HR: 1340h
AN: B33E-1080    [Abstracts]
TI: Production of Dissolved Organic Carbon and Carbon Dioxide from Boreal Forest Soils
AU: * Moore, T R
EM: tim.moore@mcgill.ca
AF: Department of Geography, McGill University, 805 Sherbrooke Street West, Montr‚al, QC H3A 2K6 Canada
AU: Pare, D
EM: dpare@cfl.forestry.ca
AF: Canadian Forest Service, Laurentian Forestry Center, Sainte-Foy, QC G1V 4C7 Canada
AB: We incubated a total of 36 forest floor (O horizon), upper mineral and peat soils from 18 Canadian forest and peatland sites, over one year at 3, 10 and 22°C and determined rates of DOC production in leachates and CO₂ production in headspace. Rates of DOC and CO₂ production decreased with time during the incubations (exponential k values -0.44 to -1.68/y, similar to those for CO₂ production) and increased with higher temperatures. Average cumulative DOC production rates were 32 and 18 ν g DOC/g soil C/d for organic and mineral soil samples, respectively, at 22°C. Temperature dependence of DOC production exhibited average Q10 values of 1.9 to 1.2 for the organic samples and 0.9 to 1.2 for the mineral samples. Partitioning of mineralized C into CO₂-C and DOC ranged from 100:1 to 1:1, depending on samples and temperature conditions. Average CO₂-C:DOC quotients increased from 6 to 7 at 3°C to 16 to 27 at 22°C and average CO₂-C:DOC production regression slopes were 5. We were unable to relate DOC production rates (per mass of C) to simple soil properties such as C content or C:N ratio.
DE: 0428 Carbon cycling (4806)
DE: 0486 Soils/pedology (1865)
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
SC: Biogeosciences [B]
MN: Fall Meeting 2005