Meeting Abstract
105.2 Tuesday, Jan. 7 08:15 Impacts of coastal spring discharge on a tidally influenced shallow marine estuary MENNING, DM*; GAREY, JR; University of South Florida; University of South Florida dmenning@usf.edu
Coastal areas around the world have undergone unprecedented population growth in the last few decades and thus are susceptible to sea level change and decreasing water quantity and quality. The relationship between surface and subsurface estuarine hydrologic processes in coastal regions has not been investigated fully and existing hydrologic models cannot easily integrate the inputs and outputs that occur through subsurface conduits that discharge into a myriad of coastal estuarine springs and seeps. Double Keyhole Spring is a brackish water system that is an example of a coastal spring that is influenced by both the Floridan aquifer and the surface estuary. Using ADV data we estimated water flow through the system varies with tidal cycle and seasonal rainfall from -1449 L/sec at high tide prior to TS Debby to 2577 L/sec at low tide after TS Debby averaging 648-1171 L/s. This flow rate is approximately one-tenth that of the Hillsborough River and demonstrates the important role coastal springs play in the interface of the Floridan aquifer and the Gulf of Mexico. Preliminary work on Double Keyhole Spring and surrounding surface sites includes mapping the spring, establishment of sampling locations, deployment of datasondes to monitor water velocity and physical water parameters, and the collection of water samples for chemical water parameters and microbial community analyses. Microbial community structure and water chemistry data from Double Keyhole Spring and the surrounding estuary indicate spatial and temporal differences between sites. Long term monitoring of Double Keyhole Spring and the surrounding estuary is necessary to show changes in water chemistry and community structure with the primary goal of determining the impacts Double Keyhole Spring discharge has on the surrounding estuary.
