HR: 1340h
AN: B33A-0846    [Abstracts]
TI: Zeta-Proteobacteria dominate the formation of microbial mats in low-temperature hydrothermal vents at Loihi Seamount
AU: * Rassa, A C
EM: cyrus64@gmail.com
AF: Western Washington University, Biology Department MS# 9160, Bellingham, WA 98225, United States
AU: McAllister, S M
EM: mcallis2@cc.wwu.edu
AF: Western Washington University, Biology Department MS# 9160, Bellingham, WA 98225, United States
AU: Safran, S A
EM: safrans@cc.wwu.edu
AF: Western Washington University, Biology Department MS# 9160, Bellingham, WA 98225, United States
AU: Moyer, C L
EM: cmoyer@hydro.biol.wwu.edu
AF: Western Washington University, Biology Department MS# 9160, Bellingham, WA 98225, United States
AB: Loihi Seamount is Hawaii's youngest volcano and one of the earth's most active. Loihi is located 30 km SE of the big island of Hawaii and rises over 3000m above the sea floor and summits at 1100m below sea level. An eruption in 1996 of Loihi led to the formation of Pele's Pit, a 300 meter deep caldera. The current observations have revealed diffuse hydrothermal venting causing low to intermediate temperatures (10 to 65°C). The elevated temperatures, coupled with high concentrations of Fe(II) (ranging from 50 to 750 μM) support conditions allowing for extensive microbial mat formation. The focus of this study was to identify the colonizing populations of bacteria generated by the microbial mats at Loihi Seamount. Twenty-six microbial growth chambers were deployed and recovered after placement in the flow of hydrothermal vents for 3 to 8 days from within Loihi's caldera. Genomic DNA was extracted from samples and analyzed by Terminal-Restriction Fragment Length Polymorphism (T-RFLP) using eight restriction enzyme treatments to generate fingerprints from bacterial amplicons of small subunit rRNA genes (SSU rDNAs). Pearson product-moment coupled with UPGMA cluster analysis of these T-RFLP fingerprints showed that these communities bifurcated into two primary clusters. The first (Group 1) had an average vent effluent temperature of 44°C, and the second (Group 2) had an average vent effluent temperature of 64°C. Representative samples from within the two clusters (or groups) were chosen for further clone library and sequencing analysis. These libraries revealing a dominance of the recently discovered zeta- Proteobacteria in the lower temperature group (Group 1) indicating that they were the dominant colonizers of the microbial mats. These microaerophilic, obligately lithotrophic, Fe-oxidizing bacteria are most closely related to Mariprofundus ferrooxydans. The higher temperature group (Group 2) was dominated by epsilon- Proteobacteria primarily of the genus Sulfurimonas, which are sulfur- and thiosulfate-oxidizing bacteria.
UR: http://fire.biol.wwu.edu/cmoyer/research.html
DE: 4803 Analytical chemistry
DE: 4805 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4912)
DE: 4815 Ecosystems, structure, dynamics, and modeling (0439)
DE: 4832 Hydrothermal systems (0450, 1034, 3017, 3616, 8135, 8424)
DE: 4840 Microbiology and microbial ecology (0465)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting