Tracking Vibrio: Population Dynamics and Community Ecology in Alabama Estuaries

Vibrio is a genus of halophilic, gram-negative bacteria found in estuaries around the globe. Integral parts of coastal cultures- like those along the Alabama Gulf Coast- often involve contact with vectors of pathogenic Vibrio spp. bacteria (e.g. consuming raw shellfish, fishing, water sports). High rates of morbidity and mortality from Vibrio spp. infections demonstrate the need for improved understanding, and ultimately prediction, of Vibrio spp. population dynamics in estuarine regions. Our study assessed meteorological, hydrographic, and biological correlates of V. parahaemolyticus and V. vulnificus at 10 sites in the Eastern Mississippi Sound System (EMSS) from April - October 2019. During the sampling period, median abundances of V. parahaemolyticus and V. vulnificus were 2.31 log MPN/L and 2.90 log MPN/L, respectively. Vibrio spp. population dynamics were largely driven by site-based variation, with sites closest to freshwater inputs having the highest abundances. The E-W wind scalar was a novel Vibrio spp. correlate in the EMSS- a relationship that warrants further study in other shallow estuarine basins. A potential salinity effect on bacterial-particle associations was identified, where V. vulnificus associated with large particles (>5 microns) in conditions outside of their optimal salinity (>18 ppt). Additionally, V. vulnificus abundances were correlated to those of harmful algal species like Akashiwo sanguinea and Heterocapsa spp. Correlates from this study may be used to inform the next iteration of predictive Vibrio models for the EMSS region and may lend additional insight to Vibrio spp. ecology and population dynamics in other shallow, microtidal estuaries.