Modeling pH and Temperature Effects as Climatic Hazards in Vibrio Vulnificus and Vibrio Parahaemolyticus Planktonic Growth and Biofilm Formation.

Climate‐induced stressors, such as changes in temperature, salinity, and pH, contribute to the emergence of infectious diseases. These changes alter geographical constraint, resulting in increased Vibrio spread, exposure, and infection rates, thus facilitating greater Vibrio‐human interactions. Multiple efforts have been developed to predict Vibrio exposure and raise awareness of health risks, but most models only use temperature and salinity as prediction factors. This study aimed to better understand the potential effects of temperature and pH on V. vulnificus and V. parahaemolyticus planktonic and biofilm growth. Vibrio strains were grown in triplicate at 25°, 30°, and 37°C in 96 well plates containing Modified Seawater Yeast Extract modified with CaCl2 at pH's ranging from 5 to 9.6. AMiGA software was used to model growth curves using Gaussian process regression. The effects of temperature and pH were evaluated using randomized complete block analysis of variance, and the growth rates of V. parahaemolyticus and V. vulnificus were modeled using the interpolation fit on the MatLab Curve Fitting Toolbox. Different optimal conditions involving temperature and pH were observed for planktonic and biofilm Vibrio growth within‐ and between‐species. This study showed that temperature and pH factors significantly affect Vibrio planktonic growth rates and V. parahaemolyticus biofilm formation. Therefore, pH effects must be added to the Vibrio growth modeling efforts to better predict Vibrio risk in estuarine and coastal zones that can potentially experience the cooccurrence of Vibrio and harmful algal bloom outbreak events. Plain Language Summary: Changes in temperature, salinity, and pH are increasing Vibrio‐human interactions in coastal communities. Multiple efforts have been developed to predict Vibrio risk, mainly using temperature and salinity measurements. However, more comprehensive models are needed to help inform decision‐makers on how to better design policies and create public health awareness. This study looks at how temperature and pH could affect the growth of the potential human bacterial pathogens, V. vulnificus and V. parahaemolyticus. Vibrio strains were grown in triplicate at different temperatures in acidic, neutral, and alkaline conditions (different pH ranges). The effects of temperature and pH were evaluated using randomized complete block analysis of variance, and the growth rates of V. parahaemolyticus and V. vulnificus were modeled using the MatLab Curve Fitting Toolbox. This study found different optimal conditions for free‐living and aggregated Vibrio growth within and between species. In addition, this study showed that temperature and pH factors significantly impact Vibrio growth. Overall, the pH effects must be added to the Vibrio growth modeling efforts to have a more comprehensive model and to better predict Vibrio risk in climate change scenarios. Key Points: Optimal growth conditions for Vibrio spp. depend on the life stage: planktonic or biofilm formationChanges in pH and temperature in coastal areas may lead to a higher Vibrio‐human interaction and influence adaptative responsespH effects must be included in Vibrio modeling efforts to predict Vibrio risk in zones with co‐occurrence of Vibrio and harmful algal blooms [ABSTRACT FROM AUTHOR]