HR: 1340h
AN: B33E-1079    [Abstracts]
TI: Comparison of Current and Historical Rates of Ecosystem Carbon Accumulation in a Northern Alberta Peatland
AU: * Syed, K H
EM: kamran.syed2@uleth.ca
AF: University of Lethbridge, Department of Biological Sciences, 4401 University Drive, Lethbridge, AB T1K 3M4 Canada
AU: Flanagan, L B
EM: larry.flanagan@uleth.ca
AF: University of Lethbridge, Department of Biological Sciences, 4401 University Drive, Lethbridge, AB T1K 3M4 Canada
AU: Carlson, P J
EM: peter.carlson@uleth.ca
AF: University of Lethbridge, Department of Biological Sciences, 4401 University Drive, Lethbridge, AB T1K 3M4 Canada
AU: Glenn, A J
EM: aaron.glenn2@uleth.ca
AF: University of Lethbridge, Department of Biological Sciences, 4401 University Drive, Lethbridge, AB T1K 3M4 Canada
AU: Ponton, S
EM: stephane.ponton@cirad.fr
AF: University of Lethbridge, Department of Biological Sciences, 4401 University Drive, Lethbridge, AB T1K 3M4 Canada
AB: As part of Fluxnet-Canada, we have been investigating the environmental controls on net ecosystem carbon dioxide exchange using the eddy covariance technique in a moderately rich (treed) fen in northern Alberta, Canada. In addition, integrated CO₂ fluxes were compared to carbon stock measurements and rates of peat accumulation. The total ecosystem carbon stock was 52,669 g C m^-2 with the vast majority (52,129) accumulated in peat over a 2 meter depth. The basal age for the peat was 2210 ± 50 years before present. The above-ground carbon stock in the two tree species was 226 g C m^-2. The oldest Picea mariana trees were aged at 135 years, and they showed a rapid increase in basal area increment starting about 65 years ago that peaked at rates of 2 cm² yr^-1 about 40 years ago. The Larix laricina trees became established approximately 45 years ago and currently have a basal area increment of 3 to 4 cm² yr^-1, much higher than the current rates (0.5 cm² yr^-1) observed for Picea mariana. The rates of peat accumulation were determined on ²¹⁰Pb-dated cores. Over the last 70 years the peat gained an average of 113 ± 12 g C m^-2 yr^-1. This was similar to net ecosystem production measured by eddy covariance (95 and 210 g C m^-2 yr^-1) over the last two years. Variation in annual net ecosystem production was associated with shifts in weather and growing season length. Current and recent historical rates of carbon accumulation were quite consistent despite significant variation in tree species growth and successional changes in this peatland over the last 70 years.
DE: 0400 BIOGEOSCIENCES
DE: 0428 Carbon cycling (4806)
DE: 0476 Plant ecology (1851)
DE: 0497 Wetlands (1890)
SC: Biogeosciences [B]
MN: Fall Meeting 2005