Seasonal Abundance of Lysogenic Bacteria in a Subtropical Estuary

Seasonal changes in the abundance of inducible lysogenic bacteria in a eutrophic estuarine environment were investigated over a 13-month period. Biweekly water samples were collected from Tampa Bay, Fla., and examined for prophage induction by mitomycin C treatment. At the conclusion of the study, we determined that 52.2% of the samples displayed prophage induction, as indicated by significant increases in viral direct counts compared with uninduced controls. Samples that displayed prophage induction occurred during the warmer months (February through October), when surface water temperatures were above 19°C, and no induction was observed in November, December, or January. This study presents clear evidence that there is seasonal variation in the number of inducible lysogenic bacteria in an estuarine environment.