Effects of Salinity Stress on Natural and Anthropogenically-Derived Bacteria in Estuarine Environments 
Ronald P. Kiene 
Department of Marine Sciences, University of South Alabama, Mobile AL 36528
Bacteria are among the most important components of ecosystems because they carry out most of the heterotrophic metabolism and nutrient regeneration. Knowledge of what controls the growth of specific bacterial groups in estuaries is presently very limited, but of great concern from a management standpoint. Aquatic bacteria are the first line of defense in coastal ecosystems because they have the potential to mitigate the detrimental effects of certain anthropogenic pollutants, through degradation and transformation. This project will examine how salinity stress affects both natural and introduced bacteria in the Mobile Bay Estuary. The effects of salinity stress on bacterial metabolic activities, especially degradation of organic matter (natural and pollutant) of will be tested. The physiological responses of bacteria to osmotic stress will be examined, particularly with regard to uptake of osmotic solutes from the water. A long term goal of this study is to characterize the microbial community structure and function, using classical and modern molecular techniques.