The Microbiome of Ruppia maritima

• Emerson Sherwood, Marine Science, University of Delaware

• Jennifer Biddle, School of Marine Science and Policy, University of Delaware

Submerged aquatic vegetation (SAV) provides necessary ecosystem services to coastal regions. SAV offers integral structural and trophic roles within their ecosystems, providing habitat and refuge to many aquatic organisms while simultaneously contributing to primary productivity. These seagrasses would not be successful without the help of their microbiomes: community assemblages of microbes that are typically specific to individual hosts. One common species of SAV found along the coasts of Southern Delaware is known as widgeon grass, Ruppia maritima. Data on the external microbial assemblages of this species is lacking, limiting the understanding of microbial community structure and function on this species. By extracting DNA from filtered water samples, isolated bacteria cultures, and plant biomass, this project characterizes the previously unknown microbiome of Ruppia maritima. Samples from field collection sites were plated on regular marine nutrient media as well as marine nutrient media with plant biomass to test differences in growth on the two types of media. A diverse group of culturable bacteria were grown, with over 50 isolates gathered from various sampling sites. The sampling site with the highest culturable diversity was Bethany Canal by the Inland Bays. Overall, there is a large range of colony coloration and morphology. Additional sequencing is being performed, with the hypothesis that the uncultured bacterial communities will host further diversity.