State Water Resources Research Institute Program
Project ID: 2012DE238B
Title: Characterization of Viral Diversity within the Mantel Fluid of the Eastern Oyster, Crassostrea virginica
Project Type: Research
Start Date: 6/01/2012
End Date: 2/28/2013
Congressional District: At large
Focus Categories: Water Quality, Ecology, Toxic Substances
Keywords: Oyster health, viruses, nonpoint pollution, habitat destruction
Principal Investigator: Wommack, Eric
Federal Funds: $ 1,500
Non-Federal Matching Funds: $ 3,000
Abstract: The eastern oyster, Crassostrea virginica, plays a vital role in estuarine environments along the east coast of North America. Oyster reefs serve as erosional barriers and provide habitat for a number of invertebrate and small fish species. In addition, these bivalves can filter large volumes of water - up to 6.8 L/h - for a few hours at a time as they feed, thus improving water quality and reducing turbidity. However, overharvesting, habitat destruction, and disease have decimated the oyster population and adversely affected these estuarine environments.
A more comprehensive understanding of factors influencing oyster fitness is crucial to restoring the oyster population and the ecosystem services they provide. Recent research has illuminated the complex relationships between metazoan hosts and the microbial communities living commensally with them. Such commensal microbial communities can influence the availability of nutrients and exclude pathogens. An investigation of the commensal microbial community in the mantel fluid of Crassostrea virginica suggests that oysters select for a bacterial community composition that is unique from the surrounding water and presumably impacts host fitness (Wommack lab, unpublished data). Missing from this analysis is an understanding of the viral impact on the microbial community.
Viruses influence microbial community structure and function through lysis and horizontal gene transfer. Lysis typically follows a 'Kill-the-Winner' approach whereby the most abundant microbial community members are infected, thus promoting greater richness and evenness within the microbial community by ensuring no single organism becomes too dominant. Little is known about the majority of viruses found within oysters, however, as most studies have focused on the few oyster-associated viruses implicated in public health risks. This study seeks to characterize the diversity of viral assemblages within the mantel fluid of Crassostrea virginica and compare this diversity to the surrounding water. Ultimately, this research will provide a more accurate picture of the regulation and impact of commensal microbial communities on oyster fitness and may lead to improvements in restoration efforts of this keystone species.