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Smith, C. G., U.S. Geological Survey, St. Petersburg, USA, cgsmith@usgs.gov
Marot, M. E., U.S. Geological Survey, St. Petersburg, USA, mmarot@usgs.gov
Osterman, L. E., U.S. Geological Survey, St. Petersburg, USA, osterman@usgs.gov

INFLUENCE OF ANTHROPOGENIC ACTIVITIES AND NATURAL PROCESSES ON HISTORIC DEPOSITIONAL PATTERNS AND ENVIRONMENTAL CHANGE IN THE MOBILE BAY ESTUARINE SYSTEM (USA)

Over the last two centuries, the interplay between natural processes and anthropogenic activities has had a significant influence on the supply and deposition of sediment to the Mobile Bay Estuarine System. Based on modern bathymetry and morphology, the bay proper consists of three depositional sub-basins: middle bay, lower bay, and Bon Secour Bay. Lead-210 (210Pb xs) geochronologies of seven box cores constrain the depositional history of the bay and each sub-basin. At the bay scale, linear sedimentation rates over the last 120 years average 0.4 cm y-1, which is slightly higher than local sea-level rise (0.298 cm y-1; Dauphin Island Tide Station, NOAA). However, differences in deposition are observed within and among sub-basins, reiterating the need to understand controls on spatially heterogeneous bay infilling. For example, sedimentation rates for the middle sub-basin east of the shipping channel are three to four times higher than rates west of the shipping channel. This difference is in part controlled by channel dredging and spoil disposal, which have isolated the western middle bay from sediment supplied by the Mobile-Tensaw Rivers.

Poster presentation

Session #:080
Date: 2/23/2012
Time: 17:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: B0885