Microbial biodiversity in the copahue geothermal region-an extreme environment dominated by an active volcano in Cordillera de los Andes

Abstract

The Copahue geothermal area is located on the Northwest of Neuquén province in Patagonia, Argentina, on the Cordillerade los Andes, one of the world?s most important mountain systems. This naturally acidic extreme environment is dominatedby the still active Copahue volcano, a stratovolcano of approx. 2965 m.a.s.l., whose cyclic eruptive periodshave shaped thelandscape,thegeo-physicochemical characteristics of the place and the microbial diversity that inhabits it. The Copahue geothermal area, of approx. 250 Km2, has two differentparts, both extreme environments: the Copahue volcano-Río Agriosystemand the geothermal ponds. Río Agrio is a natural acidic riverthat originates at two geothermal ponds a few meters below thevolcano crater and runs down its hill maintaining the low pH values for almost its entire path, despite receiving many tributary neutral water courses.On the other hand, the geothermal manifestations,pools, ponds and hot springs with a wide rangeof temperature and pH, are a constantly changing environment, highly dependent on the volcanic activity.In this work wediscuss the rich biodiversity and complex community structure of the microbial species, bacteria and archaea,that inhabit the Copahue geothermal area, and their corelation with the geology and physicochemical characteristics. TheCopahue-Caviahue geothermal system is a clear example of how the environmental and geochemical condition defined by amountain, in this particular case, the Copahue volcano, determines the shape and dynamics of the native microbial communities