HR: 13:55h
AN: H33I-02    [Abstracts]
TI: Flow, sedimentation, and biomass production on a vegetated salt marsh in South Carolina: toward a predictive model of marsh morphologic and ecologic evolution
AU: * Fagherazzi, S
EM: sergio@csit.fsu.edu
AF: Department of Geological Sciences and School of Computational Science,, Florida State University Dirac Science Library, Tallahassee, FL 32301-4120 United States
AU: Mudd, S M
EM: simon.m.mudd@Vanderbilt.Edu
AF: Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235 United States
AU: Morris, J T
EM: morris@biol.sc.edu
AF: Department of Biological Sciences and Belle W. Baruch Institute, University of South Carolina, Columbia, SC 29208 United States
AU: Furbish, D J
EM: david.j.furbish@vanderbilt.edu
AF: Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37235 United States
AB: A 1-D model for exploring the interaction between hydrodynamics, sedimentation, and plant community evolution on a salt marsh populated by Spartina alterniflora is developed. In the model tidally induced flows over marsh platforms are affected by S. alterniflora through drag forces. In general macrophyte characteristics are determined by a wide range of processes; here, based on field studies at North Inlet estuary, South Carolina, the biomass of the S. alterniflora on the marsh platform is simply related to their time of submergence under tidally induced flows. Additionally, field data collected at North Inlet are used to relate biomass to plant area per unit volume, stem diameter, and an empirical drag coefficient. Sedimentation is also related to biomass, through either organogenic deposition or trapping of suspended sediment particles. The morphologic evolution of simulated marshes is explored by varying the sedimentation process and the rate of sea level rise. Different sedimentation processes result in marshes with different morphologies. An organogenic marsh is predicted to evolve under a regime of steady sea level rise into a platform with a relatively flat surface, whereas a marsh developed primarily through a trapping mechanism is predicted to have a surface that slopes gently away from the salt marsh creek. As predicted by 0-D modeling studies, sea level rise may be accommodated up to a certain critical sea level rise rate, after which the salt marsh platform will drown. Marshes that accrete through sediment trapping adjust to changes in sea level more rapidly than marshes that accrete through organogenic deposition.
DE: 4560 Surface waves and tides (1255)
DE: 3022 Marine sediments--processes and transport
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting