Physical dynamics controlling variability in nearshore fecal pollution: Fecal indicator bacteria as passive particles

► Measured concentrations of fecal indicator bacteria (FIB) decayed exponentially. ► Spatial structure in decay was observed for both FIB groups - Escherichia coli and Enterococcus. ► A model was used to quantify the contribution of advection and diffusion to decay. ► Both processes contributed significantly to surfzone, but not offshore, FIB decay. ► The nearshore and offshore FIB observed in our study came from separate sources.