At hydrothermal vents, thermal and chemical gradients generated by the mixing of hydrothermal fluids with seawater provide diverse niches for prokaryotic communities. To date, our knowledge of environmental factors that shape bacterial and archaeal community composition and metabolic activities across these gradients within the active sulfide structures is limited. While many studies have laid the foundation for our understanding of the extent of diversity in relation to varying hydrothermal settings, few studies exists regarding the detailed spatial relationships between vent geochemistry and the abundance, distribution, and metabolic characteristics of the endolithic hosted communities. Even fewer data have been generated on the magnitude of metabolic rates and factors controlling the kinetics of these reactions have not been well constrained.
