Extremophiles
Archaea are one of the three domains of life. They dominated the earth for billions of years together with bacteria . Scientists have recently discovered two new sub-groups of archaea. They can be found throughout Yellowstone National Park, living in water with a temperature of between 50℃ and 80℃. The water there is as acidic as lemon juice and the microbial mats are red, because of the main mineral present in the water: iron oxide. This same mineral can be found on the surface of Mars as well. For that reason, these two new types of extremophiles have been called Marsarchaeota.
Dams
Scientists studied microbial mats throughout Yellowstone National Park. Although microbes there usually produce iron oxide, Marsarchaeota do not do so. They need low concentrations of oxygen. The microbes that do produce iron oxide create dams that almost block the streams emerging from the geysers. As a result, the water flowing over the dams might be no more than a few millimetres deep. The microbes on these dams (Marsarchaeota, for example) are therefore close enough to the atmosphere to extract their oxygen from it.
Origin of life
Marsarchaeota reduce iron to a simpler form. This iron cycle is believed to have been extremely important for the origin of life more than 3.5 billion years ago. The discovery of these archaea, which use the same cycle, is enhancing our existing knowledge about the evolutionary history of the earth and the tree of life. This unique life form is also giving us the opportunity to learn more about possible microbial life on Mars and the way that life is able to adapt to very high temperatures.