Hydrothermal vents are one of the most extreme environments on our planet. Hydrothermal vents are ubiquitous across the globe, discovered on nearly every ocean ridge explored to date and feature majority of the earths volcanic activity. Vents form along spreading axis, where two techtonic plates are moving apart from one anther to form new oceanic crust. Along these ridges, seawater is entrained in porous regions along the ridge flanks, geothermally heated and chemically altered by reaction with the crust. During this process magnesium and sulfate are removed, fluid is reduced and enriched in metals and dissolved gases. Eventually the acidic, reduced hydrothermal fluid gains sufficient heat to increase its buoyancy and rises to the surface. When this hot reduced hydrothermal fluid mixes with cold oxic seawater complex mineral precipitates form at the sea floor forming hydrothermal chimneys.
The unique geochemical characteristics of hydrothermal vents enable these environments to support thriving, dense and diverse populations of organisms. Here, chemoautotrophic microbes–those which fix carbon via the energy derived from the oxidation of reduced chemicals–form the base of the ecosystem. The metabolic processes occurring within these systems may be analogs of the first living systems to evolve on Earth and ecosystems on other planets. Understanding the microbial communities’ activities within hydrothermal environments will aid in the understanding of when and where life may have evolved on a hot early Earth; the depth to which life may exist in the Earth’s subsurface; and the potential for life in extraterrestrial environments.
Relationships between thermodynamic and kinetic metabolic processes