Holocene Sedimentary History of Weeks Bay, AL: Human and Natural Impacts on Deposition in a Gulf Coast Estuary

Douglas W. Haywick, Miriam L. Fearn, David T. Allison Keith G. Blackwell and Lee S. Yokel Department of of Geology & Geography University of South Alabama, Mobile AL 36688

Weeks Bay is a small (15 km2) embayment attached to the eastern side of Mobile Bay approximately 25 km southeast of Mobile. As with much of the Alabama Gulf Coast, it is an impacted region. That impact is both human-induced (e.g., industrial and agricultural pollution, urban sprawl) and natural (e.g., hurricanes, flooding). We are examining the Holocene (<10,000 years BP) stratigraphy of Weeks Bay to determine if human/natural impact leaves a record in the sediment which fills the bay. Our study will use both cores and grab samples and will investigate various sedimentological, biostratigraphic and geochemical parameters (e.g., sediment grain size, pollen and diatom content, seismic stratigraphy, mercury and heavy metal content of sediment etc). The sedimentary record also provides the means by which to answer important management questions. For example, soil loss due to deforestation or poor agricultural practices may be identified by changes in the type, and/or rate of post-settlement sedimentation within Weeks Bay. Increases in mercury and other heavy metal contents of sediment can provide data concerning the source of point sources of pollution. Holocene estuary-fill may also record short-duration, natural sedimentary events such as storm deposits and scouring events, thus providing a mechanism to determine recurrence intervals of potentially catastrophic events along the coast.  In addition to these scientific goals, we will use our study to provide undergraduate research experiences for students at the University of South Alabama. All effective management studies should provide means to train future managers and our proposal will do that by giving undergraduate students the opportunity to plan and conduct independent research.