functional genes
  • an enzyme digest experiment
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Page Last Modified: Friday, 07-Nov-2008 18:11:25 EST