Meeting Abstract

81.2  Monday, Jan. 6 10:30  Oceanic Sea Star Larvae Host Microbial Community Dominated by Cyanobacteria of the Genus Synechococcus BOSCH, I*; SNYDER, S.M.; GALAC, M.R.; JANIES, D.A; State University of New York, Geneseo; University of South Florida, St. Petersburg; University of North Carolina, Charlotte; University of North Carolina, Charlotte bosch@geneseo.edu

Sea star planktotrophic larvae provisionally identified as Oreaster sp. are abundant in the Gulf Stream and other oligotrophic regions of the Western North Atlantic. The larvae are unusual in two ways: They have the capacity to clone themselves, and they harbor large populations of sub-cuticular bacteria. We studied the diversity of the symbiont microbial community using traditional Sanger and 454 technology to sequence the V1-V3 region of the microbial 16S rDNA. Larvae were collected in the Gulf Stream, 13-15 km south of Long Key, Florida over a three-year period. Sanger sequences of cloned 16S rDNA from six groups of larvae indicated that the microbial communities were dominated by cyanobacteria of the genus Synechococcus. Less abundant microbial groups genetically matched the cyanobacterial genera Prochlorococcus and Cyanobium, and two types of heterotrophic Alphaproteobacteria. The 454 sequencing analysis of 15 individual larvae collected in May 2012 also showed dominance of the microbial flora by Synechococcus, while the second most abundant bacterial type was an Alphaproteobacteria of the order Kiloniellales. Alpha rarefaction analysis indicated that we sampled all of the bacteria present in the individual clonal larvae and beta diversity analysis showed a very high affinity between their bacterial communities. We conclude that these clonal larvae host a specialized bacterial community dominated by photosynthetic bacteria that may provide nourishment for growth and clonal reproduction in the oligotrophic open ocean.