HR: 09:30h
AN: H31F-03    [Abstracts]
TI: Geomorphic controls of catchment scale linkages between hydrologic and nitrogen cycling
AU: * Band, L E
EM: lband@email.unc.edu
AF: Dept of Geography University of North Carolina, CB#3220, Chapel Hill, NC 27599 United States
AU: Tague, C
EM: ctague@mail.sdsu.edu
AF: Department of Geography, San Diego State University, San Diego, CA 92182 United States
AU: Groffman, P
EM: groffmanp@ecostudies.org
AF: Institute for Ecosystem Studies, 65 Sharon Turnpike; P.O. Box AB, Millbrook, NY 12545 United States
AU: Kenworthy, S
EM: stephen.kenworthy@wku.edu
AF: Dept of Geography and Geology Western Kentucky University, 1 Big Red Way, Bowling Green, KY 42101 United States
AU: Tenenbaum, D
EM: davidten@email.unc.edu
AF: Dept of Geography University of North Carolina, CB#3220, Chapel Hill, NC 27599 United States
AB: Hydrologic processes have important interactions with ecological systems through the activity of biogeochemical cycles. We investigate the space/time linkages between water, carbon and nitrogen cycling in a small Mid-Atlantic Piedmont catchment, which is part of the Baltimore LTER. We document spatial and temporal patterns of near surface and deeper profiles of soil moisture with TDR, soil nitrogen transformations, riparian groundwater depths, stream discharge and nitrate concentrations at several cross sections. We develop the geomorphic organization of these hydrologic and biogeochemical stores and fluxes at the catchment scale using LIDAR derived DEM. Plot mean soil moisture in upland areas closely followed a linear trend with the topographic wetness index, ln(a/tanβ) while bottomland mean soil moisture is typically decoupled from this trend, indicating deeper, more persistent sources. Plot variance of soil moisture was highest under intermediate values of soil moisture, decreasing under both wet and dry conditions. Catchment and plot level patterns in soil moisture show important, nonlinear relations with riparian groundwater levels, stream baseflow and nitrate concentrations although riparian zones appear to be the dominant source of stream nitrate. Distributed ecohydrologic simulation of water, carbon and nitrogen cycling is compared with the multivariate pattern analysis we have carried out to further explore feedbacks and controls between hydrologic and biogeochemical processes.
DE: 1836 Hydrologic budget (1655)
DE: 1871 Surface water quality
DE: 0400 Biogeosciences
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting