Effects of Variation in River Discharge and Wind-Driven Resuspension on Lower Trophic Levels of the Mobile Bay Ecosystem 
Ronald P. Kiene1, Jonathan Pennock2, Florence Thomas3 and Jean Cowan3
1 Department of Marine Sciences, University of South Alabama, Mobile AL      36688
2 University of Alabama, Dauphin Island Sea Lab, Dauphin Island AL 36528
3 Dauphin Island Sea Lab, Dauphin Island AL 36528
Proper management of the Mobile Bay estuary and its living resources requires a fundamental understanding of current ecosystem structure and function. We hypothesize that variations in river discharge and wind-driven sediment resuspension in this shallow estuary have dramatic effects not only on the biological community and trophic structure, but also on the way in which anthropogenic materials are processed by the estuarine ecosystem. We will carry out an integrated study of trophic linkages in the microbial food web (phytoplankton and bacterioplankton) and how they are affected by natural perturbations such as pulsed freshwater flow and wind-driven sediment resuspension. The following major study questions will be addressed: 1) What is the spatial and temporal variation in net carbon production in the Mobile Bay system? 2) How do variations in freshwater delivery and sediment resuspension affect trophic efficiency in the phytoplankton and bacterioplankton communities? 3) How does advective or wind-driven shear affect sediment resuspension, nutrient exchanges and particulate carbon redistribution? Together with a companion project that is focused on higher trophic levels we will examine trophic linkages across virtually all levels of the food web. Modeling efforts will be used to guide the research, and ultimately data collected in this study will be used to refine and validate models of trophic dynamics in Mobile Bay.