1311-603 - A sign along the Bright Angel Trail in Grand Canyon warning that the plants in this area are very fragile, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America
860-288801 - Clay loaded with iron oxides and dried out, Rio Tinto, Andalusia, Spain *** Local Caption *** R?o Tinto ("Red River") is very acidic (Ph 2) and has a deep reddish hue due to iron dissolved in water. The acidity of the watercourse is linked to the drainage of pyrite, which is very present in the subsoil. Extremophilic and endemic bacteria and algae colonize the river bed, forming a fragile biofilm that evokes the hot springs of Yellowstone Park in the USA.
860-288798 - Reflections on Rio Tinto, near its source, Andalusia, Spain *** Local Caption *** R?o Tinto ("Red River") is very acidic (Ph 2) and has a deep reddish hue due to iron dissolved in water. The acidity of the watercourse is linked to the drainage of pyrite, which is very present in the subsoil. Extremophilic and endemic bacteria and algae colonize the river bed, forming a fragile biofilm that evokes the hot springs of Yellowstone Park in the USA.
860-288800 - R?o Tinto, Andalucia, Spain *** Local Caption *** R?o Tinto ("Red River") is very acidic (Ph 2) and has a deep reddish hue due to iron dissolved in water. The acidity of the watercourse is linked to the drainage of pyrite, which is very present in the subsoil. Extremophilic and endemic bacteria and algae colonize the river bed, forming a fragile biofilm that evokes the hot springs of Yellowstone Park in the USA.
860-288799 - R?o Tinto, Andalucia, Spain *** Local Caption *** R?o Tinto ("Red River") is very acidic (Ph 2) and has a deep reddish hue due to iron dissolved in water. The acidity of the watercourse is linked to the drainage of pyrite, which is very present in the subsoil. Extremophilic and endemic bacteria and algae colonize the river bed, forming a fragile biofilm that evokes the hot springs of Yellowstone Park in the USA.
860-287536 - Concretions in the caves of Choranche, cave remarkably rich in fistuleuses, fine stalagmites that can reach several meters long, Massif du Vercors, Isere, France