The hydrothermal vent microbial community includes all unicellular organisms that live and reproduce in a chemically distinct area around hydrothermal vents. These include organisms in the microbial mat, free floating cells, or bacteria in an endosymbiotic relationship with animals. Chemolithoautotrophic bacteria derive nutrients and energy from the geological activity at Hydrothermal vents to fix carbon into organic forms. Viruses are also a part of the hydrothermal vent microbial community and their influence on the microbial ecology in these ecosystems is a burgeoning field of research.[1]
Hydrothermal vents are located where the tectonic plates are moving apart and spreading. This allows water from the ocean to enter into the crust of the earth where it is heated by the magma. The increasing pressure and temperature forces the water back out of these openings, on the way out, the water accumulates dissolved minerals and chemicals from the rocks that it encounters. There are generally three kinds of vents that occur and are all characterized by its temperature and chemical composition. Diffuse vents release clear water typically up to 30 °C. White smoker vents emit a milky-coloured water between 200-330 °C, and black smoker vents generally release water hotter than the other vents between 300-400 °C. The waters from black smokers are darkened by the precipitates of sulfide that are accumulated.[2] Due to the absence of sunlight at these ocean depths, energy is provided by chemosynthesis where symbiotic bacteria and archaea form the bottom of the food chain and are able to support a variety of organisms such as Riftia pachyptila and Alvinella pompejana. These organisms use this symbiotic relationship in order to use and obtain the chemical energy that is released at these hydrothermal vent areas.[3]