49.7

Rio Tinto and its natural red waters are characterized by a pH between 1.7 and 2.5 (very acid) with high content of heavy metals (iron (mostly), copper, cadmium, manganese, etc...) but oxygen, since the organisms in the river are mostly photosynthetic. However, before the man appearance, in its waters live microorganisms that feed only on minerals and adapt to extreme habitats, such organisms are both prokaryotes and eukaryotes, including among the latter some species of fungi and algae endemic to the river. Thus, NASA chose it as habitat to study its possible similarity to the Mars atmosphere.
In summer, when lows water levels and temperatures rise, sediments acquire some bright colors and multiple forms