1. Characterization of Enrichment Cultures of Nitrate-Reducing Bacteria from Deep-Sea Hydrothermal Vents Caroline Toney* and Costantino Vetriani Deep-sea vents are one of the last frontiers of the unexplored world. These unique environments spew forth super- heated fluid that is laden with metals. The base of life which allow other organisms to live in this ecosystem are microorganisms which undergo chemosynthesis as a means of primary production. Introduction Figure 2. Sampling sites of deep- sea hydrothermal vents on the East Pacific Rise Objectives To grow cultures from samples taken at vent sites at 9°N and 13°N. To isolate anaerobic, nitrate-reducing bacteria using different techniques and media. To compare the 16S rRNA gene sequences of these organisms to the database using BLAST (Basic Local Alignment Search Tool) to assess their relatedness to other species. MediaCarbon SourceElectron Donor Electron Acceptor Temp ( °C) HB1 CO 2 H2H2 NO 3 50 & 75 Sulfurovum CO 2 N 2, thiosulfate NO 3 35 Sulfurimonas CO 2 H 2, thiosulfate NO 3 35, 50 ASWOrganicN2N2 NO 3 30 Caroline Toney crt8347@uncw.edu (828) 429-9476 Figure 1. Illustration of deep- sea hydrothermal vent flow. (Brock et al., 2006). SiteMediaTemp (°C)Identity (%)Description Alvinella Tubes HB15099,97Caminibacter mediatlanticus; Nautilia profundicula, abyssi Sulfurimonas35, 5086Sulfurospirillum carboxydovorans Alvinella sulfide HB15097, 96Caminibacter mediatlanticus HB17598Desulfobacterium pacificum Crab SpaSulfurovum3593;96;93Thioprofundum lithotrophica; Rhodobacter capsulatus; Marinobacter hydrocarbonoclasticus Sulfurimonas35, 5097Shewanella haliotis Anaerobic ASW30100Klebsiella pneumoniae Bottom Seawater Anaerobic ASW (B) 3099Shewanella haliotis Samples were taken during Nautile Dive (ND) #: ND 1726 Alvinella pompejana tubes ND 1727 Alvinella pompejana encrusted sulfides ND 1729 Fluid from Crab Spa; Bottom Seawater Acknowledgements We want to thank the crew of the R/V L’Atlante and the crew and pilots of the DSV/Nautile for sample collection We would like to offer our thanks to the members of the Deep Sea Microbiology Lab at Rutgers University their expertise, as well. This work was supported by an NSF grant. Table 2. Results of sequencing and BLAST. Conclusions The molecular characterization of the organisms cultured in the samples taken from the dives reveals that there may be new species among them. The sequences of the 16S rRNA gene from the organisms grown show that further isolation is needed for some samples in order to have a pure culture from which further investigation of the species can be done. Future work would include characterization of isolated organisms. Morphological observation and studies of optimal growth in temperature, salinity and pH will be executed. Metabolism will be studied through growth under different conditions (i.e. electron donors and acceptors, pressure, etc.), in organic substrates, and resistance to antibiotics will also be tested. Table 1. Characteristics of anaerobic media used. Alvinella pompejana. (noc.soton.ac.uk) Crab Spa (whoi.edu)