At mid-ocean ridges and back-arc basins, deep-sea hydrothermal vent deposits are recognized as important biogeochemical environments in which temperatures vary from ~2ºC to >400ºC across distances of a few centimeters. The deposits provide microhabitats for a diversity of Bacteria and Archaea that are supported by chemical gradients that result when vent fluids from the seafloor and mix with seawater. While many studies have looked for evidence of microorganisms within vent deposits, fewer have been done to discern which microorganisms are present within newly formed material, and to examine the extent to which the observed diversity in more mature deposits is a result of the steep chemical and thermal gradients, a result of community succession, or a combination of both. In this project the investigators will address this important area of research by using deployments of thermocouple arrays in Guaymas Basin. Experiments in place will be retrieved and samples recovered from around each thermocouple, and analyzed along strong thermal and chemical gradients. The investigators will use molecular techniques such as Q-PCR of 16S rRNA genes to provide a snapshot of the relative shifts (succession) in abundance of Archaea and Bacteria. The importance of certain physiologies (such as sulfate reduction, dsrB, and methanogenesis, mcrA) will be correlated to the observed temporal changes in microbial diversity. These analyses will allow the investigators to test whether there are any temporal or spatial differences in microbial colonization of the hydrothermal deposits. Furthermore thay will be able to show whether or not differences in patterns of microbial colonization exist between different vent fields. An added strength of this project is its design as a complement to an already funded project which is looking at the distribution of acidophiles in vent deposits and the influence of local mineralogy or geochemistry. The new information from this project will be included in the investigators ongoing outreach where they continue to share the excitement of new deep-sea vent discoveries with the public through writing general articles, giving lectures at schools, and through continuing education for school teachers.
