TAXONOMIC AND FUNCTIONAL ANALYSIS OF MICROBIAL MAT COMMUNITIES OF MARIANA REGION HYDROTHERMAL VENTS

Deep sea hydrothermal vents provide for chemolithotrophically-driven microbial mat communities. Although microbial primary producers are known, the metabolic pathways they use to fuel growth and fix inorganic carbon remains poorly understood along with their ecological implications. Hydrothermal vents of the Mariana Arc and back-arc have been shown to support high microbial diversity and community structure complexity due to the heterogeneity of geologic plates at this convergent plate boundary and thereby the production of heterogeneous sources of magma that generate these hydrothermal systems. To gain a better understanding of the potential metabolic pathways, functional genes found in these microbial mats from Mariana hydrothermal habitats will be assessed using quantitative PCR. Taxonomic analysis will also be conducted by quantifying the relative presence of the dominant primary producers (i.e., Zeta-, Epsilon-, and Gamma-proteobacteria). Functional genes that play a key role in carbon fixation will be addressed by distinguishing between the two primary carbon fixation pathways, i.e., the Calvin-Benson-Bassham cycle (CBB) or the reductive tricarboxylic acid cycle (rTCA). From this we can infer whether iron- or sulfur-based compounds (primarily Fe(II) or H₂S) are fueling primary production. Coupling taxonomic analysis with metabolic potential of hydrothermal microbial communities will provide insight into ecological interactions and biogeochemical cycling.