Why Search for Subsurface Life at Rio Tinto?
A surface ecosystem consisting of extremophile microbes has been identified in the Rio Tinto River. The term extremophiles refers to the fact that the microbes live in “extreme conditions” compared to the conditions that most organisms prefer. In the case of the Tinto River, the water is very acidic and has a low pH (pH=2.3 in most of the river). These acidic conditions in the river are a consequence of the oxidation of iron and sulfur minerals by water. Some of the microbes that live in the river obtain their metabolic needs from iron and sulfur minerals. These are chemoautotrophs, or organisms that live on chemical energy. The scientific objective of our experiment is to search for a similar ecosystem in the subsurface.
