HR: 1340h
AN: OS23C-1324    [Abstracts]
TI: Sediment Transport on Relatively Low-Energy Coastlines: Implications for Resuspension and Deposition
AU: Sternberg, R W
EM: rws@ocean.washington.edu
AF: University of Washington, Box 357940 School of Oceanography, Seattle, WA 98195
AU: * Ogston, A S
EM: ogston@ocean.washington.edu
AF: University of Washington, Box 357940 School of Oceanography, Seattle, WA 98195
AU: Puig, P
EM: ppuig@icm.csic.es
AF: Institut de Ciencies del March, Passeig Maritim de la Barceloneta 37-49, Barcelona, 08003 Spain
AU: Fain, A
EM: amvf10@yahoo.com
AF: Phillip Williams & Associates, Ltd, 720 California St., Suite 600, San Francisco, CA 94108
AB: The western Adriatic coastline borders a relatively low-energy (as defined by wave energy) epicontinental sea. In this environment, sediment resuspension occurs primarily in response to winter storm events, as is the case in higher-energy environments. A major difference between these types of environments is that the zone in which sediment is resuspended due to active wave processes is significantly shallower in low-energy environments than in high-energy environments, resulting in different transport mechanisms. In lower-energy environments, transport appears to occur primarily in the along-shelf direction in water depths where wave resuspension is frequent, with little across-margin transport. This is likely due to resuspension by waves in shallow water where the Ekman layer may be thicker than the water depth, while in higher energy environments wave resuspension occurs in water depths where a distinct bottom Ekman layer can form. For example, on the western Adriatic continental shelf and the Ebro River margin, both relatively low-energy environments, the along-shelf sediment flux during winter experiments was one to two orders of magnitude greater than the across-shelf flux at 12-m water depth. In contrast, on the highly energetic northern California shelf distinct downwelling signatures are seen at 60-m water depth where frequent storm resuspension is observed and the across-shelf sediment flux is persistently seaward during storms and of equal or greater magnitude than the alongshelf flux. This suggests that the resulting sediment deposit from fluvial sources along low-energy coastlines would be located in shallow water and linearly distributed along the coastline with little loss of sediment to offshore environments. In higher-energy environments, fluvial sediment would be distributed farther offshore with more sediment escaping the shelf environment.
DE: 4211 Benthic boundary layers
DE: 4219 Continental shelf processes
DE: 4223 Descriptive and regional oceanography
DE: 3022 Marine sediments--processes and transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting