Characterization and Variation of the Olympia Oyster (Ostrea lurida) Gut Microbiome

Oysters are an ecologically and commercially important animal. Bacteria and other microorganisms that travel into an oyster’s digesta via filter feeding likely depend on the surrounding habitat. This study aims to characterize the gut microbiome of the Olympia oysters (Ostrea lurida), a native oyster whose population crashed due to overexploitation. O. lurida were deployed to four sites throughout the Puget Sound to assess microbiomes across geographic location. In addition, each of the sites supports eelgrass beds and plots of bare sand, to which oysters were equally divided. Water and sediment samples were also collected to understand the resident bacterial community in the surrounding environment. 16S rRNA sequencing followed Earth Microbiome Project protocols. Characterization of the O. lurida gut microbiome is a novel finding that reveals both a host-associated microbiome and high variability by site for the rest of the microbiome. While eelgrass habitat fails to cause significant change to the oyster and environmental microbiome, variation in geographic location reveals site-specific microbe communities for the sediment, seawater, shell biofilm and gut. Microbiome significantly differs across sites and between sample types (p-value = 0.001). This has implications for future restoration efforts in the Puget Sound and stresses the importance of microbiome in and around oyster farms.