• 1. Alexandrium population biology in the Gulf of Maine

• Abstract

• 2. Hydrodynamic forcing of Alexandrium population biology

• Abstract
• Participants

• 3. Human pathogens and coastal ocean processes

• Abstract
• Participants

• 4. Microecology and evolution of two marine pathogens

• Abstract
• Participants

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Microecology and evolution of two marine pathogens: Abstract

Polz and Lerczak

Vibrio vulnificus and V. parahaemolyticus are among the most significant marine pathogens and dominate seafood-related illness in temperate regions. V. vulnificus is one of the most invasive bacterial pathogens and is held responsible for about 95% of seafood related deaths. Furthermore, it has been implicated in rising incidence of lethal wound infections acquired during recreational use of coastal waters. V. parahaemolyticus has been shown to be the causative agent of outbreaks of dysentery after consumption of contaminated shellfish harvested from temperate marine regions.

In this interdisciplinary study, we are exploring the genetic diversity of these co-existing pathogenic Vibrio populations and the conditions, which control their growth and relative abundances in a temperate estuarine environment. While total abundances of bacteria in the coastal ocean and in estuaries remain stable over time, the relative abundances of different species can vary dramatically with seasonal changes in environment conditions. Moreover, severely pathogenic and more harmless variants of the same bacterial species can co-exist in the environment and it remains unknown what triggers preferential growth in the environment of specific, dangerous variants. Specific goals are to:

1. To characterize and model dynamics and reservoirs of V. vulnificus and V. parahaemolyticus populations over seasonal cycles of environmental change.
   
2. To test the link between estuarine physics, nutrient and particle abundance and growth patterns of vibrio species over tidal cycles.
   
3. To determine the ‘rules’ (extent and bounds) of recombination, gene transfer and clonality in co-occurring V. vulnificus, V. parahaemolyticus and related vibrios.
   
4. To assess the diversity, mobility and evolutionary history of genes implicated in pathogenicity.

Our field investigations will take place in Plum Island Sound estuary in northeastern Massachusetts, a site where numerous ecological studies have been carried out in the past, including NSF sponsored Long-Term Ecological Reserve (LTER) investigations.