Spatial and temporal variation of marine bacterioplankton in Florida Bay, USA

Physical, chemical and biological parameters of the water column of Florida Bay were examined at seven study sites over an 18-month period. At the time, Florida Bay was experiencing a seagrass die-off. The data collected indicated that the presence of seagrass significantly affected the overlying water column, especially with respect to biological parameters such as, heterotrophic activity and bacterial numbers. Microbial activity and numbers were also significantly higher over areas of dying seagrass than over healthy or dead areas. The exact nature of the relationship between seagrass and bacterioplankton is not known. Correlation analyses yielded significant associations (P < 0.05) between the biological parameters (heterotrophic activity and bacterial numbers) and dissolved organic matter, chlorophyll, primary productivity, and ammonium. The possibility that other variables might have compounded and added to this effect is discussed.