Non-native macroalga may increase concentrations of Vibrio bacteria on intertidal mudflats

• Published in: Marine ecology. Progress series (Halstenbek) 2014-05, Vol.505, p.29-36
• Main Authors: Gonzalez, Dana J., Gonzalez, Raul A., Froelich, Brett A., Oliver, James D., Noble, Rachel T., McGlathery, Karen J.
• Format: Article
• Language: English
• Subjects: Gracilaria vermiculophylla; Vibrio; Vibrio parahaemolyticus
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps10771

We investigated whether the proliferation of a non-native macroalga, Gracilaria vermiculophylla, within the mid-Atlantic coast region, USA, could be related to concentrations of Vibrio bacteria in water, sediment, and oysters on intertidal mudflats where mats of the macroalga are found. Vibrio spp. are naturally found in a range of aquatic environments; in estuaries they are recognized as being biogeochemically and ecologically important. While most species are harmless, some pathogenic species (e.g. V. parahaemolyticus and V. vulnificus) can cause symptoms of disease in humans that range from gastrointestinal and wound infections to septicemia and death. Recent research efforts have focused on potential reservoirs and environmental conditions that can increase the incidence of human exposure to these species of bacteria. Our data indicated that V. parahaemolyticus, and V. vulnificus were commonly found on the macroalga in both summer and early fall. Summer and fall seasonal samplings indicated that mudflats with mats of G. vermiculophylla were associated with higher total Vibrio, V. parahaemolyticus, and V. vulnificus concentrations of proximal water, sediment, and oysters when compared with mudflats without macroalgal coverage. In addition, of all isolates confirmed to be V. vulnificus, regardless of source, 68% were confirmed as a highly virulent genotype, which indicated the presence of pathogenic forms of Vibrio across a range of matrices within the estuarine environment.