HR: 0830h
AN: B31C-0306    [PDF]
TI: Soil Respiration in a Black Spruce Forest and Adjacent Thermokarst Wetlands in Interior Alaska
AU: * Wickland, K P
EM: kpwick@usgs.gov
AF: USGS, Water Resources, 3215 Marine St., Boulder, CO 80303
AU: * Wickland, K P
EM: kpwick@usgs.gov
AF: University of Colorado, Dept. of Geological Sciences, 2200 Colorado Ave, Campus Box 399, Boulder, CO 80309
AU: Striegl, R G
EM: rstriegl@usgs.gov
AF: USGS, Water Resources, Denver Federal Center, MS413, Lakewood, CO 80225
AU: Neff, J C
EM: neffjc@colorado.edu
AF: University of Colorado, Dept. of Geological Sciences, 2200 Colorado Ave, Campus Box 399, Boulder, CO 80309
AB: Low-lying forested areas underlain by ice-rich permafrost may develop into thermokarst wetlands when permafrost thaws and no longer supports the ground above the water table. Inundation of the subsided land leads to tree death and the emergence of aquatic vegetation. The objective of our study is to determine whether soil respiration rates differ between forested areas having permafrost and adjacent thermokarst wetlands. We measured soil respiration rates weekly to bi-weekly during the 2003 growing season at a black spruce forest near Fairbanks, Alaska that contains thermokarst wetlands. The forest is underlain by permafrost at depths ranging from 40 to 50 cm, but in several areas thermokarst wetlands have formed due to the melting of permafrost to below 2 m depth. Soil respiration was measured at five locations in thermokarst wetland areas and at five adjacent forested areas having permafrost. Soil temperature and depth to ice was also measured at each location. Soil respiration rates at both the thermokarst and permafrost areas were similar in May, averaging 0.42 and 0.38 mmol CO$_{2}$ m$^{-2}$ hr$^{-1}$ respectively. Respiration increased in June to maximum measured rates of 1.55 mmol CO$_{2}$ m$^{-2}$ hr$^{-1}$ at the thermokarst sites, and 0.98 mmol CO$_{2}$ m$^{-2}$ hr$^{-1}$ at the permafrost sites. There was more variation in respiration rates among the thermokarst wetland sites than among the permafrost sites.
DE: 0315 Biosphere/atmosphere interactions
DE: 1615 Biogeochemical processes (4805)
DE: 1823 Frozen ground
DE: 1890 Wetlands
SC: Biogeosciences [B]
MN: 2003 Fall Meeting