Name: Grossman Marshall
Date: 04/25/2025
Time (EST/EDT): 01:00 pm
Location: AREL, HORN POINT LAB
Remote Access: email: mees@umd.edu

Committee Chair: Dr. Raleigh Hood, Horn Point Lab
Committee Members: Dr. Victoria Coles, Horn Point Lab Gary Shenk

Title: Modeling the impact of nutrient reductions and climate change on Vibrio Vulnificus using Chesapeake Bay Program model scenarios

Abstract: Vibrio vulnificus poses significant health risks in coastal and estuarine environments, with important implications for public health and the regional economy. Building upon the empirical modeling framework established by Jacobs et al. (2014), our study employs four different empirical models to predict: the probability of encountering V. vulnificus; its abundance in colony forming units per milliliter (CFU ml⁻¹); the probability that its abundance exceeds a critical threshold (>90 CFU ml⁻¹); and the likelihood of detecting a virulence‐correlated gene indicative of toxicity. In contrast to traditional models that focus primarily on temperature and salinity, our approach incorporates an expanded suite of water quality variables (including computed Secchi depth as a proxy for water clarity, dissolved oxygen, chlorophyll‐a, and phosphate concentrations) to provide a more comprehensive assessment of V. vulnificus dynamics in the Chesapeake Bay. The models were forced using output from Chesapeake Bay Program restoration and climate change model scenarios over a ten-year period (1991–2000), spanning conditions from business as usual to full compliance with Total Maximum Daily Load (TMDL) nutrient reduction goals. Analysis of the scenarios indicate TMDL implementation, which improves water clarity by reducing nutrient loads, and increases oxygen concentration while decreasing phosphorus and chlorophyll-a concentrations can substantially lower the probability of occurrence, abundance, probability of elevated abundance and the virulence of V. vulnificus. In contrast, climate projections alone suggest that increasing water temperatures will exacerbate Vibrio risk, extending the seasonal window of exposure. TMDL compliance reduces the risk of V. vulnificus presence and human exposure in the model climate change scenarios, however it does not fully mitigate the effects of thermal increases. The results underscore the potential for integrated management strategies that combine effective nutrient reduction with climate adaptation measures to mitigate the risk of V. vulnificus and support the long-term economic and environmental sustainability of the Chesapeake Bay region.