HR: 11:50h
AN: B42B-06    [Abstracts]
TI: Decadal Estimates for Soil Carbon Inputs and Losses for Black Spruce Boreal Forests in Interior Alaska, USA and Northern Manitoba, Canada
AU: * Manies, K L
EM: kmanies@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025 United States
AU: Harden, J W
EM: jharden@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025 United States
AU: Veldhuis, H
EM: VELDHUISH@agr.gc.ca
AF: Agriculture Canada, 362A Ellis Building Univeristy of Manitoba, Winnipeg, MT R3T 2N2 Canada
AU: Veldhuis, H
EM: VELDHUISH@agr.gc.ca
AF: Michigan State University, Department of Plant Biology 166 Plant Biology, Lansing, MI 48824 United States
AU: Turetsky, M R
EM: mrt@msu.edu
AF: Michigan State University, Department of Plant Biology 166 Plant Biology, Lansing, MI 48824 United States
AB: Soil carbon stocks represent long-term net accumulations of carbon that result from plant inputs, decomposition losses, combustion losses, and local gains and losses from lateral flow of dissolved and particulate carbon. We use several chronosequences (time since last fire) of various soil drainage types from Thompson, Manitoba and Delta Junction, Alaska to estimate decadal averages of inputs and losses to soil. Because northern soils are generally not well mixed, the shallow organic layers of these soils can be thought as discrete accumulations since the most recent fire overlies more decomposed layers that represent longer histories of disturbance and stabilization. Accumulation since the most recent fire provides an estimate of net primary production (NPP) inputs to soil and decomposition loss from these shallow layers. Accumulation of all organic layers provides an estimate of long-term inputs and decay. Shallow inputs (0.011 - 0.014 g/cm²; SE = 0.002 - 0.005) and turnover times for carbon decay (78 - 94 yrs) did not differ between sites. Long-term inputs also do not differ between the well- to moderately well-drained Alaska sites and the moderately well-drained Thompson site (0.013 g/cm²; SE = 0.005). However, our wettest chronosequence site, located in Thompson, did see higher rates of long-term inputs (0.031 g/cm2; SE = 0.009). Long-term turnover times (50 - 60 yrs) did not differ among sites.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0428 Carbon cycling (4806)
DE: 0486 Soils/pedology (1865)
SC: Biogeosciences [B]
MN: Fall Meeting 2005