USING RECENT HURRICANE EVENT LAYERS TO EVALUATE REGIONAL STORM IMPACTS ON ESTUARINE AND WETLAND SYSTEMS
Hurricane Frederic deposits are fairly widespread across eastern Mississippi Sound and Mobile Bay marshes. The Mississippi Sound sites to the west of the storm tract and in more protected locations do not contain a sedimentary record of Frederic. In Mobile Bay, on the east side of the storm track, two marsh cores record Frederic as coeval shifts in bulk density and % OC (organic carbon). At other sites closer to Frederic’s landfall (Dauphin Island and Fowl River, AL), the storm impact coincides with changes in sediment regimes that reflect a shift to increased coastal deterioration. Because of the narrowing coastal zone, the faunal record at these marsh sites could be misinterpreted as sea-level rise. However, sustained changes in bulk density and % OC indicate an underlying change in depositional regime. We conclude that geomorphic variability across the region can be a significant determinant of event deposition and that changes in environmental conditions also need to be considered when identifying event layers.