Schaffner, L. C. VIMS, The College of William and Mary, linda@vims.edu
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DISTURBANCE PROCESSES IN THE BENTHIC BOUNDARY LAYER OF AN ESTUARINE TURBIDITY MAXIMUM: IMPLICATIONS FOR BENTHIC COMMUNITY STRUCTURE AND FUNCTION
 
The dynamic nature of benthic boundary layers in estuaries is increasingly well characterized over time scales relevant to biological processes. Strong tidal forcing and high rates of sediment trapping due to gravitational circulation processes lead to the formation of estuarine turbidity maxima (ETMs) in some systems. Considerable sediment transport and seabed disturbance characterize the ETM of the York River, a subestuary of Chesapeake Bay. Particle concentrations that exceed 500 mg/L have been recorded at 10 cm elevation above the bed during spring tides. Geochemical analyses, x-radiographs, photographs and side-scan sonar provide evidence of sediment erosion/ deposition episodes that rework the upper 10s of cm of the seabed over time scales of days to weeks. These dynamic physical conditions have important implications for benthic community structure and function. Preliminary results from a field study conducted during spring 1998 reveal the presence of depauperate macrobenthic assemblages dominated by small, motile species, and the near absence of sedentary infauna in areas where sediment disturbance was most intense. As a result, macrofauna of this ETM appear to have little direct effect on sediment mixing processes, but their feeding activities result in sediment pelletization, which has significant implications for sediment biogeochemistry and transport processes.
 
Day: Wednesday, Feb. 3
Time: 09:15 - 09:30am
Location: Eldorado Hotel
 
Code: SS03WE0915E