HR: 0800h
AN: B11D-0771    [Abstracts]
TI: Mercury Accumulation in the Forest Floor of the North Central United States
AU: * Perry, C H
EM: charleshperry@fs.fed.us
AF: US Forest Service, Northern Research Station 1992 Folwell Avenue, St. Paul, MN 55108, United States
AU: Amacher, M C
EM: mamacher@fs.fed.us
AF: US Forest Service, Rocky Mountain Research Station 860 North 12th East, Logan, UT 84321, United States
AU: Cannon, W F
EM: wcannon@usgs.gov
AF: US Geological Survey, Eastern Mineral Resources 954 National Center, Reston, VA 20192, United States
AU: Kolka, R K
EM: rkolka@fs.fed.us
AF: US Forest Service, Northern Research Station 1831 Highway 169 E, Grand Rapids, MN 55744, United States
AU: Woodruff, L G
EM: woodruff@usgs.gov
AF: US Geological Survey, Eastern Mineral Resources 2280 Woodale Drive, Mounds View, MN 55112, United States
AB: Atmospherically-deposited Hg has a strong affinity for soil organic matter. Fluxes of Hg in soil water of upland watersheds are generally small, but Hg stored in soil organic matter may be released when the forest floor is consumed by fire. The contribution of Hg from forest fires relative to other anthropogenic sources is an important unknown. The Forest Service, US Department of Agriculture, Forest Inventory and Analysis (FIA) program collects soil samples from forested areas across the United States as part of its Phase 3 sampling, and annual soils inventories are underway or completed in 45 of the 50 states (Alaska, Hawaii, Mississippi, New Mexico, and Oklahoma have yet to be sampled). Our objective here is to inventory and model the spatial distribution of forest floor Hg for a transect running across the north central United States. The collection of forest floor samples was accomplished as part of the standard FIA Phase 3 Soil Quality Indicator program. Field protocols include the measurement of the thickness of the forest floor and the collection of the entire forest floor found within a sampling frame having a diameter of 30 cm. We removed approximately 0.1 g of the sample for plots in our region of interest, and these were sent for Hg analysis by cold-vapor atomic absorption. Observations of mercury concentrations were joined with the Forest Inventory and Analysis Database to assign basic location information and associated inventory data. Mean plot-level values of Hg storage were tested against ecoprovince, forest type group, latitude, and longitude using analysis of variance and geographically weighted regression. Ecoprovince and forest type group were both significant predictors of mercury storage; conifer species tend to store more mercury than hardwood species. Different forest type groups store different amounts of forest floor Hg and in widely dispersed locations.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0476 Plant ecology (1851)
DE: 0486 Soils/pedology (1865)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting