Graham Boreal peatlands are a recognized site of carbon accumulation. Recent data suggests the occurrence of two potential mechanisms for carbon retention that have not previously been quantitatively assessed, namely, the uptake and utilization of dissolved organic carbon (in the form of sugars), and production of degradation-resistant cell wall polyphenolics by charophytes and Sphagnum moss. The first of these processes removes liable forms of fixed carbon from the environment, while the second generates relatively long-term storage forms of carbon. Both processes interfere with the ability of bacteria to convert fixed carbon back to CO2, and thus contribute to peatland carbon accumulation. Cultured charophytes and Sphagnum will be used for cloning and sequencing of sugar transport genes, and for gene expression studies. Field data for charophyte diversity and biomass will be correlated with field measurements of pH, DOC, DIC, and bacterial biovolumes, and with species-specific abilities to load sugars and generate polyphenolic wall compounds measured with the use of laboratory cultures. Assessments of Sphagnum production of resistant wall materials and utilization of DOC by protonematal stages will also be made. The goal of the project is to improve estimates for the amount of carbon sequestered in peatlands.
