Water Resources Research Act Program

Details for Project ID 2013DE250B

A Biogeographic Investigation of Viral Diversity within the Eastern Oyster, Crassostrea virginica

Institute: Delaware
Year Established: 2013 Start Date: 2013-03-01 End Date: 2014-02-28
Total Federal Funds: $1,500 Total Non-Federal Funds: $3,000

Principal Investigators: Eric Wommack, Alessandra Ceretto

Project Summary: The eastern oyster (Crassostrea virginica) plays a pivotal role in the Delaware and Chesapeake Bay watersheds. Oyster reefs are sanctuaries for numerous invertebrate and fish species and protect the shoreline from erosion. In addition, C. virginica can filter large volumes of water - up to 6.8Lh-1 for a few hours at a time as they feed (1), thus improving water quality and reducing turbidity. However, the incursion of Perkinsus marinus and Haplosporidium nelsoni, the etiological agents of diseases Dermo and MSX, have resulted in increased oyster mortality rates and adversely affected the ecosystem services provided by oysters to these estuarial environments (2). In addition, Dermo-induced mortalities in the Delaware Bay have altered the natural distribution of oysters, restricting their range to lower salinity regions; yet, these areas are also under increasing disease pressure (3). A more comprehensive understanding of factors influencing oyster fitness in different locations is crucial to maintaining oyster populations and the ecosystem services they provide. Microbial communities living commensally with metazoan hosts can influence nutrient availability and exclude pathogens (4-6). Investigations of commensal bacterial communities within oysters indicate that the oyster microenvironment selects for a unique bacterial community, and this bacterial community displays geographic variability (Sakowski, unpublished data). However, to date viral populations within oysters have been largely ignored despite the fact that viruses directly impact bacterial populations through cell lysis. Additionally, several viral pathogens of oysters have been identified, but the occurrence of these viruses in the Delaware Bay is not well understood. This study will characterize the geographic variability of viral assemblages within the mantle fluid of C. virginica collected in the Delaware Bay and Chesapeake Bay watersheds. This study will leverage previous work undertaken in the lab to efficiently isolate viruses from individual oysters. Ultimately, this research will provide insight into an unexplored aspect of oyster fitness and may lead to improvements in restoration efforts of this keystone species.