HR: 0800h
AN: B41A-0159    [Abstracts]
TI: Spatial Variability of Soil CO2 Concentration from Forested and Clear Cut Sites in Nova Scotia, Canada
AU: * Bekele, A
EM: abekele@stfx.ca
AF: Environmental Sciences Research Center St. Francis Xavier University, 1 West Street, P O Box 5000, Antigonish, NS B2G2W5 Canada
AU: Black, M
EM: mblack@stfx.ca
AF: Environmental Sciences Research Center St. Francis Xavier University, 1 West Street, P O Box 5000, Antigonish, NS B2G2W5 Canada
AU: Kellman, L
EM: lkellman@stfx.ca
AF: Environmental Sciences Research Center St. Francis Xavier University, 1 West Street, P O Box 5000, Antigonish, NS B2G2W5 Canada
AU: Beltrami, H
EM: hugo@stfx.ca
AF: Environmental Sciences Research Center St. Francis Xavier University, 1 West Street, P O Box 5000, Antigonish, NS B2G2W5 Canada
AB: Spatial variability of CO2 concentration within forest soils is poorly documented because most CO2 concentration or production research has been based on point measurements representing a site or experimental treatment. This ongoing study was undertaken to examine the differences in CO2 concentration within soil profiles from two paired forested and clear-cut sites in Nova Scotia, Canada by accounting for the spatial variability caused by local topography. For each site, data were collected from four depths (0, 5, 20 and 35 cm) and ten micro sites separated by approximately 10 m and representing three local topographic features (level, trough and hump). Data collected on approximately monthly time interval from each site and depth indicated that CO2 concentration was highly positively skewed with high frequency of zero concentration values (up to 60 % of data at 20 cm depth for one of the clear-cut sites). The frequent zero concentration values were attributed to water filled soil pore spaces caused by frequent high water table at these sites. No consistent pattern could be found in CO2 concentrations among the three local topographic features. Median CO2 concentration increased up to the 20 cm depth for all sites. Box and Whisker plots of seasonally aggregated data indicated distinct seasonal pattern with higher median CO2 concentration during summer (June, July and August) and lower median CO2 concentration during winter (December, January and February). However the shape of the CO2 concentration profile were unaffected by seasonal and site differences. There was no significant difference in median CO2 concentration between forested and clear-cut sites due partly to the high variability within a site and increased variability at lower depths. Further, the CO2 concentration dynamics in these soils appear to be controlled by frequent water saturation of the soils by a shallow water table.
DE: 4806 Carbon cycling (0428)
SC: Biogeosciences [B]
MN: Fall Meeting 2005