Rio Tinto is a river flowing through the mountains of the Sierra Morena, in the beautiful Spanish region of Andalusia. The name, which in English means “Red River”, is not casual. It comes from the unusual reddish color of its waters, due to the strong presence of dissolved iron, accentuated by a large amount of other heavy materials. It is therefore not a question of pollution, but of a characteristic of the area. The river actually flows on rocks rich of iron, which, melting, is dragged by the force of water, coloring it red.
The particular wealth of metals and minreals of this area, was famous since ancient times. Its deposits were already exploited by Phoenicians. But the XIX century was actually the period of iron mines maximum use: the soil was so exploited that iron particles crept into the aquifers and into the river. However, scientists have shown that the basin had a particular charactestics even before man used this rich area. Its waters have a very complex chemistry, characterized by a very acid pH, with a high content of heavy metals. Inside, bacteria and fungi have been found but, since there is no oxygen, there are no fish. The microorganisms living in these waters feed only on minreals, they have the ability to breathe iron and they can adapt to extreme habitats!
This place is as fascinating as dangerous. In fact, due to these metals, the acidity of the river waters is 2.2, a very high level. The toxic materials absorbed by the surrounding soil do not allow any type of animal and plant life. In short, it is a landscape looking like an alien world. Not surprisingly this place, precisely because of its strong resemblance to the planet Mars, was chosen as a subject of study by NASA’s astro-biologists, focusing on its microorganisms, bacterial life forms that can live in the absence of oxygen. The study, with the participation of the Higher Council for Scientific Research, confirmed the possibility that some types of organisms could survive in restrictive conditions of the planet Mars.