Thermoacidophiles of Marine Hydrothermal Systems: Investigations of the Deep-Sea Hydrothermal Vent Euryarchaeota 2

G.E. Flores¹*, & A.L. Reysenbach¹

Corresponding author: floresg@pdx.edu
¹Portland State University, Department of Biology, Portland, Oregon, 97201

Abstract:
The deep-sea hydrothermal vent Euryarchaeota group 2 (DHVE2) appears to be endemic to marine hydrothermal systems and is currently represented by Aciduliprofundum boonei, the only obligate thermoacidophile described from these environments (Reysenbach et al., 2006). Genomic analysis of A. boonei revealed several distinguishing features including various amino acids/peptide fermentation pathways and the absence of obvious sugar transporters suggesting a peptide scavenging lifestyle (Reysenbach and Flores, 2008). Several new isolates of the DHVE2 have been obtained from the Mid-Atlantic Ridge (MAR), the Eastern Lau Spreading Center (ELSC) and 9°N along the East Pacific Rise (EPR) further demonstrating the ubiquitous distribution of the DHVE2 at deep-sea vents and the thermoacidic nature of this archaeal lineage. Preliminary analysis of pyrosequencing, and QPCR data from sulfide samples collected along the MAR is beginning to elucidate the relationship between the type of vent feature and the occurrence of the DHVE2.

Keywords:
Microbiology, Ecology, Archaea, Thermophiles

Contributions to Integration and Synthesis:
Results from our recent expeditions to two of the Integrated Study Sites (ISS) continue to illustrate the widespread distribution of thermoacidophiles at vent sites around the globe. Many of these vent sites have contrasting fluid chemistries resulting from different host rocks underlying the vent fields which may be influencing the distribution of thermoacidophiles. I am particularly interested in how these differences in geochemistry influence the distribution of thermoacidophiles and how thermoacidophiles in turn are helping to shape their local environment. Integration of the geochemical and mineralogical data from the different ISS sites will aid in my understanding of these processes allowing me to determine the ecological significance of thermoacidophily in marine hydrothermal systems.

References:
Reysenbach, A. L. and G. E. Flores. (2008) Electron microscopy encounters with unusual thermophiles helps direct genomic analysis of Aciduliprofundum boonei. Geobiology, 6; 331-336.
Reysenbach, A. L., Liu, Y., Banta, A. B., Beveridge, T. J., Kirshtein, J. D., Schouten, S., Tivey, M. K., Von Damm, K. L. and M. A. Voytek. (2006) A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal vents. Nature, 442: 444-447.